Well efficiency assessment in geothermal fields for horizontal drilling

Abstract

A research study is conducted to evaluate the well efficiency assessment of horizontal wells in geothermal fields. The study is comprised of developing the field by means of drilling 15 wells, and conducting reservoir simulation. Drilling planning of vertical and horizontal wells are studied together with their respective time and cost estimates. The time estimate of horizontal geothermal wells is benchmarked to previously drilled vertical and horizontal oil wells, since the data belonging to horizontal wells was not available for study. The findings indicate that the horizontal drilling scenario would take only 7 months more than the vertical drilling scenario. Monetary wise; horizontal wells for a geothermal field is estimated to be drilled 41% more in cost. A hypothetical geothermal field model is generated for the simulations, using TOUGH2. The simulations of four scenario sensitivity analyses reveal that drilling of horizontal wells provide efficient energy extraction out of a geothermal field, in comparison having the wells drilled vertically. The approach provides powerful comparison without having made any investment in the hypothetically simulated geothermal field. The study is a novel in kind since in country such as Turkey there is no horizontal well drilled within the geothermal fields. The analysis of the results indicate that energy production from the horizontal wells are greater than the energy production of vertical wells, definitely paying off the additional investment costs for horizontal drilling and completion.