Investigation and Application of Perforation Optimization Method on Shale Gas Horizontal Well with Numerical Simulation of Multicluster Fracturing under Dense-Segment Pattern.

ABSTRACT

Multicluster fracturing of horizontal wells has evolved into a mature and widely adopted technique for exploiting unconventional oil and gas fields. A well-designed multicluster completion strategy can yield an ideal fracturing outcome, significantly enhancing production rates and potentially delivering substantial economic benefits. Nevertheless, empirical evidence suggests that fractured horizontal wells frequently exhibit pronounced nonuniform production profiles, a prevalent issue stemming from the irregular geometry of propagated fractures. This issue critically constrains production rates. To mitigate the adverse effects of low-uniformity fracture propagation, it is imperative to elucidate the factors influencing uniformity levels and their corresponding patterns. Despite extensive discussions on hydraulic fracture propagation mechanisms and optional factors in hydraulic fracturing engineering, there exists a notable oversight regarding the optimization of perforation parameters to achieve improved fracturing uniformity during well completion procedures. This paper introduces an optimization method for perforation parameters based on a fully coupled pseudo-3D numerical model of multicluster fracturing. The impact patterns of cluster spacing, perforation number, and initial perforation diameter on multifracture propagation results and uniformity levels are thoroughly examined. The multicluster fracturing model, developed using the displacement discontinuous method (DDM), is coupled with material balance, pressure transmission, hole erosion computation, and initiation asynchrony estimation. To quantify the uniformity level of the fracturing result, the modified propagation uniformity index (Ufm) is employed. Simulation results from 20 cases are categorized into six groups based on varied changing patterns of perforation parameters, leading to the identification of five recommendations for optimizing perforation parameters. By implementation of the discussed optimized perforation parameters, successful fracturing outcomes were realized.