Cementing technology suitable for Pingdingshan salt cavern gas storage

Pingdingshan salt cavern gas storage is characterized by thick salt formations, deep targets and multiple mudstone interbeds, so its cementing job is difficult and shall meet more requirements. The difficulties that occurred during the previous cementing were analyzed, such as circulation loss, poor cementation quality and no slurry returning to the wellhead. Then, a series of comprehensive measures were specifically studied to guarantee the smooth cementing and cementing quality, including brine cement slurry formula optimization, borehole preparation, prepad fluid optimization, well drilling and casing running. Well PT1 is an exploration well in Pingdingshan salt cavern gas storage. In this well, the single-stage cementing section of production casing is long, borehole size is large and wellbore conditions are complex. Its circulation loss during cementing is avoided by adopting salt-resisting cement slurry system whose comprehensive performance is good and adjusting and circulating the performance of drilling fluids sufficiently. And consequently, the cementing difficulties of Pingdingshan salt cavern gas storage are solved. The research results provide the valuable experience for the subsequent cementing operation in this area.