Identification of Morphologies of Gas Hydrate Distribution Based on AVA Analysis

There are two basic distribution morphologies of gas hydrates in nature: pore-filling and fracture-filling. Identification of gas hydrate morphologies is essential for improved resource evaluation and exploitation. Improper exploitation may cause seafloor instability, lead to atmospheric venting, and exacerbate the greenhouse effect. To identify gas hydrate morphologies, we combine rock physics modeling and amplitude variation with angle (AVA) analysis to study the theoretical AVA patterns of the bottom simulating reflector (BSR) beneath the pore-filling and fracture-filling gas hydrate bearing sediments (GHBS), respectively. The theoretical results show completely different AVA patterns between these two morphologies. The AVA of the BSR beneath the pore-filling GHBS shows a Class ? anomaly with negative intercept and gradient. However, the AVA of the BSR beneath the fracture-filling GHBS exhibits a Class IV anomaly with negative intercept and positive gradient. In addition, the theoretical AVA intercept ...