A Practical Solution Model for Transient Pressure Behavior of Multistage Fractured Horizontal Wells with Finite Conductivity in Tight Oil Reservoirs

Pin Jia,Xianzhe Ke,Defeng Wu,Hengfei Yin,Linsong Cheng,Zhuang Li,Mohammad Sarmadivaleh

doi:10.1155/2021/9948505

Abstract

Fractured horizontal wells have been widely used to develop unconventional oil and gas reservoirs. In previous studies, most studies on the transient pressure behavior of multistage horizontal wells were based on the assumption of single porosity medium, in which the coupling relationship of natural fractures and artificial fractures was not taken into account or artificial fractures were assumed to be infinitely conductive. In this paper, the fracture is finite conductive, which means that there is flow resistance in the fracture. Based on point-source method and superposition principle, a transient model for multistage fractured horizontal wells, which considers the couple of fracture flow and reservoir seepage, is built and solved with the Laplace transformation. The transient pressure behavior in multistage fractured horizontal wells is discussed, and effects of influence factors are analyzed. The result of this article can be used to identify the response characteristic of fracture conductivity to pressure and pressure differential and provide theoretical basis for effective development of tight oil reservoirs. The findings of this study can help for better understanding of transient pressure behavior of multistage fractured horizontal wells with finite conductivity in tight oil reservoirs.

Highlights

Tight oil reserves are always be seen as the alternative resources for conventional oil reservoirs due to their abundant reserves
As the artificial fractures caused by massive hydraulic fracturing and natural fractures form a complicated fracture system near wellbore, the percolation mechanism and production performance of multistage fractured horizontal wells are different from conventional fractured horizontal wells
Zhao et al [16] and Guo et al [17] presented a transient percolation model for multistage horizontal wells in shale gas reservoirs with dualporosity medium assuming that the artificial fractures are infinitely conductive

Summary

Introduction

Tight oil reserves are always be seen as the alternative resources for conventional oil reservoirs due to their abundant reserves. Yao et al presented a semianalytical model for multistage horizontal wells in which the pressure drawdown in horizontal wellbore is coupled with the reservoir, taking account of the finite conductivity of the fractures with point-source function method [15]. Zhao et al [16] and Guo et al [17] presented a transient percolation model for multistage horizontal wells in shale gas reservoirs with dualporosity medium assuming that the artificial fractures are infinitely conductive. On basis of the current research of fractured horizontal wells, this article builds a transient model in dual-porosity medium for multistage horizontal wells in tight oil reservoirs which takes into account of finite conductivity in the artificial fractures.

Physical Model

Mathematical Model

Characteristic of Type Curves and Sensitivity Analysis

Field Example

Summary and Conclusions