Abstract

The presence of gas hydrates along the Indian continental margins has been inferred mainly from bottom simulating reflector (BSR) and the gas hydrate stability zone thickness map. Multidisciplinary investigations have confirmed gas hydrate deposits in KG basin after drilling. In the present study, BSR like features are observed during the analysis of 2D and 3D seismic data of Andman deep water basin. It shows all the characteristics of classical BSR such as mimicking the seafloor, cutting across the underlying and overlying dipping strata and exhibiting strong amplitude. The polarity of the event is opposite to that of the sea floor reflection. Seismic sections from 2D and 3D surveys in the study area show that amplitude of BSRs at several places is large coupled with high interval velocity (1950m/s) just above the BSR whereas at some places amplitude of BSR is small along with the interval velocity of the order of 1750m/s. Base of the Gas hydrate stability zone in Andman area varies between 200-650ms indicating different Temperature-Pressure conditions. Double BSRs are also seen on seismic sections pertaining to the study area-B indicating changes in P-T conditions during past 10-20K years