Modeling Perforation Orientation and Hole Size Effects on Hydraulic Fracture Distribution in Horizontal Wells

Abstract

ABSTRACT A modeling study was conducted with the objective of investigating the effects of perforation design and perforation size consistency on treatment allocation in multicluster limited entry treatments. The numerical model couples an advanced wellbore and perforation flow simulator and a well-established fracture simulator, which enables realistic modeling of complex perforation designs and pumping schedules. The study demonstrates that low variability of entry hole dimension among perforations is an important prerequisite for optimization of multicluster treatment uniformity. Variation of initial diameter due to noncentralized perforation gun positioning is shown to cause preferential slurry distribution to larger perforations, faster erosion, and further shift of distribution to the most eroded perforations. Erosion of perforations receiving a major fraction of proppant reduces the pressure drop for the entire cluster and thus eliminates the positive effect of higher friction on proppant distribution along the stage. Perforation designs with consistent initial perforation sizes, e.g., achieved using zero-phasing perforation guns, are shown to result in more uniform treatment distribution among clusters. INTRODUCTION & MODEL DESCRIPTION The completion efficiency and production of horizontal multistage hydraulically fractured wells are strongly affected by the uniformity of slurry and proppant distribution among multiple simultaneously stimulated perforation clusters within a stage. Depending on the fracturing treatment design, various factors related to either reservoir properties and their variability (Kresse et al., 2023) or peculiarities of proppant transport in a well and perforation tunnels can determine treatment distribution regularity. In the case of limited entry designs, commonly employed to improve treatment distribution among multiple intervals, perforation friction is used to mitigate variation of slurry flow rates to different clusters. High values of perforation friction are usually achieved by reducing the number of perforations (Somanchi et al., 2017) and, accordingly, are more sensitive to inconsistencies in the dimensions of the fewer entry holes. Moreover, the reduction in the number of holes leads to an increased amount of proppant pumped through the individual perforation and facilitates erosion, which can diminish the positive effect of initially high friction and aggravate treatment distribution nonuniformity (Thiessen et al., 2021).