The Cementing Quality Improvement Technology of 9–5/8" Casing in the South China Sea HPHT Gas Field

Poor cementing quality of 9–5/8" casing in the South China Sea high temperature and high pressure (HTHP) gas well leads to severe annular pressure, which hinders the development of HPHT gas fields in Yingqiong Basin, South China Sea. We solve this problem and comprehensively improve the cementing quality by adjusting the specific gravity of mud to increase the safe operation window and create suitable conditions for cementing, combined with pre-flushing technology, rheology matching technology, casing centering technology, and safe & efficient displacement technology to improve the efficiency of flushing and displacement. The practical application of two highly deviated gas wells in Yingqiong Basin of South China Sea shows that this cementing technology has strong operability, successfully overcomes the difficulties of 9–5/8" casing cementing HTHP gas wells, and effectively solves the problem of poor cementing quality of 9–5/8" casing once and for all.