带压更换采油树技术

为解决传统方法更换生产井和注水井采油树下总闸门时存在的施工周期长、作业成本高、易造成储层污染的问题,进行了带压更换采油树技术研究。从封堵油管、密封井口、下入和起出油管堵塞工具入手,设计了能承压35 MPa的油管堵塞器,抗拉240 kN的打捞筒,最大拉力157 kN、最大推力227 kN的双向液压缸和抗内压70 MPa、密封压力35 MPa的防喷管等关键工具,制定了带压更换采油树工艺流程,形成了带压更换采油树技术。带压更换采油树技术在大港油田ZH4×2井进行了现场试验,与未应用该技术的油井相比,占井周期缩短约20 d,提前恢复注水约400 m3,节约费用约7.8万元,并且有效避免了储层污染,保持了油藏的注采平衡。这表明,带压更换采油树技术能显著缩短作业周期,降低作业成本,具有广泛的推广应用前景。 

The Technology of Replacing Christmas Trees under Pressure

In order to solve the problems of replacing the master valves beneath the Christmas trees of producers and injectors with traditional methods, such as long construction period, high operating cost and reservoir damage, a series of studies were conducted on Christmas tree replacement under pressure, including tubing plugging, wellhead sealing, pulling and running the plugging tools. A tubing plug with pressure-bearing 35 MPa, an overshot with tensile strength 240 kN, a two-way hydraulic cylinder with maximum tensile force 157 kN and maximum thrust 227 kN, and a lubricator with burst strength 70 MPa and sealing pressure 35 MPa have been manufactured. The technological process was developed to replace the Christmas tree under pressure, and tested on site at Well ZH4×2 in Dagang Oilfield, it can shorten the period of the well cycle by about 20 days, recover water injection in advance about 400 m3, and achieve cost savings of 78, 000 Yuan or so per well, compared with conventional technologies, thus effectively avoid reservoir damage and keep injection-production balance. Application results showed that the technology of replacing the Christmas tree under pressure can solve such problems as long construction period, high operating cost and reservoir damage, etc.