Multicomponent Seismic for Gas Hydrate Monitoring

The first offshore methane hydrate production test will be conducted by METI and JOGMEC/MH21 in early 2013 in the eastern Nankai Trough, Japan. The test aims to prove the applicability of the depressurization technique for MH production. The flow test intervals will be at shallow sediment depths but at deep water depths. JOGMEC plans to carry out a multi-component seismic survey to monitor the dissociation of MH by the depressurization technique in the flow test scheduled in early 2013. JGI, Inc. has developed deep-water OBC system (Deep-sea Seismic System, DSS) with OCC Corp. and deployed the DSS close to the production test well in August 2012. After deployment, the DSS system was buried by ROV. Then we carried out the baseline 2D/3D multicomponent seismic survey. The results show the good quality to delineate the methane hydrate concentrated zone. After the baseline survey, we have left the DSS on seafloor and remains there until the monitoring surveys scheduled in April and August 2013, because the fixed location of the sensors is crucial for time-lapse monitoring survey.