Proceedings of the 8th International Conference on Gas Hydrates (ICGH8-2014), Beijing, China, 28 July - 1 August, 2014 REVIEW OF THE FINDINGS OF THE IĠNIK SIKUMI CO2-CH4 GAS HYDRATE EXCHANGE FIELD TRIAL Brian ANDERSON∗ Department of Chemical Engineering, West Virginia University and National Energy Technology Laboratory, Morgantown WV 26507, USA Ray BOSWELL National Energy Technology Laboratory, Pittsburgh PA 15236, USA Timothy S. COLLETT U.S. Geological Survey, Denver CO 80225, USA Helen FARRELL ConocoPhillips, Houston TX 77252, USA Satoshi OHTSUKI Japan Oil, Gas and Metals National Corporation, Chiba JAPAN Mark WHITE Pacific Northwest National Laboratory, Richland WA, 99352, USA Margarita ZYRIANOVA U.S. Geological Survey, Denver CO 80225, USA ABSTRACT The Iġnik Sikumi Gas Hydrate Exchange Field Trial was conducted by ConocoPhillips in partnership with the U.S. Department of Energy, the Japan Oil, Gas, and Metals National Corporation, and the U.S. Geological Survey within the Prudhoe Bay Unit on the Alaska North Slope (ANS) during 2011 and 2012. The 2011 field program included drilling the vertical test well and performing extensive wireline logging through a thick section of gas-hydrate-bearing sand reservoirs that provided substantial new insight into the nature of ANS gas hydrate occurrences. The 2012 field program involved an extended, scientific field trial conducted within a single vertical well (“huff-and-puff” design) through three primary operational phases: 1) injection of a gaseous phase mixture of CO2, N2, and chemical tracers; 2) flowback conducted at down-hole pressures above the stability threshold for