油井水泥浆高温悬浮稳定剂的开发及性能研究

Development of and Study on a High Temperature Suspension Stabilizer for Oil Well Cement Slurries

针对油井水泥浆高温沉降失稳问题,引入疏水单体N-十四烷基丙烯酰胺,制备了一种高温悬浮稳定剂,并测试了稳定剂的热增黏性能,分析了热增黏机理。综合评价了高温悬浮稳定剂对油井水泥浆沉降稳定性、流变性能、稠化性能和水泥石抗压强度的影响。结果表明,高温悬浮稳定剂通过分子间疏水缔合作用增加高温水泥浆的黏度;稳定剂的适用温度为60~150℃,最佳加量为0.15%;控制水泥石的密度差在0.025 g/cm3以内,具有非常良好的防沉降性能;稳定剂保证水泥浆的稠度系数变化很小,在4.441~5.760 Pa·sn范围内,保证水泥浆浆体稠度稳定;稳定剂对水泥石强度影响较小,水泥石强度满足固井施工要求。

A high temperature suspension stabilizer has been developed to deal with sedimentation of oil well cement slurries at elevated temperatures.The viscosifying property of the suspension stabilizer at high temperatures was tested and the mechanisms of viscosifying at high temperatures analyzed.The effects of the high temperature suspension stabilizer on several properties of cement slurries,such as sedimentation stability,rheology,thickening curve and compressive strength of the set cement,were evaluated through laboratory experiment.It was found that the high temperature suspension stabilizer increases the viscosity of the cement slurry at elevated temperatures through hydrophobic association between molecules.The density difference of the set cement can be controlled within±0.025 g/cm3 by the addition of the stabilizer,indicating that the stabilizer has excellent sedimentation prevention property.The consistency coefficient of the cement slurry was maintained in a narrow range by the stabilizer,between 4.441 Pa·sn and 5.760 Pa·sn,and this made the consistency of the slurry stable.The strength of the set cement,which was almost not affected by the use of the suspension stabilizer,satisfied the needs of well cementing job.