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Abstract Fractured reservoirs are distributed with natural fractures of various shapes and sizes, which are the main reservoirs. Due to the uneven distribution of natural fractures, the current main method of fracture reforming is to communicate the natural fractures through hydraulic fractures and to establish a flow channel between the fractures and the wellbore. Clarifying the expansion law of hydraulic fractures in fractured reservoirs is conducive to enhancing the effect of reservoir modification. In this paper, a numerical model of hydraulic fracture extension in a reservoir based on a discontinuous discrete fracture model is established. Firstly, a reservoir fluid-solid coupling stress model is established, and then the discrete fracture model is used to construct the hydraulic fracture, which allows the hydraulic fracture to expand along the initially delineated mesh, and the minimum strain energy density criterion is used to determine the expansion path. According to the different distribution patterns of the seam holes, three reservoir types with fracture characteristics are established in this paper. The simulation results of reservoirs with different natural fracture characteristics show that natural fractures perturb the local stress field and deflect the extension path of hydraulic fractures. The more developed the natural fractures are, the more pronounced the perturbation effect is. According to the different relative positions of hydraulic fractures and natural fractures, they can be divided into frontal repulsion and lateral attraction, which are not conducive to the communication between hydraulic fractures and natural; increasing the net pressure inside the hydraulic fractures can enhance the dominant role of the hydraulic fractures when they intersect with natural fractures, and reduce the degree of deflection, which is conducive to the breakthrough of the natural fractures’ repulsion, and communicate with natural fractures in the direction of the dominant stress. The pressure at the injection point when the hydraulic fracture penetrates the natural fracture is mainly controlled by the flow energy loss in the hydraulic fracture and the leakage rate of the natural fracture. The optimization of the fracturing fluid performance can reduce the penetration pressure and enhance the extension range of the hydraulic fracture. The results of this paper provide references for the fracturing modification evaluation of fractured reservoirs.
Hui et al. (Mon,) studied this question.