AVO crossplot analysis in unconsolidated sediments containing gas hydrate and free gas: Green Canyon 955, Gulf of Mexico

• DOI: 10.1190/segam2012-1104.1
• Publication Date: 2013-04-15T23:47:27Z
• Authors: Zijian Zhang; Daniel R. McConnell; De-hua Han
• Keywords: 01 natural sciences; 0105 earth and related environmental sciences

Summary An analysis of amplitude variation with offset (AVO) observations is applied in hydrate-bearing sands, free-gascharged sands, and hydrate-over-gas sands. The elastic model parameters (Vp, Vs, and density) are obtained from well log measurements and a rock physics model. The study suggests that presence of gas hydrate and free gas affect the AVO of shallow unconsolidated sediments containing gas hydrate and free gas. Low-concentrated gas hydrate and low-concentrated gas hydrate overlying free gas have weak AVO behaviors while highly-concentrated gas hydrate and highly-concentrated gas hydrate overlying free gas have strong AVO behaviors. Both highlyconcentrated gas hydrate and highly-concentrated gas hydrate overlying free gas are Class I AVO anomalies but the intercept of AVO is stronger negative for highlyconcentrated gas hydrate overlying free gas. They may occur in different locations in the AVO intercept and gradient plane.