磨料射流切割技术在水下井口弃置应用中的探讨

Application of water abrasive suspension cutting technology in subsea wellhead removal

目前国内水下油气田、深水钻完井正处于快速发展阶段,近2年也有多个水下井口油气田进入整体弃置阶段。海洋弃井作业规范规定,在领海及以内水域永久弃井时,所有套管、桩、井口装置等的切割位置应深于海底泥面4m,在领海以外残留海底的井口设施,不得妨碍其他海洋主导功能的使用。本文结合磨料射流切割技术与水下井口回收技术,以南海某油田弃置为例,进行磨料射流设备的水下井口弃置技术研究,研究技术可行性、技术方案及思路,所得结论可为我国深水水下井口弃置作业提供一种思路。

At present,deepwater oilfields and deepwater drilling&completion are in the stage of rapid development in china. In recent two years,many deepwater oilfields have entered the stage of overall abandonment. The specification of offshore well abandonment stipulates that the cutting position of all casings,piles,wellhead devices,etc. shall be 4m deeper than the seabed mud surface when abandoning the well permanently in the territorial sea,and the wellhead facilities remaining on the seabed outside the territorial sea shall not hinder the use of other marine dominant functions. Combined with water abrasive suspension cutting technology and subsea wellhead recovery technology,taking the abandonment of an oilfield in the South China Sea as an example,this paper studies the subsea wellhead removal technology of water abrasive suspension cutting equipment,and studies the technical feasibility,technical scheme and ideas.The conclusion can provide an idea for the abandonment of deepwater subsea wellhead in China.