A methodology for determining the optimal well spacing in sandstone geothermal reservoirs through production-reinjection equilibrium simulation

Abstract

Objective In order to accomplish the objective of sustainable development and utilization of geothermal energy, it is imperative to elucidate the optimal production-reinjection well spacing considering varying quantities and temperatures of reinjection. Methods The thermal reservoir of the Guantao Formation in northern Shandong Province is selected as the research subject, and a conceptual model and mathematical model for layered thermal reservoir development are established. COMSOL Multiphysics multifield coupling simulation software is employed to develop a geothermal production-reinjection well spacing calculator. The accuracy of the model is validated through parameter fitting and simulation results. Results Based on the software APP development function, which is guided by the input of ordinary users, the relevant parameter input was simplified for ease of use, leading to the establishment of an application for calculating geothermal production-reinjection well spacing. In contrast to previous studies that solely focused on production-reinjection well spacing, this study calculates optimal spacings under various conditions to meet real-world operational needs. The results indicate that the optimal production-reinjection well spacings, without experiencing thermal breakthrough are 290, 330, 360 m and 390 m at flow rates of 40, 60, 80 and 100 m3/h respectively. Conclusion In the layered conductive sandstone thermal reservoir area of northern Shandong, a reliable geothermal production-reinjection well-spacing calculator was developed through simplification of the conceptual model and credible numerical simulation results. Hydrothermal numerical simulation serves as a robust approach to determine rational production-reinjection well spacings, which are crucial parameters for geothermal development and utilization projects including exploitation quantity, recharge quantity, injection temperature, and production-reinjection well spacing. These determinations contribute to the sustainable development and utilization of geothermal resources.

Keywords

• sandstone geothermal reservoir
• production-reinjection project
• production-reinjection well spacing
• thermal breakthrough
• hydrothermal coupled modeling
• app