The Control Method of the Longitudinally Full-utilization during Integral Fracturing in Multi-layer Reservoirs

ABSTRACT: To address the high costs associated with traditional multi-stage fracturing techniques and the ineffective reservoir stimulation in multi-layer fracturing, this study aims to establish a vertical full-utilization control method for multi-layer simultaneous fracturing in vertical wells. Based on a fully coupled fluid-solid 3D fracture propagation numerical model, the influence mechanisms of reservoir heterogeneity, perforation parameters, and temporary plugging parameters on multi-layer fracture propagation and fluid diversion characteristics were systematically investigated. Key findings include:(1) Optimal selection of perforation intervals effectively mitigates the impact of interlayer geomechanical differences, promoting balanced fracture initiation across vertically distributed reservoirs. (2) When the interlayer tensile strength difference is 1 MPa, a perforation friction of 5 MPa achieves synchronized fracture propagation. (3) For cases where the minimum horizontal principal stress in the middle layer exceeds that of adjacent layers by 2 MPa, a perforation friction of 7.5 MPa maintains balanced multi-fracture growth. Conversely, when the middle layer exhibits 2 MPa lower stress, perforation friction should be reduced to 2.5 MPa. (4) Temporary plugging agents enable dynamic adjustment of fracturing fluid distribution, ensuring uniform fluid intake and synchronized propagation of multiple fracture clusters. This research provides theoretical foundations and technical guidelines for optimizing multi-layer fracturing parameters in vertical wells.