Numerical Analysis of Fracture Closure Pressure through Diagnostic Fracture Injection Test

ABSTRACT: The diagnostic fracture injection test based on the response of bottomhole pressure to fracture state is widely applied to estimate the reservoir parameters, in which closure pressure can be effectively identified. In this paper, A 2D fluid-solid coupling model using the cohesive zone method is built to simulate the fracture injection test, and the effect of rock mechanical property, in-situ stress and angle between fracture and primary stress on the fracture closure pressure is discussed. The results reveal that the minimum principal stress is the main influencing factor, in addition, as the elastic modulus and tensile strength increase, the closure pressure increases. When there is an angle between the fracture and the maximum horizontal principal stress, it should be noted that the closure stress value increases. The simulation results can provide the guidance for the calculate of closure pressure in the diagnostic fracture injection test.