高温高密度盐水基钻井液性能

Performance of high-density brine-based drilling fluid with high-temperature

为解决盐水基钻井液高温高密度条件下性能维护困难的问题,通过系列流变性实验并结合粒度分布和Zeta电位分析等,研究老化温度、密度及黏土含量对钻井液性能的影响.结果表明:老化温度和黏土含量对高密度盐水基钻井液黏土聚结有重要影响,黏土聚结程度随黏土含量增大而增大,聚结的临界温度随膨润土质量分数增大而降低;同时,高密度钻井液的亚微米颗粒体积分数较低密度钻井液的高,高温作用将增加钻井液的亚微米颗粒体积分数;高温和高密度将使钻井液Zeta电位降低,使体系胶体稳定性变差.尽量降低高温高密度钻井液中黏土含量,并配合使用耐温抗盐高效护胶剂是维护其性能稳定性的重要途径.

As it is difficult to maintain the drilling fluid performance under conditions of salt water,high temperature and high density,a series of rheological experiments combined with the particle size distribution and Zeta potential analysis were used to clarify the impact of temperature,the concentration of bentonite and density on drilling fluid properties by the authors.The results show that the aging temperature and clay content have important effect on clay coalescence.The degree of clay coalescence increases with the increase of clay content of the base slurry.The critical temperature of coalescence de-creases with the increase of clay content.And sub-micron particle content of high-density drilling fluid higher than that of the low-density drilling fluid.High aging temperature will increase sub-micron particle content.High temperature and high density will make the Zeta potential of drilling fluid to reduce,so that the colloidal stability variation.In order to maintain the performance stability of the high-density drilling fluid,the clay content should be maintained at a low level.The using of efficient colloid protection with heat-resistant and salt resistance is also an important way to maintain its performance stability.