Specific character of the bottom simulating reflectors near mud diapirs: Western margin of India

Abstract

Multi-channel seismic recording was carried out along the western continental margin of India in the early nineties for the exploration of hydrocarbons. Analysis of seismic data demonstrated a characteristic reflector, which usually coincides with the predicted base of methane hydrates stability field and mimics the sea- floor, known as the bottom simulating reflection (BSR) on marine seismic reflection data. Existence of reflections which mimic the seafloor, reverse polarity, seismic blank zone, strong diffraction patterns around the mud diapirs, weak amplitude blocks and pock- marks suggests that gas hydrates are present in deep- water regions. Five characteristic seismic facies asso- ciated with bottom simulating reflectors and mud diapirs were identified. In this study, we present the results of seismic surveys which indicate the existence of natural gas hydrates in the western margin of India. These results will be applied to select areas for coring (or drilling) and detailed exploration such as 2D seis- mic survey with long offset or 3D seismic survey in the future.