Synthesis and assessment of heat-resistant cement retardant SCR180L for oil producers

Slow development of strength or super retarding may occur at top of cement slurry under large temperature difference during cementing of deep well, super-deep well, and long cementing intervals. To address these problems, an innovative heat-resistant retardant SCR180L was developed by using 2-Acrylamido-2-Methylpropane (AMPS), N-vinylpyrrolidone (NVP) and itaconic acid (IA) as raw materials. In addition, infrared spectrum was used to characterize structure of the co-polymer. Lab test showed that SCR180L can satisfy demands of cementing operations with circulation temperature of 70-180 ℃. Under 100 ℃ and 50 MPa, the thickening time of cement slurry with 0.9%-1.8% SCR180L is prolonged to 127-331 min. Under 150 ℃ and 70 MPa, the thickening time of cement slurry with 2.7%-3.6% SCR180L is further prolonged to 214-409 min. The more retardants added, the longer thickening time can be observed. Under temperature difference of 70 ℃, favorable growth of cement slurry strength is observed, with the cement strength at 24 h over 14 MPa. The retardant displayed high salinity resistance up to 18%. Field applications reveal that SCR180L has outstanding heat resistance and is applicable for a wide range of temperatures. With insignificant impacts on compression strength of the cement, the innovative retardant can satisfy demands for cementing operations in deep wells, super-deep wells, and long cementing intervals where large temperature difference may exist