Abstract

The most commonly used marker for the investigation of gas-hydrates is the Bottom simulating Reflector (BSR) that is caused by the hydrated sediments underlain by either brine or free-gas saturated sediments. To understand the nature of BSR and to quantify the amount of hydrates and/or free-gas across the BSR, we theoretically compute the AVO intercept (A) and gradient (B) from BSR for various gas-hydrates models. The study demonstrates that the crossplot of A and B attributes can be used as an excellent indicator to detect free-gas below the BSR. We apply the approach to a seismic data in the Makran accretionary prism (Arabian Sea) and the result indicates that the BSR is due to ~10% hydrated sediments underlain by ~5% free-gas saturated sediments.