Numerical Simulation of Non-Uniform Modified Zipper-Fracture Design

Thanks to astonishing advances in oil and gas technology, new fracturing designs have been developed to enhance production of trapped hydrocarbons, especially in low-permeable shale reservoirs. The new completion designs aim at mitigating side-effects of stress shadowing whereas enhance the far-field fracture complexity. This paper concentrates on the “Modified Zipper-Frac” (MZF) design as one of those techniques, which increases the stress interference between the fractures to enhance the hydrocarbon production. In the present study, the Cohesive segments method in combination with Phantom Node Method, termed CPNM, is established to simulate the initiation and propagation of multiple fractures along arbitrary, solution-dependent paths. The proposed CPNM is capable of simulating non-planar hydraulic fracture propagation for studying the stress shadow effects resulted from existing induced fractures. As opposed to original MZF, the stress shadow effects are managed through non-uniform fracture spacing. In this paper, the advantages and disadvantages of the stress shadowing effects, as a function of fracture spacing, on the fracture propagation path, pore pressure of the formation, and in-plane shear stress have been studied.