DRILLING FLUID TECHNOLOGY OF TWO LONG OPEN HOLES

Intermediate casings in Well JinGu 1-2 and JinGu 1-3 were lessened because of the economic restriction, this made the open hole section as long as 3 627.31m and 3 639.71m. In particular, after φ241.3mm hole drilling, a directional drilling operation had to be designed to be done in open hole interval of Jingu 1-3, it was very difficult for drilling fluid. According to the lithology of formation and the characteristics of drilling operation, it was required that the drilling fluid had good capability of suppression, except this, mainly solve the problems of stucking prevention, hole sloughing prevention, prop pant-carrying and antileakage. This paper presented a series of appropriate technological measures of polymer drilling fluid system, RH8501 lubricant and plastic ball, sulfonated asphalt hole sloughing prevention and so on. These technologies can basically meet the drilling requirements after the field application, and experiences were also obtained.