Initial Geophysical and Geological Assessment of an Industry 3-D Seismic Survey Covering the JAPEX/JNOC/GSC Mallik 5L-38 Gas Hydrate Research Well

Thomas A. Brent¹, Micheal Riedel², M. Caddel³, M. Clement⁴, Scott, R. Dallimore², and Timothy S. Collett^5
1 Geological Survey of Canada - Calgary, Calgary, AB
² Geological Survey of Canada, Sydney, BC
³ BP Canada Energy Company, Calgary, AB
⁴ Veritas GeoServices, Calgary, AB
⁵ U.S. Geological Survey, Denver, CO

Industry 3D seismic covers the JAPEX/JNOC/GSC et al. Mallik 5L-38 gas hydrate well. Interpretation supported by biostratigraphy indicates a normally-faulted anticline with 5L-38 occupying the northern downthrown crest. This EW-striking fault, near 5L-38, has 800 m throw interpreted 700 m below gas hydrate levels. Fault offset at 5L-38 gas hydrate levels is probably several hundred metres less, because syn-depositional fault movement during or after Late Eocene time is suggested. Down hole velocity surveys at Imperial Mallik wells, P-59, J-37 and A-06, infer 105, 225, and 135 m gas hydrate, respectively, compared to 116 m known at 5L-38. Gas hydrate seismic characterization includes: multiple, generally weak, near-horizontal events; amplitude features on geologic reflectors; amplitude “blanking” and; chaotic vertical reflective zones surrounding faults. Recognized data contamination include amplitude-frequency degradation beneath lakes and reverberated energy. Noted are spatial correspondence of some subsurface faults with position/orientation of surface lakes, suggesting a possible genetic link.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005