Geothermal energy production utilizing abandoned oil and gas wells

The objective of this study is to demonstrate the feasibility of acquiring geothermal energy from existing abandoned oil and gas wells. The equations describing the heat exchange between fluid and rocks are developed, and parametric studies are conducted in order to specify the optimum values of the main parameters. Computational results indicate that the geothermal energy produced from abandoned wells depends largely on the flow rate of fluid and the geothermal gradient. The temperature of extracted liquid is 129.88 degrees C, and it drops to 127.92 degrees C after ten years of operation. It is observed that both hot water and electricity can be acquired from the abandoned wells. Results also indicate that the distance of two wells should not be less than 40 m in order to avoid interaction between them. Furthermore, the financial reward of electricity is 36833.26 US $/year for a retrofitted well. (C) 2011 Elsevier Ltd. All rights reserved.