Application of Seismic Attributes for Identification of Gas Hydrate Bearing Zone and Free Gas Beneath it

Gas hydrate is an ice like form of concentrated gas (>99% methane) and water found in the sediments of permafrost regions, marine continental margins and seafloor of deep sea at depths far shallower than conventional oil and gas. The first indicator of gas hydrate in deep sea is bottom simulating reflector (BSR). BSR approximately mimics sea-floor and cuts across reflection of statigraphic origin and have reverse polarity respect to seabed reflection. A second significant seismic characteristic of gas hydrate-cementation is called amplitude blanking. The presence of hydrate and free gas change the seismic properties of host sediments. Relative acoustic impedance and absorption quality factor attributes can be used for analyzing them. In this study, we have analyzed the gas hydrate indicators in 2-D seismic sections of deep sea sediments of Iran with seismic attributes.