A Calculation Model for Hydraulic Fracture Height Considering Interlayer Slip Energy Dissipation

Summary The height of hydraulic fractures is a pivotal parameter in determining the volume of reservoir stimulation. Accurate prediction of fracture propagation across geological layers is crucial for designing optimal hydraulic fracturing operations and ensuring safety and cost-effective execution. One of the challenging issues in hydraulic fracturing research is accurately analyzing the impact of rock layer bedding planes on the height of hydraulic fractures. This paper equates the energy dissipated by interlayer slip to the increment of the equivalent fracture toughness of the corresponding layer and analyzes its impact on the height of hydraulic fractures. A hydraulic fracture height propagation model considering the influence of bedding planes is established, and the effects of interlayer spacing, in-situ stress, and fracture toughness on fracture height propagation are analyzed. The findings reveal that the energy dissipated by interlayer slip notably decelerates fracture tip propagation, leading to a stepped height propagation profile as fractures intersect bedding planes. Furthermore, both interlayer spacing and in-situ stress are crucial factors determining the propagation height of fractures. Reduced interlayer spacing and elevated in-situ stress enhance resistance to fracture propagation, necessitating higher pressures for continued propagation through bedding planes. In contrast, the effect of the rock layer’s fracture toughness on fracture height is relatively limited. The model presented herein offers a theoretical framework for estimating hydraulic fracture height in layered formations.