Discrete-Fracture Modeling of Complex Hydraulic-Fracture Geometries in Reservoir Simulators

Xu, Yifei (The University of Texas at Austin) | de Araujo Cavalcante Filho, Jose Sergio (Petrobras) | Yu, Wei (Texas A&M University) | Sepehrnoori, Kamy (U of Texas)



Hydraulic fracturing is a dominant technology in unconventional resources development. Recent advances in fracture-diagnostic tools and fracture-propagation models make it necessary to model fractures with complex geometries in reservoir-simulation studies. In this paper, we present an efficient method to model fractures with complex geometries with reservoir simulators. Through nonneighboring connections (NNCs), an embedded discrete-fracture modeling (EDFM) formulation is applied to reservoir simulators to properly model fractures with complex geometries such as fracture networks and nonplanar hydraulic fractures. We demonstrate the accuracy of the approach by performing a series of case studies with two commercial reservoir simulators and comparing the results with local-grid-refinement (LGR) models and a semi-analytical solution. The limitations of the model are also discussed. In addition, the results show its computational efficiency as the complexity of fractures increases. We also present two numerical case studies to demonstrate the applicability of our method in naturally fractured reservoirs. The nonintrusive application of the EDFM allows insertion of the discrete fractures into the computational domain and the use of original functionalities of the simulators without having access to the source code of the simulators. It may be easily integrated into existing frameworks for unconventional reservoirs to perform sensitivity analysis, history matching, and production forecasting.