高温高压全油基钻井液流变性研究与评价

Research and Evaluation on the Rheological Property of High Temperature and High Pressure White Oil-base Drilling Fluid

选用Rheo-Stress 6000型高温高压流变仪,测定不同密度、不同温度(60℃、120℃、150℃、180℃和200℃)和压力梯度下白油全油基钻井液的流变特性。实验结果表明,无论哪种密度的油基钻井液,温度升高都使其表观粘度、剪切应力降低,压力增加都使其增大:150℃的高温下,随着压强的增加,钻井液粘度增幅越来越小,后期趋于平缓,温度和压力同时作用于钻井液流体时,温度占主导作用;在较高的压力和温度下,白油全油基钻井液体系仍有很好的塑性粘度和动切力;此配方白油全油基钻井液在高温高压条件下体系稳定,剪切稀释性好。

In the experiment, Rheo-Stress 6000 HTHP rheometer was used to test the rheological behavior of white oil-base drillingfluid through varying the density, temperature （the variation value of temperature ： 60 ℃, 120 ℃, 150 ℃, 180 ℃ and 200 ℃） andpressure gradient. The experimental results indicate that the apparent viscosity and the shear stress of the white oil-based drilling fluidreduce with the temperature rising and enhance with the increase of pressure; under the elevated temperature of 150 ℃, with thepressure increasing, the amplification of drilling fluid viscosity rises more and more smaller, and flattens out in the later period; whenthe temperature and pressure are effect on drilling fluid at the same time, the temperature has more effect on it than the pressure. Thewhite oil-base drilling fluid system still has great plastic viscosity and shearing stress under higher temperature and pressure conditions.Under the condition of high temperature and pressure, this formula makes the white oil-base drilling fluid system stabilize and havegood shear thinning behavior.