NUMERICAL SIMULATION OF HYDRAULIC AND NATURAL FRACTURE INTERACTION AND PROPAGATION

The production of unconventional reservoirs has revolutionized the oil and gas industry strongly, through the development and innovative applications including horizontal drilling, shale stimulation by hydraulic fracturing and microseismic monitoring of the stimulation. However, pre-existing fractures in hydrocarbon reservoirs make it difficult to propagate the hydraulic fracture and possibly the microseismic interpretation of the stimulation. In addition, the interaction between hydraulic fractures and natural fractures may lead to complex networks of fractures which can connect with shallower layer aquifers or geological faults and eventually increasing of activation risk and seismicity induced on the area. This work presents a numerical technique using the finite element method to study the interaction of hydraulic and natural fractures and to predict the direction of fracture propagation (cross, arrest or open the natural fracture). The hydraulic fracture was simulated using cohesive elements with fully coupled model of flow, stress and damage. The constitutive Mohr-Coulomb model was implemented in the cohesive elements through the UMAT user routine to represent the natural fracture behavior. Comparison of the numerical and published experimental studies results has shown good agreement.