A drilling assembly, a coupling device for such drilling assembly, and a method of drilling holes in the underground using the drilling assembly

摘要

The invention relates to a drilling assembly for coiled tubing drilling. The invention further relates to a coupling device for such drilling assembly and a method of using the drilling assembly. The coupling device comprises a drill tube (1) and a drill pipe (2) and is characterised in comprising an upper rotating motor (6), which is able to rotate the drill pipe (2), thus permitting firstly the drilling of rectilinear bore holes by coiled tubing drilling, secondly the reduction of friction between the drill pipe and an inner side of a bore hole, and thirdly the use of stabilisers to increase directional stability of the drill pipe. In this manner it is possible to drill faster and to drill longer holes, especially in a horizontal direction.