UBC Faculty Research and Publications

Interference Fracturing: Non-Uniform Distributions of Perforation Clusters that Promote Simultaneous Growth of Multiple Hydraulic Fractures Peirce, Anthony; Bunger, Andrew

Abstract

One of the important hurdles in horizontal well stimulation is the generation of hydraulic fractures (HFs) from all perforation clusters within a given stage despite the challenges posed by stress shadowing and reservoir variability. In this paper we use a newly-developed, fully coupled, parallel-planar 3D HF model to investigate the potential to minimize the negative impact of stress shadowing and thereby to promote more uniform fracture growth across an array of HFs by adjusting the location of the perforation clusters. In this model the HFs are assumed to evolve in an array of parallel planes with full 3D stress coupling while the constant fluid influx into the wellbore is dynamically partitioned to each fracture so that the wellbore pressure is the same throughout the array. The model confirms the phenomenon of inner fracture suppression due to stress shadowing when the perforation clusters are uniformly distributed. Indeed, the localization of the fracture growth to the outer fractures is so dominant that the total fractured area generated by uniform arrays is largely independent of the number of perforation clusters. However, numerical experiments indicate that certain non-uniform cluster spacings promote a profound improvement in the even development of fracture growth. Identifying this effect relies on this new model’s ability to capture the full hydro-dynamical coupling between the simultaneously evolving HFs in their transition from radial to PKN-like geometries.

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