快速永久弃井方法在海洋临时弃井探井中的应用

使用水下井口的油田弃置时，需要对储层按要求做永久弃井，而井口仍保留下来的临时弃井探井进行永久弃井作业。常规弃井方法是用半潜式钻机割生产套管后，打一个浅层环保水泥塞，然后于泥线以下4 m割表层套管和导管。使用半潜式钻机弃井的费用高昂，探索使用海洋工程船打环保弃井水泥塞并从泥线以下4 m割各层套管进行永久弃井的方法将会大大降低永久弃井费用。研制的“射孔、打水泥塞联作工具”允许一次性下入联作工具，通过射孔配合双封隔器的使用得以在两个环空中打环保弃井水泥塞。高压水力射流喷砂套管切割工具把液体的压力能转换为动能形成水力割刀，一次性可切割多层次套管串。利用海洋工程船，配合“射孔、打水泥塞联作工具”和高压水力射流喷砂套管切割工具，可以方便地把临时弃井的探井进行永久弃井施工，其施工费用较半潜式钻机弃井费用大大降低。该弃井方法在Chanter-15井成功地尝试，为作业者弃井施工提供了一种新的降本增效方法。

Application of Fast Permanent Abandoned Wells on Offshore Temporarily Abandoned Wells

When the offshore oil fields with subsea wellheads to be decommissioned, it is required to permanently abandon the exploration subsea wells which have been temporarily abandoned by setting abandonment cement plugs for reservoirs. The conventional abandonment method is to utilize a semi-submersible drilling rig to cut production casing, and set a shallow environmental cement plug, then cut surface casing and conductor 4 m below seabed. The abandonment cost is quite high from a semi-submersible drilling rig, the cost should be reduced dramatically by utilizing an offshore engineering vessel to set shallow environmental abandonment plug and cut casing strings 4 m below seabed. The perforation and cement setting combination tool allows running the tool in one trip to set environmental abandonment cement plug across 2 annuli by using perforation guns and 2 retrievable packers. High pressure hydraulic jetting abrasive casing cutting tool converts the fluid pressure energy to the kinetic energy to cut several casing strings in one go. By using the perforation and cement setting combination tool, and the high pressure hydraulic jetting abrasive casing cutting tool, the temporarily abandoned exploration wells can be permanently abandoned from an offshore engineering vessel. This abandonment method is much cheaper than abandoning from a semi-submersible drilling rig. The successful abandonment method in Well Chanter-15 provided a new cost reduction and synergy method for the operator to abandon the well construction.