pH值对高密度钻井液流变性能的影响

Influence of pH value on rheological performance of high-density drilling fluid

郭靖 李天太 张喜凤 郭必虎 张斌 梁红军

西安石油大学石油工程学院，陕西 西安 710065 长庆石油勘探局巡视组，陕西 西安 710065 塔里木油田公司勘探事业部，新疆 库尔勒 841000

随着油气勘探地下条件的日趋复杂，在钻井过程中不得不使用密度在2.25 g·cm-3以上的高密度钻井液。通过大量实验，研究了在添加PAC-HV（高黏度聚阴离子纤维素衍生物）前后，pH值对高密度钻井液流变性能的影响规律。实验结果表明：当加碱量为0.9%时，聚合物钻井液的pH值在8.5 ～ 9.5时，钻井液的表观黏度、塑性黏度和动切力最小，钻井液的流变性最佳；由于PAC-HV的包被作用，钻井液黏度的大小受pH值影响程度显著。该研究成果将为高密度钻井液在各个油田现场的推广使用，提供基础理论依据。

Because of the complex downhole geological conditions,the high-density drilling fluids(high than 2.25g/cm3)have to be used
in some oilfields. Based on lots of tests, the influence of pH value on rheological performance of high-density drilling fluid have
been researched at the different conditions of adding PAC-HV and without PAC-HV. The experimental results show that when
alkali quantity reaches 0.9%and pH value reaches 8.5-9.5, the values of AV, PV and VP become minimal, and the performance of
drilling fluids becomes best. Because of the package action of PAC-HV, the viscosity of drilling fluids is influenced. The study
results offer a theoretical foundation for the high-density drilling fluids widely used to other oilfields