Modeling of Hydraulic Fracturing in a Poroelastic Cohesive Formation

Abstract

This paper investigates the main parameters that affect the propagation of a fluid driven-fracture in a poroelastic medium. The fracture results from the pumping of an incompressible Newtonian viscous fluid at the fracture inlet, and the flow in the fracture is modelled by the lubrication theory. Rock deformation is assumed as porous-elastic. Leak-off in the host rock is considered to account for the diffusion effects in the surrounding formation. The propagation criterion is of the cohesive type. Finite element analysis was performed to compute the fracturing pressure and fracture dimensions as a function of the time and length. It was found that higher pressures are needed to extend a fracture in a poroelastic medium than in an elastic medium, and the created profiles of poroelastic fracture are wider. It was found that grain compressibility plays a minor role and does not result any significant difference in the fluid pressures and fracture dimensions. Wider fracture profiles are obtained with higher injection rates. The fluid pressures and the fracture apertures are larger in the case of a high permeability formation.