黑色正电胶-聚合醇钻井液在前9井的应用

前9井是中原油田白庙构造北翼的一口评价井，完钻井深为4296m。该井沙二及沙三段地层易缩径、掉块及垮塌，从而引起起下钻遇阻划眼，造成井下复杂。采用了聚磺钾盐钻井液体系，因沙河街地层缩径、垮塌引起井下复杂，造成井眼两度报废填井侧钻。第二次侧钻时采用黑色正电胶-聚合醇钻井液。现场应用及与老井眼钻井情况对比表明；黑色正电胶-聚合醇钻井液有很好的抑制防塌性及较强的井眼净化能力．很好地解决了沙河街组地层缩径、垮塌掉块等现象，井眼稳定；同时具有很好的润滑性及油气层保护作用，保证了钻井施工安全顺利；而且维护方便，性能稳定。

application of MMH polyol drilling fluid in well Qian-9

Well Qian-9 is an appraisal well with total depth of 4296 m. it is located in Baimiao block of Zhongyuan oilfield. Wellhole collapse and shale shrinkage frequently take place in the well which result in pipe stucking and long section reaming. A polysulfonated potassium drilling fluid was firstly used, but downhole complexities were so serious because of the above problems that the hole had to been cemented and sidetrack drilled twice. MMH polyol drilling fluid was used alternately. Comparing with polysulfonated potassium drilling fluid, field using showed that MMH polyol drilling fluid exhibited good inhibition and slouging control, better lubricity and oil reservoir protection properties. Wellhole collapse and shale shrinkage have been prevented and the borehole maintained stable.