Geophysical Characterization and Attenuation Correction Applied for Hydrate Bearing Sediments in Japan Sea

Estimation of rock properties from seismic data is important for exploration and production activities in the petroleum industry. Considering compressional velocity—the speed propagating body waves formations—and quality factor (Q)—a measure frequency-selective energy losses through formations—both are usually estimated multichannel data. Velocity during processing reflection either time or depth domain. In marine acquisition, Q can be following sources: Vertical Seismic Profile (VSP) surveys, where sources located near sea surface geophones distributed at along a borehole; data, also receivers (conventional survey with streamers) on floor (use nodes Ocean Bottom Cables (OBC)). The aforementioned acquisition devices, VSP, conventional streamers, nodes, OBCs much more expensive than single-channel one receiver per shot due to cost operation. There numerous old new datasets academia oil industry that have been acquired devices. However, there paucity work addressing estimation velocity this type equipment. We investigate Using windowed discrete Fourier transform single trace, we calculate peak dominant frequency changes time. geologic environment, higher frequencies attenuated shallow depths (time), while lower remain deeper positions. From rate which time, estimate effective (Qeff). when using Kirchhoff migration process events far vertical projection contribute trace given Then, an underestimation occurs. To compensate effects distant lower-frequency content contaminating shorter events, propose linear equation correct migrated Effective its correction five lines surveyed Joetsu Knoll, SW-NE anticline structure eastern margin Sea Japan. These results linked geomorphological geological features field. Knoll known site massive gas hydrates (GH), occur first hundred metres Neogene sediments and, together chimneys, play role wave absorption. Qeff maintains spatial relationship between high low regions. region Q, below 124 has average value 57, occurs anticlinal hinge tends coincide Simulating Reflector (BSR) resides. coexistence GH free coincides very P gradient 0.225 s−1. BSR occurrence, geometry testify progressive hydrate depletion northward dome.