岩层大通道纳米复合水泥封堵材料研究

Study on nano-composite cement plugging material for large channel of rock stratum

摘要:

我国青藏高原地区构造运动活跃，地层中易形成大通道空隙，钻孔施工过程中易发生涌突水、渗漏、孔壁垮塌等问题。针对上述问题，对普通硅酸盐水泥与硫铝酸盐水泥的基础性能进行系统测试，进一步筛选适宜的减水剂、早强剂、纳米SiO2及抗分散剂以调控水泥浆液的综合性能，研制出一种纳米复合水泥基封堵材料。通过测定该材料的流动度、可泵期、凝结时间、抗压强度及动水留存率等关键指标，对其工作与力学性能进行了综合评价，并结合扫描电子显微镜（SEM）观测，对材料强度提升及抗分散性能增强的内在机理进行了分析。结果表明，所研制的纳米复合封堵材料具备良好的流动性、可控且较短的凝结时间、较高的早期强度及优异的抗动水冲刷能力，能够满足岩层大通道条件下的注浆封堵施工需求，为后续相关研究提供了参考。

Abstract:

The tectonic movement in the Qinghai-Tibet Plateau is active in China, and large channel voids are easily formed in the stratum. In the process of drilling construction, problems such as water inrush, leakage, and hole wall collapse are prone to occur. In view of the above problems, the basic properties of ordinary Portland cement and sulphoaluminate cement were systematically tested, and the suitable water reducing agent, early strength agent, nano-SiO2 and anti-dispersant agent were further screened to regulate the comprehensive performance of cement slurry, and a nano-composite cement-based plugging material was developed. The working and mechanical properties of the material were comprehensively evaluated by measuring the key indicators such as fluidity, pumpable period, setting time, compressive strength and dynamic water retention rate. Combined with scanning electron microscopy ( SEM ) observation, the internal mechanism of material strength improvement and dispersion resistance enhancement was analyzed. The results show that the developed nano-composite plugging material has good fluidity, controllable and short setting time, high early strength and excellent resistance to dynamic water erosion, which can meet the requirements of grouting plugging construction under the condition of large channel in rock strata, and provide reference for subsequent related research.