Shuiwen dizhi gongcheng dizhi (Nov 2022)
A study of numerical simulations for enhanced geothermal reservoir parameters and thermal extraction based on microseismic data
Abstract
The development of clean, stable, and renewable hot dry rock geothermal energy is significant for alleviating the energy crisis, reducing environmental pollution, and improving human health. Enhanced geothermal system (EGS) is an advanced technology for developing geothermal energy efficiently by stimulating hot dry rock reservoir. This technology involves a complex hydro-thermal coupling process. A numerical approach is usually applied for analyzing heat extraction. In this paper, taking the geothermal reservoir of the Cooper basin in Australia as the research object, two models–a 3D zonal homogeneous permeability model and a heterogenious permeability model – are established based on the measured microseismic data of hydraulic fracturing. The latter one is inversed from microseismic data. The temperature field, seepage field and thermal performance of the reservoir are numerically studied, and their differences are compared and analyzed. The results show that with the same injection-production flow rate, fluid flows more quickly from the injection well to the production well while the temperature drops relatively more rapidly in the inhomogeneous model due to the dominant channel revealed by dense microseismic events near the wellbore. In the homogeneous model, the dominant flow channel is not as pronounced as in the previous model, and the temperature decreases more slowly. During the operation of the geothermal reservoir model, the change in heat recovery of the zonal homogeneous model is relatively stable, with a decline of 3.74%, and that of the inhomogeneous model is rather obvious, with a decline of 12.72%. Compared with the inhomogeneous model, a smaller temperature drop and a higher heat recovery exist in the homogeneous model. However, the permeability in the actual reservoir is uneven, and the simulated heat recovery of the zonal homogenization model is higher than the actual recovery. Therefore, the simulation results of the inhomogeneous model have more reference significance for practical engineering.
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