非金属微粉低密度水泥浆的制备

Synthesis of low-density slurry with nonmetal micropowder

低密度水泥浆可解决低压易漏井固井时水泥浆漏失的难题,但由于其水泥石抗压强度低、体积收缩大,严重影响了固井质量和油井寿命.用外掺法在水泥颗粒空隙中添加非金属微粉,降低水泥石的孔隙率和收缩率,并提高其抗压强度.研究结果表明,与相同密度(1.4 g/cm3)掺有漂珠的低密度水泥浆相比,掺有非金属微粉的低密度水泥石的抗压强度显著提高,水化1 d后有害孔率降低了72.4%,7 d体积收缩率降低了58.9%,水泥浆的工程性能基本满足固井施工的技术要求.

Low-density slurry can be used to slove the problem of lost circulation, however, because of low compressive strength and big volume shrinkage of set cement, the quality of cementing and the life of oil-well will be affected. Using the external-adding method with adding of nonmetal micropowder to the gap of the grain of the cement can reduce the gap ratio and the ratio of the shrinkage of set cement, thus increase the compressive strength. Lab researches demonstrate ： compared with the low-density slurry with floating bead at the same density（ 1.4 g/cm^3 ）, low-density slurry with nonmetal powder improves the compressive strength highly. After hydrating 1 day, the harmful hole ratio reduces 72. 4%, and after hydrating 7 days, the shrinkage ratio of the volume reduces 58.9%. The engineering performance of the slurry can meet the needs of cementing.