纳米基低密度水泥浆体系的研究与应用

Study and Application of Nanometer Low-density Cement Slurry

卢海川 宋伟宾 谢承斌 陈若堂 高继超 安少辉 霍明江

LU Haichuan SONG Weibin XIE Chengbin CHEN Ruotang GAO Jichao AN Shaohui HUO Mingjiang

低密度水泥浆体系常存在耐压能力与稳定性差、抗压强度低等问题，在降低成本的情况下性能往往较差，难以满足各油田降本增效的要求。针对这一问题，将纳米材料引入低密度水泥浆中。用聚羧酸类表面改性剂对粒径为 20～ 70 nm、主要成分为硅、钙等元素的纳米材料 X进行表面改性，并将主要成分为硅氧化物的高需水材料与适量空心微珠复配得到高需水减轻增强材料 LEM。研究了用改性纳米材料 X、LEM、水泥、降失水剂、缓凝剂和水制备的密度为 1.30～ 1.50 g/cm3水泥浆的性能，并在胜利油田进行了现场应用。结果表明，改性纳米材料X可显著改善水泥浆稳定性、提高水泥石强度；纳米基低密度水泥浆体系具有良好的耐压性能，60 MPa加压前后的密度差可控制在 0.05 g/cm3以内；水泥浆在较大水灰比的条件下仍保持良好的稳定性和较高的抗压强度，且成本低，缓解了成本和性能之间的矛盾。该纳米基低密度水泥浆在胜利油田的应用效果良好，固井作业成本大大降低。表 6参12

The low-density cement slurry often had the problems of poor compression resistance，bad stability and low compressive strength. It often presented poor performance if the cost was reduced，which could not meet the requirements of reducing cost and increasing efficiency of oilfield. Aiming at the problems，the nanotechnology was introduced into low-density cement slurry. The nanometer material X with size 20—70 nm which composed of silicon，calcium and other elements was modified by polycarboxylic acid surface modifier. Lightening and strengthening material LEM with high water demand was prepared by the combination of material mainly composed of silicon oxide and hollow microsphere. The performance of low-density cement slurry （ 1.30 — 1.50 g/cm3）prepared by modified nanometer material X，LEM，cement，fluid loss additive，retarder and water was studied，and field application was carried out in Shengli oilfield. The results showed that the modified nanometer material X was able to obviously improve the stability of cement slurry and enhance the strength of cement stone. The nanometer low-density cement slurry could resist high pressure，whose density difference could be controlled within 0.05 g/cm3 after exerting pressure to 60 MPa. The nanometer low-density cement slurry with high water cement ratio was able to keep excellent stability and high strength. What is more，it relieved the contradiction between cost and performance of normal low-density cement slurry. The nanometer low-density cement slurry presented low cost and well comprehensive performance and had been successfully applied in Shengli oilfield.