超低渗透钻井液研究与应用

Study and application of ultra-low permeable drilling fluid

在水基钻井液中加入一定量的零滤失井眼稳定剂即可以形成超低渗透钻井液。室内在水基钻井液中加入一定量的零滤失井眼稳定剂后,对钻井液的API滤失量、砂床滤失量、岩心滤失量、岩心承压能力、裂缝封堵和储层渗透率恢复值进行了评价。结果表明,砂床滤失量不是时间平方根的函数,与API滤失量没有对应关系;超低渗透钻井液对不同孔隙的砂床、岩心和裂缝具有很好的封堵能力,甚至实现零滤失;通过增强内泥饼封堵强度可大幅度提高岩心承压能力;超低渗透钻井液能有效保护储层,2%加量时储层渗透率恢复值大于85%。

The addition of zero-filtration borehole stabilizer in water-based fluid can form ultra-low permeable drilling fluid.In laboratory,the properties of the formed fluid such as its API filtration,core filtration,core bearing ability,fracture sealing and reservoir permeability restore value,etc.were evaluated.The results show the ultra-low permeability can protect the reservoir effectively;the reservoir permeability restore value can be above 85% .