Study on the law of fracture propagation from multiple cluster limited entry perforation in shale reservoir

Abstract

The induced stress interference is serious under the condition of dense cutting fracturing, which makes it more necessary to optimize perforation cluster parameters to promote balanced propagation from multiple perforation clusters. The fracture propagation model is proposed by coupling rock deformation and fluid flow, and fracture morphology quantitative evaluation index is established to study the fracture propagation law under limit entry perforating parameters. The results show that the influence area of induced stress field becomes more complex due to the dense cutting fracturing. For the case of high density and uniform distribution of perforation holes, the heterogeneous propagation of multiple fractures is significant due to the induced shadow effect on the internal cracks. In the case of a fracturing interval with six perforating clusters, the strategy of small diam eter and low perforating density can effectively promote the uniform propagation from multiple clusters. In the case of non-uniform limited perforating, keeping the total number of perforations unchanged, increasing the number of perforations in the middle two clusters, and reducing the perforation number at both ends of the same fracturing stage, the limited entry perforation strategy can effectively optimize the fracture morphology and im prove the efficiency of multi cluster fracturing.