关键词: 岩屑, 井斜角, 环空返速, 钻井液性能

Abstract: In drilling process, drill bit breaks the rock into cuttings of different sizes and shape that accumulate at the bottom of a well. Bits may be broken repeatedly if the cuttings could not be cleaned up on time, and thus affect drilling rate and increase drilling cost. In high angle deviated well and extended reach well, cuttings are easily to build up cutting bed, leading to pump building, bit bouncing and drill pipe sticking. Borehole cleaning is therefore a key technique for drilling of high angle deviated well. This paper detailed the danger of cutting bed and processing, analyzed the factors affecting hole angle, velocity in annular, drilling fluid performance, flow state of drilling fluid, and rotation of drilling tool, and put forward some effective methods to solve the cutting migration in high challenge directional wells. It pointed out that the most effective method to clean cuttings away was to be based on moderate use of large-displacement tools, improvement of drilling fluid performance, and with the help of the tools removing cuttings bed.

Key words: cuttings, hole angle, velocity in annular, drilling fluid performance