Simulation Study of Acid Fracturing Initiation with Consideration of Rock Mechanics Parameter Variations

Deep carbonates hydrocarbon resources are abundant and hold significant potential for sustainable energy development in future. Acid fracturing is an effective technology for carbonate reservoirs development; however, it is difficult to predict the rock initiation pressure for acid fracturing, which restricts the efficient development of carbonate reservoirs. In this paper, the changes of elastic modulus, Poisson's ratio and tensile strength of carbonate rock samples are tested under different acid treatment duration and temperature, and rock mechanics parameter evolution models for acid treatment rocks are obtained by experimental results fitting. Then, the evolution models are embedded into fracturing finite element calculation program to predict fracture initiation pressures accounting the dynamic evolution of rock mechanics parameters for acid fracturing. The error between the predicted fracture initiation pressure and the field data is only 0.46