Application of Integration Gas-Lift on Offshore Oilfield

Using artificial island as a production platform is a common method to develop offshore oilfield with technology and equipment which used on land oilfield in China, it is a long-term, high efficient and low-cost development strategy of offshore Oilfield. However, there are some new challenges on the selection of artificial lift, such as intensive wellhead, limited space, complex well track and higher health safety environment requirement. For the project of Nanpu offshore oilfield, integration Gas-lift was selected as the artificial lifting method by consideration of the characters of artificial island and high gas oil ratio in Nanpu reservoir. In order to overcome the challenges mentioned above, the gas-lift design method was improved for the highly deviated well, many down hole tools such as packers were invented to apply to highly deviated well, several gas-lift production strings were researched to be used in different situation. The new reliability technology that has 4 grades’ control system was implemented to ensure the process safety. This project ultimately achieved a successful result by all implementations. Over ten years of operation, the integration gas-lift platform has built 136 wells and produced 1,500,000 ton's oil, maximum production is 1,200 ton per day. There is no accident happened on the platform. Moreover, this practice provides a good example for new long-term, high efficient and low-cost development strategy, it also can be an invaluable reference for other offshore oilfields.