Research and Application of Suspending Agent for Cementing Isolation Fluid Enduring 220 °C

The utilization of suspending agents for isolation fluids is accompanied by certain challenges, including inadequate temperature resistance, suboptimal salt resistance, and limited pollution resistance. Through the optimization of organic and inorganic suspending materials, and the employment of orthogonal experiments, the BCS-Z suspending agent for high-temperature resistant isolation fluids has been developed. Performance evaluation experiments have demonstrated that this suspending agent exhibits commendable suspending properties. Through precise adjustment of the quantity added, the suspending agent ensures that the density difference between the upper and lower layers of the isolation fluid remains within a range of 0.05 g/cm3, thereby ensuring the absence of free fluid. The suspending agent exhibits notable temperature resistance, withstanding temperatures up to 220°C. It is resistant to salt by 15%, and it has been demonstrated to have excellent anti-pollution properties. Furthermore, when it is added to the cement slurry system, it has been shown to have no effect on the thickening time or cause abnormal thickening curves. The substance has been utilized in over 40 wells, including high-temperature and complex deep wells such as Tarim and Liaohe. The suspension stability of the isolation fluid at elevated temperatures is satisfactory, and on-site construction has proceeded efficiently.