Abstract: A deep-water oilfield in the eastern South China Sea is developed by natural energy depletion. In order to protect the reservoir to the maximum extent, extend the life of the oil well and increase the recovery rate, according to the characteristics of the reservoir, the basic well conditions and the operation requirements, a well completion technology using the wellbore pressure control formation isolation valve is proposed. This technology has been successfully applied on site and achieved good reservoir protection effects, which has a positive significance for the development of deepwater oil fields.