A New Calculation Method of Well Leakage in Gas Well with Annular Pressure

Safety and Environmental Protection Branch, CNOOC Energy Technology & Services, Haikou, Hainan, China

^* Corresponding author: luoheng2@cnooc.com.cn

Abstract

The gradual promotion of the concept of gas well integrity has made major oil and gas fields pay more and more attention to the integrity management and evaluation of gas wells with annular pressure. Annular leakage rate is one of the key parameters for gas well integrity evaluation. However, the leakage rate measurement of high-temperature, high-pressure, and acid-containing gas wells has high risks and costs, which are often difficult to obtain in field operations. In order to obtain the bottom hole leakage rate parameters of the gas well to assist the integrity evaluation, this article is based on the safety valve leakage model and the small hole leakage model, combined with the characteristics of the gas well with annulus pressure, the idea of applying the annulus leakage rate calculation from the perspective of model mechanism is analysed, and the model parameters are clarified as well. The application of the two leak models is compared by case wells calculation, which verifies their rationality and feasibility. The research of this paper provides a theoretical basis for the leakage evaluation of gas well with annular pressure, and promotes development of gas well integrity management research.