ANALYSES OF PRODUCTION TESTS AND MDT TESTS CONDUCTED IN MALLIK AND ALASKA METHANE HYDRATE RESERVOIRS: WHAT CAN WE LEARN FROM THESE WELL TESTS?

Proceedings of the 6th International Conference on Gas Hydrates (ICGH 2008), Vancouver, British Columbia, CANADA, July 6-10, 2008. ANALYSES OF PRODUCTION TESTS AND MDT TESTS CONDUCTED IN MALLIK AND ALASKA METHANE HYDRATE RESERVOIRS: WHAT CAN WE LEARN FROM THESE WELL TESTS? Masanori Kurihara∗ , Kunihiro Funatsu and Hisanao Ouchi Japan Oil Engineering Company 1-7-3 Kachidoki, Chuo-ku, Tokyo, 104-0054, Japan Yoshihiro Masuda (School of Engineering, The University of Tokyo) Koji Yamamoto (Japan Oil, Gas and Metals National Corporation) Hideo Narita (National Institute of Advanced Industrial Science and Technology) Scott R. Dallimore (Geological Survey of Canada, Natural Resources Canada) Timothy S. Collett (United States Geological Survey) Steve H. Hancock (APA Petroleum Engineering Inc.) ABSTRACT Pressure drawdown tests were conducted using Schlumberger’s Modular Formation Dynamics Tester™ (MDT) wireline tool in the Mallik methane hydrate (MH) reservoirs in February 2002 as well as in the Mount Elbert (Alaska) MH reservoirs in February 2007, while a production test was conducted applying a depressurization method in one of the Mallik MH reservoirs in April 2007. All of these tests aimed at measuring production and bottomhole pressure (BHP) responses by reducing BHP below the MH stability pressure to estimate reservoir properties such as permeability and MH dissociation radius. We attempted to analyze the results of these tests through history matching using the numerical simulator (MH21-HYDRES) coded especially for gas hydrate reservoirs. Although the magnitude of depressurization and the total duration spent