Abstract:Shale oil horizontal wells were arranged in Shengli oilfield, including Luojia and some other blocks for shale oil development. With shale bedding and micro fissure developing, the borehole instability is extremely easy to be caused in drilling process. At the same time, due to the long horizontal section, there are the difficulties of lubrication and borehole cleaning. For the construction difficulties and risks, the drilling fluid scheme for shale oil reservoir was worked out by research: amine-based and oil-based drilling fluid system being used for the second and the third sections respectively, and the drilling construction was successfully completed. The drilling fluid technology used for shale oil reservoir in Shengli oilfield is introduced in this paper and the discussion is made on some technical problems in the application.