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Control of Deep Structure on Reservoir Properties and Distribution: Fullerton Field, West Texas
November 2004 Presentation in PDF Format
Fullerton Clear Fork Field

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Figure 2

Effect of Deep Faults on Reservoir Character

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Figure 16

Integrated Geological and Engineering Characterization of
Fullerton Clear Fork Field in Andrews County, Texas
Structural Controls on Reservoir Development

Preliminary interpretation in a 16,700-acre 3-D seismic survey (Figure 2) in the southern portion of Fullerton field and 35 2-D seismic lines over the northern portion of the field indicate numerous deep-seated E-W and SW-NW-striking faults. These faults bound many present-day structures and appear to have influenced reservoir facies distribution.

Faults display major offsets through Devonian and older strata and appear to be the cause of subtle displacements in Wolfcampian- to Leonardian-age strata and/or changes in stratigraphic architecture and facies (Figure 16). In areas underlain by unfaulted horst blocks, for example, seismic data generally display flat, continuous reflections and cores display predictable facies and cycle development patterns indicating typically flat platform depositional environments. In areas of deep-seated faults, in contrast, seismic data display a more chaotic signature and cores exhibit features indicative of deeper water, slump, and downslope transport. These relationships suggest steepened slopes caused by ongoing tectonic instability in these areas.

Whereas most structural interpretations of the Central Basin Platform region suggest that the area became tectonically quiescent after the Wolfcampian, seismic and core data from Fullerton field indicate continued activity along structural features well into Leonardian time. Our data further suggest that this activity locally had significant impact on depositional processes and thus may play a profound role in the distribution of porosity and permeability in these reservoirs.

For more information, please contact Steve Ruppel, principal investigator. Telephone 512-471-2965; e-mail stephen.ruppel@beg.utexas.edu.
January 2004