Study on the Ground Measurements of Key Parameters of Tubing Leakage Point in Sustained Annular Pressure Gas Well

Sustained annular pressure (SCP) is a common phenomenon in offshore gas fields, which poses a threat to the integrity of gas Wells. Among all the causes, the leakage of tubing string poses the greatest threat to the safety of production. In production practice, it is necessary to measure the key parameters of the leakage point to evaluate the risk. Aiming at this demand, the gas flow model in tubing and the pressure build up model in A-annulus are established. A method to determine the key parameters of leakage point was proposed based on the dynamic liquid level test and annular pressure releasing down test. Through analyzing the flow conditions of leakage point at different data points, the cross-validation method of test data was presented. This method not only provides two kinds of optional test methods for key parameters of leakage point, but also evaluates the reliability of test data, so it has a good value of popularization in offshore gas fields.