Research and Application of Anti-water Channeling Cementing Technology in Changqing Oilfield

After years of water injection development, Changqing Oilfield has entered the late stage of high water content development. The cementing of adjustment wells is challenged by issues such as dense and numerous water injection wells, nonuniform formation pressure, dynamic formation fluids, factors affecting production and site-specific constraints. To address these challenges, a specific material named powder anti-dispersant agent (HAPA) was developed based on the theories of electric double layer compression and adsorption bridge bridging through rational molecular structure design. A fully dry-mix, early-strength, underwater non-dispersion cement slurry was formed by encapsulating cement particles within a network structure of polymer chains entangled with the powder material that does not disperse when exposed to water. This enhances the cohesion of the cement slurry and prevents the cement particles from being dispersed by external water erosion, thereby endowing the cement slurry with the ability to resist water invasion. Combined with cementing technology such as casing centralization, balanced pressure design, displacement control with gradual pump rate variations, make up anti-water channeling cementing technology, an effective anti-water channeling cementing technology for adjustment wells in the Changqing Oilfield has been established. According to incomplete statistics, this anti-water channeling cementing technology has been applied to 10 wells in Changqing Oilfield. And has achieved a 100% qualified rate for cementing quality at both the first and second interfaces, which effectively solving problems such as multiple water layers, small spacing between oil layer and water layer, and active bottom water, thus effectively ensuring the sealing integrity of cement sheath.