By OGJ editors
HOUSTON, Dec. 9 -- A two-well cyclic steam pilot to test feasibility of producing shallow tar in the Maverick basin may be close to start-up.
Exploration Co., San Antonio, and Newmex Minerals Inc., Calgary, are awaiting regulatory approvals that Newmex said are expected shortly. TXCO drilled two wells to the Upper Cretaceous Lower San Miguel sandstone on its Chittim B lease earlier this year (see map, OGJ, Oct. 4, 2004, p. 30).
The companies, which have a large lease block in Maverick and Zavala counties, plan to apply cyclic steam stimulation and truck produced tar 100 miles to a heavy oil processing facility. If the pilot succeeds, the initial development plan takes in 5-1/4 sq miles.
Newmex said a report on its acreage prepared by consulting engineers described the tar as "one of the most dense, viscous and sulphur-laden hydrocarbon deposits in the world.
"The gross thickness of sand varies from approximately 20 to 80 ft (6.1 to 24.4 m). The tar saturations range from 20 to 60% but seldom average greater than 55% in a continuous 25 ft (7.6 m) interval."
Previous uneconomic pilot projects in earlier decades recovered tar of 2° to minus 2° gravity from accumulations at 2,000 ft or less in the San Miguel. Tar at one of the earlier pilots was essentially a solid at 95° F. reservoir temperature, had a 500° F. initial boiling point, and contained more than 10 wt % sulfur.