耐高温油井水泥缓凝剂SCR180L的合成及评价

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

针对深井、超深井、长封固段固井中大温差下水泥浆顶部强度发展缓慢或超缓凝的难题,以2-丙烯酰胺基-2-甲基丙磺酸（AMPS）、N-乙烯基吡咯烷酮（NVP）和衣康酸（IA）为原料开发了新型高温缓凝剂SCR180L,并用红外光谱对共聚物的结构进行了表征。室内研究表明,SCR180L可满足循环温度范围为70~180℃的固井需求;100℃、50 MPa下,加入0.9%~1.8%SCR180L的水泥浆稠化时间延长到127~331 min;150℃、70 MPa下,加入2.7%~3.6%SCR180L的水泥浆稠化时间延长到214~409 min,且随缓凝剂的加量增加而有规律的延长;温差70℃条件下水泥浆强度发展良好,24 h水泥石强度大于14 MPa;缓凝剂抗盐能力可达到18%。现场应用结果表明,缓凝剂SCR180L耐温性能好,温度适应范围广,对水泥石抗压强度的影响不明显,可以满足深井、超深井及长封固段、大温差固井的应用需求。

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 SCR180 L 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 SCR180 L 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% SCR180 L is prolonged to 127-331 min. Under 150 ℃ and 70 MPa, the thickening time of cement slurry with 2.7%-3.6% SCR180 L 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 SCR180 L 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