A multicomponent 3D seismic tool for shallow gas geohazard detection onshore Gulf Coast

Abstract

Current study demonstrates that multicomponent 3D survey is an efficient tool not only to detect gas but also to delineate its migration pathways in shallow sediments. We have determined that thermogenic gas detected in the study area is represented by amplitude and velocity anomalies, including bright spots, gas clouds, gas sags, and phase changes. Evidence of these anomalies attributed to gas presence is provided by well correlation and amplitude variation with offset crossplot analysis and is further supported by the imaging disparity between P- and converted-S-wave data. Current mapping results suggested a predominant vertical gas migration through faults from the unreported petrochemical products in some sulfur caverns. This conclusion is contrary to earlier studies, which suggest a primarily lateral migration from a gas storage cavern 1219 m (4000 ft) to the west.