Induced Stress Interference of Hydraulic Fracturing in Shale Reservoir

Abstract

Multistage fracturing in horizontal wells has been widely applied in shale reservoirs over the past decades, contributing to substantial productivity gains through the generation of a complex fracture network. The optimal cluster spacing and stage spacing in shale wells are determined based on the in situ geological characteristics and the induced stress interference generated by hydraulic fractures. The study of induced stress is particularly valuable because the in situ geological conditions are unable to be altered. In this article, an analytical method, which provides a conducive tool to compute induced stress, was introduced to explore the induced stress interference on complex hydraulic fracture networks. Commencing with induced stress around a single hydraulic fracture, the composite stress field was then computed with numerical simulation. The innovation of this article is that it proposed and verified horizontal reversal criteria, vertical reversal criteria, and the optimal cluster or stage spacing for forming the complex fracture network. The research obtained from this study will work as a beneficial resource for completion and reservoir engineers, empowering them to optimize the cluster spacing and stage spacing to maximize simulated reservoir volume in the shale reservoir development.