Inflow performance for highly deviated wells in anisotropic reservoirs

Abstract

Based on source function method and coordinate transformation, an inflow model for a highly deviated well in an anisotropic reservoir is developed according to reservoir-wellbore coupling. On this basis, the inflow performance of a highly deviated well in an infinite slab anisotropic reservoir with impermeable top and bottom boundaries are studied under both constant rate and constant bottom-hole pressure. For a highly deviated well producing at a constant rate in an infinite slab reservoir with impermeable top and bottom boundaries, when the equivalent permeability and other parameters are constant, the smaller the anisotropy ratio, the shorter the duration of early-time radial flow and intermediate-time transition flow, and the earlier the appearance of late-time pseudo radial flow is. With the increase of deviation angle, the influence of vertical permeability increases, while the influence of horizontal permeability decreases. When the anisotropy is weak, the influence of deviation angle on the inflow performance is less. With the increase of anisotropy, the influence of deviation angle increases significantly. Key words: anisotropy, highly deviated well, inflow performance, reservoir-wellbore coupling