Some continuum considerations of the hydraulic fracturing process : Hanson, M E; Shaffer, R J Proc 19th US Symposium on Rock Mechanics, Stateline, Nevada, 1–3 May 1978, V1, P283–287. Publ Reno: University of Nevada, 1978

Abstract

The hydraulic fracturing process has been the subject of analysis with newly developed two-dimensional theoretical numerical models. These models include descriptions of both the elastic continuum and porous flow fields which are coupled to permit study of the effects of pore pressure changes on the fracturing process. Three hydraulic fracturing problem areas have been the subjects of analysis with these models. These include (1) the observable surface deformation due to horizontal layering near a vertical hydrofracture. For layering which is defined by changes in the Poisson's ratio across the layer with constant Young's modulus in the medium, the positions of the maximum slope and deflections on the surface did not change much from the homogeneous case. On the other hand, changes in Young's modulus across the layers resulted in some change in the position of the maximum slopes and deflections. (2) The effects of changes in the pore pressure and thus the stress field around the fracture due to migration of the fracturing fluid into the material surrounding the fracture. The pore pressure effects are evidenced by a reduction in the compressive lobes adjacent to the fracture faces and a widening of the dilatational lobes surrounding the fracture tips asmore » the pore pressure increases. The results also indicate that the stress intensity factors decrease as the pore pressure around the fracture increases. (3) The effects of layering on the stress field around the fracture. Here the elastic parameters can have a significant effect on the stress field around the fracture.« less