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How does the JOIDES Resolution take cores?
One of the goals of the deep sea drilling program is to be able to drill in water depths that exceed the limits of what oil and gas companies attempt. In the 1980s, drill ship was able to core the seafloor using "riserless drilling" which was not used by the oil and gas industry at the time. A riser is a large diameter pipe that connects the Blowout Preventer (BOP) on the seafloor to the floating drill rig. The riser is used to pump drilling mud to the bit and circulate out cuttings. The IODP "riserless drilling" does not use a BOP on the seafloor; instead the program used seawater as a drilling fluid, and cuttings circulate out of the deep ocean hole and are deposited onto the seafloor without creating biohazards. One major advance is the ability of the JOIDES Resolution drill ship to maintain its floating position using motor thrusters and mitigate motion due to ocean heave and current.
Until technological advances were invented to compensate for ship motion, it was very difficult to log the deep ocean boreholes after coring. Logging and drilling research for IODP is done today from the Lamont Doherty Earth Observatory in Palisades New York, and the benefits spread to the oil and gas industry. This includes research into using riserless wells in ultra deep water, and reentry of older wells. Open hole in the seafloor after core recovery is used for down hole observation using seismometers in earthquake prone areas like Japan and eastern Pacific Ocean. The borehole cavities are also monitored for extended periods of time for geochemical changes, fluids, and formation temperature. Lamont Doherty research has advanced the IODP logging capabilities by using (LWD) Logging While Drilling and capturing logs all the way to the seafloor, and in geophone logging for shear wave information.
Let’s look at the deep ocean cores
Dr. Jeff Fox took us on a tour of the IODP core storage facility which was just down the hall from his office at Texas A&M. The drilling program has drilled 1700 boreholes all over the world. The Gulf Coast Repository (GCR), located at Texas A&M houses cores collected by ODP and IODP from the Pacific and Indian Oceans core from other storage locations that are being transferred here. These cores are used to study paleontology, climate change, gas/methane hydrates and the biosphere, life in the oceans and physics of heat transfer. As Dr. Fox opened the door to the core storage facility a cold air blast reminded us the cores are permanently stored at 40 degree F. He pulled open a 30 foot core box and we observed that cores were stored in plastic and paper boxes, rather than in wood boxes like oil cores. The ODP sediment cores they were thinner than petroleum cores, an inch or so across, and stored in their original 31-foot long sections. Actually only half the original core is permanently archived. The other half of each core is sacrificed for scientific study and sampled into bags and sent out around the world for testing and study. While we talked, curatorial specialist Rachel Culberson was taking samples from white core. This core was a Turonian aged, calcareous, vitreous tuff from the eastern Indian Ocean. Dr. Fox said the core lab has distributed over 2 million samples to scientists all over the world and that scientists can request samples using the internet website----.
Scientists needed for deep ocean research
How about these job requirements for work on the JOIDES Resolution: Core Description. Macroscopic visual description, microscopic and entry into database. Measure physical property data on a split core including color reflectance, magnetic susceptibility, and digital images. Interpretation of depositional processes, X-ray diffraction and geochemistry. Stratigraphic correlation: work with real time coring information and use magnetic readings, gamma ray and gamma ray attenuation for logging after coring is completed. Biostratigraphy: sampling cuttings from coring and taking samples from the core to do nannofossils and diatom identification. Fossils are use to assess paleo-water depths. Magnetostratigraphy: measure core for paleomagnetism and absolute orientation of deformation structures. Organic geochemistry: monitor cores for hydrocarbons, conduct analysis on water in pores inside the core. Down hole logging: Lamont Doherty sends scientists to implement the open hole logging program. Seismic site surveys are also done and vertical seismic profiling.
This is Part I of the Guest Night Feature presentation. Click here to read Part II.
Myths, Half-Truths and Other Bits of Trivia I had hoped to debunk a few myths about the oil industry this month. Unfortunately, there are so many myths at both ends of the spectrum that it is difficult to know where to start. There seems to be an element of truth in most of them regardless of their orientation. In some cases, the element of truth may be very small. In other cases, it is a matter of semantics. Such as the “myth” that contends that production from the Arctic National Wildlife Refuge will do little to reduce our dependence on oil imports from Saudi Arabia; therefore, it does not justify exploiting a pristine wilderness. The first part of that statement is probably true on two levels. The United States imports more oil from Canada, Mexico and Venezuela than it does from Saudi Arabia, thus any imports that may be offset could be allocated across the board and the specific reduction on Saudi oil would be limited. In addition, any production that may ultimately come from the Arctic National Wildlife Refuge is several years in the future, if it ever comes, and would likely do more to offset the declining production of the lower 48 states and the North Slope than reduce imports. Hence, the myth is partly correct. It just depends on how you look at it. The probability that any myth could be convincingly debunked is probably low. Of course, long odds do not keep us from drilling wells, and they do not keep me from tilting windmills. There are a couple of myths that can be addressed and at least partially debunked. The first is that the oil industry owns Washington, DC. Since money and influence are virtually synonymous in DC, this contention is probably based on the amount of political contributions that come from oil and gas sources. However, the $26 million the oil and gas industry contributed during the 2004 elections ranked 16th among the various industries tracked by The Center for Responsive Politics — far behind such notables as lawyers and law firms ($182 million), real estate ($96 million), securities and investments ($91 million), and health professionals ($74 million). If money talks, it is no surprise that lawyers have such a large influence inside the DC beltway.Much has been made in the media of the oil industry’s (especially Enron’s) long-term planning than extreme price fluctuations. A predictable market takes some of the risk out of large investment decisions. I need to credit the Wilderness Society for pointing out how effective fuel efficiency can be in reducing oil consumption, although I think it may have misquoted the EPA. The original quote is “According to the Environmental Protection Agency, increasing fuel efficiency standards for new vehicles by just 3 miles per gallon would save more than 1 million barrels of oil per day.” My initial thought was that this was an exaggeration of some magnitude. However, that is a true statement if it is applied to the average fuel efficiency of the entire fleet of automobiles and light trucks on the road today and not merely to the new vehicles. The 240 million automobiles and light trucks in the United States consume approximately 380 million gallons of gasoline per day with an average fuel efficiency of approximately 20 mpg. That means Americans drive about 7.6 billion miles or 32 miles per vehicle every day. The fuel efficiency numbers work when applied to the total automotive fleet; increasing the average fuel efficiency to 23 mpg will indeed save 1 million barrels of oil per day. It is not a myth; a 15% increase in average fuel efficiency on all automobiles and light trucks will ultimately result in a 5% reduction in US oil consumption.
Click to read the complete article including candidate bios andreason for running for office.
HGS 2006-2007 Board Candidates
President-elect Linda Sternbach Martin Cassidy
Vice President Frank Walles Andrea Reynolds
Secretary Natalie Uschner Jennifer Burton
Director Chuck Caughey Robert Merrill Bonnie Milne-Andrews Valdis Budrevics
Treasurer-elect James Foradas John Jordan
Editor-Elect Steve Earle
Abstract
The oceans and their underlying sediments and rocks act as natural laboratories that record the Earth''s dynamic processes from past to present. Scientific deep-ocean drilling, sampling and borehole measurements collected during the past 40 years are enhancing our knowledge of the Earth, giving clues to the distribution of mineral resources, to global climate change and to potential natural disasters. While some technologies used in the oil and gas industry are deployed for scientific research, other methods and tools developed specifically for deep-ocean drilling are also finding applications in the energy industry.
For the complete article, click here to download the PDF file.
This article is reprinted from the Schlumberger Oilfield Review
Note: Clients of Schlumberger can register for a free account on their Premium Content site, which includes the four most recent Oilfield Review issues.
HGS Earth Science Teacher of the Year Award It is time to nominate this year''s HGS Teacher of the Year. The winner will receive a $1000 cash award from the HGS and will represent the HGS at the Section level of the GCAGS. The GCAGS Teacher of the Year winner will receive another $1000 and be nominated to the national level of AAPG. The AAPG Teacher of the Year will be granted $5000 plus an all expense paid trip to the 2006 AAPG national convention to receive the award. If your nominee is interested in pursuing this award, have them check out the GCAGS and AAPG for details, qualifications and forms. Forms and other required materials need to be sent to Awards Chairperson at the HGS Office by May 1, 2006. For more information go to the GCAGS web site at: www.gcags.org/teacheroftheYear.htm and the AAPG site at: foundation.aapg.org/tchr_of_year_award/index.cfm.
Click here to read March 06 Bulletin
Technical Meetings
13 HGS General Dinner Meeting
The Value of an Integrated Subsurface Model: 3D
Seismic Limitations in Prediction of Reservoir in the
Grand Isle Production Area, Offshore Louisiana
19 SIPES Luncheon Meeting
Migration Without the Math: Did the Greeks Really
Know All This?
21 GSH Potential Fields Group Dinner Meeting
The 4-D Gravity Method and Water Flood
Surveillance at Prudhoe Bay, Alaska
23 HGS International Explorationists Dinner Meeting
Mass Transport Complexes in Offshore Trinidad
and Worldwide Analogs
25 HGS Northsiders Luncheon Meeting
Facies and Sequence Stratigraphy of the Abo
Formation in the Kingdom Field Area, Terry and
Hockley Counties,West Texas
27 HGS Environmental and Engineering Dinner
Meeting
A Historical Overview of Pierce Junction
33 HGS North American Explorationists
Dinner Meeting
Late Paleozoic Deformation in the Permian Basin
Region: Styles, Patterns, Kinematics and Effects
on Petroleum Reservoirs
35 HGS General Luncheon Meeting
The Princess Discovery, Sub-Salt Gulf of Mexico:
Challenges of Sub-Salt Imaging in a Fast-Paced
Sub-Sea Development
Other Features
41 HGS Undergraduate Scholarship Foundation
Presents Six Scholarships
45 Geo-Legends 2006
by Paul Britt
47 NAPE 2006
by Paul Britt
49 HGS Short Course Offerings Announced for
AAPG 2006
by Kara Bennett
51 Government Update
by Henry M.Wise and Arlin Howles
Working for America’s Energy Future and a Quality Environment
by Chris Oynes, Regional Director, Gulf of Mexico, Minerals Management Service
The Minerals Management Service (MMS) Gulf of Mexico OCS Regional Office strives to be a showcase of careful, safe and efficient administration of the nation’s offshore oil and gas and other mineral resources. Only close cooperation and consultation with state and local governments and the wide array of industry and other constituencies that exist can make this possible. The MMS’s Gulf Regional Office has responsibility for OCS oil and gas and some other mineral matters from offshore Texas to Maine, although most activity is concentrated in the Gulf of Mexico.
The offshore oil and gas industry in the federal part of the Gulf of Mexico is truly a large and multifaceted group. In October 2004, 105 exploration wells were being drilled in Gulf waters and 33 of these were in water depths of 1,000 feet or greater. Currently, there are approximately 4,000 producing platforms, of which about 1,962 are major platforms (954 of these are staffed by personnel). About 152 companies are active in the Gulf.
These are exciting times in the Gulf of Mexico. The Gulf’s contribution to the nation’s energy supply is truly remarkable. Production in the federal portion of the Gulf OCS amounted to 23% of the nation’s natural gas production (just under 5 trillion cubic feet) and about 30% of the nation’s oil production (570 million barrels) in 2002. Deepwater production has been rising rapidly. Three lease sales are planned in 2005-one each in the Western, Central and Eastern Gulf regions.
Excitement in the Gulf focuses on three areas. First is deepwater. In 2004 the MMS released the report Deepwater Gulf of Mexico 2004: America’s Expanding Frontier OCS Report MMS 2004-021) (http://www.gomr.mms.gov/homepg/whatsnew/techann/
2004/2004-021.pdf) on deepwater activity. The report addressed the intense interest in the oil and gas potential in the deepwater tracts in the Gulf of Mexico. About 14 new deepwater projects were planned to start production in 2004 in the Gulf of Mexico. The use of advanced technology is a marvel in the OCS program. In November 2003, ChevronTexaco drilled an exploratory well in a world record water depth of 10,011 feet of water on Alaminos Canyon Block 951. The MMS approved in 2002 the first use in the United States of synthetic (fiber) mooring systems. The MMS has previously released an environmental assessment of the effect of deepwater exploration, development and production. Many changes and new analysis are under way.
A second area is ultra-deepwater (5,000 feet and greater), where a number of discoveries have recently been made. In October 2004, exploratory wells were being drilled by ChevronTexaco in 9,226 feet of water (AC 815), BP in 7,591 feet (WR 724) and Dominion in 7,946 feet (DC 445). A third area of excitement is the deep shelf. This area on the shelf is in shallow water depth but lying below 15,000 feet geologically has hardly been explored. MMS is offering incentives to look for deep natural gas in this area.
The MMS always remains concerned that OCS operations need to conducted in a safe manner. Related to this, the MMS issued final revisions in its drilling regulations in March 2003 and issued new final regulations concerning training of OCS workers. Through its inspection program, the MMS conducted more than 16,000 safety and environmental inspections of offshore oil and gas activity last year. An environmental assessment of the effects of seismic activity was recently issued.
The MMS conducts an extensive environmental studies program in the Gulf of Mexico, having sponsored more than 220 environmental studies in the Gulf of Mexico and costing over $130 million, to assess the effects that oil and gas drilling and production may have on the marine, coastal and human environments. Recent reports have focused on deep sea life, deep spills, sperm whales and economic effects. An award was made on biotechnology research. A contract to collect ocean current data with Mexico was issued.
In the Eastern Gulf of Mexico, comparatively few leases exist (146) but much activity is planned. Twenty exploration plans have been filed on leases issued as a result of Sale 181 held in December 2001. Eight exploration wells have been drilled already. In the Eastern Gulf, lease sale 189 was held in December 2003. A final environmental impact statement on Sales 189 and 197 was released on May 30, 2003.
Several proposals to import LNG into the United States through a regassification plant located out in the ocean in the Gulf of Mexico have been filed.
There is no offshore oil and gas activity off the Atlantic seaboard. The last remaining 8 leases in existence offshore North and South Carolina were relinquished back to the government in November 2000. No Atlantic lease sales have been held since 1983. The last exploratory well was drilled in 1984.
The MMS Gulf of Mexico OCS Region Office’s role in all this activity is substantial. By law, the MMS must approve every exploration well, every production proposal and the structural design of every platform as well as every pipeline, and it must issue literally dozens of other approvals for the design and operation of facilities and measurement of product. It conducts extensive environmental review of proposed projects. MMS also conducts thousands of inspections every year to ensure operational safety and protection of the marine, coastal and human environment.
These immense tasks are the responsibilities of the 600 employees in the MMS Gulf Region Office and require their professional training in a host of disciplines. To accomplish this mission, we employ petroleum engineers, geophysicists, geologists, marine biologists, oceanographers, other environmental scientists, offshore inspectors and computer personnel among other professionals.
The Gulf of Mexico OCS Region (GOMR) is one of three regional offices of the Minerals Management Service (MMS), an agency that manages more than a billion offshore acres and collects about $10 billion dollars in mineral revenues annually. From the days of its predecessor agencies and the creation of MMS in 1982,
Volunteers of the Month
Janet Combes is an Exploitation Geologist at ExxonMobil Production Company, and has been actively involved in a variety of HGS committees and projects for years. Some of these include having been on the HGS board (Director), founder (and member) of the Northsider’s Committee, Co-chair for Earth Science Week, member of the Museum committee, etc. Most recently, she was responsible for the overwhelming success of the society’s participation in CAST. CAST is the Conference for the Advancement of Science Teaching, the annual meeting of the Science Teachers Association of Texas (STAT). STAT is a statewide organization of elementary through college level science teachers dedicated to maintaining the highest levels of science education in Texas schools. One of their goals is to cooperate with other science-oriented organizations in the promotion of good science teaching. CAST was held in Houston on October 27-29th, 2005 at the Reliant Center.
Janet recognizes the importance of sharing our enthusiasm for geoscience with K-12 educators in order to prepare the next generation to join our profession. CAST was last held in Houston in 2003 and Janet was an active participant. She kept in touch with the CAST staff and was personally invited back this year as an HGS representative. She learned that teachers were especially interested in the topic of soils and so she immediately began planning a short course on soils, which was very warmly received. Months before the meeting, she began recruiting volunteers for CAST and kept track of the many field trips, short courses and workshops offered by HGS volunteers. Janet personally led a field trip to Blue Lagoon that was especially popular with teachers, a trip so successful that she has been requested to give it again to two other groups.
HGS participation at CAST is the responsibility of the Academic Liaison Committee. Janet went above and beyond the call of duty when she completely took over the coordination of all CAST activities days before the meeting started when the chairman of the committee had a baby and began maternity leave! The many positive comments from CAST participants show that Janet did an excellent job! And she did all this as she was supporting her family in Louisiana that suffered through Hurricane Katrina.
Janet has a BS in Geology from Louisiana State University, a Masters in Geology from the University of Texas, and a PhD in Geology from the University of Texas at Austin.
The HGS Board acknowledges and thanks Janet for her spirit of volunteerism, and dedication and work for the Houston Geological Society.
Cheryl Desforges is a geologist at Ryder Scott, currently working on reserve analysis projects with Ryder Scott engineers. She has been quite active this past year in the Houston Geological Society, serving as Co-chairman of the Finance Committee, assisting in revising the forms used in the budget process and serving as liaison with the investment advisors; elected as Treasurer-Elect for 2005-06; chairing the Continuing Education Committee (2004-05); and serving as Co-Chairman of the Coastal Subsidence Conference sponsored by the Houston Geological Society and the Engineering and Science Council of Houston (ECH).
Cheryl and the Continuing Education Committee successfully organized the 2005-2006 four-part mini-series on Petroleum Reserves. She led her committee in the innovative addition of videotaping the Continuing Education Series on Petroleum Reserves. She was responsible for obtaining the donations that paid for the equipment that is now available for any group in HGS to use. (CD-ROMs for the successful Petroleum Reserves course are available through the HGS office.)
The Subsidence Conference held last November was successful in a large part because of Cheryl’s efforts to keep the committee on track, avoid special group interests, attract diverse speakers (proponents and opponents) and raise donations to defray costs of the symposium. Several of Cheryl’s committee members reported, “This event would not have been a success without Cheryl’s efforts.”
Although attendance was down because of the hurricane aftermath, the presentations resulted in animated question and answer sessions. For those who could not attend, the conference was taped and CD-ROMs will be available later this year.
Cheryl has a BS in geology from Texas Christian University and an MS in physical science/geology and an MBA (finance) from the University of Houston. She is a member of AAPG, GSA and SEG and is a licensed Professional Geologist in the State of Texas. Before coming to Ryder Scott, she worked for a variety of companies, the most recent being Subsurface Consultants & Associates and Randall and Dewey, Inc.
The HGS Board acknowledges and thanks Cheryl for her spirit of volunteerism, and dedication and work for the Houston Geological Society.
The Ozone Hole — A Crisis Averted?
by Bill Rizer, Editor-elect
As geologists we are often asked by friends or relatives to explain some earth-related topic or issue that has been on the news or in the science section of the local newspaper. One example that comes to mind and seems to reappear every so often is the ozone hole. Most of us know that ozone (O3) is a somehow important constituent of our atmosphere and that recently scientists have noted a worrysome “hole” in the ozone layer over Antartica. However, if you are like me, that is pretty much all that you know. This article represents my attempt at gaining some small degreee of understanding, sufficient to enable me to provide a somewhat reasonable explanation when I am asked to comment on the ozone layer and why it is important. In the course of this brief investigation, a story emerged that is at once scientifically engaging and emotionally encouraging because it illustrates how a potentially disasterous man-made environmental crisis can be averted when a responsible society takes appropriate action based on information provided by a watchful scientific community.
Most of us are familiar with the ozone watches and alerts that we hear on the radio, usually during those hot sultry days in the summer when there is little wind. Near the surface, ozone is a potent toxin that forms when nitrogen oxide gases from vehicle and industrial emissions react with volatile organic compounds (paint thinners and other carbon-containing chemicals that evaporate easily into the air). In the troposphere, that part of the atmosphere near the Earth’s surface, the natural concentration of ozone is about 10 parts per billion (ppb) which is 0.00001%. According to the Environmental Protection Agency, exposure to ozone levels greater than 80 ppb for 8 hours or longer is unhealthy (NASA, 2000). Such concentrations occur in or near cities during periods when the atmosphere is warm and stable. The harmful effects can include throat and lung irritation or aggravation of asthma or emphysema.
Fortunately for us, most atmospheric ozone is found in the stratosphere, the region of the atmosphere between about 10 and 50 km (32,000 -164,000 ft) where ultraviolet radiation is very high (Figure 1). Ozone is created when extreme ultraviolet radiation from the sun breaks an oxygen (O2) molecule into two free oxygen atoms. These then combine either with each other to form O2 or with O2 to form ozone (NASA, 2000). In general, ozone concentrations are low, a few molecules per million, even in the stratosphere. The peak concentration of ozone occurs at an altitude of roughly 32 km (20 miles) above the surface of the Earth. At that altitude, ozone concentration can be as high as 15,000 ppb (0.0015%). The standard measure for ozone is the Dobson Unit (DU).
A vertical profile (Figure 1) of O3 concentration with altitude shows that most of the ozone is found from 10-30 km. Despite its low concentration, this ozone layer is critical for life on earth as we know it. Stratospheric ozone absorbs all of the UV-c, most of the UV-b, and about half of the UV-a sunlight radiation incident on the atmosphere and prevents it from reaching the surface. Exposure to the highly energetic UV-c, and/or an increase in exposure to UV-b and to a lesser extent UV-a can lead to increased incidence of skin cancer, and can cause damage to our immune systems, marine organisms, and sensitive crops.
Normally, stratospheric ozone is produced and destroyed at a fairly constant rate, that is until modern society altered that balance by producing increasing levels of CFCs (chlorofluorocarbons). CFCs, found in older refrigerants, fire extinguishers, and certain solvents, reach into all levels of the stratosphere and decompose into ozone-depleting gases such as chlorine (Cl2) and bromine (Br2). One Cl2 or Br2 molecule can destroy 105 molecules of O3. Human activity contributes 82% of ozone-depleting chlorine to the atmosphere; explosive volcanic eruptions contibute only 3%.
The Ozone Hole
Farman et al. (1985) surprised atmospheric scientists when they announced a rapid decrease of 50% in total ozone that occurred over Halley Bay, Antarctica, each year over the period from 1975 to 1984, reaching the lowest annual values in early October. Furthermore, they found that spring total ozone values had decreased from 300+ DU in the late 1950s and early 1960s to around 200 DU in the early 1980s. Prior to this discovery, many scientists had recognized an annual variation in ozone levels over Antartica, but had not observed the dramatic annual decrease in total ozone over such a short time in early spring or the steady annual decline in total ozone that had been occurring since the late 1950s. Subsequent analyses of records dating back to the 1950s along with newer satellite data using the Total Ozone Mapping Spectrometer (TOMS) confirmed the Farman, et al. (1985) findings and demonstrated that the region of severe ozone depletion covered essentially the entire continent of Antarctica (Figure 2).
Each year the ozone hole develops in August and reaches a maximum in late September or early October before shrinking and disappearing in November or December. In a period of only a few weeks, the total amount of ozone can decrease by up to 50%, from 300 DU to 200 DU or less. The term ozone hole is defined as the area within which total ozone is 200 DU or less. Analysis of the historical data indicate a dramatic increase in the size of the ozone hole from the late 1970s to the present (Figure 3).
The largest Antarctic ozone hole measured to date occurred in 1998, and averaged 10.1 million square miles (Solomon, et al. 2005). This year’s ozone hole measured 9.4 million square miles at its peak between September and mid-October, slightly larger than in 2004. For 10 of the past 12 years, the Antarctic ozone hole has been larger than 7.7 million square miles. Before 1985, it measured less than 4 million square miles (NASA, 2005).
Causes of the Ozone Hole
The Antarctic ozone hole is primarily the result of destruction of stratospheric ozone by increasing levels of man-made chlorine and bromine combined with the pa
AAPG Convention Set for April 9-12
By AAPG Convention Organizing Committee
Of the 11 times that Houston has hosted the AAPG Convention (since 1924), only two conventions were held at times of historically high oil and gas prices. The last time a convention was held in Houston during an oil boom was in1979, 27 years and a generation ago! The 2006 AAPG Convention in Houston will be another landmark “oil boom” convention. Since 1979, Houston has grown substantially in people and technology making Houston today a thriving energy capital, a crossroads of technology and a gateway of “know-how” to the world.
Back in 1979, high prices followed the peak output of U.S. domestic oil production. In 2006, our industry is facing the possibility that at this time in history we could be at the peak of global oil production. AAPG is planning a forum entitled “Winning the Oil End Game-The Future of Hydrocarbon Resources in Our Global Economy” at the April 2006 convention to debate the issue. However controversial these issues may be, one thing is certain: geologists have always been at the center of energy exploration, from the early wildcatters to space exploration. AAPG is pleased to announce that Apollo 17 astronaut Jack Schmitt, the only AAPG member to have walked on the moon, will share his ideas about future exploration and energy at a special forum.
The AAPG today is made up of an ever-expanding global association of petroleum professionals. This is reflected in the convention logo, representing a diverse group of talented geoscientists of various backgrounds, having multiple skill sets, and coming from many geographic locations.We are pleased that our logo also reflects the latest technologies that these teams employ. (Of particular note is the innovative forum “Women as Leaders in the E&P Industry”.)
Conventions are all about people and ideas. Ideas drive this year’s AAPG program. The theme of the meeting, “Perfecting the Search” (a quote from the late Michel T. Halbouty), reflects efforts to improve our abilities to find and produce hydrocarbons commercially as we strive to become better scientists and explorers. The strength of the technical program is our foundation. Technical achievement paves the way to profitable business so geologists can “Deliver on our Promises.” Mindful that exploration is a business, we have taken steps to ensure that business relevance is integral to this program. Sessions such as “Energizing the World in the 21st Century” will occur all day during the Monday program. CEOs of oil companies will share their visions of the future. Other business-relevant sessions include “Overcoming Challenges for E&P in the 21st Century,”“Reserves Now and in the Future” and “Show Me the Money! How Wall Street Logic, NYMEX Traders and Capital Markets Impact You.”
For additional information, see below and also the AAPG web page: http://www.aapg.org/. Registration discounts apply prior to February 17. In addition, you can be a part of the convention by volunteering, judging or sponsoring.
Contact Jim Grubb, Volunteer Chairman
(713-591-1155), George Klein, Judging Chairman (281-937-
9436) or Gonz Enciso, Sponsorship Chairman (713-422-8261).
Technical Program
The technical program builds on the convention theme “Perfecting the Search, Delivering on Promises,” beginning with oral and poster sessions on discoveries, case studies and techniques with an additional focus on the business of our profession. This year we have over 875 papers consisting of 432 posters and 446 oral papers.
Program themes are:
• Successful Business Strategies with the landmark forum “Energizing the World in the 21st Century” beginning the technical program.
• Delivering Resources and Environmental Quality for a Sustainable Future
• Learning from Exploration and Exploitation Successes, Failures and Mistakes, with the opportunity to study Bypassed Pays and Plays
• Giant Fields of the World, Their Implications and What They Have to Teach Us which includes the Giant Fields Core Workshop and Giant Fields Core Poster Session
• Play Openers and Where They Are Leading Us
• Perfecting the Search for AAPG Convention continued on page 15
Unconventional Plays and Technology, which in addition to discussing various unconventional reservoir types includes the Halbouty Lecture by Harrison Schmitt “Wildcatting on the Moon”
• Integrating Geology, Geophysics and Engineering to Deliver Success
• Reservoir Characterization and Modeling, focused on geological and geophysical input to reservoir analysis and ultimately fluid movement
• Stratigraphy and Petroleum Systems
• Structure and Tectonics
Forums
Contributions of the GulfCoast to geoscience technology
Th
In Every Issue
From the President by Dave Rensink
From the Editor by Paul Britt
Webnotes by Art Berman
Technical Meetings
HGS General Dinner Meeting
Exploration Implications of Different Structural Styles
and Processes of the Ultra-Deep Shelf Province,
Northern Gulf of Mexico
HGS International Explorationists Dinner Meeting
New Insights into South Atlantic Rifting from the
Santos and Campos Basins, Offshore Brazil —
A Tale of Two Basins
SIPES Luncheon Meeting
Twilight in the Desert: The Coming Saudi Oil Shock
and the World Economy
HGS Northsiders Luncheon Meeting
West Cameron 76 Field and Deep Lower Tertiary
Framework Revealed Using Sequence Stratigraphy
Integrated with SPICE
Joint HGS/HAPL Luncheon Meeting
MMS Plan for Deep- and Ultra-Deepwater Leasing
in the Gulf Of Mexico and Assessing 2005 Hurricane
Damage to the Outer Continental Shelf
HGS North American Explorationists
Dinner Meeting
Structural Architecture, Petroleum Systems and
Geological Implications for the New Hydrocarbon
Province of the Covenant Field Discovery, Sevier
County, Utah
Other Features
AAPG Convention Set for April 9–12
Working for America’s Energy Future and a Quality
Environment
Volunteers of the Month
Government Update
The Ozone Hole—A Crisis Averted?
Click here to download a copy of the February 2006 Bulletin
Webnotes February 2006
by Arthur E. Berman
HGS Web Manager
What is the best or easiest way to capture information from a Web page?
Ask a scientist almost any question, and he will probably say, “It depends.” It depends on what you want to copy from the Web and how you want to use it.
I will go through several ways to do this over the next few months but this month I want to focus on the most basic approach.
Copying a Web Page to Send as an E-mail Attachment
Most people know that if you copy the address of the Web page or URL (uniform resource locator) and paste it into the body of your e-mail, the person who receives the e-mail can either click on the url and directly launch the Web page from which it came, or can copy and paste the url into the address area of his/her Web browser, hit enter and get there that way. I think that there is an easier and more effective way to do this that also gives you and the recipient a record and retrievable copy of the Web page.
Here’s how I recommend saving a Web page:
When you send your e-mail, attach this file just as you would a Word document or any other file attachment. The recipient can double-click the file’s icon and their Web browser will launch and open the file as a Web page.
If you locate files saved as HTML, you can simply drag them from an open directory and drop them on an open page in your Web browser and the Web page will open.
Magic! More about copying Web pages next month.
From the Editor
by Paul Britt
Not Your Father’s AVO
Tsunamis, hurricanes, and now volcanoes are in the news as potential geo-hazards. AVO to our readers usually means amplitude variation with offset. But in this case it is the Alaska Volcano Observatory (AVO), a joint program of the United States Geological Survey (USGS), the Geophysical Institute of the University of Alaska Fairbanks (UAFGI) and the State of Alaska Division of Geological and Geophysical Surveys (ADGGS). AVO, formed in 1988, uses federal, state and university resources to monitor and study Alaska’s hazardous volcanoes, to predict and record eruptive activity, and to mitigate volcanic hazards to life and property. Mt. Augustine in Cook Inlet, Alaska (Figure1), poses the potential of eruption and possible tsunami, based on increasing seismic activity around the mountain (Figure 2).
Mt. Augustine Volcano is a 1250-meter-high stratovolcano in southwestern Cook Inlet about 280 km southwest of Anchorage and within about 300 km of more than half of the population of Alaska. Explosive eruptions have occurred six times since the early 1800s (1812, 1883, 1935, 1964-65, 1976, and 1986). The 1976 and 1986 eruptions began with an initial series of vent-clearing explosions and high vertical plumes of volcanic ash followed by pyroclastic flows, surges, and lahars on the volcano flanks. Unlike some prehistoric eruptions, a summit edifice collapse and debris avalanche did not occur in 1812, 1935, 1964-65, 1976, or 1986. However, early in the 1883 eruption, a portion of the volcano summit broke loose forming a debris avalanche that flowed to the sea. The avalanche initiated a small tsunami reported on the Kenai Peninsula at English Bay, 90 km east of the volcano. Plumes of volcanic ash are a major hazard to jet aircraft using Anchorage International and other local airports. Ashfall from future eruptions could disrupt oil and gas operations and shipping activities in Cook Inlet. Eruptions similar to the historical and prehistoric eruptions are likely in Augustine’s future.
Mt. Augustine is one of the many volcanoes on the USGS’watch list. Like the Gulf Coast hurricanes late last year, it has the capacity to pose a threat to oil and gas operations in Alaska, as well as potential harm to human activities and wildlife. Like a hurricane, an eruption cannot be prevented through human intervention, and the only response possible is advance warning and preparation. The AVO maintains a website on volcanoes, at www.avo.alaska.edu, that includes detailed seismic activity, and also a webcam of Mt. Augustine Volcano based in Homer, Alaska, which updates every 5 minutes. The backbone of AVO’s volcano monitoring program consists of networks of continuously recording seismometers installed at selected volcanoes. Seismic data are relayed to AVO facilities in Fairbanks and Anchorage where they are analyzed both automatically and by analysts. Alaska has 129 major volcanic areas, 44 of which are historically active, and 45 that were active in the Holocene.
The West Coast/Alaska Tsunami Warning Center (WC/ATWC) in coordination with the USGS is watching the current activity at Mt. Augustine closely, because it has the potential for generating a tsunami that could threaten the US coastal populations. A tsunami resulting from an eruption of Mt. Augustine could cause dangerous flooding of low-lying coastal areas surrounding the Lower Cook Inlet between the Barren Islands to the south and Kalgin Island to the north. The shallow depths of the upper region of Cook Inlet would cause the tsunami to diminish considerably, making the risk to Anchorage extremely low.
“Large flank collapses have been observed on other volcanoes in modern times: Bezymianny 1956, Sheveluch 1964, and Mt. St. Helens 1980. The seismic energy release from each was approximately equivalent to a magnitude 5 earthquake. These events are our best indication of what may be observed on seismic networks due to a potentially tsunamigenic flank collapse at Mt. Augustine. During the last two Mt. Augustine eruptions, the largest recorded seismic energy release associated with the eruption was equivalent to a magnitude 3.2 earthquake.”2 So, if magnitude 5 equivalent seismic activity is recorded at Mt. Augustine, a tsunami generating flank-collapse could occur.
The Mt. Augustine Volcano is just one example of potential geo-threats that can be found around the world. Fortunately, in at least some areas, resources are devoted to the study and observation of these threats, an example of geology being used to protect the public welfare and safety.
Footnotes
1 From the Alaska Volcano Observatory Website
2 From the National Oceanic and Atmospheric Administration - National
Weather Service Website.
EDITOR’S NOTE: As the Bulletin was going to press, the AVO reported two eruptions of Mt. Augustine Volcano in the early morning hours of January 11, and again on January 13. Ash clouds were reported to 30,000 ft and 34,000 ft, respectively. The ash cloud from the January 13 eruption is expected to impact the shoreline of Kamishak Bay and could impact Kodiak Island as well. No tsunami threat was issued. The “Level of Concern Code” remains at red. More details are available at www.avo.alaska.edu
From The President
by Dave Rensink
Statistics and Other Marginally Useful Information
We in the petroleum industry tend to forget that there are other extraction industries in Texas. That was recently brought home to me when my wife mentioned that she heard on the radio that Texas is one of the biggest producers of lignite coal in the United States. My immediate retort was, “that can’t be right.” After all, when was the last time you saw a coal mine in Texas? If I had asked you to bet on how much coal Texas produced, you would have won if you picked any number over zero. The fact is that Texas is THE LARGEST producer of lignite coal in the United States. Texas is also the fifth largest coal producer overall behind Wyoming, West Virginia, Kentucky and Pennsylvania. Most of it comes from 3- to 10-foot seams in the Wilcox Group in east and southeast Texas. It is probably no surprise that approximately 98% of the lignite is used to generate electricity in Texas. We also have the distinction of being the largest consumer of coal in the United States, nearly all of which is used for electric power generation.
Did you know Texas generates approximately 10% of the total US electric power? In fact, Texas is the biggest electricity generator of the fifty states. We produce nearly 70% more electricity than Florida and twice as much as Pennsylvania and California. We are also the largest consumer of electric power, followed by California and Florida. Texas may be a net exporter of electricity, but in 2003, we consumed nearly as much as we produced. We are the second most populous state behind California and ahead of New York and Florida. Texas has 7.6% of the US population, yet we consume almost 10% of the electricity. We are the largest consumer of electricity in all three categories-residential, commercial and industrial. It may be possible to point to economic reasons for our disproportionate consumption of electricity, but I would bet the real culprit is the environment. Air conditioning is virtually essential to our well-being and the quality of life in Texas, but it comes at a cost.
In the vein of other lesser known facts about Texas minerals (at least known by me), the following is from the Bureau of Economic Geology. Based upon USGS estimates of the quantities of minerals produced in the fifty states in 2003, Texas continued to be first in crushed stone and second in portland cement, construction sand and gravel, salt, common clays, gypsum, talc and zeolites.
HGS is an affiliated society of AAPG, but that does not mean we cannot serve the minerals side of the business. We have already established special interest groups in international and North American exploration, environmental and engineering geology, and neogeos. If there is sufficient interest, there is every reason that a minerals exploration group could also be established. All we need are interested participants and volunteers to organize the meetings. If we have a minerals constituency that believes it is not being served with the current organizational structure of HGS, let me know. I am confident the board would support the organizational efforts of any group that feels it has been marginalized. In the words of a former Louisiana politician, “Le me hep ya.”
As long as we are dealing with statistics, here are some that I did know and that ought to concern us all. The country with 4.6% of the world’s population consumes 24.7% of world’s oil pro- duction and 23.4% of its natural gas production. That same country only produces 42% of is crude oil requirements. That means we import 12 million barrels of oil every day. Fortunately, we do produce 85% of the natural gas we consume. The balance of our natural gas needs is imported from Canada. At current product prices, we are exporting approximately 790 mil- lion dollars per day ($660 million for oil and $130 million for natural gas). That is about a third of our total trade deficit.
If you are sitting on a pile of US dollars and you do not live in the United States, there is not much you can do with them besides buy US goods, services, companies and real estate or US treasury securities. It probably is no surprise to anyone that in September 2005, $2.066 trillion of US debt was in foreign hands (that is 26% of the total US debt), but it may surprise you to know where most of it was located. Japan held 33.3%, mainland China held 12.2%, the UK held 8.8%, and Caribbean banking centers held 5%. Surprisingly, OPEC is down the list at 2.6%.
The Caribbean banking centers held $103 billion of US debt instruments in September 2005. During the first nine months of 2005, their holdings (whoever “they” are) have ranged from $94 to $125 billion. Also during the first nine months of the year, the total debt held by foreign entities has risen by $156 billion. Beyond the fact that these are mildly interesting statistics, what is the point? A macro-economist would probably say that we are part of global economy and there is no point. I take the view that money seems to be one of our biggest exports, and in the not too distant future, the United States will no longer be owned by Americans. That thought scares me more than the potential worst-case consequences of global climate change.
Do not forget to check the February and March meeting schedule on the HGS Website.
In Every Issue
From the President
by Dave Rensink
From the Editor
by Paul Britt
Member News and
Announcements
GeoEvents Calendar
HGS Membership
Application
HGA/GeoWives
Webnotes
Professional
Directory
Technical Meetings
HGS General Dinner Meeting
Geo-Legends 2006
A Tribute to Four “All-Star” Geologists
HGS International Explorationists Dinner Meeting
Traditional and New Play Types of the Offshore
Tano Basin of Côte d’Ivoire and Ghana,West Africa
HGS Northsiders Luncheon Meeting
Deep Woodbine Exploration Models and Concepts
and Status of Current Activity
HGS Environmental and Engineering
Dinner Meeting
Environmental Considerations for Tight Gas Sands
Development on Private Lands
SIPES Luncheon Meeting
Unconventional Drilling Methods for
Unconventional Reservoirs
GSH Potential Fields Group Dinner Meeting
Analysis of Magnetic Anomalies from the
South-Central Alberta Foothills, Canada
HGS North American Explorationists
Dinner Meeting
A Microbial Smackover Formation and the Dual
Reservoir-Seal System at the Little Cedar Creek Field
In Conecuh County, Alabama
HGS General Luncheon Meeting
The Gunnison Field Discovery Story–Garden Banks
Block 668, Gulf of Mexico
Other Features
SAFOD—The San Andreas Fault Observatory
at Depth and Its Relevance to Oil and Gas
by Bill Rizer
Coastal Subsidence Conference Attracts
Diverse Forum
by Arthur E. Berman
Government Update
by Henry M.Wise and Arlin Howles
Click here to download a copy of the January 20006 Bulletin.
SAFOD—The San Andreas Fault Observatory at Depth and Its Relevance to Oil and Gas
by Bill Rizer
Introduction
A long-standing dream of many geoscientists was realized on August 2, 2005, when a drill hole at the SAFOD site near the town of Parkfield, California, penetrated a seismically active segment of the San Andreas Fault (the Fault) at a depth of approximately 2 miles (Figure 1).
The ambitious Earthscope project (van der Vink et al, 2005) is a major national research effort designed to further understanding of the properties, the structure, and the forces and deformation processes operative in the crust of North America. A part of Earthscope, the San Andreas Fault Observatory at Depth (SAFOD) is itself a major research effort of the USGS and the State of California that is funded by the National Science Foundation (NSF). The primary objective of SAFOD is to “study the physical and chemical processes that control deformation and earthquake generation within an active plate-bounding fault zone” (Zoback et al, 1998). SAFOD will establish an observatory within a segment of the Fault to study the basic mechanical, fluid, and seismic properties and processes operative along the active San Andreas system. Principal investigators for the SAFOD project are Mark Zoback of Stanford University and Steve Hickman and Bill Ellsworth of the USGS at Menlo Park, California.
Figure 1.
The location of the SAFOD site was chosen near Parkfield for a number of reasons.
• The area is accessible.
• It is just north of the section of the Fault that slipped in the M 6.0 Parkfield earthquake in 1966 (Figure 1).
• Parkfield was already the site of a major research effort by the USGS in earthquake prediction and, therefore, was very well documented geologically and geophysically.
In this region, the Fault was slipping through a combination of small-to-moderate magnitude earthquakes and aseismic creep (Hickman et al, 2004). The Fault at the surface was creeping at about 2 cm/year, with most of the displacement occurring in a zone that was at most only 10 m wide. Numerous microearthquakes (less than M 2.0) had been detected along the Fault near SAFOD at depths of 2.5 to 12 km. This area had been the focus of repeated magnitude M ~6.0 earthquakes over the past 150 years—in 1857, 1881, 1901, 1922, 1934 and 1966 (Bakun and McEvilly, 1979). The first, in 1857, was a foreshock to the great Fort Tejon (M 7.9) earthquake that ruptured the Fault from Parkfield to the southeast for over 180 miles. When drilling started in 2002, another M 6.0 earthquake was overdue. The idea was to locate SAFOD at a position along the Fault just northwest of the segmented expected to rupture next.
The Pilot Hole
Prior to drilling the main borehole, a 2.2-km-deep vertical pilot hole was drilled about 2 km southwest of the surface trace of the Fault (Figure 2). Drilling of the pilot was funded by the International Continental Drilling Program (ICDP), with NSF and USGS support (Hickman et al, 2004). The location was chosen to be close enough to the Fault to help
identify the most likely area of slip on the Fault and to guide the primary borehole to intersect that area. The pilot hole was logged for fractures, stress and temperature, and packer tests were run for stress, permeability and fluid sampling. A 40-level multicomponent seismic array was installed in the casing for monitoring microseisms and for serving as a part of 2-D and 3-D seismic surveys run to better define the structure of the site. The hole was instrumented for long-term monitoring of pore-pressure, strain, temperature and seismic activity. The well was completed in the summer of 2002.
Geologic data, microseismic monitoring and geophysical imaging from sensors in the pilot hole and on the surface were used to locate and guide drilling of the primary observation well at a sufficient accuracy to allow for drilling and coring deviated holes through the fault zone. The plan for the lateral core and wellbores (Figure 2) called for starting “kickoff” at a vertical depth of about 2.5 to 3 km and continuing through the fault zone into the “intact” rock on the other side.
Figure 2.
The main SAFOD observation well was spudded only 10 m from the surface location of the pilot. Drilling of the main observation well began in June 2004 on the Pacific Plate about 2 km west of the surface trace of the Fault (Figure 1) and continued to the middle of October. Drilling resumed in June 2005 with the wellbore penetrating the Fault in August 2005. The SAFOD observatory will be completed in 2007.
Somewhat ironically, the anticipated M 6.0 Parkfield earthquake occurred in September 2004, before drilling of the main observation well was completed. The quake ruptured roughly the same segment of the Fault that had ruptured in 1966, as predicted.
Fault Strength and Stress
While most of the research at SAFOD is geared toward fundamental questions related to earthquake prediction, many of the results could have very real impact on the oil and gas industry. One area being addressed has been the subject of considerable debate for many years: the strength of faults and the level of shear stress acting on them. Some of the data and analyses generated by SAFOD have already had an effect on this debate. Data from the pilot hole have provided important new information on the state of stress in the crust immediately adjacent to the Fault. Interpretation of well tests, image logs, shear wave logs and cores seem to bolster earlier arguments (e.g., Zoback et al, 1987) that suggest the San Andreas Fault may be very “weak,” that is, it may have little frictional resistance to slip or, equivalently, can support only limited levels of shear stress.
The strength of faults like the San Andreas has been a contentious issue for quite some time. The debate involves what has been called the stress/heat flow paradox (Lachenbruch and Sass, 1988; Zoback et al., 1998). A “weak” fault is one whose strength is on the order of the stress relieved by an earthquake on that fault (typically < 20 MPa), while a “strong” San Andreas would have a substantially greater strength, on the order of 50-100 MPa (e.g., Lachenbruch and McGarr, 1990; Fletcher and Mariagiovanna, 1999; Scholz, 2000). According to Zoback et al (1998) arguments in favo
Polar Flip-Flop
by Paul Britt, HGS Bulletin Editor
Global warming is the hot earth science issue in the news, followed by closely by the tsunami threat and lack of warning systems to populated coastal areas, then regionally by subsidence issues here in the Gulf Coast. Well down on the list of public awareness, below even the threat of an asteroid strike (a favorite of Hollywood), is magnetic polar reversal.
James Ross located the magnetic North Pole for the first time in 1831 after a lengthy arctic journey, during which his ship got stuck in the ice for four years. Roald Amundsen found the pole again in 1904 and discovered that it had moved—at least 30 miles since its discovery by Ross. The pole kept moving north at an average speed of 6 miles per year, accelerating lately to about 25 miles per year, according to Larry Newitt of the Geological Survey of Canada, whose job it is to keep track of the pole’s movement. Every few years, Newitt goes north in search of the magnetic north pole. At the moment, it is located in northern Canada, about 375 miles from the nearest town, Resolute Bay, population 300. At its current rate of movement, it could leave North America in a few decades and reach Siberia.
Globally, the Earth’s magnetic field has weakened since the 19th century by 10%. However, the dipole moment, a measure of the intensity of the magnetic field, is now 8 3 1022 amps 3 m2, twice the million-year average of 4 3 1022 amps 3 m2, according to University of California professor Gary Glatzmaier.
The Earth’s magnetic poles have reversed, or swapped places, numerous times in the past, evidenced by magnetic “stripes” found parallel to mid-ocean ridges, magnetic evidence in lava flows and other paleomagnetic evidence. The reversals come at irregular intervals spaced 5,000 to 50 million years apart, averaging about 250,000 years. The last one was about 750,000 years ago.
The Earth’s magnetic field comes from the rotation of the Earth’s core. The solid iron inner core, about 70% the size of the Moon, spins at its own rate, about 0.2% faster than the surrounding Earth. This inner core is surrounded by a molten outer core, which behaves as its own ocean, with currents and “hurricanes” much like the Earth’s surface oceans.
Glatzmaier and associates have developed a computer model based on the Earth’s core to simulate the behavior of the magnetic poles. The strength of the magnetic field waxes and wanes, the poles drift, and occasionally flip. They have also learned what happens when the poles flip. Reversals take a few thousand years to complete, and contrary to popular belief, the magnetic field does not vanish. The field gets more complicated, with poles emerging in unaccustomed places, and multiple magnetic poles. According to Glatzmaier, it is still a planetary field, protecting the Earth’s surface from radiation and solar storms.
Others who believe that the protective magnetic field will weaken sufficiently to allow additional radiation to reach the Earth’s surface contrast with Glatzmaier’s opinion on what happens during a pole reversal. And some tie the Earth’s magnetic flip-flop to the Sun’s pole reversals.
The South Atlantic Anomaly (SAA) is a region where the Earth’s inner van Allen radiation belt makes its closest approach to the planet’s surface. As a result, the radiation intensity is higher over this region. The SAA is produced by a dip in the Earth’s magnetic field, caused by the fact that the center of the magnetic field is offset from its geographic center by 280 miles. In this region, satellites passing through it receive higher doses of radiation. The International Space Station had additional shielding installed for travel through this region, and the Hubble Space Telescope does not take observations while in the SAA. Some cite the SAA as evidence of a weakening magnetic field and imminent pole reversal.
The Sun underwent a polar reversal in 2001, according to NASA reports, an event that happens every 11 years, at the peak of the sunspot cycle, or solar maximum. The Ulysses spacecraft, launched in 1990, provided a unique view—from the top down. This solar observation will likely aid us in our interpretation of the Earth’s magnetic field behavior. The next solar magnetic pole reversal is scheduled for 2012. Don’t miss it!
Of course, the pole reversal issue receives casual press, at best. Perhaps it is because we should get ample warning as the magnetic field weakens over time. Or perhaps it is because human intervention can’t be blamed for its occurrence. In any case, it is an example of the importance of studying the Earth on which we live.
Recommended reading:
http://science.nasa.gov/headlines/y2001/ast15feb_1.htm
science.nasa.gov/headlines/ y2003/29dec_magneticfield.htm
http://www.psc.edu/science/Glatzmaier/glatzmaier.html
Tackling the Issues
by Dave Rensink, HGS President
One of the nice things about being president of the HGS is that you are periodically asked to participate in some of our finest programs. HGS co-hosted a conference on coastal subsidence in early November with the Engineering, Science and Technology Council of Houston (ECH). The co-chairs, Cheryl Desforge (HGS treasurer-elect) and Glen Carlson (ECH), and their steering committee deserve high praise for organizing and staging the conference. The purpose of the conference was to discuss the data included in a 2004 NOAA study by Kurt Shinkle and Roy Dokka, which documented the relatively rapid rate of subsidence of surveyed benchmarks in south Louisiana. This study has precipitated a considerable amount of discussion, both positive and negative. HGS and ECH felt this topic deserved a full and public airing because of the short- and long-term significance of the causes of the subsidence. As the loss of wetlands moves from an environmental issue to an economic issue, the public’s demands for a solution will increase by an order of magnitude. This means the size of the projects and the resulting expenditure of public funds increase substantially. We believe project planners and decision makers need as broad an exposure as possible to all of the processes, both natural and manmade, that affect subsidence in order that they may make informed
decisions on potential mitigation projects.
If you heard Dr. Dokka’s talk at our November 2004 lunch meeting or read Art Berman’s article in the October 2005 HGS Bulletin, you are familiar with the issues of subsidence, and as a geologist, you are familiar with the causes. Although groundwater withdrawal may be a major cause of subsidence in the greater Houston area, it is certainly not the only cause. Groundwater withdrawal and shallow oil, gas and associated water production definitely contribute to subsidence in south Louisiana and southeast Texas, but they are most likely local in scope and are not the only causes. Yet, in the search for an easy solution to the problem, fluid withdrawal has become the only consideration in the minds of many. Conventional wisdom has once again obscured the pursuit of a solution. Man’s activities may have accelerated the rate of subsidence in certain parts of the Gulf of Mexico basin, but they did not start it. Basin subsidence, sediment compaction, salt movement, gravity gliding and growth faulting started over 160 million years ago when the Gulf of Mexico began to open. There is no reason to think these processes have stopped in the last 50 years.
Speaking of man influence of long-term processes, let’s consider global warming. In my opinion, it is difficult to refute the validity of global warming. In a general sense, the earth has been warming since the end of the last glacial epoch—10,000 to 12,000 years ago. I will agree that the earth’s surface temperature has fluctuated during this period, but the earth is generally warmer today than it was 12,000 years ago. Continental glaciers have been retreating and sea level has been rising as a result of solar heating since
long before the industrial revolution. Man’s influence on natural processes, specifically the increase in the concentration of CO2 and water vapor in the atmosphere, may have marginally increased the rate of the earth’s heating, but man did not start it. At worst, we may have successfully accelerated climatic conditions that would have occurred at some point in the future.
We are not likely to stop global warming, even if it were possible to immediately stop all CO2 emissions. The best that can be expected is to return to the previous rate of temperature change. It is also likely that it would take an extended period of time to return to the prior rate of change because of the inertia that has probably resulted from the warming of the oceans. It would be similar to expecting a loaded VLCC (very large crude carrier) to come to an immediate stop when the engines are stopped. There may be legitimate long-term reasons to reduce CO2 emissions, but the hope of stopping global warming in the immediate future is not one of them. If that statement does not elicit some
comment, either no one reads this column or no one cares. Before you write or call, remember your training. Natural processes tend to be cyclic. Why should the earth’s climate be any different? Not long before global warming became a global environmental issue, the primary climatic concern was the possible return of a mini ice age similar to that which occurred in Europe between 1300 and 1800.
Another piece of conventional wisdom to consider is the reason for the increase in the amount of water vapor in the atmosphere. Water vapor is far more prevalent in the atmosphere and may be a more efficient “greenhouse gas” than CO2. Yet, conventional wisdom says that the increase in water vapor in the atmosphere is a feedback effect of increasing air temperature (warm air is capable of holding more water vapor than cool air), and the amount of water vapor generated by burning fossil fuels is not a significant problem. Thus, conventional wisdom says that water vapor content is increasing only because air temperature is increasing, and the increasing air temperature is the result of increasing concentrations of CO2. The premise that the amount of water vapor generated by human activity may not be significant in relation to the amount of water vapor that can enter the atmosphere as a result of evaporation from soils, lakes and oceans is possibly correct. However, my point is that conventional wisdom has dismissed a potentially significant contributor to climate change as largely a non-issue because any increase in the amount of water vapor in the atmosphere is a direct result of man’s activities. Is that a true statement? Similarly, conventional wisdom seems to have dismissed earth’s ccentric orbit, its proximity to the sun, and its axial inclination toward the sun as major contributors to climate change.
If you are looking for easy solutions, it is possible to make a good correlation between the increase of CO2 in the atmosphere and the increase in coal consumption worldwide since the 1930s. It comes as no surprise that approximately 90% of the coal consumed has been used to generate electricity. Nuclear energy is a viable alternative to coal in electric power generation, but you seldom hear anyone advocating shutting down coal-fired plants and building nuclear plants. There is also a belief that people who live down-wind of a coal-fired plant may be exposed to more radiation through the release of uranium and thorium from the coal than those who live in proximity to a nuclear plant. For those of you who are interested in statistics, the top five energy sources used in electric power generation in the United States are coal (52%), nuclear (21%), natural gas (14%), hydro (7%) and petroleum (3%). If there truly is a compelling reason to significantly reduce CO2 emissions, how do you want to do it and at what price?
HGS is hosting a Geo-Legends panel on Janua
Robert M. Sneider Memorial
by Arthur E. Berman, Thomas J. Feldkamp and Lynne D. Feldkamp
Robert M. Sneider passed away on October 29, 2005. He was 76 years old and is survived by his daughter and two sons. Bob was a great petroleum geologist and a role model and mentor of the highest level of integrity and standards.
Bob lived a life above all of service to the profession of geology, science, his many friends and protégés, and the public. He likely learned that mindset of professional service and mentorship from his own mentor, Gus Archie. He had a long career of exploration successes and dedication to teaching, exemplified by receiving the AAPG’s Sydney Powers Medal in 2001, the Association’s highest award and honor.
I first met Bob on a recent-clastics sedimentation class he taught along with his colleague Larry Meckel in 1981. During the week, as we traveled from Houston to New Orleans, Bob shared not only his vast knowledge of clastic geology but also his unique and systematic approach to learning and living. While participants in that class learned much about the topic of sedimentation, I, for one, learned most about how to be an effective person and geologist.
The first stop on that field seminar was in the floodplain of the Brazos River near Sugar Land, Texas. Bob explained how the Brazos River had changed its course several times over the past 18,000 years and advised us to buy flood insurance if we ever bought a house anywhere near this area. He explained that the greatest danger to homeowners was not from flooding of the river but from slow-moving tropical storms that could produce large amounts of rain in low-lying areas. As it turned out, I bought a house in the exact area of that first field trip stop when I moved to Houston many years later. To the confusion of my Realtor and family, I bought flood insurance despite the fact that our house was outside the 500-year floodplain of the Brazos. I had learned what nearly everyone did: always pay attention to Bob Sneider’s advice. Bob took his own advice when he purchased a condominium on Galveston Island some years ago: he made sure it was above the seventh floor (above the highest tidal surge reported from the 1900 hurricane) and that the building’s foundation was anchored into the Pleistocene rather than just the Holocene sand.
Bob was generous with his time and always found a way to get together to talk. I once went to Bob for advice on a job change that I was considering. He said, “I understand why you want to make the change and I don’t disagree with your reasons, but I ask you to take the weekend and think, is there is anything else that you can still learn from your present employer before you make the decision?”
I thought this was an odd request, but I took Bob’s advice and thought about his question all weekend. I called him Monday morning and said, “Bob, I can still learn to run a workstation and the company will give me the opportunity to learn Spanish.” I stayed in that job for 5 more satisfying and productive years. Knowing how to use a workstation and speak Spanish have defined my career since talking to Bob that afternoon.
Bob and Ramona Sneider at the dedication of the Bureau of Economic
Geology Houston Research Center, June 4, 2004.
Bob often reminded his many students and protégés, “Run your business like you plan to stay in business.” In many ways, that characterized his life. He did everything with great thoroughness, thoughtfulness and enthusiasm. He believed in cataloging and updating information. Bob would commonly read or hear some piece of information about reservoir pressure or quality and he was soon adding it to a graph that he just happened to have with him and was continually updating.
He appreciated and understood complexity, but also believed that geology and life ultimately reduced to relatively straight-forward situations and decision. He taught his students that most reservoirs, in all their variety, generally could be thought of as either bars or channels. Like much of Bob’s wisdom, his observations have stayed with those he taught and mentored because of their fundamental truth and usefulness.
Bob Sneider’s 48-year career began in 1957 at Shell Oil Company, where he worked for nearly 18 years. During those years, Bob and his family moved often but settled in Houston in 1967. In 1974, Bob started Sneider and Meckel Associates, Inc. with Larry Meckel. He formed Robert M. Sneider Exploration, Inc. in 1981. Bob was involved in worldwide exploration, production, property acquisition, research, training and management.
During Bob’s career, he and his associates helped client companies by finding new opportunities through the application of integrated geological-geophysical-petrophysical and petroleum engineering techniques in both frontier and mature areas. He led the industry in cataloging geological, petrophysical and engineering properties of reservoir, seals and flow barrier rock types from around the world.
Bob actively participated in many professional societies, receiving numerous professional accolades, and was a mentor to countless professionals during his career. He was a distinguished lecturer for the AAPG, PESA and SPE. In 2000, he became a member of the National Academy of Engineering. He was an honorary member of the AAPG and named the 2001 recipient of the Sidney Powers Medal, AAPG’s highest award.
Bob and his wife Ramona were full partners in life. Bob often acknowledged that his success was due to the steadfast support and assistance of his wife. They raised a family of three children. They were enthusiastic grandparents. After their children were grown, Bob and Ramona enjoyed time together, much of it traveling the world and seeing friends. Ramona passed away just two weeks before Bob and those who knew Bob and Ramona Sneider find no mere coincidence in this.
Bob will be greatly missed by the Houston Geological Society and by all who knew him.
Coastal Subsidence Conference Attracts Diverse Forum
by Arthur E. Berman, photos by Matt Kolodney
More than 120 people attended the “Coastal Subsidence, Sea Level and the Future of the Gulf Coast” conference November 3–5 to hear differing views on the risks of subsidence for coastal areas of Texas and Louisiana including Houston.
The Houston Geological Society and the Engineering, Science and Technology Council of Houston (ECH) joined together to organize and present the meeting at the Northwest Conference Center in Cypress, Texas. The goal of the conference was to provide a forum where differing parties could present their positions and potentially come to consensus on what action would be appropriate for Texas.
Keynote Speaker Dave Zilkoski of the NGS
The HGS and ECH organized the meeting to increase public and governmental awareness of the complex issues involved in subsidence and to provide a forum for discussion of all aspects of the subsidence issue. The hope was to open lines of communication so that policy makers, their technical advisors and the public might have a better understanding of coastal subsidence, how to quantify and predict it, as well as plan infrastructure around its effects.
These were perhaps idealistic expectations considering the fundamental differences dividing the various parties in the subsidence debate for the Gulf Coast. While everyone involved in the debate over subsidence agrees that there are many aspects and factors that contribute to subsidence, there clearly are also camps that favor a single cause as being the most significant.
Keynote Speaker Virginia Burkett, USGS
The Harris Galveston Subsidence District (HGSD) represents the strongest voice favoring ground water withdrawal as the chief cause of subsidence in the Houston area. Changes in ground water pumping directed by the HGSD have resulted in impressive reduction or elimination of subsidence in low-lying areas of Houston. There are, however, portions of the metropolitan area that are undergoing significant subsidence that is not easily explained or fully understood.
The other pole in the subsidence debate is represented by Dr. Roy Dokka, professor at Louisiana State University and co-author of the 2004 Technical Report NOS/NGS 50, “Rates of Vertical Displacement at Benchmarks in the Lower Mississippi Valley and the Northern Gulf Coast.” Dokka’s report concludes that rates of subsidence in southern Louisiana are significantly greater than previous estimates and that modern subsidence includes a tectonic component. HGS members may recall that Dr. Dokka addressed an HGS General Luncheon Meeting held jointly with the Society of Petroleum Engineers (SPE) in November 2004 on “Anatomy of a Silent Disaster: Ongoing Subsidence and Inundation of the Northern Margin of the Gulf of Mexico Basin.”
The diverse array of participants at the Coastal Subsidence Conference included state and local government and regulatory officials from Texas and Louisiana, representatives from various federal agencies such as the National Oceanographic and Atmospheric Administration’s (NOAA) National Geodetic Survey (NGS) and National Hurricane Center, and the United States Geological Survey (USGS). The conference was also attended by university researchers and faculty from the University of Texas, Texas A&M University, Rice University, University of Houston, Tulane University and Louisiana State University (LSU), along with representatives from a variety of geological, environmental, petroleum and engineering companies.
The first day of the three-day conference was devoted to understanding coastal subsidence, the methods used to measure subsidence and techniques used to evaluate the contribution of ground water withdrawal, oil and gas production, engineering projects and geological factors to the overall subsidence budget. The second day addressed the economic and cultural effects of subsidence and the results of mitigation efforts, options and consequences. A field trip on the third day visited sites of active faulting and subsidence within the Houston area.
Conference leadership team (left to right): Front: Glenn Carlson (ECH) and Cheryl Desforges (HGS). Rear: Dave Rensink (HGS) and Art Schroeder (ECH)
HGS President Dave Rensink began the conference Wednesday morning and gave a keynote address that afternoon titled “An Introduction to the Origin of the Gulf of Mexico and Its Role in Subsidence.” Other keynote addresses included Dave Zilkoski of the NGS on “The Importance of an Accurate Subsidence Network for the Establishment of Vertical Control and Subsidence Rates,” and Virginia Burkett of the USGS on “Subsidence and Future Relative Sea Level Rise in the Gulf Coast.”
Guest speakers included Sam Webb, Deputy Commissioner for Coastal Resources Program, Texas General Land Office, who discussed “Coastal Subsidence: Finding Common Ground”; John Anderson of Rice University, whose topic was “Long-Term Subsidence Along the West Louisiana and East Texas Coast”; and Ron Neighbors, HGSD, who spoke on “The Politics and Public Policy Issues of Subsidence.”
HGS President Dave Rensink described the purpose of the conference. “The idea is to expose participants to as many of the cause and effect relationships of subsidence as we possibly can. We want to make sure that everyone who is involved in the decision-making process is considering as many aspects of the problem as there really are and not focusing on only one or two aspects of the problem.”
Roy Dokka added to Rensink’s comments. “I think society needs to understand what that risk is. It needs to be honest with people who live there saying, here’s the potential. There is no guarantee in life. We can’t guarantee anything. What we can do is to see what may happen. Public officials that have responsibility for these things need to understand them and then express them to the community so that the people who live there also understand. Geological insights are too important to be left just to geologists.”
It is safe to say that most attendees were aware that subsidence is a problem for coastal regions of the Gulf of Mexico. Probably not all were equally aware of the complexity of the issue. Most participants agreed that the conference was successful in raising awareness that coastal subsidence cannot be easily explained in terms of one cause or factor.
Meeting organizers w
We were in a kind of dark age. If during the age of technology the world was drunk on possibilities, the post-modern world of the second half of the 20th century was terrified by the horrors of technology. If the earlier Age of Technology was outward and expansive, post-modern technology is inward and compressed. Early 20th century people dreamed of flying cars and television phones. Now that we can build these devices, the interest is no longer there.
Monday, December 12, 2005
Westchase Hilton • 9999 Westheimer
Social 5:30 p.m., Dinner 6:30 p.m.
HGS Joint General and North American
Dinner Meeting
Cost: $25 Preregistered members; $30 non-members & walk-ups
The HGS prefers that you make your reservations on-line through the HGS website at www.hgs.org. If you have no Internet access, you can e-mail reservations@hgs.org, or call the office at 713-463-9476 (include your name, e-mail address, meeting you are attending, phone number and membership ID#).
CLICK TO REGISTER
by Michael R. Hudec (speaker), Martin P.A. Jackson, and Daniel D. Schultz-Ela Bureau of Economic Geology, Jackson School of Geosciences, The University of Texas at Austin
AAPG Matson Award paper, AAPG 2005 annual meeting, Calgary
A Compressional Origin for Minibasins near the Sigsbee Scarp, Gulf of Mexico
The conventional explanation for minibasin subsidence is that it is driven by gravity— that minibasins exist because their fill is dense enough to sink into the underlying evaporites, expelling salt into the adjacent salt highs. This explanation is valid if the average density of the sediments is greater than the density of the salt, but it cannot account for subsidence of thin, less dense clastic sequences into salt. Seismic thrusts, and (3) postthrusting, in which sand bodies may extend across the entire minibasin. Understanding minibasin evolution can there- fore improve prediction of reservoir continuity in supra-salt plays.
Seismicdata show that many minibasins started sink-ing into salt when their siliciclastic fill was much thinner than the 1.5- to 2-km thickness necessary for compaction to invert the density contrast. For such minibasins, some mech- anism other than gravity must be involved.
We investigated mechanisms of minibasin subsidence using a 3,600-km2 prestack depth-migrated 3D seismic dataset near the Sigsbee Scarp, northern Gulf of Mexico. This dataset covers 27 minibasins of varying size and thickness. These data indicate that mini- basin initiation was synchronous with shortening, as indicated by the presence of thrust faults in the deeper parts of many minibasins (Figure 1). A compressional origin of mini-basins is also consistent with finite-element models showing that laterally shortened minibasins will subside even if their fill is less dense than the salt but it cannot account for subsidence of thin, less dense clastic sequences into salt.
Figure 1. Thrust faults affecting the deep section in many minibasins indicate that these basins formed in compression. Reservoir distribution within the minibasin depends on whether the sands were deposited prethrusting, synthrusting, or postthrusting. Data © Veritas Marine Surveys, Houston, Texas.
The sedimentary fill of compressional mini- basins can be divided into three stages (Figure
1): (1) prethrusting, which is typically shale- prone and may predate the existence of a basin, (2) synthrusting, in which sands are deposited in synclinal subbasins between thrusts, and (3) postthrusting, in which sand bodies may extend across the entire minibasin. Understanding minibasin evolution can therefore improve prediction of reservoir continuity in suprasalt plays.
The specific cause of shortening that led to minibasin formation is currently unknown. The orientation of thrust structures is highly variable. Their pattern suggests that shortening was parti- tioned by flow boundaries defined at shallow levels within and above the salt sheet. If so, suprasalt processes may have been an important control.
Biographical Sketch
MIKE HUDEC received his PhD from the University of Wyoming in 1990 and spent the next eight years at Exxon Production Research, where he specialized in salt tectonics, extensional tectonics and seismic interpretation. He moved to Baylor University in 1997 as an assistant professor in Structural Geology. In 2000, Hudec moved to the Bureau of Economic Geology, where he is codirector of the Applied Geodynamics Laboratory, an industry-funded research consor- tium studying salt tectonics. His current research interests include advance mechanisms for salt sheets, processes in mini-basin intitiation and construction of a digital atlas of salt tectonics.
MARTIN JACKSON received his PhD from
Previous GeoBLOG Topics (Click to View):
Letter From Korla, Xinjiang Autonomous Region, People’s Republic of China
Richard Nehring Clarifies U.S. Production Data
Arthur E. Bermanbermanae@gmail.comThe opinions in GeoBLOG! are mine, and do not necessarily represent the opinions of the Houston Geological Society.
Letter From Korla, Xinjiang Autonomous Region, People’s Republic of China
I’m writing from a part of China that is closer geographically and ethnically to Kazakhstan, Kyrgyzstan and Turkmenistan than it is to what most of us think of as China. I’m here doing geology in the Tarim Basin, a key area in China’s effort to become more energy independent. The Tarim Basin is obviously quite remote but a recently completed gas pipeline now connects over 30 TCF of natural gas with markets in Shanghai, nearly 3000 km away from here. The basin is also an important producer of liquid petroleum. A recent Paleozoic discovery near the Tazhong Field has estimated reserves of between 2-3 BBOE!
Tarim Basin Map Showing Korla
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I’m staying in Korla which is the oil center of the Tarim Basin. It is a city of about 350,000 people. To get here I took a 3.5 hour, 2400 km flight from Beijing to Urumqi, the regional capital of the province of Xinjiang. Then I took a 45 minute flight across the Tianshan, or Heavenly Mountains, which rise 6400m above Urumqi and have peaks 25,000 feet above sea level. The Tarim Basin is about the size of Texas without the Panhandle and other of its extremities and produces oil and gas from everything from the Cambrian to the Tertiary.
Tianshan (Heavenly Mountains) rise to 25,000 ft above sea level
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I’ve spent most of the past 10 days interpreting core of the Carboniferous and Ordovician sections and discussing plays and prospects with PetroChina geologists and geophysicists.
PetroChina geologists and geophysicists discussing plays
(note the ping pong table as a map display surface!)
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This work followed a 2 week field excursion in September where I was taken to outcrops of Cambrian through Carboniferous exposures. As a result of these last two visits, we have developed new exploration and production models for several of their exploration and production projects.
PetroChina Core Facility in Korla
Mr. Wang demonstrating how he brings core boxes down to the core display area
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It hasn’t been all work here in Korla. I have been invited to several banquets hosted by PetroChina and GCC Group Corp, the company that brought me to China. I’ve had a chance to try several local restaurants that specialize mostly in lamb dishes reminiscent of the Middle East and Mediterranean.
Downtown Korla in snow, January 24, 2006.
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The city of Korla is thriving with construction projects everywhere. Most signs here are in Chinese, Arabic and English. This area is the center of the ancient Silk Routes and much of the local tradition focuses on that mythical past. Korla is a modern city with all the conveniences found in the western world. As of this trip, I now have a DSL intenet connection in my hotel room!
Next week, Spring Festival begins in China. Tonight I hear fireworks all over the city. Spring Festival is a time when most Chinese return to their home towns to be with family and celebrate the coming end of winter. This winter has been among the coldest in recent history in northwestern China. Before leaving Texas, I had to search for the down jacket I brought to Houston from Denver many years ago but I’m sure glad I have it now.
The Great Sumatra-Andaman Earthquake of December 26, 2004: New Insights That Will Change the Next 40 Years and the Plate Tectonic Paradigm
by Arthur E. Berman
Nearly one year ago, the Great Sumatra-AndamanEarthquake produced the most destructive tsunami in history, with 283,000 people dead or missing in the Indian Ocean region. Modern geophysical data recorded during the earthquake and tsunami revealed unprecedented complexity in the mechanics of plate boundary rupture. No inversion model successfully accounts for the slip or rupture pattern produced by this event. New understanding of plate boundary behavior and mechanics that arises from the Great Sumatra-Andaman Earthquake may ultimately modify the existing plate tectonic paradigm.
The earthquake initiated just before 8:00 a.m. local time at the epicenter on the morning of December 26, 2004, approximately 255 km (158 mi) south-southwest of Banda Aceh off the western coast of northern Sumatra (Figure 1). There was no warning for the earthquake or the ensuing tsunamithat rapidly reached the shores of the Indian Ocean, devastating coastal areas of Indonesia, Thailand,Myanmar, India and Sri Lanka.
An Exceptional Earthquake
The Great Sumatra-Andaman Earthquake was exceptional in every way. Its 1300-km (807-mi) rupture length is the longest of any known earthquake (Hanson, 2005). The rupture zone was as much as 240 km (149 mi) wide (Lay and others,2005). The rupture lasted over an hour, making it the longest known rupture period of any earth- quake (Hanson, 2005). It deformed an entire hemisphere, moving global positioning system (GPS) stations in southern India 4 m (13 ft) with peak-to-peak ground motion over 9 cm (3.5 in) in Sri Lanka (Bilham, 2005). No point on Earth was undisturbed, with peak ground motion greater than 1 cm (0.4 in) everywhere (Park and others,2005).
The Great Sumatra-Andaman Earthquake was the second largest earthquake in instrumental history releasing 4.3 × 1018 Joules (Bilham, 2005). This is approximately equivalent to a 100-gigaton nuclear explosion or the total energy used in the United States in 6 months. The tsunamiproduced by the earthquake displaced 30 km3 (7.2 mi3) of sea water (Bilham,2005). The 9.3 moment magnitude (Mw)of the earthquake was equal to the sum of all moment magnitudes of earthquakes during the decade that preceded it (Lay and others, 2005). The earthquake andtsunami killed more people than any othernatural disaster in history.
The Great Sumatra-Andaman Earthquake was also exceptional as the first very large earthquake to be recorded and measured by a spectrum of digital technologies that were not available during other large earthquakes of the 20th century. Previous great earthquakes—the 1960 Chile Earthquake(Mw = 9.5) and the 1964 Alaska Earthquake (Mw = 9.1)—saturated existing analog measurement and recording equipment. The Sumatra-Andaman event was recorded by a global network of broadband,high dynamic range, digital seismometers. It was the first major earthquake to be monitored by the GPS. In addition, it was thefirst application of digitally recorded, long-period, free-oscillation modal geophysics.
A moment magnitude of 9.0 was initially calculated for the Great Sumatra-Andaman Earthquake. In March 2005, researchers at Northwestern University determined that the true magnitude was 9.3—approximately 3 times the energy released by a 9.0 event—after taking into account the full length and slip of the rupture,particularly the “slow slip” of the rupture’s northern portion (Fellman, 2005).
Rupture Segmentation and Slow Slip
The December 2004 earthquake trajectory may be divided into three segments, along with a fourth segment created by the contiguous March 2005 Nias Earthquake (Figure 2). Rupture initiated at a depth of about 30 km (18.7 mi) within the Sumatra segment. Rupture speed was slow and slip was small for the first 50 seconds. Rupture then expanded over the approximate 420 km (261 mi) of the Sumatra segment at an average speed of 2.7 km/s(1.7 mi/s) and rapid slip of between 5 and 20 m (16.4-65.6 ft) (Lay and others, 2005).
From 230 to 350 seconds, rupture progressed along the 325-km (202-mi) Nicobar segment of the earthquake with an average 5 m (16.4 ft) of rapid slip and an average rupture speed of 1.1 km/s (0.7 mi/s). In the Nicobar segment, an additional 5 m of slow slip proceeded up to 3500 seconds after rupture initiation (Lay and others, 2005).
The Andaman segment of the December rupture was characterized by less than 2 m (6.6 ft) of slip from 350 to 600 seconds after rupture initiation. An additional 5 m of slow slip occurred from 600 seconds to more than 3500 seconds. Rupture speeds in the northern segment were only about 0.3 km/s (0.2 mi/s) (Lay and others, 2005). The most remarkable aspect of the Great Sumatra-Andaman Earthquake was the slow slip that followed the initial, rather characteristic rupture and unzipping of a plate boundary. Slow slip tripled the earthquake’s energy release and accounts for the revision of its moment magnitude from 9.0 to 9.3. Slip along the northern segments of the rupture zone occurred too slowly to generate tsunami waves. Had slip been as rapid on the Nicobar and Andaman segments of the rupture as on the Sumatra portion, the resulting tsunami would have been many times more devastating than what actually occurred.
The March 28, 2005, Nias Earthquake may be thought of as a large, late aftershock. It had a moment magnitude of 8.7 and an average 8 m (26.3 ft) slip along a 300-km (186.5-mi) segment. It was probably produced by plate boundary failure because of stress changes that resulted from the December 26 rupture. No significant tsunami was produced by this rupture.
Slow slip is poorly understood and its causes are largely empirical at present. Slow slip occurred where plate convergence became increasingly oblique. It also coincided with a change in age of the subducting lithospheric plate from 60 Ma to 90 Ma between the Sumatra and Andaman rupture segments. Age and accompanying textural differences may have resulted in changes in mechanical coupling along the fault plane: subduction of younger lithosphere may have provided a broader contact area (Lay and others, 2005). Subduction of older lithosphere to the north may have contributed to displacement transfer across zones of previous back-arc spreading and associated dispersion of rupture energy (Figure 2).
Slow slip excited several of Earth’s fundamental resonances called free vibrational oscillations. Free oscillations were first reported after Fourier analysis of digitized analog seismic records from the 1960 Chilean earthquake. When seismic
Geo-Legends 2006, January 9, will Feature Life Stories
from Four Much-Admired Geologists
by Linda Sternbach, HGS Vice President
The HGS dinner meeting on Monday, January 9,2006, will be a special panel discussion featuring four great names in geology: Albert Bally, Arnold Bouma, Peter Rose (current AAPG president) and Peter Vail, who will be presenting their perspec- tives on the past, present and future applications of geology and oil exploration. The event will include a social hour, elegant dinner and a two-hour talk program to be held at the Westchase Hilton hotel, 9999 Westheimer, in west Houston.
It has become a great HGS tradition to host a “Legends” panel discussion dinner every few years. The first “Legends in Wildcatting” program in 2001 featured prominent oil legends Marlan Downey, Joe Foster, George Mitchell, John Seitz and Gene Van Dyke and was moderated by Jim Funk. The second program, called “Legends in Wildcatting, 2003,” featured Michel Halbouty, Bill Barrett, Thomas Barrow, Marvin Davis and Robbie Gries and was moderated by Charles Sternbach.
It’s time for the Legends theme to recognize that behind great oil businessmen are great geologists who have created the scientific technical work that ultimately results in discovery of oil and gas. Our four invited panelists are well-known names, both for their careers of teaching and their experience in practical hydrocarbon exploration. What they all have in common is that all four Geo- Legends worked for major oil companies during the 1960s and1970s, and then changed careers to be outspoken teachers and communicators.
However, each panelist has an individual point of view on geology and geophysics as professions, based on their unique careers. The HGS dinner program on Monday, January 9, will include a presentation from each panelist, and then a group discussion on how geologists work today and what can happen to our profession in the future. The audience will have a forum to ask questions to the panelists. HGS plans to create a video record of the event.
HGS members can sign up for the Geo-Legends program using the HGS webpage at www.hgs.org. We expect this event to be highly attended and are making space for 250 people. We suggest that HGS members and their guests pre-register before Friday, January6. The cost is $25 for HGS members and $30 for non-members.
Albert W. Bally
Geo-Legend: Seismic Interpretation of Complex Structure
Bally has dedicated his career to the complicated task of geophysical interpretation and analysis of complex subsurface structures. He realized that seismic reflection data was key to unraveling highly deformed rocks. His research on fold-thrust belts, basin analysis and the concept of “orogenic float” is classic work. Bally is a pioneer in “thin-skinned tectonics”—originally from research in the Canadian Rocky Mountain fold and thrust belt. His work has provided excellent guidance to geologists drilling for oil in deformed tectonic provinces.
Albert Bally was born in The Hague, Netherlands, in 1925. He became interested in geology as a boy exploring the volcanoes and foothills around Rome and spent his early years in Indonesia, Switzerland and Italy. He received a PhD degree in geology from the University of Zurich in 1953, completing a study of an area in the Central Alpenines, Italy, in his thesis. Bally did post-graduate research at the Lamont-Doherty Geological Observatory of Columbia University, New York before finding his way into the oil business.
In 1954, Bally was offered a position with Shell Oil Company. He began with Shell Canada in Alberta, where he explored for prospects in the Rocky Mountain overthrust belt. Exploration programs at Shell during that period included the Rocky Mountains and foothills of Alberta, British Columbia, the Northwest Territories and northern Yukon. From 1962 to 1966, as chief geologist, he was concerned with all Canadian exploration matters. In 1966, Bally was transferred to Houston as manager of geological research (U.S.) for Shell Oil in 1968, exploration consultant in 1976 and senior exploration consultant in 1980. While at Shell, he was involved in exploration in the U.S. offshore and onshore. During the early 1970s, his focus was the study of global geology as well as more detailed studies in the Western Cordillera and the sedimentary basins of the United States, including Gulf Coast growth faults and their effect on sedimentation and hydrocarbon traps. Over the span of his career, Bally has studied seismic and tectonics in Tibet, China, Italy, the Canadian Arctic, the Gulf of Mexico, Perdido fold belt, Morocco, Venezuela, offshore Nigeria and Romania.
Upon retirement from Shell after 27 years, he became Harry Carothers Weiss Professor of Geology at Rice University in Houston, Texas. He was department chairman at Rice early in his career, and established the department’s geophysics program. His insight in melding geology and geophysics has been the hallmark of his research and teaching. A major focus of investigation has been on reconciliation of the complex structural geology of the earth’s upper crust with lower crust and mantle. Bally’s research activities at Rice significantly contributed to the study of
regional, crustal de-coupling in compressional, extensional and strike-slip provinces. Bally is now Rice emeritus professor, yet very active in current research. For example, he is now co-editing a two-volume book called The Phanerozoic Geology of the World.
Exploration geologists are grateful to Bally for publishing illustrated seismic lines from petroleum areas all over the world to illustrate the best ways to interpret difficult seismic terrains. Bally’s concept of the seismic atlas as workbook was ground- breaking. Seismic Expression of Structural Styles: A Picture and Work Atlas (AAPG Studies in Geology, 1983) is a three-volume set that illustrates practical seismic interpretation in worldwide extensional provinces, compressive/strike slip systems and rifts/passive margins. His second work, Atlas of Seismic Stratigraphy (AAPG Studies in Geology #27, 1987–89), is a multivolume set that describes interpretation procedures and key definitions of sequence stratigraphy in rift systems, passive margins, the Gulf of Mexico, fore-deep environments, active margins and deep sea environments.
Bally has been president of the Geological Society of America (1988) and initiated the famous Decade of North American Geology (DNAG) publication series. In the 1980s, he was part of the JOIDES Ocean Deep Drilling Project and COCORP conti- nental reflection profiling projects. He has received many prestigious awards including the Sidney Powers Medal from the AAPG (1998), OTC Distinguished Achievement Award (2003) and Career Contribution Award for Structural Geology and 1990 to 1992, he
December 2005 Houston Geological Society Bulletin
Technical Meetings and Other Features:
HGS Joint General and North American Dinner Meeting: A Compressional Origin for Minibasins near the Sigsbee Scarp, Gulf of Mexico
SIPES Luncheon Meeting: Martian River Deltas and the Origin of Life Other Features
Geo-Legends 2006, January 9, wiil Feature Life Stories from Four Much Admired Geologists
by Linda Sternbach
The Great Sumatra–Andaman Earthquake of December 26, 2004: New Insights That Will Change the Next 40 Years and the Plate Tectonic Paradigm
by Arthur E. Berman
Government Update by Henry M.Wise and Arlin Howles
HGS Financial Summary for 2004–2005 by Ken Nemeth
In Every Issue:
From the President by Dave Rensink
From the Editor by Paul Britt
Member News and Announcements
GeoEvents Calendar
HGS Membership Application
HGA/GeoWives
Webnotes
Professional Directory
Click here to download this HGS Bulletin.
The Houston Geological Society Continuing Education Committee Presents:
Coastal Subsidence, Sea Level and the Future of the Gulf Coast
The Conference (held November 3-5) was a huge success! If you missed it, you still have a chance to get a copy of the proceedings and the field trip guide book. Hear what everyone is talking about! For just an additional $25, you can get the seminar talks on CD-ROM. This CD allows you to see the speakers slides and listen to their talks, even if you weren’t there!
To order your copy, download order form and send with payment to the HGS:
Houston Geological Society (Subsidence) Fax (713) 463-9160
10575 Katy Freeway, Suite 290 http://www.hgs.org/
Houston, Texas 77024
Order information:
No. of copies Price Each Total Price
Proceedings (Abstracts) (print copy) $20.00
Field Trip Guidebook (print copy) $20.00
Recorded version of the Seminar on CD-ROM (2 disks) $25.00
Purchase all three of the above and save $10!Proceedings (Abstracts), Field Trip Guidebook, and Seminar on CD $55.00
Shipping and Handling $5.00 $5.00
The Debate Over Subsidence in Coastal Louisiana and Texas
Arthur E. Berman
On August 29, 2005, Hurricane Katrina devastated coastal areas of Louisiana and Mississippi. New Orleans may be lost. In that city, levees were breached and pumps failed. Eighty percent of the city is flooded with up to 20 feet of water this morning.
Bad policies by politicians and planners contributed to the city’s vulnerability. Geologists and coastal scientists have been arguing for decades, unable to agree on the causes or rates of subsidence. Officials and the public understandably felt justified in making no decisions or temporary decisions because experts could not reach agreement. The scientific community must now accept some responsibility for choosing debate and inaction over collaboration and consensus for the public good in Louisiana.
An editorial in the New York Times stated, “At the same time, there must also be an honest recognition of the fact that no amount of engineering - levees, sea walls, pumping systems, satellite tracking systems - can fully bring nature to heel” (New York Times, 2005).
Katrina will be called a natural disaster but subsidence is the root cause of the problem. An event like this was anticipated for decades by geologists and coastal experts because of ongoing subsidence in the northern coastal region of the Gulf of Mexico. If it had not been Katrina, it would have been some other hurricane; if it had not been this year, it would have been another, probably in our generation.
The latest chapter of the continuing debate over subsidence in coastal Louisiana and Texas was triggered by publication of NOAA TECHNICAL REPORT NOS/NGS 50 (Technical Report 50) a year ago. The report warned that subsidence rates in southern Louisiana were far greater than many workers believed and that swift height modernization was imperative.
Scientists are clearly divided into camps that support different views of the cause for subsidence. Some believe that ground water withdrawal is the principal cause for subsidence. Others blame oil and gas extraction and many blame the reclamation and restoration efforts of the Army Corps of Engineers. Technical Report 50 suggests that none of these causes fully account for subsidence rates in southern Louisiana and that natural, geological processes must be considered.
The great American geologist Thomas Crowder Chamberlin gave an address to the Society of Western Naturalists in 1889 about the unfortunate tendency of scientists to promote their ideas and theories often to the exclusion of an integrated and balanced perspective of all possibilities. There is, I believe, a tragic lesson in the debate over subsidence in the Gulf Coast of Louisiana and Texas that Chamberlin described precisely.
“Our desire,” he said, “to reach an interpretation or explanation commonly leads us to a tentative interpretation that is based on relatively hasty examination of a single example or case. Our tentative explanation, as such, is not a threat to objectivity, but if we then begin to trust it without further testing, we can be blinded to other possibilities that we ignored at first glance. Our premature explanation can become a tentative theory and then a ruling theory, and our research becomes focused on proving that ruling theory. The result is a blindness to evidence that disproves the ruling theory or supports an alternate explanation” (Chamberlin, 1890).
The silent disaster that Technical Report 50 co-author Roy Dokka has been describing found its voice this week in Hurricane Katrina.
Reaction To NOAA Technical Report NOS/NGS 50
In July 2004, NOAA TECHNICAL REPORT NOS/NGS 50 (Technical Report 50) was published by the National Oceanographic and Atmospheric Administration (NOAA)’s National Ocean Service (NOS) and National Geodetic Survey (NGS). The subtitle of the report aptly abstracts its content: rates of vertical displacement at benchmarks in the Lower Mississippi Valley and the Northern Gulf Coast. Technical Report 50 concludes that rates of subsidence in southern Louisiana are significantly higher than previously thought. The report’s authors, Kurt Shinkle, National Geodetic Survey, and Roy Dokka, Louisiana State University, estimate that southern Louisiana rates of subsidence are between 200 and 5000% greater than previous estimates. The mean subsidence rate for southern Louisiana, they say, is 11mm (0.43 inches) per year (Berman, 2005).
The report has ignited a debate of surprising intensity considering its conventional method of analysis and its geologically unremarkable inference that the Gulf of Mexico basin is subsiding at rates greater than can be explained by human efforts to extract fluids from the subsurface. Dr. Roy Dokka, the report’s second author, has been attacked both for the rates of subsidence cited in Technical Report 50 and for his belief that much of the subsidence is due to natural, geological causes.
“Subsidence is much more widespread and much faster than previously thought,” Dokka says. While the rates (in Technical Report 50) are specific to the past 100 years and may not reflect the current rate of subsidence, Dokka says, “you can’t extrapolate these rates without looking at the future,” and he “absolutely” thinks the rates are natural and will continue (Sever, 2005). Natural causes, according to Dokka, include tectonic and depositional processes such as crustal down-warping, sediment loading, compaction, salt movement and gravity slumping, as well as eustatic sea-level rise.
Bob Morton, a geologist at the USGS Center for Coastal and Watershed Studies (CCWS), is Dokka’s most vocal critic. Morton believes that most, if not all, of the subsidence and accompanying land loss in southern Louisiana is due to oil and gas production. In a recent interview with TexasMonthly, Morton stated that Dokka’s research was “scientifically questionable” and suggested that the LSU scientist may be more interested in grabbing headlines than in scholarly pursuit (Cartwright, 2005).
“Terms like sediment loading and gravity sliding made perfect sense millions of years ago but they don’t necessarily apply today,” Morton says. “What Dokka doesn’t tell you is that his data is recalculated from data that is at least ten years old. Maybe it applies today and for the next 100 years and maybe it doesn’t. Withdrawing fluids from the subsurface produces the same results as sediment loading---but it’s induced, not natural” (Cartwright, 2005).
Kristy Milliken, a gr
Book Review: The Man Who Found Time: James Hutton and the Discovery of the Earth’s Antiquity,
George O. Chandlee Source Environmental Sciences, Inc.
Repcheck, J., The Man Who Found Time: James Hutton and the Discovery of the Earth’s Antiquity, 247 pages, Perseus Publishing, $26.00.
Thoughtful observation and reconciliation of fact and belief is a fundamental process for geoscientists. These are actions imple- mented daily and are the source of new concepts and theories. These are recurring themes throughout the history of geological science. As Jack Repchek points out in his book The Man Who Found Time: James Hutton and the Discovery of the Earth’s Antiquity, such is the case for the 18th-century Scottish gentleman farmer and natural philosopher James Hutton. Hutton studied his land, tended to his farm, observed the subtle and slow changes in the land and developed a novel conclusion: changes in the earth, erosion, topographical changes and the like that he observed could not be attributed to one cataclysmic flood 6,000 years ago, as was taught by the Church. More likely, it appeared that the forces of volcanoes, earthquakes, wind and rain could have sufficed to produce the landscape. These are slow-acting forces, however. Therefore, the missing factor must be “deep and immense time”; time so deep that these forces would have ample opportunity to produce an observable impact. In 1788, Hutton formally presented proof that the earth was much older than the 6,000 or so years being taught by the Church. In fact, its age was incalculable and could conceivably be tens or hundreds of millions of years old.
Copernicus, Galileo and Darwin are frequently regarded as key figures in the emancipation of science from the binding dogma of religious orthodoxy. But James Hutton should be included among them as a pioneering observer. Biblical scholars had per- sistently “demonstrated” for centuries that the first day of Creation occurred in approximately 4000 BC. In fact, biblical chronology, as the discipline of precise biblical dating was called, was one of the most rigorous “sciences” of the pre-Renaissance era. Many recognized figures from church history, including the prophet Elijah, St. Augustine, St. Bede, St. Thomas Aquinas and even Martin Luther had commented on the age of the earth.
Hutton’s insight laid the foundations of modern geology and provided a necessary framework for the theory of evolution. In The Man Who Found Time, Repcheck argues that Hutton deserves recognition similar to Copernicus, Galileo and Darwin for helping to separate science from theology. In this book,Repchek touches on biblical chronology, the Scottish Prince “Bonnie Prince Charlie” and the Scottish Enlightenment. He paints a portrait of a gifted if enigmatic man who insisted on accepting the face value of his observations.
Hutton’s discovery was important at its time because no other scientist argued against the chronology set out by the Bible. In fact, scientists made their observations fit into the Bible’s time- line. In a way, Hutton’ s theory contradicted prevailing orthodoxy more than the theories of Copernicus, Galileo or Darwin: Copernicus made the sun, not the Earth, the center of the uni- verse; Galileo challenged ideas about the structure of the solar system; and Darwin shed light on the origins of man. Hutton’s research and claims neutralized the Biblical chronology of Earth’s history and completely changed our concept of the history of the planet. Hutton deduced that, in terms of man’s presence, the Earth practically has no beginning or end.
Very little information is available about Hutton’s personal life, but Repcheck does a first-class job of providing insights about his life and times. As background information, Repchek digresses in several directions. For example, Repcheck gives an excellent and fascinating history of biblical chronology and discusses in detail the Scottish Enlightenment in which Hutton participated. There is also an interesting account of Scottish history during Hutton’s lifetime and the period preceding it, including the rebellion led by Bonnie Prince Charlie.
Hutton was a contemporary of powerful and well-recognized members of the Scottish Enlightenment, such as David Hume, Adam Smith and James Watt. However, Hutton’s 1795 book, The Theory of the Earth, was so long, obscure and poorly written that it nearly fell into obscurity. Charles Lyell rescued and promoted Hutton’s ideas. James Hutton’s work set the stage for geologist Charles Lyell and the early geologists, who would use and verify Hutton’s ideas. Unfortunately, Hutton was soon forgotten in the annals of history, mainly because his only published major work was so academic and indecipherable that it was largely ignored.
The Man Who Found Time is full of interesting information, a significant portion of which is devoted to discussing the history of the Church and the Scottish Enlightenment, as well as details of Hutton’s life. This book will be of interest to geologists because it provides a perspective into the life of Hutton, the man known as the “father of deep time.” Repcheck does an excellent job in establishing and returning the credit due Hutton. Geoscientists will find the book engaging and full of information concerning the times and personality of Hutton.
November 2005 Houston Geological Society Bulletin 53
There is good geological evidence for past climate changes and good evidence that the currentwarming period is one of the natural changes not caused by ananthropogenic increase of a small amount of CO2 volume in theatmosphere. The percentage of change may be great, but theThis article will attempt to prove the paleo-geological relationship
with the ever-changing global climate and the futility ofattempting to change the climate by the removal of a smallamount of CO2 from the atmosphere.