|Conducting Scientific Studies of Natural Gas Hydrates to Support the DOE Efforts to Evaluate and Understand Methane Hydrates||Last Reviewed 05/16/2011|
The United States Geological Survey (USGS) conducts scientific studies of natural gas hydrates in support of DOE efforts to evaluate and understand methane hydrates, their potential as an energy resource, and the hazard they may pose to ongoing drilling efforts. This project extends USGS support to the DOE Methane Hydrate Research Program previously supported under DE-AT26-97FT34342 and DE-AT26-97FT34343.
U.S. Geological Survey at Denver, CO, Woods Hole, MA, and Menlo Park, CA.
The USGS Interagency Agreement (IA) involves laboratory research and international field studies in which DOE/NETL has a significant interest. Geological and geophysical support for these efforts is critical to their success, and the USGS is uniquely qualified to provide this support. The IA was divided into the following four separate tasks:
USGS research on arctic hydrates supported U.S. DOE research being conducted with BP Exploration Alaska (BPXA) and others on resource characterization of the Prudhoe Bay/Kuparuk River region of the Alaska North Slope. Task 1 utilized geologic, geochemical, and geophysical (2-D and 3-D seismic surveys) data from northern Alaska together with other new data sources, including wireline and mud log surveys of wells of opportunity, to assess the occurrence and distribution of known gas hydrate accumulations on the North Slope of Alaska.
USGS research on marine hydrates was coordinated with the U.S. DOE Gulf of Mexico (GoM) Methane Hydrate Joint Industry Project (JIP). Task 2 utilized geologic, geochemical, seismic, electrical, geothermal, and bottom photography data to understand the occurrence, and potential hazard to drilling, of subsurface gas hydrates in the northern GoM and to disseminate this knowledge on a regional scale. Laboratory studies complemented field studies by making measurements in controlled environments. Laboratory studies included complete analysis of the JIP core samples and investigation of techniques to create hydrate from dissolved methane.
Task 3 supported research at the USGS Gas Hydrate Petrophysics Laboratory in Menlo Park, California, and at Woods Hole, Massachusetts using the Gas Hydrate and Sediment Testing Laboratory Instrument (GHASTLI). The physical states of hydrates in marine sediments are important in assessing the effects of hydrates on sediment properties, such as sediment thermal and mechanical stability. Computed x-ray tomography (CT) has proven to be a powerful tool for investigating the distribution of gas hydrates in sediment cores down to the grain and pore scale. Scanning electron microscopy (SEM), powder x-ray diffraction (XRD), and neutron scattering (NS) are three other techniques used for investigating the gas hydrate distribution, grain and pore texture, and also the hydrate mineralogy (sI, sII and/or sH). The Task 3 sample characterization effort utilized these techniques, and others, to complement on-board and post-drilling studies.
Task 4, added in fiscal year 2006, supported the cooperative projects between the U.S. and international partners. In collaboration with the Directorate General of Hydrocarbons (DGH) of India, the USGS helped to develop more accurate assessments of Indian marine gas hydrates for potential future production tests. A major drilling program, conducted during the summer of 2006, gathered data that will be used to assess the energy resource potential of gas hydrates offshore of India. This task provided the necessary equipment and expertise for geotechnical and geochemical studies for the drilling program.
The technical depth of USGS scientists and engineers brings an additional important dimension to the research activities of the DOE Methane Hydrate R&D Program. In the Arctic, decades of geological and geophysical investigation were brought to bear to help understand the full extent of the hydrate resource. These efforts, in collaboration with DOE and industry partners such as BP Exploration Alaska (BPXA), made important contributions to our understanding of how arctic hydrates may someday be developed as a source of natural gas.
USGS research on marine hydrates made important advances in our understanding of the occurrence, and potential hazard to drilling, of subsurface gas hydrates in the northern GoM. This information provided industry with better tools and data as oil and gas development moves into areas where gas hydrates could present potential hazards. As we gain a better understanding of the nature and distribution of marine gas hydrates, USGS and DOE scientists and engineers, along with industry, will someday work together to develop this valuable resource.
USGS laboratory scientists investigating the physical states of hydrates in arctic and marine settings have played a vital role in assessing the effects of hydrates on sediment properties, such as sediment thermal and mechanical stability, and ultimately in developing cost-effective production methods.
USGS support for multinational cooperative projects added to the comprehensive knowledge base of the geologic occurrence of gas hydrates along continental margins and in the assessment of the energy resource potential of gas hydrates globally.
Task 1 ? Characterization and Assessment of Natural Gas Hydrates in Permafrost Environments
This task addressed the critical issues associated with potential production of gas hydrates (and associated free gas) in the Prudhoe-Kuparuk area of the Alaska North Slope. The primary focus was to assess the geophysical characteristics of in situ natural gas hydrates and to support U.S. DOE-funded extended gas hydrate production tests of the Eileen and Tarn gas-hydrate/free-gas accumulations.
USGS worked directly with BPXA and their contractors to design and implement the North Slope of Alaska Mt. Elbert 1 Gas Hydrate Test Well, which was spudded on February 3, 2007.
The USGS coordinated the efforts of BPXA and the U.S. DOE at Milne Point, Alaska, and participated in wellsite wireline coring, well logging, and sampling/pressure testing using a modular formation dynamics tester (MDT) during the 22-day drilling program. The project cored to a depth of 760 meters, logged to a depth of 914 meters, and tested for gas hydrate response at four depth intervals using MDT. From the coring program, there was 85% recovery, with approximately 250 samples selected for laboratory analyses and 11 gas-hydrate samples preserved in either liquid nitrogen or pressure vessels for analysis.
The major scientific achievement at this site is that two high-saturation gas hydrate-bearing intervals were identified, as predicted from pre-drilling geological and geophysical analysis using prospecting methods developed by the USGS. The two units were an upper 14-m thick gas hydrate-bearing reservoir of sandstone (unit ?D?) and a lower 16 m thick unit, also a reservoir. Both units had gas hydrate saturations of 60?75%. Two technological firsts were also achieved: (1) conducting wireline retrievable coring in the relatively unconsolidated sub-permafrost sediments in the North Slope and (2) conducting open-hole MDT testing within gas hydrate-bearing intervals. For more information see the BP Exploration Alaska project, ?Alaska North Slope Gas Hydrate Reservoir Characterization" (DE-FC26-01NT41332).
The wireline logging produced an outstanding dataset of permafrost and gas hydrate properties. The open-hole MDT testing also produced an outstanding dataset of gas hydrate response during testing. Research is now being conducted to analyze the physical formation properties of the Mt. Elbert samples and to compare the detailed drilling results with pre-drilling models so that the models can be refined and improved. A Mt. Elbert data set was also developed as a case study to be utilized in the DOE-funded ?International Effort to Compare Methane Hydrate Reservoir Simulators?.
Using calibration data from the Mt. Elbert gas hydrate stratigraphic test well, the USGS has reprocessed and inverted 3-D seismic data to further refine the limits of the Milne Point Units C and D gas hydrate occurrences. This effort has resulted in the generation of an updated time-depth model, a structural map, a hydrate saturation map, and hydrate reservoir thickness maps for Mt. Elbert prospect. The USGS continues to participate in project meetings focused on detailed planning for the future Alaska North Slope long-term gas hydrate production testing program under a new IA, DE-FE0002911. USGS efforts also included developing and editing papers prepared for the North Slope of Alaska Mount Elbert Gas Hydrate Stratigraphic Test Well Scientific Results Volume, to be published as a special edition of Marine and Petroleum Geology. USGS scientists made a major commitment to this special volume by authoring and/or coauthoring over half of the 25 papers included in this publication.
USGS scientists provided technical and scientific support for the ConocoPhillips (CP) project by contributing to the development of the coring and logging research plan for the upcoming ?CO2 gas hydrate production test well.? The USGS contributions included providing required geologic data from our historical work in northern Alaska, and providing expert knowledge on well logging, conventional coring, pressure coring, seismic characterization, sediment physical properties, organic geochemistry, and process modeling.
With the Bureau of Land Management, the USGS processed and analyzed 3-D seismic grids and related 2-D seismic and well data from the National Petroleum Reserve-Alaska (NPRA) in order to identify gas hydrate prospects. This research focused on gathering existing geologic and geophysical data to construct a new gas hydrate stability map for the eastern portion of the NPRA. The research resulted in a new North Slope Alaska gas stability field map as interpreted from the USGS ?Borehole Temperature Logs from Arctic Alaska". These data have been released on the following web site, http://esp.cr.usgs.gov/data/bht/alaska/ [external site].
In a related effort, in collaboration with the Bureau of Land Management, the USGS completed the first assessment of undiscovered technically recoverable gas hydrate resources beneath the North Slope of Alaska. For the Northern Alaska Gas Hydrate Total Petroleum System, the USGS estimated that the total undiscovered natural gas resources in gas hydrate are about 85 trillion cubic feet (TCF). More information can be found at http://pubs.usgs.gov/fs/2008/3073/ [external site].
Task 2 ? Subsurface Gas Hydrate Occurrence in the Gulf of Mexico
The primary focus of this task was on archiving and interpreting geological and geophysical data from the 2005 and 2009 Chevron JIP drilling expeditions. Logging and drilling results provide the opportunity to correlate the occurrence of gas hydrate with seismic signature and then extrapolate hydrate distribution around the site-survey seismic grid. In addition, the drilling results provided lithologic, thermal, chemical, and other geological information essential for interpreting the depositional environment, age, and other factors that influence hydrate formation. The USGS completed the special issue of Marine and Petroleum Geology which details the scientific results of the 2005 DOE-Chevron JIP Gulf of Mexico Drilling Program. The volume of 16 peer-reviewed papers was published in November 2008.
The USGS led an effort to review and assess drilling targets for the 2009 JIP logging-while-drilling (LWD) expedition. During the summer of 2007, five meetings were held to review the data and to discuss recommendations for optimal target sites. The group considered eight sites throughout the northern Gulf of Mexico and eliminated four of them from further consideration, including one of the sites originally designated as a potential priority gas hydrates site (AC857). For more information and analysis on these sites see Fire in the Ice Winter 2009 and ICGH 2008 Site Selection for DOE/JIP Gas Hydrate Drilling in the Northern Gulf of Mexico under "Additional Information" below.
In late April and early May 2009, the USGS participated in the JIP Leg II drilling and logging expedition, providing scientific leadership to this successful research effort. The most important operational and technical accomplishments of this drilling expedition included:
The objective of the 21-day expedition was to confirm the hypothesis that gas hydrates can occur at high saturations within reservoir quality sands in the Gulf of Mexico. This objective was fully met, with highly-saturated gas hydrate-bearing sands discovered in at least two of the three sites drilled. The presence of significant gas hydrate accumulations in both pore-filling mode in sands and as fracture-filling material in shallow muds, should make both Walker Ridge and Green Canyon prime locations for future research into the energy potential of gas hydrates in marine environments. USGS scientists are involved in coordinating and contributing to the reporting of the GoM JIP Leg II drilling results including the Initial Results Report (IR) and Downhole LWD Data Report. The USGS is also involved in the planning of the JIP Leg III expedition which will involve additional logging and testing of new pressure core and core transfer tools, as well as limited coring activity.
Task 3 ? Laboratory Investigations of Gas Hydrates
As part of this task, the USGS used knowledge gained from the drilling expeditions to better plan and conduct laboratory experiments that reproduce the physical property and hydrate formation results obtained through drilling. Initial flow tests using the Gas Hydrate and Sediment Testing Laboratory Instrument (GHASTLI) to investigate hydrate formation from dissolved-phase methane were conducted throughout 2006 and 2007. Findings showed that for low saturation levels, both the acoustic and shear failure responses of the sample mimicked results from water-saturated sand samples in which no methane or hydrate was present. These findings were in agreement with studies from Georgia Tech suggesting pore-space hydrate saturations must exceed about 40% before significant physical property changes occur in the sample.
The GHASTLI was also used to study acoustic and shear strength properties on sediment recovered during the 2005 Gulf of Mexico JIP field program. This sample was unique because it was the first pressure core transferred into a Parr vessel and sealed with a new ball-valve system that preserved the initial pressure during shipment to Woods Hole. Hence, the sample was depressurized only once, immediately before the transfer into GHASTLI. This sample provided an important benchmark for GHASTLI regarding handling and transferring samples that have never been depressurized. Lessons learned were applied to the transfer of pressure samples collected during the Indian National Gas Hydrate Program (NGHP) Expedition 01 drilling.
Based on lessons learned from the Gulf of Mexico JIP test, three existing ball-valve samples from the 2006 Indian NGHP Expedition 01 program were successfully transferred into GHASTLI. These tests provided an opportunity to understand the effects of dissociation on physical properties and to compare the properties measured with previous samples using GHASTLI. Results were incorporated into an abstract submitted for the February 2008 Indian NGHP Expedition 01 Symposium in New Delhi.
In addition to the GHASTLI, the USGS Gas Hydrates Petrophysics Laboratory developed an apparatus to prepare hydrate samples from saturated sand packs in a more uniform manner than has been previously possible. The new apparatus allows slow rotation of samples during the reaction process to avoid water pooling, thus allowing investigation of the effects of higher levels of hydrate saturation in pore space. Waterflood hydrate formation studies were completed using this apparatus to test the viability of forming methane hydrate in sediment from free gas, then displacing the gas with water to initiate subsequent hydrate growth in the absence of free gas. A comparison between a dissolved-phase methane hydrate formation test and formation using a waterflooded, methane-charged, hydrate-bearing sand was presented at the American Geophysical Union conference in December 2009.
A proper understanding of the physical properties of gas-hydrate bearing sediment requires input of researchers from diverse disciplines, including geomechanics, geochemistry, and geophysics. To provide this multi-disciplinary field with a review of the most relevant physical properties of hydrate-bearing sediments, the USGS led an intensive three day workshop in Atlanta, Georgia, March 16?19, 2008. The workshop drafted a comprehensive summary of the current state of electrical, mechanical, thermal, and fluid flow properties of hydrate-bearing sediments, and will be used to guide future research in these areas of study.
Task 4 ? International Gas Hydrate Collaboration
This task facilitated USGS field participation and some post-cruise geochemical and geotechnical analysis of samples recovered during drilling from May to August 2006 along the Indian continental margins. USGS scientists supported the drilling operations for the 3-leg cruise by coordinating the outfitting of the ship, staffing scientific specialists, providing operational logistics, and in making decisions about prioritizing drill sites. While the bulk of the USGS support occurred at sea where more than 20 research wells were drilled, the effort also included post-cruise analysis of pressure cores as well as distribution of pressure cores to other laboratories for future analysis, and completing the Initial Results volume for the 2006 India Gas Hydrates Drilling Program. The final volume includes sections on methods, operational summaries, chapters on each of the 21 sites, together with extensive appendices with data summaries and downhole log data. In addition, the USGS helped to organize the post-drilling science results symposium held in New Delhi, India, February 6?10, 2008. At the symposium, interpretations of the drilling data were shared by all participants and plans were finalized for chapters to be included in the science results volume. This meeting included all cruise participants plus representatives of the major gas hydrate drilling projects from around the world.
The USGS continues to be an active participant in activities to establish international partnerships and collaborations. Recent efforts have focused on developing operational and research plans for the next Indian gas hydrate drilling expedition being proposed for either 2010 or most likely early 2011. DGH and the USGS are building several working groups, including ?technical? and ?operational? teams that will be responsible for the design of the next drilling expedition. The USGS has completed its review of the NGHP Expedition 01 Report which will be published as a USGS Scientific Investigations Report.
The USGS continues to support efforts to build future working relationships with Korea and Taiwan. In addition, collaborative research with Canada continues, including, for example, analysis of biomarker results obtained on IODP Expedition 311 samples, and on-board and post-cruise geochemistry analyses from the August 2008 Cascadia Margin expedition (see Fire in the Ice Fall 2008).
This USGS/DOE Interagency Agreement was completed on June 30, 2010. Project status is now being reported under Interagency Agreement DE-FE0002911.
Project Start: April 11, 2005
Project End: May 31, 2010
DOE Contribution: $2,144,332
Performer Contribution: na
NETL ? Robert Vagnetti (email@example.com or 304-285-1334)
USGS ? Carolyn Ruppel (firstname.lastname@example.org or 508-457-2339)
In addition to the information provided here, a full listing of project related publications and presentations as well as a listing of funded students can be found in the Methane Hydrate Program Bibliography [PDF].
USGS Hydrate From Ice (HyFI) Test System [external site - USGS]
Mount Elbert Science Team, 2007, Alaska North Slope well successfully cores, logs, and tests gas-hydrate-bearing reservoirs: Fire in the Ice, DOE/NETL Newsletter, Winter, 2007, p. 1-4
Press Release: Petroleum News, February 25, 2007, North Slope gas hydrate well hits target ? BP-operated Mount Elbert well confirms presence of gas hydrate accumulation and enables coring and testing of gas hydrate zone, by Alan Bailey, http://www.petroleumnews.com/pntruncate/608307478.shtml.
2008 ICGH Paper - Seeding Hydrate Formation in Water-Saturated Sand with Dissolved-Phase Methane Obtained from Hydrate Dissolution: a Progress Report [PDF] - August, 2008
2008 ICGH Paper - Geologic and Engineering Controls on the Production of Permafrost-Associated Gas Hydrate Accumulations [PDF] - August, 2008
2008 ICGH Paper - Indian Continental Margin Gas Hydrate Prospects: Results of the Indian National Gas Hydrate Program (NGHP) Expedition 01 [PDF] - August, 2008
2008 ICGH Paper - Physical Properties of Repressurized Samples Recovered During the 2006 National Gas Hydrate Program Expedition Offshore India [PDF] - August, 2008
2008 ICGH Paper - Seismic Mapping of Gas Hydrate Deposits in the Krishna-Godhavari Basin Offshore India [PDF] - August, 2008
2008 ICGH Paper - Site Selection for DOE/JIP Gas Hydrates Drilling in the Northern Gulf of Mexico [PDF] - August, 2008
2008 ICGH Paper - Investigation of Gas Hydrate-Bearing Sandstone Reservoirs at the "Mount Elbert" Stratigraphic Test Well, Milne Point, Alaska [PDF]- August, 2008
2008 Hydrate Peer Review [PDF-6.16MB] - "Physical properties of hydrate-bearing and baseline sediment: laboratory and field studies"
The publications listed below are from 2008 and after. For a complete listing of publications and presentations related to this project access the Methane Hydrates Bibliography .
Collett, T.S., Agena, W.F., Lee, M.W., Zyrianova, M.V., Bird, K.J., Charpentier, R.R., Cook, T., Houseknecht, D.W., Klett, T.R., Pollastro, R.M., and Schenk, C.J., 2008, Assessment of gas hydrate resources on the North Slope, Alaska, 2008: U.S. Geological Survey Fact Sheet 2008?3073, 4 p.
Ellis, M., R. Evans, D. Hutchinson, P. Hart, J. Gardner, R. Hagen, 2008, Electromagnetic surveying of seafloor mounds in the Gulf of Mexico, Mar. Petr. Geology, vol. 25, 960-968 (doi:10.1016/j.marpetgeo.2007.12.006).
Hart, P., D.R. Hutchinson, J. Gardner, R.S. Carney, and D. Fornari, 2008, A photographic and acoustic transect across two deep-water seafloor mounds, Mar. Petr. Geology, vol. 25,969-976 (doi:10.1016/j.marpetgeo.2008.01.020).
Hutchinson, D.R., P.E. Hart, T.S. Collett, K.M. Edwards, D.C. Twichell, and F. Snyder, 2008, Geologic framework of the Keathley Canyon Gas Hydrate Research Well, Northern Gulf of Mexico, Mar. Petr. Geology, vol. 25, 906-918 (doi:10.1016/j.marpetgeo.2008.01.012).
Lee, M., Collett, T., 2008, Integrated analysis of well logs and seismic data to estimate gas hydrate concentrations at Keathley Canyon, northern Gulf of Mexico, Mar. Petr. Geology, vol. 25, 924-931. (doi:10.1016/j.marpetgeo.2007.09.002).
Lee, J.Y., J.C. Santamarina, and C. Ruppel, 2008, Mechanical and electromagnetic properties of northern Gulf of Mexico sediments with and without THF hydrates, Mar. Petr. Geology, vol. 25 (doi:10.1016/j.marpetgeo.2008.01.019).
Lorenson, T., G. Claypool, and J. Dougherty, 2008, Natural gas geochemistry of sediments drilled on the 2005 Gulf of Mexico JIP cruise, Mar. Petr. Geology, vol. 25, 873-883. (doi:10.1016/j.marpetgeo.2008.01.017).
Pohlman, J.W., C. Ruppel, D. Hutchinson, R.Z. Downer, R.B. Coffin, 2008, Assessing sulfate reduction and methane cycling in a high salinity pore water system in the Northern Gulf of Mexico, Mar. Petr. Geology, vol. 25, 942-951. (doi:10.1016/j.marpetgeo.2008.01.016).
Ruppel, C., Boswell, R., and E. Jones, 2008, Scientific results from Gulf of Mexico gas hydrates joint industry project Leg 1 drilling: Introduction and overview, Mar. Petr. Geology, vol. 25, 819-829 (doi:10.1016/j.marpetgeo.2008.02.007)
Winters, W.J., B. Dugan, and T. Collett, Physical properties of sediments from Keathley Canyon and Atwater Valley, JIP Gulf of Mexico Gas Hydrate Drilling Program, Mar. Petr. Geology, vol. 25, 896-905, (doi:10.1016/j.marpetgeo.2008.01.018)
Wood, W.T., P.E. Hart, D.R. Hutchinson, N. Dutta, F. Snyder, R.B. Coffin, and J.F. Gettrust, 2008, Gas and gas hydrate distribution around seafloor seeps in Mississippi Canyon, Northern Gulf of Mexico, using multi-resolution seismic imagery, Mar. Petr. Geology, vol. 25, 952-959 (doi:10.1016/j.marpetgeo.2008.01.015)
Presentations and/or Abstracts
Collett, T.S., 2008, Assessment of gas hydrate energy resources: December 2, 2008, MIT (Cambridge, MA). Presentation in the MIT/USGS ENI Methane Hydrate Seminar Series.
Collett, T.S., Agena, W.F., Lee, M.W., Zyrianova, M.V., Bird, K.J., Charpentier, R.R., Cook, T., Houseknecht, D.W., Klett, T.R., Pollastro, R.M., and Schenk, C.J., 2008, Assessment of gas hydrate resources on the North Slope, Alaska, 2008: Series of Power Point Presentations prepared for Department of Interior and Congressional briefings presented in Washington DC, November 17-21, 2008, (hard copy and on CD-ROM).
Collett, T.S., Agena, W.F., Lee, M.W., Zyrianova, M.V., Bird, K.J., Charpentier, R.R., Cook, T., Houseknecht, D.W., Klett, T.R., Pollastro, R.M., and Schenk, C.J., 2008, Assessment of gas hydrate resources on the North Slope, Alaska: Fall Meeting of the American Geophysical Union, December 15-19, 2008, San Francisco, California, Proceedings, Abstract OS43F-08.
Collett, T.S., Dallimore, S.R., and Paull, C., 2008, Fate of methane released on the Arctic Shelf from thawing permafrost and decomposing gas hydrate: Proceedings of the IODP Arctic Ocean History Workshop, from speculation to reality, November 3-5, 2008, Bremerhaven, Germany, 2 p., (abstract, presentation).
Collett, T.S., et al., 2008, U.S. Geological Survey gas hydrate energy resource studies: Proceedings of the NRC Committee reviewing the activities authorized under the Methane Hydrate research Development Act (renewal) of 2005, 38 p. (presentation only)
Haacke, R., M. Riedel, J. Pohlman_, K. Rose, L. Lapham, T.S. Hamilton, R. Enkin, G.D. Spence, and R.D. Hyndman, 2008, A recent investigation of gas hydrate as a factor in northern Cascadia accretionary margin frontal ridge slope failures and cold seep biogeochemistry. American Geophysical Union, Dec 15-19, San Francisco, CA.
Heuer, V.B., Lorenson, T., Pohlman, J.W., Lever, M.A., Yoshinaga, M., Elvert, M., Hinrichs, K., 2009, The stable carbon isotope biogeochemistry of acetate in sediments from the NE Pacific: a synthesis. International Meeting on Organic Geochemistry, Sept 9-13, Bremen, Germany.
Heuer, V.B., Pohlman, J.W., Torres, M.E., Lever, M.A., Elvert, M., Hinrichs, K.-U., 2009, The stable carbon isotope biogeochemistry of acetate in sediments from the NE Pacific: a synthesis. IODP-ICDP-Kolloquium, March 19-21, Potsdam Germany.
Pohlman, J.W., Elvert, M., Rossel, P., Hinrichs, K., 2009, Distribution of polar and apolar lipids within biogeochemical regimes of a gas hydrate-bearing hydrocarbon cold seep. International Meeting on Organic Geochemistry, Sept 9-13, Bremen, Germany
Riedel, M., Yu, P., Collett, T., Lorenson, T., Paull, C., Collett, T., and Dallimore, S., 2008, Methane seepage from the Arctic Shelf; 20 Years of research on the Beaufort Sea Margin: Fall Meeting of the American Geophysical Union, December 15-19, 2008, San Francisco, California, Proceedings, Abstract U23D-0086.
Pohlman, J.W., M. Riedel, W. Waite, K. Rose, L. Lapham, T.S. Hamilton, R. Enkin, G.D. Spence, R.D. Hyndman and R. Haacke, 2008, Geochemical Investigation of Slope Failure on the Northern Cascadia Margin Frontal Ridge. American Geophysical Union, Dec 15-19, San Francisco, CA.
Ruppel, C., 2008, ?Methane Hydrates and Methane Seeps: The Potential of Biogeophysical Measurements for Identifying Microbial Hotspots?, AGU Chapman Conference on Biogeophysics, Portland, ME, October 2008.
Ruppel, C., 2008, ?Before Production?.The Challenges of Finding and Evaluating Gas Hydrates,? October, 2008, MIT (Cambridge, MA). Presentation in the MIT/USGS ENI Methane Hydrate Seminar Series.
Ruppel, C., 2008, Arctic Ocean Drilling to Study the Impact of Climate Change on Shallow Shelf Methane Hydrates, Arctic Ocean History Drilling Workshop, Bremerhaven, November, 2008.
Ruppel, C., (Invited) 2008, Multiscale heterogeneity in methane flux regimes between and within major marine gas hydrate provinces, EOS Trans. AGU, 89(53), Fall Mtg Supplement, Abstract OS31D-02.
Ruppel., C., Walter, K., Pohlman, J., and M. Wooller, Gas Hydrates and Perturbed Permafrost: Can Thermokarst Lakes Leak Hydrate-Derived Methane?, EOS Trans. AGU, 89(53), Fall Mtg Supplement, Abstract U23D-0084.
Wooller, M.J., Leigh, M., _Pohlman J.W., Ruppel C. and Walter, K., 2009, Source characterization and temporal variation of methane seepage from thermokarst lakes on the Alaska North Slope in response to Arctic climate change. Developing Long Term International Collaboration on Methane Hydrate Research and Monitoring in the Arctic Region, February 18-20, Texel, The Netherlands.