The development of many shale plays has been met with significant challenges, including low production rates and rapid production declines, and many ideas and concepts have been tried to address these. Multi-well completions, like ‘Simulfracs’ and ‘Zipper fracs’ for example, have been attempted as a means to increase production, but these have met with only limited success.

The authors have shown in previous work that multi-well completions increase the in-situ stress field around the created hydraulic fractures, which has the effect of stabilizing natural fractures and weakness planes (making them more resistant to shear). Further, the authors have also shown in previous work that the increase in shear from the tip of propagating hydraulic fractures, in a Zipper frac multi-well completion for example, is a complicated factor of well spacing, frac spacing, hydraulic fracture length (for a given well spacing), natural fracture mechanical properties, and in-situ stress.

In this paper, we present the results of a discrete element model numerical study of multi-well completions simulated in a fully hydro-mechanical coupled fashion. Building upon the previous work of the authors and others, the influence of changes in the in-situ pressure are considered in order to more completely understand the mechanical interactions between propagating hydraulic fractures and natural fractures during multi-well completions. The study includes a parametric study of well configuration, in-situ stress conditions, in-situ pressure, and mechanical properties on the ability to enhance natural fracture shear from multi-well completions and increase hydrocarbon production.

The quantitative results of the study provide a direct means to consider when multi-well completions may help increase hydrocarbon production. Further, the results of the study also provide a means to optimize the application and design of multi-well completions as a function of the in-situ stresses, in-situ pressure, the mechanical properties of the natural fractures and weakness planes, and well configuration, which, ultimately, should lead to improved well economics.

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