Optimization of Velocity String Drainage and Gas Recovery Process for Sour Gas Wells in Jingbian Gas Field

Abstract

In view of the gradual attenuation of gas well energy during the development of Jingbian gas field, the liquid carrying effect of some gas wells with small gas production becomes worse, the drainage effect of 60 % gas wells is not ideal, and the H2S content of the lower paleo-sulfur gas wells is high, the salinity is high, there is a certain corrosion, and most of the drainage measures cannot be implemented. The optimization of sulfur-resistant velocity string was carried out from the aspects of velocity string size and pipe material, and the appropriate pipe diameter and pipe material were selected. A new type of broken disc speed string plug was developed, which successfully solved the problem that the existing plug could not be broken or returned after construction. The field application results show that compared with the 27/8 “ string, the liquid carrying flow rate is reduced by 82 %. After 2.5 years of service, the anti-corrosion performance of the pipe is good. The cumulative increase of the well is 445.4 thousand cubic meters, and the effective rate of the measures is 97.45 %. The stable and continuous liquid carrying of the gas well is realized, which has a good application effect. It has certain reference significance for the implementation of the drainage gas recovery technology of the velocity string in the lower ancient sulfur gas well.