Stress interference calculation model and its application in volume stimulation of horizontal wells

A new model for calculating stress fields of fractured media was established by incorporating stress correction factor based on displacement discontinuity boundary element method. The accuracy of the new model is close to 3D displacement discontinuity model, and its calculation is significantly simplified. An algorithm for multi-fracture propagation geometry was proposed based on fracture criterion and fracture growth rate law, which was used to investigate multi-fracture stress interference and propagation geometry. The results show that the size of stress interference is determined by the shortest dimension of fracture face, which is 1.2−1.5 times fracture height when fracture length is longer than fracture height, and 1.2−1.5 times fracture length when fracture length is shorter than fracture height. The larger the ratio of fracture spacing to fracture height, or the smaller the ratio of net pressure to the differential principle stress, the more close to well-bores the deviation position is, and the larger the deviation angle is. The middle fracture propagates to the fracture at a further distance and one dominating fracture propagates longest when three-cluster fractures are not equally spaced, while the middle fracture propagates straightly when three-cluster fractures are equally spaced.