Seismic imaging of a seepage gas hydrate system with a harrow-like acquisition geometry

Seepage gas hydrate systems are abundant around the world. However, it is very challenging to characterize this type of gas hydrate because the internal structure of a seepage structure is difficult to image by the conventional seismic exploration method. Here, a novel approach is proposed to achieve high-resolution seismic imaging of a seepage gas hydrate system related to a pipe structure. Raw seismic data with small-size bins are acquired with a harrow-like acquisition geometry that uses one long cable (up to 2000 m) and multiple short cables (less than 1000 m). A high-frequency GI gun is used as a source. During processing, velocity analysis and footprint attenuation are more focused. Seismic imaging resolution has been greatly improved. A small-scale carbonate layer that is hard to identify on the conventional profile is well revealed on the new profile. The new profiles also better depict the boundary and internal structure of the pipe structure. These improve our understanding of seepage gas hydrate systems. Our approach provides an important complement to conventional offshore seismic exploration.