Cementing technology for gas channeling prevention in Qiaogu Block of Tahe Oilfield

The stratum of the Kapushaliang group and Kumugeliemu group is unstable, causing downhole problems such as bore hole collapse, shrinkage and bit sticking. The gas layer in liner section is active, so it is difficult to prevent gas channeling. Through analysis and summary on early cementing treatments, taking formation lithology characteristics into account, micro-swell brine cement slurry for gas channeling prevention was optimized, with API fluid loss less than 50 mL, SPN value less than 3, and compressive strength higher than 14 MPa/24 h. The new gas channeling model, which considered the impact of cement slurry static cementing strength, filter loss and wellhead loading,was used to accurately forecast gas layer stabilization. The cementing technology and parameters were optimized and improved. The technology was applied in 2 wells and achieved good results, with excellent cementing quality in isolation interval, which met the requirements of cementing in Qiaogu Block.