关键词: 深层页岩, 断层, 非均匀应力场, 压裂缝网, 地应力差

Abstract: Deep shale formation faults are relatively developed, and the nearby geostress field presents non-uniform distribution. The fractures generated by hydraulic fracturing may propagate non-planarly, asymmetrically and irregularly, which further affects the volume of fracture network. To address this problem, taking the actual fault in Well Y101, South Sichuan Block as an example, a non-uniform stress field characterization model and a compression fracture network expansion model of the faults in the complex deep shale gas formation were established to analyze the influence of fault characteristic parameters on the ground stress, and to quantitatively study the influence of fault type, fault distance, length, height, strike, dip angle and distance on the fracture network volume. The results show that the larger the displacement, length and height of the fault, the greater the geostress deflection angle and geostress difference, and the smaller the volume of fracturing fracture network. The larger the dip angle of the fault and the distance away from the fault, the smaller the geostress deflection angle and geostress difference, and the bigger the volume of fracturing fracture network. The larger the strike of fault, the greater the geostress deflection angle, the smaller the geostress difference, and the bigger the volume of fracturing fracture network. The influence degree of the following fault parameters on the volume of fracture network is in descending order: dip angle, strike, fault displacement, distance, height and length. The study can provide a theoretical basis for the optimization design of fracturing fracture network under the complex structure of deep shale.

Key words: deep shale, fault, non-uniform stress field, fracturing fracture network, geostress difference