Frio, Yegua objectives of E. Texas 3D seismic

Where 3D Seismic Search is Planned [29078 bytes]

Houston companies plan to explore deeper formations along the Sabine River on the Texas and Louisiana Gulf Coast.

PetroGuard Co. Inc. and Jebco Seismic Inc., Houston, jointly secured a seismic and leasing option from Hankamer family et al. on about 120 sq miles in Newton County, Tex., and Calcasieu Parish, La. PetroGuard, which specializes in oilfield rehabilitation, has production experience in the area.

Historic production in the area spans three major geologic trends: Oligocene Frio/ Hackberry, downdip and mid-dip Eocene Yegua, and Eocene Wilcox. In the southern part of the area, to be explored first, the trends lie at 9,000-10,000 ft, 10,000-12,000 ft, and 14,000-15,000 ft, respectively.

The area is too far south for Austin chalk to be prospective at economic depths.

Output Exploration Co., an affiliate of Input/Output Inc., Houston, acquired from PetroGuard and Jebco all exploratory drilling rights in the option area. Output will conduct 3D seismic operations over nearly half the acreage this summer. Data acquisition started late this spring.

Output plans to use a combination of a traditional land recording system and I/O's new RSR 24 bit radio telemetry system because the area spans environments from dry land to swamp.

Exploration sparse

Historic seismic exploration in the area has consisted of a regional 2D spec survey in 1993 and several small proprietary projects that targeted specific prospects, Jebco said.

This will be the first major effort to apply large-scale 3D imaging to define exploration objectives in the area. Following the 18 month lease option period, Jebco and PetroGuard will be able to license the 3D data to other companies wishing to explore the area.

Newton County has been the site of oil and gas production since the 1930s from reservoirs ranging from shallow Frio sands to the Cretaceous Austin chalk. Most fields in the survey area are largely depleted, and recently exploration has targeted mainly deeper downdip Yegua and Wilcox potential.

This exploration has been based largely on 2D seismic data, which delineated the major structural trends.

Fields in the area associated with the dominant southwest-northeast trending faults include in Calcasieu Parish, West Starks (2 million bbl of oil and 24.4 bcf of gas), and in Newton County, Sabine Tram (3.78 million bbl and 9.39 bcf), South Newton (6.9 bcf), Devil's Pocket (2.8 million bbl and 7.4 bcf), Gist (9.8 million bbl and 9.2 bcf), and Hartburg (6 million bbl and 20.5 bcf).

Between the major fault trends, predicted stratigraphic traps have eluded explorationists that used traditional 2D seismic data. Only a few wells have been drilled in the option area the past 10 years, searching primarily for mid-dip and downdip Yegua sands.

Successful delineation of stratigraphic plays in the Frio and Yegua trends would open up a new play reaching from Hardin, Jasper, and Newton counties across the Sabine River into western Louisiana.

Additional new potential is predicted by defining new fault block offsets to existing and historic production and by better seismic definition of deep objectives, primarily in the expanded Yegua and Wilcox sections.