Equivalent flow channel model for doublets in heterogeneous porous geothermal reservoirs

• Published in: Renewable energy 2021-07, Vol.172, p.100-111
• Main Authors: Zhao, Zhihong, Dou, Zihao, Liu, Guihong, Chen, Sicong, Tan, Xianfeng
• Format: Article
• Language: English
• Subjects: Doublets; Equivalent flow channel; Geothermal reservoir; Thermal breakthrough; Tracer test
• ISSN: 0960-1481; 1879-0682
• DOI: 10.1016/j.renene.2021.03.024

This study presents a general numerical modeling framework for application to doublets in heterogeneous porous geothermal reservoirs. Extension of the equivalent flow channel model for fractured media leads to an inverse model that combines an analytical solution of solute transport equation with differential evolution method for global optimization. When constrained by data from tracer tests, the inverse model can calculate the geometric and transport parameters pertaining to equivalent flow channels that link injection and production wells. A distinct forward model is developed based on an analytical solution for heat transport in equivalent flow channels, where the parameters calculated from the inverse model serve as inputs for predicting thermal breakthrough at production wells. A case study uses the modeling framework in combination with data from tracer tests to calculate the parameters of equivalent flow channels that link two distinct doublets at Dezhou geothermal field, Shandong, China, followed by the prediction of production well thermal breakthrough. The results show that flow channel parameter values are similar for the two doublets. A sensitivity analysis is performed to understand the roles of flow channel dimensions and flow rate in equivalent flow channels in thermal breakthrough curves at production wells. •Equivalent flow channel model for doublets in heterogeneous reservoirs is developed.•Two tracer tests at the Dezhou geothermal field are studied by the proposed model.•Effects of channel dimensions and flow rate on production temperatures are studied.