Enhancing geothermal power generation from abandoned oil wells with thermal reservoirs

Using abandoned oil wells for geothermal power generation can relieve energy problem, save drilling cost, and govern the pollution caused by the residual oil of the abandoned oil wells. In this paper, a novel method for enhancing the geothermal utilization efficiency by developing thermal reservoirs is presented. A 2-D thermal reservoirs coupling with 1-D wellbore heat transfer model was set up to simulate geothermal energy production, and the effects of the thermal reservoirs on the geothermal production and electric power output were analyzed. The study results showed that the geothermal well with thermal reservoirs could produce about 4 times the heat and electric power output as that without thermal reservoirs. Moreover, the thermal reservoirs parameters would impact the heat production and power generation significantly. Especially, the heat production and electric power output increased with the thermal reservoirs depth and the fluid injection rate, however increased with the thermal reservoirs length firstly, and then decreased, which indicated that there was a maximal heat production and power generation at an optimal reservoir length. Simultaneously, the fluid loss in the thermal reservoirs increased with the thermal reservoirs depth and length as well as thermal reservoirs porosity.