A Pressure Coring Operation and On-board Analyses of Methane Hydrate-bearing Samples

As a part of the offshore production test program, in June and July of 2012, Japan Oil, Gas and Metals National Corporation (JOGMEC) conducted coring operation in the Eastern Nankai Trough where the first offshore production test of methane hydrates was to be conducted. By using a pressure coring device, Hybrid PCS developed by Japan Agency of Marine Science and Technology (JAMSTEC), Aumann and Associate Inc. (AAI), and JOGMEC, pressure conserved cores were recovered from methane hydrate-bearing sandy formations although some technical difficulties encoutered. The samples were analyzed onboard by Pressure Core Analysis and Transfer System (PCATS, GeoTek). Some samples were sent to onshore laboratories for further analyses. Continuous 60m intervalin a methane hydrate concentrated zone was cored and fairly good core recovery and pressure conservation rates were achieved. The obtained data are used for reservoir characterization of methane hydrate concentrated zone from where gas was produced during the actual production test conducted in March 2013.