一种低温早强低密度水泥浆

Study and Application of Low Temperature Early Strength Low Density Cement Slurry

低温下,常规低密度水泥浆体系早期强度发展缓慢,水泥石胶结能力差,影响了水泥环封固质量,浅层易漏井固井质量问题日益突出,为此,进行低温早强低密度水泥浆体系研究。根据紧密堆积理论及综合室内实验研究,研制了密度为1.30~1.50 g/cm^3的低温早强低密度水泥浆体系,主要优选了超细胶凝材料和锂盐复合早强剂,增加了低密度水泥石的致密性,提高了低密度水泥石的早期强度,25℃凝结时间为13 h,24h抗压强度为10.2 MPa。该体系具有低温早期强度高,凝结时间短,稳定性好等优点。在大庆油田现场成功应用2口井,固井质量合格率100%,取得良好的应用效果。

The early strength of conventional low density cement slurries developed very slowly at low temperature,and the poor cementing ability of these slurries negatively affect the quality of well cementing.In shallow wells with frequent mud losses,this problem is quite common.To resolve this problem,studies have been conducted on low temperature early strength low density cement slurry.Based on the close packing theory and laboratory experimental study,low temperature early strength low density(1.30-1.50g/cm3)cement slurries were developed.Ultra-fine gelled material and an early strength agent made by compounding lithium salts were used to improve the soundness and early strength of the low density set cement.The setting time of the low density cement slurry at25℃is13h,and the24h strength is10.2MPa.This low density cement slurry has high early strength at low temperatures,short setting time and good stability.It has been used on2wells in Daqing Oilfield with great success,and the well cementing jobs were100%qualified.