Analysis of transient production rate performance of horizontal well in fractured low permeability reservoirs based on finite element method

Abstract

The proportion of oil produced from low permeability reservoir has increased in China in recent years and the nonlinear seepage exists in low permeability reservoirs widely according to laboratory tests and field experiences. Most previous scholars' research only focus on threshold pressure gradient, which cause result less accurate than the model considering nonlinear section of the seepage characteristic curve when interpreting transient production rate performance due to nonlinear seepage and stress sensitivity. A mathematical model of horizontal wells in fractured low permeability reservoirs considering nonlinear coefficient is established in this paper, which is solved by finite element method (FEM). Sensitive analysis is conducted on relevant parameters including permeability modulus, nonlinear coefficient and so on. With the effect of nonlinear cross flow, the concaves of derivative curves of pressure and production rate become shallower and move to the right. The paper significantly improves the reliability of interpretation results of fractured low permeability reservoir production rate data. [Received: March 8, 2018; Accepted: July 5, 2018]