Flow Modeling in Rock Fracture for Long Time Simulation of Geothermal Reservoirs

The exploitation of geothermal power is an energy source with great potential for the future. But the exploration and development of deep geothermal energy is connected with high cost and risk, these require a reliable numerical prediction. The analysis of geothermal reservoir is usually interested in long time physical properties (e.g. 50–100 years). Typical CFD simulation tool could be used somehow, but the computational effort may be limited due to incompatibility of small scale heterogeneities. Here we developed flow modeling in rock fracture, which describe the different characteristic flow in different dimension. The fluid flow in tube is described by one dimensional flow (1D flow), while flow in rock fracture is modeled as two dimensional flow (2D flow) on fracture plane. The 1D flow in tube and 2D flows in fracture are coupled to represent three dimensional flows in reservoirs. The solution of coupling system (1D and 2D flow) is obtained by iterative procedure, while the flow inside 2D fracture is calculated by cellular automaton. This algorithm is relatively fast for calculating flow inside rock fracture, especially for long time behavior of 3D–geothermal reservoir. (© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)