The Numerical Approach for Predicting Productivity from Mutiple-fractured Horizontal Wells under Non-Darcy Conditions

Abstract

Abstract Horizontal wells with multiple fractures are becoming more prevalent in tight gas reservoir. However, it is uneasy to obtain the applicable deliverability formula of multiple-fractured horizontal wells using analytical method in consideration of multiple factors, such as the non-Darcy effect, interference between fractures, the coupling effect with reservoir, and formation heterogeneity. This project investigates the deliverability formula of multiple hydraulically fractured horizontal wells in tight gas reservoir using a special numerical method with a focus on the existence of non-Darcy effect and formation heterogeneity. Numerical model expected from daily production data, including wellhead pressure history and production history, is obtained using the numerical well test method, which has an advantage in considering reservoir heterogeneity and complex boundary. The effect of non-Darcy in gas well is discussed using rate dependent skin when constructing the numerical model. The parameters of the numerical model on multiple fractured horizontal well are validated compared with analysis of real pressure build-up well test data. Productivity well test is then simulated based on the previous numerical model, and binomial deliverability equation is obtained from simulated productivity well test curve. The error of absolutely flow rate which derives from the simulation results and modified isochronal test from the field is less than 6%. This paper provides a fast and reliable numerical tool to multifractured horizontal well performance prediction in tight gas reservoir, especially considering non-Darcy effect and reservoir heterogeneous.