Consolidation of geologic studies of geopressured-geothermal resources in Texas. 1990 Annual report

In a five-county area of South Texas, geopressured-geothermal reservoirs in the upper Wilcox Group colocated with heavy-oil reservoirs in the overlying Jackson Group. In 1990, research at the Bureau of Economic Geology concentrated on evaluating the potential of using geopressured-geothermal water for hot-water flooding of heavy-oil reservoirs. Favorable geothermal reservoirs are defined by thick deltaic sandstones and growth-fault-bounded compartments. Potential geothermal reservoirs are present at a depth of 11,000 ft (3,350 m) to 15,000 ft (4,570 m) and contain water at temperatures of 350 F (177 C) to 383 F (195 C) in Fandango field, Zapata County. One potential geothermal reservoir sandstone in the upper Wilcox (R sandstone) is composed of a continuous sand body 100 ft (30 m) to greater than 200 ft (>61 m) thick. Fault blocks average 2 to 4 mi{sup 2} (5.2 to 10.4 km{sup 2}) in area