Presence of Bottom Simulating Reflectors (BSRs) in Western Continental Margin of India: An Appraisal

Nittala Satyavani, Naresh Kumar Thakur, and Kalachand Sain
National Geophysical Research Institute, Hyderabad, India

Occurrences of gas hydrates were inferred based on the preliminary analysis of multi-channel seismic (MCS) reflection data from the western continental margin of India (WCMI). The Bottom Simulating Reflector (BSR) identified on the seismic reflection record is the most important indicator of the Gas Hydrate and they have been identified in the WCMI. The BSR in this region is not a continuous reflector but occurs in segmented fashion. The MCS data has been analyzed to construct a realistic velocity model depicting the structure of gas hydrate. Modeling done using the finite difference method and by waveform inversion indicates the presence a very thin layer of free gas underlying the hydrate. We analyzed the reflection seismic data from this area for probable presence of free gas by performing a complex trace analysis to study the variation of reflection strength, apparent polarity and instantaneous frequency along individual reflections. The other proxies like faulting, pockmarks, venting, diapirs were also identified and studied. The promising results will be elaborated in the ensuing conference.

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