By OGJ editors
HOUSTON, July 23 -- Preheating has started at one tar sand pilot and is due to start later this quarter at another pilot in the Maverick basin 125 miles southwest of San Antonio.
Formation preheat started June 1 at a steam-assisted gravity drainage pilot in Chittim field in Maverick County near the Zavala County line, and high temperature steam injection and initial production is to start in the quarter ending Sept. 30, said operator TXCO Resources Inc., San Antonio (see map, OGJ, Aug. 13, 2007, p. 38).
Preheating is to start in the current quarter in Saner Ranch field in the same area. The Saner Ranch project consists of one pilot with five vertical wells in an inverted five-spot pattern and another with three horizontal wells, both testing fracture-assisted steamflood technology. Two 50 MMBtu steam generators are being installed.
The projects are aimed at recovering hydrocarbons from the Cretaceous San Miguel formation. TXCO Resources operates both projects with 50% interest, and Pearl Exploration & Production Ltd., Calgary, has 50%.
The companies are evaluating the three technology configurations and hope to decide as early as 2009 whether recovery warrants commercial operation.
Conoco Inc. engineers in the late 1980s called the South Texas tar "one of the most dense and viscous hydrocarbons in the world."