Rob B. Leslie
Digital image processing of 3-D seismic attributes enables the interpreter to enhance subtle structural and stratigraphic lineaments which may be overlooked using conventional interpretations techniques. By applying various adge-enhancement algorithms to attributes such as seismic amplitude, thickness, and two-way-time measurements, the azimuth and lateral extent of small faults, fluid contacts, and stratigraphic discontinuities can be quickly discerned. This paper will illustrate examples from several 3-D surveys including the Gulf of Mexico where enhanced images were used to aid in interpretation for the primary development of Main Pass 252 (Prospect BUD).
MP 252 was purchased in the May 1985 lease sale by Shell Offshore Inc. The exploratory well that was drilled in late 1985 found considerably less pay than expected. Based in the results of this well, the reserves for BUD were reduced considerably. The rationale behind the reserve reduction was that the exploratory well was drilled in the highest seismic amplitudes region and it was believed that subsequent wells would encounter significantly less pay.
Digital image processing was applied to seismic attributes extracted from the BUD 3-D seismic survey. The enhanced images that resulted from this work suggested a geologic model with considerably more stratigraphic variability than previously interpreted. Based on the interpretation, a seven well development program was recommended in 1990 and successfully completed in 1991. Four of the seven wells came in much better than expected, doubling the expected reserves for this field. In addition, the logs and side wall cores support the channel/levee interpretation which arose from the interpretation of the enhanced attribute images.
AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994