DEEP PERMEABLE STRATA GEOTHERMAL ENERGY AS A NEW ENERGY SOURCE IN THE DELAWARE AND VAL VERDE BASINS OF WEST TEXAS

The Permian Basin is known as a world class oil and gas province. But an as of yet unrealized but tangible, renewable energy source lies dormant within its depths: geothermal. Most deep wells, particularly those in the Delaware and Val Verde Basins, have encountered BHT data commonly in the 140o to 160o Celsius range, with higher temperatures being reported. Although drilling creates a local disequilibrium thermal state, wells reentered many months after equilibrium is reestablished document temperatures from 12o C to 32o C higher. Thus it is likely that temperatures available from oil industry drilling records are far lower than what actually exists in the subsurface.

The basic requirements of an exploitable deep permeable strata geothermal energy (DPSGE) region are similar to requirements for oil and gas exploration: 1) a sufficiently high geothermal gradient; 2) a significantly large, porous and permeable reservoir to receive and heat injection fluids; and 3) a seal to contain the system. After more than 70 years of active exploration and production within the Permian Basin, the existence of reservoirs and seals are unquestionably documented throughout the literature. Significant temperatures at depth are well known, but not well documented. This is not because data does not exist, but because no concerted effort has been mounted to investigate deep geothermal potential in the Permian Basin. Preliminary work identified several deep gas fields within which temperatures ranged from as low as 115o C to over 160o C. The temperatures within these deep Ellenburger fields are sufficiently high to generate live steam, in situ. Four of the fields lie well above the steam threshold and are prospective for conventional power generation or as feed stock to a hybrid system, whereas one field is in the realm of hot water/steam, and would be capable of driving an ammonia-gasification turbine system. Geothermal reservoirs in the Delaware and Val Verde Basins should provide low level but extremely long term, power generation, and significantly broaden the availability of geothermal energy.