Several operators stand to benefit if early gas flow rates from a horizontal Cretaceous Pearsall shale well in the Southwest Texas Maverick basin hold up.
The Pearsall shale, for decades a marginal producer in vertical wells, 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 horizontal 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.
The gas rate later impoved to 3.8 MMcfd.
Myers 2-683H is the company’s third horizontal Pearsall well to be frac 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 horizontal wells gave up about 1 MMcfd each after open hole completions with multistage packers and sleeves (see map).
The company, which has 100% working interest in the Myers well through completion, conducted microseismic monitoring from an 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 frac-stimulated in the future.
It was also welcome news to others who had tried to extract commercial gas flows from the Pearsall through vertical wells for decades, such as in Los Cuatros field discovered in the 1970s. To what extent the play emerges will depend on the combination of lateral lengths, number of frac stages, and other elements of the completion process.
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).
The company is involved in large joint venture acreage positions in the basin with EnCana Corp., Anadarko Petroleum Corp., and St. Mary Land & Exploration Co.
The Myers well is on TXCO-EnCana properties. TXCO expects to begin frac treatments under the TXCO-Anadarko-St. Mary Land joint venture in the third quarter of 2008.
