Numerical Simulation of the Effect of Natural Fracture in Hydraulic Fracture Propagation Based on the Cohesive Zone Model

In many cases some barriers like low permeability, secondary porosity and decreasing in formation permeability due to damages casued by drilling, asphaltene and other problems confine oil production rate in unacceptable region and These problems reduce percentage of oil recovery from these reservoirs, These problems can be solved by utilizing hydraulic fracture method. A new model based on cohesive zone method coupling stress-seepage damage filed is developed to simulate the interaction between hydraulic fracture and natural fracture with using ABAQUS software. The effect of differential stress and approaching angle on the intersection between hydraulic fracture and natural fracture, as well as the effect of natural fracture cementing strength on the geometry of  hydraulic fracture propagation, have been investigated. While the hydraulic fracture initiates, propagates, and intersects with the natural fracture, it can either deflect into it or cross it by severing the natural fracture. The greater the approaching angle and differential stress , the easier it is for the hydraulic fracture to cross the natural fracture.The behavior of hydraulic fracture changes from deflection to crossing as the natural fracture cementing strength is increased.