Geothermal energy production from a pair of abandoned oil or gas wells with a horizontal section
An alternative solution for geothermal energy production from abandoned oil and gas wells was proposed, from a pair of abandoned oil or gas wells with a horizontal section, which will extend the lifetime of the operation to 10 -20 years. Previous studies focused on extracting geothermal energy from a single abandoned well, where the life time of the operation would be significantly less. In the present study, water as the primary fluid is injected into one of the wells called the injection well, pumped through the horizontal well and then up through the second well, the production well. This allows for a significant increased lifetime of the geothermal energy production, as the primary fluid in the pipe can be heated up by the horizontal section once the vertical injection well has cooled off. In order to preserve the heat absorbed by to the primary fluid, the production well is insulated so there is negligible heat loss. The primary fluid heats up a secondary fluid, which completes the Rankine cycle and electric power is produced. The mathematical model takes into consideration the conservation of mass, momentum and energy. An implicit forward in time central in space finite difference scheme was chosen in order to solve the diffusion equation. Depending on the radius of the well, the possible power production varied from 1.23 MW to 2.87 MW, even after 10- 20 years of operation, in the South Texas region.