Application of Extended Finite Element Method (XFEM) to simulate hydraulic fracture propagation from oriented perforations

Date
2014-05
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Abstract

Majority of hydraulic fracture treatments are performed in cased, perforated wells. Perforations serve as the channel of fluid communication between wellbore and formation and as a starting point for hydraulic fracture to lower breakdown pressure. Hydraulic fracture propagation is intended to be in the direction of perforations, but they are not necessarily extended in the direction initiated. If not aligned with the direction of Preferred Fracture Plane (PFP), fractures reorient to propagate parallel to the plane of the least resistance. Extended Finite Element Method (XFEM) has been introduced as a powerful numerical tool in solving discontinuity problems to overcome the drawback of conventional Finite Element method especially when simulating fracture propagation. Using capabilities of XFEM in commercial FE software, a model was developed to investigate the effect of perforation orientation on fracture propagation. Different parameters and design configuration including perforation angle, perforation length, rock mechanical properties, stress anisotropy and changing medium properties are examined to better understand fracture propagation from cased perforated wells and come up with better perforation design when a hydraulic fracturing treatment is intended. The results from this study showed that hydraulic fracture propagation pattern is affected by the perforation deviation from preferred fracture plane (PFP) and perforation length. As expected, horizontal stress anisotropy and rock mechanical properties were found to have strong influence on fracture propagation from perforations. The simulation results from this study offer methods to enhance perforation design for hydraulic fracture treatment especially in case of high stress anisotropy and high uncertainty on preferred fracture plane.

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Keywords
Extended finite element method, Hydraulic fracture, Fracture propagation, Perforation, Reorientation
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