Maverick fracs unlock Pearsall shale gas

Aug. 7, 2008
Cretaceous Pearsall shale flowed gas at the rate of 3.5 MMcfd with 2,500 b/d of frac fluid after a five-stage frac job at a well in the Maverick basin, said TXCO Resources.

By OGJ editors
HOUSTON, Aug. 7 -- Cretaceous Pearsall shale flowed gas at the rate of 3.5 MMcfd with 2,500 b/d of frac fluid after a five-stage frac job at a well in the Maverick basin, said TXCO Resources Inc., San Antonio.

Flowing tubing pressure is 3,875 psi, and the flow rates continued to rise as the frac fluid returned, the company said. The company pumped 750,000 lb of sand and 59,000 bbl of frac fluid and had recovered only 15% of the fluid as of Aug. 7.

Myers 2-683H is the company's third horizontal Pearsall well to be fracture treated this year and the first to be successfully treated with five stages. It is also the first Pearsall well in which the horizontal lateral, 3,000 ft long, was fully cased, cemented, and perforated for limited entry, TXCO Resources said.

Two earlier wells gave up about 1 MMcfd each after open hole completions with multistage packers and sleeves.

The company, which has 100% working interest in the Myers well through completion, conducted microseismic monitoring from a nearby offset well during the treatment, allowing it to observe and modify the stimulation in real time.

The $5 million well cost included a vertical pilot hole and the five frac stages, and the company still plans to run production logs.

The Myers well provided the company with valuable data that will be used to improve frac designs on other Pearsall wells to be drilled and fracture-stimulated in the future.

TXCO Resources' combined Pearsall project area exposes the company to the overpressured shale play on more than 848,000 gross acres (340,000 net acres) in the Southwest Texas basin (see map, OGJ, Aug. 13, 2007, p. 38).