Automatic Fault Extraction (AFE) of Faults and a Salt Body in a 3-D Survey from the Eugene Island Area, Gulf of Mexico

Dorn, Geoffrey A.¹, Huw E. James² (1) University of Colorado, Boulder, CO (2) Paradigm Geophysical, Houston, TX

Traditionally faults are picked from discontinuities in seismic amplitude and from Coherency (discontinuity) volumes. This remains one of the most tedious and time-consum-ing aspects of 3D seismic interpretation. Several attempts that have been made to automate fault interpretation in the past have failed to deliver acceptable interpretations with less effort in less time than manual methods.

Automatic Fault Extraction (AFE) is a process designed to automatically interpret fault surfaces from 3-D Coherency volumes. AFE significantly improves efficiency in the 3-D fault interpretation, providing accurate and detailed interpretations of fault surfaces. These sur­faces can help improve the performance of horizon auto tracking and segmentation algo­rithms, minimizing problems with miscorrelation across faults. AFE combines signal pro­cessing technology with geologic rule based steps and a suite of tools to enable automated and semi-automated fault interpretation. The input to AFE is a 3D discontinuity volume. The output is a volume of relative fault probability, fault polylines and fault surfaces. Any discon­tinuity attribute may be used for input.

The application of this technology on a 3D survey from the Eugene Island area of the Gulf of Mexico produces fault surfaces that compare well with manually interpreted fault surfaces. The AFE process also detects and interprets the boundary of a salt body in the survey.