Abstract: Integration of Geophysical and Surface Geochemical Data Leads to New Field Discovery, Montague County, Texas

SMITH, SAM, DANIEL HITZMAN, and JAMES TUCKER

The integration of hydrocarbon microseepage analysis with seismic data directed explorationists to a new play concept and resulted in a new field discovery in North Texas. In the northern portion of a three square mile area, 3-D geophysical surveys identified a prospective Ellenberger trap at approximately 7200 feet. A reconnaissance microseepage survey of the area was conducted in December, 1995, using the Microbial Oil Survey Technique (MOST). The seismic prospect possessed a weak and slightly offset hydrocarbon microseepage signature. A stronger and larger microbial anomaly was located in a structural trough bounded on both sides by large structures.

In February, 1996, additional MOST samples were collected in a tighter grid pattern over the area of interest. The original seismic prospect remained associated with a weak hydrocarbon anomaly oriented perpendicular to the structural trend of the prospect, while the strongest and largest hydrocarbon anomaly continued to be located in the seismic low south of the structure. Review of geologic play analogs for North Texas suggested that the trough might contain channel conglomerates, an additional exploration target found in Montague County.

The seismic prospect was drilled at the crest of the structure in February, 1996. The well encountered 6 feet of tight Salona sand in the Ellenberger section. Attempted completion efforts failed to recover commercial hydrocarbons. A well was drilled in the trough and encountered 2 separate conglomerate zones with 10 feet of pay each. Initial production in lower zone was 500 mcfpd and 5 bopd. The next well found 3 conglomerate zones including 22 feet of pay in the lower zone with initial production near 1mmcfpd. Additional development wells are scheduled for the Park Springs Conglomerate.

This project is a good example of the use of surface geochemistry to evaluate seismic prospects and the use of geology to evaluate a geochemical lead. The conglomerate play would not have been scrutinized nor pursued without the positive microbial anomalies.

AAPG Search and Discovery Article #90944©1997 AAPG Mid-Continent Section Meeting, Oklahoma City, Oklahoma