Gas-hydrate interpretation from 3D seismic attributes: An example from the Gulf of Mexico

Abstract

Gas hydrates are a recognized drilling geohazard. If not mitigated, they may result in plugged blowout preventors, gas kicks, blowouts, borehole instability, gas leaks outside casings, and inadequate cementing operations. Gas hydrates located within the gas-hydrate stability zone (GHSZ) are difficult to interpret solely from seismic amplitudes. In this paper, we apply a multifaceted approach using the velocity pullup method in combination with 3D visualization of seismic attributes for the interpretation of gas hydrates within the GHSZ. The approach is applied to an area in the eastern part of the Gulf of Mexico in water depths greater than 2400 m. The practical outcome of this study is the choice of safe drilling locations outside of areas where gas hydrates have been interpreted to be present.