Geothermal energy production from oil/gas wells and application for building cooling

One significant source of low-temperature geothermal energy is the coproduced hot water from oil/gas field production. In the United States, daily oil production has reached above 8 million barrels per day in recent years. Considering various conditions of wells, 5-10 times this volume of water can be coproduced with a temperature in the range of 120 to 300°F. Like other geothermal resources, such energy source is under-utilized due to its typically long distance from consumption sites. Many oil/gas fields, however, are relatively close (less than 10 miles) to population centers. For instance, some petroleum fields in Pennsylvania are only a few miles away from the towns in the Pittsburg area and some fields in Texas are quite close to Houston. In this paper, we evaluate geothermal potential from oil/gas wells by conducting numerical simulation and analysis of a fractured oil well in the Hastings West field, Texas. The results suggest that hot water can be continuously coproduced from oil wells at a sufficient rate (about 4000 gallons/day from one well) for more than 100 years. Viable use of such geothermal source requires economical transportation of energy to consumers. The recently proposed two-step geothermal absorption (TSGA) system provides a promising energy transport technology that allows large-scale use of geothermal energy from thousands of oil/gas wells.