--> Abstract: Improved Identification and Characterization of Deepwater Thermogenic Hydrocarbon Macro-Seepage Using High-Resolution AUV Geophysical Data; #90063 (2007)

Datapages, Inc.Print this page

Improved Identification and Characterization of Deepwater Thermogenic Hydrocarbon Macro-Seepage Using High-Resolution AUV Geophysical Data

 

Samuels, Bruce. M1, Harry Dembicki2 (1) C & C Technologies, Lafayette, LA (2) Anadarko Petroleum Corp, Houston, TX

 

The search for seafloor hydrocarbon macro-seepage is an important part of deepwater exploration programs. Detecting thermogenic hydrocarbons at the seafloor provides strong evidence for the presence of a working petroleum system in the subsurface. This knowledge can substantially reduce the risk in drilling expensive deepwater wells.

Using conventional seismic data to detect potential seep features is often inadequate. 2-D data is limited to imaging the seafloor directly along the seismic grid lines. Because hydrocarbon seeps are often small features, they are not always easily recognized in seafloor extractions from 3-D data due to lack of resolution. As such, many seep features may be easily overlooked when relying on these data.

 

In contrast, AUV geophysical surveys utilizing detailed bathymetry, side scan sonar, and sub-bottom acoustic profiling allow for high-resolution seafloor and near-seafloor characterization. The morphologies of seafloor features can be directly tied to perturbations of sub-bottom sediments below each feature providing insight into the presence of potential hydrocarbon seeps. This can then be related to deeper structures and faults imaged on conventional seismic establishing the link between subsurface reservoirs, migration pathways, and potential seafloor seeps.

 

This study shows how higher resolution AUV geophysical data was an extremely valuable tool for selecting coring locations in the Gulf of Mexico. The combination of detailed bathymetry, side scan sonar, and sub-bottom profiling was essential for differentiating between coring locations with high potential for thermogenic hydrocarbon seepage and places where no hydrocarbon seepage was expected.

 

AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California