An application of AVO derived attributes to analyze seismic anomalies of gas hydrate bearing sediments in Makran offshore, Pakistan
Tóm tắt
The presence of gas hydrates in Makran area of Pakistan is confirmed by seismic evidences in the form of a strong reflector known as bottom simulating reflector (BSR). Amplitude versus offset (AVO) analysis is performed to analyze seismic behavior of free gas zone beneath BSR. This analysis is carried by considering a free gas zone beneath a gas hydrate-bearing zone and overlying a fully water saturated interval. Different pairs of AVO-derived attributes are applied to differentiate free gas and gas hydrates saturated sediments. Based on our analysis, it is concluded that low and high saturation of gas hydrates can be deduced from seismic amplitude anomalies. Low and high saturation of gas hydrates can be distinguish able from background trend. The fluid factor, pore space modulus and Poisson reflectivity are found more sensitive attributes for discrimination of gas hydrates saturation.
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