New Method of Productivity Equation for Multibranch Horizontal Well in Three-Dimensional Anisotropic Oil Reservoirs

Abstract

As a highly efficient production method, multibranch horizontal well is widely used in the development of low permeability reservoirs, naturally fracture reservoirs, heavy oil reservoirs, shallow layer reservoirs, and multilayer reservoirs, because it can significantly improve the productivity of a single well, inhibit edge or bottom water coning, and enhance oil recovery. This paper presents a new productivity equation for multibranch horizontal well in 3D anisotropic reservoirs. By applying coordinate transformation, a 3D anisotropic reservoir is transformed into an equivalent isotropic reservoir with considering wellbore deformation and vertical radial flow. An analytical solution of multibranch horizontal well productivity in 3D anisotropic reservoirs is obtained by using pseudo-3D solving method and similar flow replaces theory. The results show that branch number n, branch length (l), and permeability anisotropy degree (β3) are the three main factors that have big effects on the production rate of multibranch horizontal well.