凹凸棒土悬浮液高温流变特性初步探究

A preliminary study on rheological properties of attapulgite slurry at high temperature

凹凸棒土(ATP)适于配制盐水钻井液,其流变性研究主要集中在常温条件下,而高温流变特性的研究尚未见诸文献。文中就ATP加量、测试温度、氯化钠、抗高温聚合物等因素对ATP高温流变性的影响进行了充分的试验,并就其流变模式进行了拟合与优选。结果表明:1)ATP悬浮液黏度随自身加量增加而升高,随测试温度升高而降低,温度高于190℃且加量低于6%时,加量对黏度的影响不显著;2)相比于赫巴模式与卡森模式,宾汉模式更适于对凹凸棒土190℃以上的流变特性进行表征;3)氯化钠与抗高温聚合物对凹凸棒土悬浮液高温下黏度的保持均具有一定的促进作用,在160~190℃范围内使得其悬浮液黏度有所提升,加量越高,发生提升现象对应的温度值越低。上述结果对于凹凸棒土抗高温钻井液的配制及其在高温下流变特性的变化规律探究具有一定的理论意义。

Attapulgite(ATP)is commonly used in brine drilling fluid,and the study on its rheological properties are mainly studied at room temperature,while the high temperature rheological properties of ATP slurry have not been found in the literature.The effects of the addition of ATP,test temperature,sodium chloride,high temperature resistant polymer on the rheological properties of the ATP slurry were fully tested in this paper,and the rheological models under different conditions were fitted and optimized.The results showed that:(1)the viscosity of ATP increased with the increase of own addition,but decreased with test temperature increase.When the temperature was higher than 190℃and the addition was lower than 6%,the addition had no significant effect on the viscosity;(2)compared with Herschel-Bulkley model and Casson model,Bingham model was more accurate in characterizing the rheological properties of ATP slurry above 190℃;(3)both NaCl and high temperature resistant polymer have a certain effect in promoting the viscosity of ATP slurry at high temperatures.The viscosity of slurry is increased in the range of 160-190℃,the higher the addition was,the lower the temperature point corresponding to the increase.This research is of certain theoretical value for the preparation of attapulgite based drilling fluid and the study of change rule of its rheological properties at high temperatures.