Analysis of Surface and Subsurface Anomaly, Jaybird Field, Garza County, Texas

G. Pat Bolden

The Jaybird field-SB II structure is an excellent example of a surface drainage anomaly where streams outline the surface structure by flowing along the faults and downdip slopes. The surface drainage indicates that Swenson-Barron field is separated from the SB II structure.

San Andres structure in Swenson-Barron field at 2,200 ft in depth reveals about 10 ft of closure. A 2-ft reversal on the Ellenburger structure gives the subsurface clue that the SB II structure is separated from Swenson-Barron field.

Landsat images define the faults on the surface and help determine the seismic line placement. The surface anomaly also is defined by Landsat images as well as the connection of faults between the seismic lines.

High-multiplicity seismic profiles reveal the high-angle reverse faulting and a flower structure that is part of the Double Mountain lineament. Seismic interpretation used with drainage, Landsat, and left-lateral wrench-faulting interpretation techniques confirm the SB II structure.

Jaybird field was discovered in August 1976 by the HCM, Swenson Estate 1 well. A successful development test was drilled 1.5 mi north of the discovery in December 1982. Development between the two wells continues.

The discovery of the Jaybird field-SB II structure is an example of using an old technique such as drainage-pattern interpretation with the new techniques of Landsat imagery to define the areal extent and fault directions of the structure. Integrating these techniques with the seismic data to define the fault directions and interpreting wrench faulting to determine fold direction produces an integrated picture of the structure and an oil field.

AAPG Search and Discovery Article #91037©1987 AAPG Southwest Section, Dallas, Texas, March 22-24, 1987.