Application of Waterproof Cable Joint in Small Diameter Directional Hole

Abstract:

Along with the development of small diameter geological exploration and under the influence of formation conditions, hole accidents and hole inclination requirements, more directional drilling construction is needed. In small diameter borehole, the MWD instrument can not be put down through drill pipe of 50 or 60mm in diameter. By technical research, field tests and the improvement, a set of small diameter waterproof cable joint was developed, which solved the key technical difficulty of controlled directional drilling. The concrete steps are as following: separate the measuring probe tube and the transmission cable; connecting directional measuring probe tube and the drill pipe in advance, then put it to the predetermined depth together; through the drill pipe, the top and lower joints being connected in drilling fluid to realize electrical connection and signal transmission to complete the directional operation. This method was tested in ground detection and grouting project in a coal mine of DF33 fault and coal exploration with successful application.