大管径长距离深水海底管道除水惰化技术

De-watering Technology for Large Diameter and Long Distance Deep-water Pipeline

南海某深水项目22吋海管从深水气田回接至浅水区的中心平台,每条海管回接距离约80km。1号海管除水惰化作业使用了临时清管球发射器,采用压缩空气和压缩氮气驱动6个清管球,进行海管除水、海管干燥、海管除盐以及海管惰化,并继续加压使高纯度氮气达到气田开井所需的背压;2号海管则使用深水跨接管携带两个清管球,通过高纯度氮气驱动,实现了海管的除水、干燥、除盐、惰化功能。该项目是国内首次深水天然气田开发,工程实践的特殊性不言而喻,对将来深水项目开发具有较好示范意义。

One deepwater gas field in South China Sea is tied back to a fixed platform on the continental shelf via twoapproximately 80km subsea pipelines from an infield PLEM. Six pigs driven by compressed air and compressed nitrogen were launchedfrom temporary pig launcher in Pipeline1 to accomplish the dewatering,desalting and inerting. After that,pipeline kept beingpressurized to required production back pressure. Differently,two pigs pre-installed in the PLEM side spool were used for Pipeline2dewatering. High purity nitrogen was used to push the pigs moving from PLEM to CEP. This project is the first deepwater gas fielddevelopment in China which can set up a meaningful example for deepwater project in future.