东海老井眼处置再利用技术

在无空余槽口的情况下，选择产能衰竭的老井进行井眼处置，然后依托现有导管架设施侧钻定向井或大位移井，可以经济有效地开发海上现有油气田周边小构造。考虑侧钻过程中摩阻扭矩是制约侧钻井眼延伸极限的关键因素，通过设计最优化的井眼轨迹、选择最佳侧钻方案、最大限度地处置好老井眼以获得最佳侧钻位置，是降低侧钻井钻完井期间摩阻扭矩和钻机负荷的关键，也是保证侧钻深井或大位移井安全、高效完成的关键。东海地区通过开展侧钻前老井眼处置相关的技术研究，优选侧钻方案，优化老井处置过程中套管切割位置和套管打捞施工工艺，优选和加工打捞工具，成功利用两口产能枯竭的井进行老井眼处置再利用，钻成了两口超深大位移井。通过老井眼处置再利用，为东海打捞回收长距离、大尺寸套管作业积累了丰富的作业经验，形成了成套的东海老井眼套管处置新技术，为东海今后利用老井槽侧钻调整井积累了宝贵的技术经验。

Disposal and Reuse Technology of Old Boreholes in the East China Sea

In the absence of vacant slots, selecting old wells with depleted productivity for the borehole disposal, and then relying on existing jacket facilities to sidetrack directional wells or extended reach wells, which can economically and effectively develop small structures around existing offshore oil and gas fields. Considering that the drag torque during the sidetracking process is the key factor restricting the extension limit of the sidetracking hole,by designing the most optimized well trajectory, selecting the best sidetracking plan, and maximizing the disposal of the old borehole to obtain the best sidetracking position, it is the key to reduce the drag torque and rig load during sidetracking drilling and completion. It is also the key to ensuring the safe and efficient completion of sidetracking of deep wells or extended reach wells. In the East China Sea area, by carrying out technical research related to the disposal of old boreholes before sidetracking, the sidetracking plan is optimized, the casing cutting position and the casing salvage construction technology during the disposal of the old well are optimized, and the fishing tools are optimized and processed. Using two wells with exhausted production capacity for disposal and reuse of old boreholes, two ultra-deep extended reach wells are drilled successfully. Through the disposal and reuse of old boreholes, we have accumulated rich operating experiences for the salvage and recovery of long-distance and large-size casing operations, a complete set of new technologies for the disposal of old boreholes casings in the East China Sea has been formed, and valuable technical experiences have been accumulated for the future use of sidetracking adjustment wells in old well slots.