Mechanisms for Forming Methane Hydrates in Petroleum Systems

Principal Investigator: Steven L. Bryant (in collaboration with Ruben Juanes, MIT)

In the long term, methane hydrates are an interesting potential resource. In the Arctic, hydrate accumulations with large saturations (more than 70% of pore space) are well documented, making the energy density (MCF per unit volume of rock) an order of magnitude greater than in tight gas sandstone or shale gas reservoirs. Similar accumulations exist in sands below sufficiently deep water. We have developed a sedimentological model of a process by which such accumulations may have formed below the permafrost in Arctic regions. Crucially, the model explains why good reservoir sands are often only partially filled with large saturations of hydrate, and why layers containing mostly water often occur between layers of containing hydrate.

(a) 10th percentile, F32, and 50th percentile, F72, of grain size versus depth in Mt. Elbert well. (b) Capillary entry pressure estimated from (a) and Eqs. (26)-(32) versus depth (dotted line) along with estimated initial gas saturation (red solid line) when BGHSZ was above the zone in which hydrate is currently observed. The initial gas saturation changes as BGHSZ moves down through the gas column and hydrate forms. (c) Gas saturation profile (red) when BGHSZ has moved downward through the gas column to a depth of 655m and the resulting hydrate saturation (green fill). Gas zones I and II are no longer communicating due to the capillary barrier at 664 m. (d) Final hydrate saturation profile (using Tx=2077) after BGHSZ has moved below the bottom of gas column. The log derived hydrate saturations (Lee and Collett, 2011) are shown as dots.

Publications and Presentations

  • Peng, Yao. "Study of Methane Hydrate Formation and Distribution in Arctic Regions: from Pore Scale to Field Scale," Ph.D., The University of Texas at Austin, 2011.
     
  • Behseresht, J. and Bryant, S. "Effect of Relative Permeability Characteristics and Gas/Water Flow on Gas-Hydrate Saturation Distribution," SPE 147221 prepared for presentation at the SPE Annual Technical Conference and Exhibition held in Denver, Colorado, USA, 30 October-2 November 2011.
     
  • Behseresht, J. and Bryant, S. "Sedimentological and Transport Control on Hydrate Saturation Distribution in Arctic Gas-Hydrate-Bearing Deposits," Proceedings of the 7th International Conference on Gas Hydrates (ICGH 2011), Edinburgh, Scotland, United Kingdom, July 17-21, 2011.
     
  • Behseresht, J., Peng, Y., Bryant, S. and Winters, W. "Sedimentological Control on Arctic Gas-Hydrate-Bearing Deposits," Gordon Research Conference on Natural Gas Hydrate Systems, Colby College, Waterville, ME, June 6-10, 2010.
     
  • Behseresht, J., Peng, Y., Bryant, S. and Winters, W. "Sedimentological Control on Arctic Gas-Hydrate-Bearing Deposits," AAPG 2010 Annual Convention and Exhibition, New Orleans, Louisiana, April 13, 2010.
     
  • Peng, Y., Behseresht, J., Bryant, S. and Winters, W. "Sedimentological Control on Arctic Gas-Hydrate-Bearing Deposits," poster GC51A-0707, American Geophysical Union Fall Meeting, San Francisco, 14-18 Dec. 2009.
     
  • Behseresht, J., Peng, Y., Prodanovic, M., Bryant, S., Jain, A., and Juanes, R. "Mechanisms by Which Methane Gas and Methane Hydrate Coexist In Ocean Sediments," OTC19332, Proceedings of the 2008 Offshore Technology Conference, Houston, Texas, U.S.A., 5-8 May 2008.

For additional info, please contact Steven L. Bryant (Steven_Bryant@mail.utexas.edu).