Coupled Hydro-Geomechanical Simulation of Hydraulic Fracture Propagation in Unconventional Reservoirs Using a Mesh Fragmentation Technique
Marcela Seixas1; Leila Beserra2; Leonardo Guimarães1; Osvaldo Manzoli3
1 Universidade Federal de Pernambuco; 2 Universidade Federaal de Pernambuco; 3 Universidade Estadual de São Paulo
doi:10.20906/CPS/CILAMCE2015-0507
Resumo
The interest in studies related to the hydraulic fracturing process has increased over the last decade, mainly due to the exploitation of unconventional reservoirs, which is growing and becoming more important to the current energy demand, with the estimation of the existence of large shale reserves spread over several countries. Numerical modelling of such processes is a challenging task because of the complexity of the physics involved, and because of the structurally complicated geometry of the reservoir. The interaction between rock's mechanical properties, in-situ stresses, and heterogeneities such as natural fractures and weak bedding planes is determinant of the induced fracture geometry. To solve this kind of coupled hydro-mechanical problem, the Finite Elements Method is one of the most versatile and widely used. The present study propose a numerical technique called "mesh fragmentation", that uses solid finite elements with high aspect ratio combining with a proper strain softening constitutive model to reproduce the effects of fractures formation process. This methodology, based on the Continuous Strong Discontinuous Approach, consists in introducing these high aspect ratio elements between regular elements of a finite element mesh. Some advantages of this technique are that it can be easily adapted to standard finite elements programs and no tracking algorithms are necessary to follow the evolution of the fracture. The case studies presented in this paper show the ability of the proposed technique to model hydraulic fracturing propagation in unconventional reservoirs.
Palavras-chave: Hydraulic Fracturing; Numerical Simulation; Fragmentation Technique; High Aspect Ratio Elements