Overview of analytical , experimental and numerical models for interactions between hydraulic fracture and natural fractures

Overview of analytical , experimental and numerical models for interactions between hydraulic fracture and natural fractures

Hydraulic fracturing was developed mainly as a technique to increase recovery from oil reservoirs, but it now is applied in a wide range of subsurface engineering applications. Initial hydraulic fracturing analyses were assumed a single fracture propagated symmetrically from a borehole in a stressed elastic continuum. However, it is recognized that pre-existing fractures have considerable impacts on hydraulic fracture propagation, distributions of fluid pressure and stresses in the surrounding rock. We are sure that natural fractures can divert hydraulic fracture paths significantly which creates difficulties in proppant transport and eventually job failure. There are fundamental questions as to how the hydraulic fracturing can be affected by preexisting faults, rock joints and etc. Therefore, developing a greater understanding of the mechanics of hydraulic fracturing in naturally fractured rock masses should be an industry-wide imperative. In this paper, we will review the recent analytical, experimental and numerical investigations that have been done to simulate propagation of hydraulic fracture in naturally fractures reservoirs. Finally, we will categorize a wide range of parameters, including the configuration of hydraulic fracture/natural fracture, the inclination angle of natural fracture, in-situ stress state, and the frictional properties along the natural fracture that may affect the interaction mechanism including the penetration, arrest, offset crack propagation, and diversion when the hydraulic fracture (HF) joins with the natural fracture (NF)