ABSTRACT: A Three-Dimensional Reflection Seismic Survey over the Dollarhide Field, Andrews County, Texas

Mike Reblin, Greg Chapel, Chuck Keller, Steve Roche

A three-dimensional seismic survey over the Dollarhide field, Andrews County, Texas, was collected and analyzed from August 1988

through July 1989. Discovered in 1945, the field is described as a large faulted anticline. This presentation describes the design, preplanning, acquisition, and processing of this survey and the preliminary results of the interpretation.

The primary geophysical purpose of the survey is to accurately image the location of the faulting within the Dollarhide field to aid in the future planning of enhanced recovery methods.

To design the three-dimensional (3-D) survey, information including depth, velocity, maximum dip, and reflection data quality are compiled. A subsurface bin size of 110 ft inline by 110 ft crossline is determined to sample adequately the subsurface for processing through 3-D migration.

Two innovations are employed to reduce the costs of the survey: wide-line sampling and simultaneous sweeping. The wide spacing of the source and receiver lines results in fewer swaths to collect and lower surface access costs. In data processing, the data volume is interpolated to a finer sampling prior to 3-D migration.

The second cost-reduction technique is to use two sets of vibrator sources, simultaneously sweeping. The source separation is accomplished by upsweep/downsweep and phase rotation/summing, giving greater than 40 db of signal separation.

Conventional data processing techniques are applied to the data volume plus 3-D DMO; 3-D migration then produces the data volume for interpretation on a work station.

The interpretation of the 3-D data volume yields the following observations: (1) The major north-south fault bounding the field on the east side can be located with more detail; (2) the cross-faulting within the producing field is more extensive than supported by the geologic interpretation from the 40-ac well control.

AAPG Search and Discovery Article #91003©1990 AAPG Annual Convention, San Francisco, California, June 3-6, 1990