Exploring the propagation of hydraulic fracture with nonuniform stress based on the block distinct element method

Abstract

The stress field is a critical factor for fracture propagation in hydraulic fracturing. Attention should be paid to fracture propagation with the nonuniform stress field. A stress field with gradient was established to investigate the influence of the nononuniform stress on fracture propagation. Based on the three‐dimensional block distinct element model the fracture propagation law with nononuniform stress was obtained. The mechanism of stress gradient and magnitude of uneven fracture propagation was revealed. Aiming at the uneven propagation, the influence of elastic modulus and construction parameters was analyzed. The results show that the influence of the elastic modulus follows the χ2 distribution equation and the influence of construction parameters can be expressed by the product of the injection rate and fluid viscosity. This conclusion is of theoretical significance for fracturing with nonuniform in situ stress.