Although hydraulic fracturing has been used for several decades in the stimulation of hydrocarbon reservoirs, a thorough understanding of the interwoven phenomena is still lacking, especially in the case of porous media. This paper describes a two-dimensional numerical approach allowing the study of the fluid/rock skeleton interaction. The elastic stress analysis is coupled with the transient fluid-flow phenomenon. By introducing a failure criterion based on the critical stress intensity factor, quasi-static situations can easily be studied and instability conditions outlined.
This approach was used to interpret fracture initiation, fracture reopening as well as fracture closure after shut-in. The pressure/time curves generated for each of these phenomena clearly depend on the percolation characteristics of the fracturing fluid and the contact time as well as on the intrinsic properties of the rock mass.