Abstract: When an offshore oilfield enters into its later high water-cut period, it is more and more difficult to lift, store and treat the produced water with the cost on the rise, causing a great pressure on the offshore oil field in the energy saving and pollution-reducing areas. In addition, part of platform facilities cannot satisfy the demand for treatment. CNOOC has developed a new-type downhole oil-water separator and designed the pipe string for the process, thus creating a set of suspending downhole oil-water separation and re-injection process suitable for offshore oilfields. The maximum outer diameter of the new-type oil-water separator is 130mm and the handling capacity reaches 1200 cubic meters per day. The whole process system adopts the suspending three-pass joint device to establish the flow path, ensuring that a large flow channel is established in the wellbore. The downhole parameters monitoring and adjusting facilities can make realtime inspection and adjustment of the entrance pressure of the oil-water separator on the surface to ensure the separation efficiency of the system. With a large handling capacity, this system is compact in structure. The process is similar to the process of the production pipe string of electric submersible pump currently used in offshore oilfields, significantly lowering the risks for operation and service.

Key words: offshore oilfield, downhole, oil-water separation, pipe string, real-time inspection, parameters adjustment

摘要： 海上油田进入中高含水期后,产出水的举升、存储和处理难度加大,费用增加,给海上油田节能减排带来巨大压力,部分平台设备负荷无法满足处理要求。通过研发新型井下油水分离器,设计配套工艺管柱,开发出一套适合海上油田的悬挂式井下油水分离及回注工艺。新型井下油水分离器最大外径为130mm,处理量达1200m3/d,整个工艺系统采用悬挂式三通接头装置建立流动通道,可以保证在井筒内建立大流量流动通道;配套的井下参数监测及调控装置可在地面完成油水分离器出入口压力及流量的实时监测和调控,以保证系统分离效率。该系统处理量大、结构紧凑,工艺与目前海上油田采用的电潜泵生产管柱工艺类似,大幅降低了作业及运行风险。

关键词: 海上油田, 井下, 油水分离, 管柱, 实时监测, 参数调控