Development and EGR technologies of offshore gas fields in China

In China offshore, there are 30 producing gas fields, with 288 wells, mainly in the Yinggehai, Southeast Hainan, Pearl River Mouth, East China Sea shelf and Bohai Bay basins. These gas fields demonstrate high exploration costs, engineering construction costs, drilling/completion costs and production & operation expenses, and also great difficulties in development adjustment and treatment implementation, which restrict the offshore application of relevant methods and technologies that have been adopted in development of onshore gas fields. For improving the development benefits of offshore gas fields, it is necessary to review and collect the research results and application experience with respect to the development and enhanced gas recovery (EGR) technologies. In this paper, according to the characteristics of gas reservoirs, offshore gas fields are classified into condensate gas reservoirs, low-permeability gas reservoirs, edge/bottom-water gas reservoirs, high-temperature and high-pressure sour gas reservoirs, and deep-water gas reservoirs. The five types of gas reservoirs are analyzed in terms of their geological characteristics, development performance and production problems. Then, the development and EGR technologies for such gas reservoirs and their applications are reviewed with typical cases. Finally, the orientation and potential of development and EGR technologies for offshore gas fields in China are presented. © 2023 Natural Gas Industry Journal Agency. All rights reserved.