The application belongs to the technical field of oil and gas
field development, and discloses a CO2 flooding gas
injection well annular pressure leakage point discrimination method, treatment measures and a device. The method comprises the following steps: during the injection stop, sampling is carried out by using a field oil casing annular
sampling valve, the return of annular protection fluid is observed, and the leakage point position is judged in combination with the oil casing pressure change dynamic in the previous gas injection process; if no annular protection fluid is returned during sampling, and the returned medium is all gas, then pressure relief testing is carried out through the external
discharge pipeline, during the pressure relief process, the external
discharge valve is kept at a constant opening, and the tubing pressure, casing pressure, output
gas composition and output gas temperature change are recorded at the same time; according to the obtained pressure relief condition, in combination with the output
gas composition and temperature change, the leakage point position is judged. The application comprehensively analyzes and judges the leakage point by the oil casing annular sampling, the oil casing pressure, the output
gas composition and the temperature change during the casing pressure relief process, and provides an important basis for the annular pressure leakage reason judgment and
risk control in the CCUS development process.