Geology of the Gladys McCall Geopressured-Geothermal Prospect, Cameron Parish, Louisiana

The Gladys McCall prospect lies at the western edge of the Rockefeller Wildlife Refuge about 88 km (55 mi) southeast of Lake Charles in Cameron Parish, Louisiana. The test well is 4825 m (15,831 ft) deep and was drilled in 1981 under the U. S. Department of Energy geopressured-geothermal research program. The well was shut in at the end of October 1987 after it had produced over 27 million barrels of brine and 676 MMscf gas, without any significant pressure decline. The stratigraphic section seen in this test well consists of alternating sandstones and shales with about 350 m (1150 ft) of net sand between 4393 m (14,412 ft) and 4974 m (16,320 ft). The producing reservoir is bounded on the north and south by faults. The east-west dimension is poorly defined due to lack of deep well control. Eleven prospective production zones have been identified. The pressure maintenance and the continuous high brine yield from the reservoir may be due to laterally overlapping and connected sandstones, communication between overlying and/or underlying reservoirs, growth faults acting as passageways for brine, shale dewatering, or possible communication of zones behind the casing.