Parameter-Variable Experiments for Conductivity of Acid Etched Fractures

Abstract

Abstract Conductivity of acid etched fractures is the decisive factor of results of acidizing treatment. At present, tests for etched fracture conductivity are in all cases executed using fresh acid under fixed experimental conditions, which determines that the test results can only capture fracture conductivity of the near-wellbore zone. This paper investigates fracture conductivity in cases of varied acid concentrations, temperatures, fracture widths and flow velocities along the fracture length direction, via the parameter-variable experiment for fracture conductivity. Results show that the combined changes of acid concentrations, fracture widths and injection rates have considerable impacts upon the conductivity distribution of etched fractures along the fracture length. Maximum etched fracture conductivity occurs within a certain distance from the wellbore. Variation of acid concentration along the fracture length is the main reason for changes in fracture conductivity, while variations in fracture widths and acid flow velocities may greatly reduce the effective etching length of the etched fracture.