Development of Sealing Joint for Collecting Slip Ring

The cable from the collecting slip ring is connected with the cable from the coiled tubing drum union, and the power supply from the surface to the downhole electric drilling tool and signal transmission are delivered via the cable passing through the coiled tubing. The high-pressure sealing at the coiled tubing drum and the reliable suspension of the cable inside the coiled tubing are two key factors affecting the safe and reliable operations of the coiled tubing electric drilling tool system. Given this, the sealing joint for collecting slip rings is developed for the annulus sealing and cable suspension of the coiled tubing-through cable near the bottom diameter of the drum. The tool is mainly composed of the bayonet, bayonet seat, sealing packing, upper joint and lower joint. The testing of the pressure bearing and suspension capacities of the tool shows that the developed sealing joint meets the requirements of 70 MPa sealing pressure and 10 ton cable suspension weight. The tool delivers high-pressure reliable sealing via “manual + packing” operations, and moreover, it offers a high suspension capacity by tightly clamping the separated armor steel wires of the cable. The development of this tool is of great significance to the safe and reliable operations of the surface coiled tubing drum for the coiled tubing electric drilling tool.