Quantitative well placement optimisation of five-spot patterns in an anisotropic oil reservoir

This article describes the influence of anisotropic permeability on the development effects of five-spot patterns. To calculate the seepage problem in anisotropic reservoirs, a coordinate conversion method is used to transform the anisotropic reservoir into an equivalent isotropic reservoir; and the streamline model is used to analyze the development process. The results indicate that the anisotropic permeability has destruction and reconstruction effects on general well patterns, and the relative angle between the direction of maximum principal permeability and the well line direction is a key factor for the occurrence of these effects. The relation between the destruction effect and the reservoir anisotropy is analyzed quantitatively. To prevent the destruction of well patterns, a general analytical solution for the well placements of five-spot patterns is provided to optimise the development effects of anisotropic oil reservoirs. The results provide theoretical guidance for the reasonable construction of five-spot patterns in anisotropic oil reservoirs.