Arctic Gas Hydrate Production Testing Field Studies – A Review

Timothy Collett

In the last 10 years, a combination of field, laboratory, and modeling studies have led to significant advancements in our understanding of the gas hydrate reservoir systems in Arctic permafrost and marine environments. Two of the most studied permafrost-associated gas hydrate accumulations are those at the Mallik site in the Mackenzie River Delta of CA and the Eileen gas hydrate accumulation on the North Slope of Alaska. The Mallik gas hydrate production research site has been the focus of three geologic and engineering field programs (1998/2002/2007/2008 Mallik Gas Hydrate Testing Projects) and yielded the first fully integrated production test of a natural gas hydrate accumulation. The science program in support of the 2007 Mount Elbert gas hydrate test well project in northern Alaska generated one of the most comprehensive data sets on an Arctic gas hydrate accumulation along with critical gas hydrate reservoir engineering data. In 2011/2012, the Ignik Sikumi gas hydrate production test well program was conducted in northern Alaska to investigate a new production method in which carbon dioxide injected into a gas hydrate-bearing rock unit can release methane while sequestering carbon dioxide in hydrate form. Advancements in wireline logging and formation testing, along with full scale gas hydrate production testing associated with the Mallik, Mount Elbert, and Ignik Sikumi projects have yielded valuable insight into how gas hydrates are physically distributed in sediments and the occurrence and nature of pore fluids (i.e., free-water along with clay- and capillary-bound water) in gas-hydrate-bearing reservoirs. Information on the distribution of gas hydrate at the pore scale has provided invaluable insight on the mechanisms controlling the formation and occurrence of gas hydrate in nature along with data on gas hydrate reservoir properties (i.e., hydrate saturations, porosities, permeabilities, etc.) needed to accurately predict gas production rates for various gas-hydrate production schemes. The Mallik and Ignik Sikumi production test results have also provided invaluable insight to the design criteria for the next generation of extended gas hydrate production tests. These projects have also demonstrated the utility of conventional geophysical techniques to map gas hydrate reservoirs and enabled new resource estimates as well as consideration of strategies to realize field development.

AAPG Search and Discovery Article #90177©3P Arctic, Polar Petroleum Potential Conference & Exhibition, Stavanger, Norway, October 15-18, 2013