一种低温浅层多功能抗窜水泥浆体系

Multi-function Anti-channeling Cement Slurry for Low Temperature Shallow Wells

针对低温浅层井油气水窜问题,开发了一种新型多功能复合型水泥浆体系。该水泥浆以有机物和无机高价阳离子复合而成的无氯型早强剂为主体,并添加能提高水泥浆抗窜阻力的防窜降失水剂。室内实验表明,该水泥浆具有早期强度高、后期强度不衰退、过渡时间短、失水量低、稠化时间可调、微膨胀等特点,能够从多方面控制窜流的发生;在低温下的滤失量小于50mL;同时该体系避免了其它早强剂由于引入大量氯离子而对套管造成的电位腐蚀及对地层的污染,从而能够保护储层,延长油井的使用寿命。

A new multi-function cement slurry system is developed for use in low temperature shallow wells to combat the oil and gas channeling.This cement slurry is formulated with a chloride-free early strength agent compounded with an organic material and an inorganic multi-valent cation,and a filtration reducer which improves the performance of anti-channeling of the cement slurry.Laboratory study shows that this slurry has a high early strength,a sustained later strength,a short transition time,a low filtration rate,an adjustable thickening time and a very small expansion,thus preventing the occurrence of channeling.The filtration rate of the slurry is less than 50 mL at low temperatures.Since there's no chlorides in the system,corrosion to casing string and contamination to formation are circumvented.