On the stress shadow effects of multiple stage hydraulic fracturing in unconventional reservoirs by using cohesive phantom node method

Production efficiency from low permeability shale reservoirs demands promoting techniques including horizontal well drilling and multiple hydraulic fracture stimulation. Developing robust numerical models for hydraulic fracturing is imperative inasmuch as an appropriate fracturing job in a porous medium cannot be extended to another owing to different characteristics and limited access to the field data acquisition. In order to represent a method, which is capable of capturing the nonplanar hydraulically fluid-driven crack propagation with unpredictable path, in one hand, and tackling the feasible emergence of multiple cohesive cracks in a porous medium with fracture process zone at the crack tip, on the other hand, the cohesive segments method in combination with phantom node, called CPNM herein, is employed to simulate 3-D non-planar hydraulically driven fracture problem in a quasi-brittle shale medium. In this paper, double and triple-stage fracturing in a quasi-brittle shale layer are modelled by using CPNM. It has been concluded that the stress shadow impacts of hydraulic fractures on each other influences significantly not only fractures' path and aperture, but also pore pressure formation.