Abstract: The segregated completion technique has been the main method to protect the reservoir of highly-deviated /horizontal wells, control water and perform staged stimulation. The oil/water swelling packer which is based on swelling rubber is the key tool for segregated completion technology. This paper summarizes the technical and application feature systematically, studies the swelling sealing mechanism and influence factors have been carried on research and providing the main technical indicators after packer swelling and technical features of five types of swelling packers. The results show that the influence of acid, alkali and salt on the swelling rubber are less than 10% and the oil swelling packer has the outstanding technical advantages of easy operation, reliable setting, multi-expansion and permanent expansion. For the application in BP101D, a highly deviated/high temperature, high pressure, high sulfur well in Amu Darya Gas Field, it is predicted that the yield is more than 110×104 m3/d. The bottom well completion technology use permanently-segregated completion string which takes the oil swelling packer and sliding sleeve as core tools. The successful segmentation of reservoir provides a technical window for future water blocking, effective water control at fixed point and staged stimulation, and the technical support and guarantee for continuous production of high-yield gas.