The purpose of this study is to establish sediment lithology and quantification of methane in hydrates hosted in fine-grained sediments from the Gulf of Mexico (GoM), a marine site of methane hydrate occurrence. The results will help establish a correlation between laboratory data and hydrate accumulation field data on dispersed hydrates in the natural environment.

Brookhaven National Laboratory (BNL), Upton, New York 11973

Gas hydrates are located in permafrost and marine environments and show potential as a vast methane source worldwide. However, methane is about 17 times more potent a greenhouse gas than CO2 and the inherent instability of hydrate deposits to temperature and pressure changes leading to uncontrolled methane release poses severe constraints on methane production methods under consideration. It is now documented from the accumulated well log data that hydrates show a wide variation in gas saturation, nature of accumulation, and heterogeneity of host sediments even within a specific hydrate site (Collect, 1998). A suite of new techniques and tools (Murray et al., 2006) such as the interval velocity method are being deployed to characterize and quantify gas hydrate concentrations in hydrate reservoirs (Dai et al., The Leading Edge, 2004). Marine hydrates constitute much larger deposits than those found in permafrost with accumulations that are several meters thick below the seafloor — though hydrate mounds are also found on the seafloor, likely formed through gas seepage.

The unconsolidated system is an excellent representation of hydrate mounds on the seafloor. Below the seafloor, the effect of overburden pressure is dominant as a function of depth and may affect methane saturation in a hydrate deposit. The accurate representation of such a natural system will be achieved via the application of overburden pressure on a sediment sample. The hydrate formation/dissociation kinetic data can yield hydrate-saturation-as-a- function-of-depth data, though there is paucity of kinetics data on natural sediments as hosts. Recently, studies were reported by Winters et al. (AAPG Hedberg Conference, 2004) and Kneafsey et al. (J. Pet. Sci. Eng., 2006) on hydrate formation in porous media, mostly with coarse sands as hosts.

The present focus is on laboratory-prepared consolidated cores of methane hydrates hosted in depleted fine sediments recovered from the Gulf of Mexico (GoM) under subsurface-mimic conditions. We plan to quantify macro- and micro-level changes in lithology that accompany formation/decomposition of methane hydrates hosted in fine-grained sediments. Collectively, the BNL data would allow development of a correlation between measured laboratory data and hydrate reservoir field data on highly dispersed hydrates hosted in very fine silt (<2 µm) in the Gulf of Mexico (GoM). These data have relevance to the climate change aspect of methane hydrates within the DOE-led multi-agency Methane Hydrate (MH) program.

The BNL integrated approach combines elements of fundamental science, unique apparatus, instruments, education, results dissemination, and collaborations to understand the inherent instability of methane hydrate in porous media and its impact on climate change.

Characterization and study of host sediments from known methane hydrate sites will add to the understanding of factors that are crucial to kinetic stability of methane hydrate in sediments—information needed for reservoir models. Differences or similarities in the decomposition of hydrate from sediment samples with different characteristics will be observed. These differences or similarities may ultimately have a bearing on field assessments of hydrate occurrences and their potential for uncontrolled methane release under perturbation and the consequent impact on climate change.

• As part of the Flexible Integration Study of Hydrate (FISH), a synthetic hydrate system was developed including Labview data collection, multiple test cells, precision on temperature controls, probes for spatially-resolved data acquisition, the capability to form both consolidated and unconsolidated hydrates, and the capability to form unconsolidated cores and membrane to eliminate hazardous hydrate formation.
• Three samples taken from varying depths (667 m, 50 m and 0.1 m) at the Blake Ridge Methane Hydrate Site were analyzed using computed microtomography (CMT) and x-ray diffraction (XRF) techniques to characterize depleted sediments.
• Computed microtomography images of hydrates formed from the THF/seawater in both Ottawa sand and glass beads have been completed and 2-D and 3-D images are being constructed.
• A comparison of static and dynamic modes of hydrate formation concluded that the static mode is more representative of seafloor conditions, and that the dynamic mode disrupts sediments.
• Completed methane hydrate formation/dissociation runs with varying system, sediment, and water conditions in both recovered depleted field sediment samples and various known sediment systems.
• Completed a sensitivity study of the effects of gas flow rate on hydrate formation in a laboratory system resulting in documented differences between laboratory and natural hydrate-sediment samples.
• Developed three specialized titanium (Ti), high-pressure, x-ray, CMT micro-cells (one fitted with a cooling jacket) as well as the required specialized CMT technique for use in imaging of hydrate formation/dissociation using the Beamline X-2B, the National Synchrotron Light Source (NSLS).
• Completed preliminary hydrate (both THF and methane hydrate) formation/dissociation studies with real-time CMT imaging to discern structural features of hydrates at the pore scale. Results indicated displacement of the sediment (glass beads in these experiments) by the pore filling nature of both the THF and methane hydrates.
• A manuscript describing the CMT of the THF-hydrate work was submitted in February 2008 to Applied Physics Letters and published in July 2009.
• The Discovery channel contacted the BNL Public Affairs to film the BNL hydrate work. The plan is to show the NSLS and the FISH unit. The filming was conducted in August 2009.

All work under this effort has been completed. Separate final reports for the FY08 FWP work plan, and the FY08 activities carried over into FY09 (June 08 - Dec 09) were prepared. The reports, summarizing the effort and results, can be found in the “Additional Information” section below.

$500,000

$0

NETL – Rick Baker (richard.baker@netl.doe.gov or 304-285-4714)
Brookhaven National Laboratory – Devinder Mahanjan (dmahajan@bnl.gov or 631-344-4985)

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].

FY09 Final Report [PDF-1.71MB] (June, 2008 - December, 2009)

FY08 Final Report [PDF-1.21MB]

2008 Hydrate Peer Review [PDF-5.00MB]

An article on this project is presented in the Fall 2005 edition of the hydrate newsletter,  "Fire in the Ice".

Pertinent Publications [Those marked with * are refereed] 
M. Eaton, P. Kerkar, D. Mahajan, K. Jones, and R. Kleinberg. Methane Hydrate Formation in the Laboratory using Fine Depleted Natural Sediments as Hosts. Session: Gas Hydrates and Clathrates, Division of Fuel Chemistry, 236th ACS National Meeting & Exposition, Philadelphia, Pennsylvania, USA. August 17-21, 2008 (for presentation).

D. Mahajan, P. Kerkar, K.W. Jones, R.L. Kleinberg, W.B. Lindquist, S. Tomov, and H. Feng. Natural Gas Hydrate Mimics: Understanding Hydrate Growth Phenomenon in Host Systems. International Geological Congress OSLO 2008. Session: Exploration and Assessment of Gas Hydrates (GAH-03), Oslo, Norway, August 6-14, 2008 (for presentation).

M. Eaton, K.W. Jones and D. Mahajan. Methane hydrate formation/decomposition in depleted sediments. Proc. Geol. Soc. (London), In press (2007)*.

L. Zheng, H. Zhang, M. Zhang, P. Kerkar, and D. Mahajan. Modeling methane hydrate formation in marine sediments. AAPG Bullet, In press (2007)*.

K. W. Jones, D. Mahajan, W. B. Lindquist, P. Kerkar, M. A. Celia, C. A. Peters, W. Um, M. Rockhold, and H. Feng. Application of Synchrotron Computed Microtomography and Micro X-ray Fluorescence to Energy/Environmental Problems. Application of Synchrotron Computed Microtomography and Micro X-ray Fluorescence to Energy/Environmental Problems. International Symposium Breaking Frontiers: Submicron Structures in Physics and Biology, Zakopane, Poland. 19 - 24 May 2008.

D. Sloan, P. Brewer, R. Charter, N. Dutta, A. Johnson, E. Jones, K. Juenger, M. Kastner, D. Mahajan, S. Masutani, R. Swenson, J. Whelan, S. Wilson, R. Woolsey. “Four Critical Needs to Change the Hydrate Energy Paradigm from Assessment to Production”. The 2007 Report to Congress by The U.S. Federal Methane Hydrate Advisory Committee. Offshore Technology Conference 2008 (OTC08), Houston, Tx. May 5-8, 2008. OTC Paper Number: OTC-19519-PP.

K.W. Jones, P.B. Kerkar, D. Mahajan, W.B. Lindquist, and H. Feng. Microstructure of natural hydrate host sediments. Nuclear Instruments and Methods in Physics Research, B. 261, 504-507 (2007)*.

D. Mahajan and P. Somasundaran, eds. Final Report, March 2007. International Workshop on Science & Technology Issues in Methane Hydrates R&D. Sponsored by Engineering Conference International (ECI)- Cosponsors: US DOE, MMS-DOI, ConocoPhillips. JIP-Chevron. Kauai, Hawaii, March 5-9, 2006.

D. Mahajan, C.E. Taylor and G.A. Mansoori. An Introduction to Natural Gas Hydrate/Clathrate: The Major Organic Carbon Reserve on Earth. J. Pet. Sci. & Eng., 56(1-3) 1-8 (2007)*.

M. Eaton, D. Mahajan, and R. Flood. A Novel High-Pressure Apparatus to Study Hydrate-Sediment Interactions. J. Pet. Sci. & Eng. 56(1-3) 101-7 (2007)*.

K.W. Jones, H. Feng, S. Tomov, W.J. Winters, M. Prodanovic and D. Mahajan. Characterization of Methane Hydrate Host Sediments Using Synchrotron Computed Microtomography (CMT). J. Pet. Sci. & Eng., 56(1-3) 136-45 (2007)*.

M. Eaton, P. Kerkar, K. Jones, H. Feng, W. Winters, D. Mahajan. Mimicking Marine-based Natural Systems: A Study of Sediment-Hydrate Interactions Under In Situ Conditions. Inter-laboratory Hydrate Workshop, Colorado School of Mines, Golden, CO, September 19-20, 2006.

M. W. Eaton and D. Mahajan. Methane Hydrate Kinetics in Depleted Host Sediments using the FISH unit. Science & Technology Issues in Methane Hydrates R&D International Workshop, Kauai, Hawaii, March 5-9, 2006.

Prasad Kerkar, Keith Jones, Huan Feng, and Devinder Mahajan. Spectroscopic Characterization of Host Sediments. Science & Technology Issues in Methane Hydrates R&D International Workshop, Kauai, Hawaii, March 5-9, 2006.

P. Servio, M. Eaton, D. Mahajan, and W.J. Winters. Fundamental Challenges to Methane Recovery from Gas Hydrates. Topics In Catal. 32(3-4) 101-08 (2005)*.

M. Eaton, D. Mahajan, R. Flood, T. Koga, and M. Rafailovich. Hydrate-Sediment Interactions in Novel High- Pressure Apparatus. Symposium on Symposium on Gas Hydrates and Clathrates. Co-sponsored by the ACS Petroleum Chemistry and Fuel Divisions. 229th ACS National Meeting, San Diego, CA. March 13-17, 2005.

K.W. Jones, H. Feng, S. Tomov, W. J. Winters, Michael Eaton, and D. Mahajan. Morphology of methane hydrate host sediments. Symposium on Symposium on Gas Hydrates and Clathrates. Co-sponsored by the ACS Petroleum Chemistry and Fuel Divisions. 229th ACS National Meeting, San Diego, CA. March 13-17, 2005.

D. Mahajan, P. Servio, K.W. Jones, H. Feng, W.J. Winters. Methane hydrate studies: Delineating properties of host sediments to establish reproducible kinetics, Chapter 16 in Advances In the Studies of Gas Hydrates, C.E. Taylor and J.T. Kwan, eds., Kluwer Academic Publishers, Inc., New York, New York, pp. 239-50 (2005)*.

D. Mahajan, T.F. Kotzle, W.T. Klooster, L. Brammer, R.K. McMullan, and A. N. Goland. Crystal Growth, Structure Characterization, and Schemes for Economical Transport: An Integrated Approach to the Study of Natural Gas Hydrates. Ann. N.Y. Acad. Sci. 912 940 (2000)*.

D. Mahajan. “Technical Challenges to Mining Methane Hydrates: The next Energy Frontier”. Marine Sciences and Atmospheric Sciences Colloquium Series, Stony Brook University, New York. February 6, 2004.

D. Mahajan, K. W. Jones, H. Feng, and W. J. Winters. Methane Hydrate Studies: Delineating Properties of Sediments Using Synchrotron Computed Microtomography (CMT). Presented at the Symposium on Gas Hydrates, 2003 AICHE Spring National Meeting, New Orleans, LA March 30- April 3, 2003. Abstract # 78a.

P. Servio and D. Mahajan. Kinetic Reproducibility of Methane Production from Methane Hydrates. Symposium on Synthetic Clean Fuels from Natural Gas and Coal-bed Methane: 30 Years Since First Oil Crisis (Co-sponsored by the ACS Fuel and Petroleum Chemistry Divisions), 226th ACS National Meeting, New York, NY. September 7-11, 2003.

D. Mahajan, T. F. Koetzle, L. Brammer, W. T. Klooster, R. L. McGraw, R. K. McMullan, and G. Senum. Structure Characterization and Sono-Stimulated Kinetic Study with Tracers in Pressure Vessels: An Integrated Approach to the Study of Gas Hydrates. Symposium on the Fundamentals of Advanced Materials for Energy Conversion, Session on Gas Clathrate Hydrates. 2002 TMS Annual Meeting, Seattle, WA, February 17-21, 2002.

Relevant Awards and Other Professional Accomplishment 
2008 - C.E. Taylor and D. Mahajan, Co-Organizers. Session on Gas Hydrates and Clathrates, Division of Fuel Chemistry, 236th ACS National Meeting & Exposition, Philadelphia, Pennsylvania, USA. August 17-21, 2008.

2008 - Editorial Board Member, The Open Petroleum Journal, BENTHAM Science Publishers, Ltd.

2007 - Outstanding Mentor Award, Office of Science, United States Department of Energy

2007 - Editorial Board Member, International Journal of Oil, Gas and Coal Technology.

2007 - J. Petroleum Science & Engineering. Special volume: “Gas Hydrates and Clathrates” 56(1-3), D. Mahajan and C.E. Taylor, eds.

2006 - Member, Technical Steering Committee, Inter-Laboratory Hydrate Workshop, Colorado School of Mines, Golden, CO, September 19-20

2006 - D. Mahajan and P. Somasundaran, Organizers. International Workshop on Science & Technology Issues in Methane Hydrates R&D. Sponsored by Engineering Conference International (ECI)- Cosponsors: US DOE, MMS-DOI, ConocoPhillips. JIP-Chevron. Kauai, Hawaii, March 5-9.

2005 - Session Organizer. Symposium on Gas Hydrates and Clathrates. Co-sponsored by the ACS Petroleum Chemistry and Fuel Divisions. 229th ACS National Meeting, San Diego, CA. March 13-17