Pressure-transient analysis for a vertically fractured well at an arbitrary azimuth in a rectangular anisotropic reservoir

Abstract

The principal focus of this paper is on pressure-transient analysis for a finite-conductivity fracture at an arbitrary azimuth in a rectangular anisotropic reservoir. An analytical solution is derived by spatial integration of point-source along the direction of the fracture for a fracture at an arbitrary azimuth in a rectangular reservoir. Furthermore, type curves are generated to investigate the influence of the main parameters on transient pressure behavior, including permeability anisotropy, azimuth of the fracture, reservoir's outer boundary, and fracture conductivity. Strong effects of horizontal permeability anisotropy and azimuth of a fracture on transient responses can be observed. The more the fracture deviates from the direction of maximum horizontal permeability, lesser the drawdown needed to maintain constant flow rate. Therefore, it seems that the optimum orientation for the hydraulic fracture is perpendicular to the direction of maximum horizontal permeability. Outer boundary size dominates pseudo-steady-state flow and aspect ratio mainly affects the periods of radial flow and compound-linear flow. The existence and duration of bilinear flow and formation linear flow are mainly determined by dimensionless fracture conductivity. This paper provides a theoretical basis for well pattern deployment and fracture configuration in anisotropic reservoirs.