高强增塑低密度水泥浆体系研究

常用的低密度水泥浆体系在低压易漏地区固井存在强度低的缺陷,油气勘探开发对低密度水泥浆体系提出了更高的要求。研究开发了以漂珠、水泥颗粒、微硅颗粒和颗粒级配增强剂为主构成的4级颗粒填充结构及与之配套的增韧复合纤维构成的高强增塑低密度水泥浆体系,对水泥石强度、水泥环抗冲击能力、水泥浆性能、浆体稳定性进行了室内实验。实验结果表明,水泥浆具有流变性能好、失水量小、稠化过渡时间短的优点,可显著提高低密度水泥石的综合强度、水泥浆的稳定性和防窜能力,与其他外加剂也有良好的配伍性。在胜利油田及川东北地区进行了现场应用,效果良好,为解决当前低压易漏井的固井问题提供了一个可行的途径。

Design of plasticized cement slurry system with high strength and low density and its application

The conventional cement slurry system with low density has the shortage of low strength while cementing the region with low pressure and easily lost circulation. So it needs to be improved to fulfill the higher requirement of oil/gas exploration and development. A four-level particles filled structure, mainly made up of microspheres, cement particles, micro-silicon particles, intensifiers for particle gradation, and a systematic plasticized slurry system with high strength and low density consisting of composite toughing fibers are developed. A laboratory experiment is conducted to test the cement strength, the anti-impact of cement loops, the performance of cement slurry, and the stability of slurry. Results show that cement slurry has the advantages of good rheological property, less loss of water, and short transition time. It can greatly improve the composite strength of cement rocks, the stability and anti-channeling property of cement slurry. What's more, it is compatible with other additives. The cement slurry has been applied in Shengli Oilfield and northeastern Sichuan, and good results have been attained. This is a feasible approach to solve the problems of cementing the wells with low pressure and easily lost circulation.