超高温钻井液的高温流变性研究

考察了高温高压条件下超高温水基钻井液的流变性能，以实验室研制的超高温钻井液为研究对象，用Fann50SL 型高温高压流变仪对钻井液的流变性能进行了测定，并利用回归分析方法对实验数据进行处理。实验结果表明，高压条件下，超高温钻井液的表观黏度和塑性黏度随温度的升高而降低，210 ℃后黏度随温度升高稍有增大。回归分析表明，高温高压条件下，超高温钻井液流变模式遵循着卡森模式。建立了预测井下高温高压条件下超高温钻井液表观黏度的数学模型。实验数据验证表明，利用该数学模型计算出的数值与实测值吻合度较高，为超高温钻井液的现场应用提供了计算依据。

Study on the Rheological Properties of Ultra-high Temperature Drilling Fluids

The rheological properties of ultra-high temperature drilling fluids developed in our laboratory are measured using Fann50SL HT-HP rheometer and the experimental data with the temperature from 90 ℃ to 240 ℃ were analyzed using the regression method.The experimental results show that the apparent viscosity and plastic viscosity of ultra-high temperature drilling fluids decrease with temperature increasing under high pressure conditions,but slightly increase in viscosity after 210 ℃.The results of regression analysis show that the Casson rheological model can describe the rheological properties of ultra-high temperature drilling fluids under high temperature and high pressure conditions,and the mathematical model is established to predict the apparent viscosity of ultra-high temperature drilling fluids under high temperature and high pressure conditions.The verification by experimental data indicates that the calculation results of mathematical model keep high consistence with the measured data,which provides scientific basis for field applications of ultra-high temperature drilling fluids.