Modeling of optimal installation of geothermal stations in the isotropic and shear-isotropic porous water reservoirs

Abstract

Purpose. Investigation of the optimal placement of geothermal stations in isotropic and shear-isotropic porous aquifers for effective using. The method of investigation. The numerical modeling of pressure distribution around geothermal stations in the anisotropic water porous reservoirs is carried out using a combined finite-element-difference method. Results. Analysis of the obtained results shows that the most effective using of the geothermal stations is possible in permeable reservoirs. In low-permeable reservoirs, the technical possibilities of using stations are significantly reduced. At the same time, the presence of shear isotropy of the reservoirs in all cases leads to decreasing of the filtration properties. For low- or extremely low-permeable reservoirs, the most optimal is the diagonal-cross-shaped arrangement of the geothermal stations relatively their main axes of anisotropy, in which production and injection wells alternate. The originality. For the first time, on the base of numerical modeling using a combined finite element-difference method, optimal configurations for the placement of geothermal stations in isotropic and shear-isotropic reservoirs were estimated. It was shown that in the low-permeable reservoirs it is possible to install a limited number of geothermal stations, when the distances between the production and injection stations do not exceed 25 m. At the same time, the most optimal arrangement of geothermal stations in the low-permeable reservoirs is the diagonal-cross-shaped installation relatively its main axes of anisotropy, in which production and injection wells alternate. Practical implementation. Theobtainedresults have showed that the intensity of filtration processes around geothermal stations significantly depends on their mutual location in low-permeable isotropic and shear-isotropic reservoirs. At the same time, the most optimal is the diagonal-cross-shaped location of the stations relatively the main axes of the anisotropy of the reservoir. The presented combined finite-element-difference method can be used for resolving various practical problems relatively the optimal location of geothermal stations.