塔河超深裸眼分层注水管柱变形计算与对策

Deformation Calculation and Technical Measure to the Pipe String of Ultra-deep Open Hole Separate Zone Water Injection in Tahe Oilfield

塔河油田奥陶系碳酸盐岩油藏的分层注水存在注水层位深、地层温度高、下部为裸眼完井的特殊性,前期试注井裸眼封隔器K341失效导致试注失败。为了分析失效原因,建立了超深分层注水管柱的力学模型,分别计算了试注管柱在不同工况(入井、坐封、注水、关井、洗井等)在各种力学效应综合作用下封隔器K341相对于带水力锚的套管封隔器Y241的蠕变量。计算表明,当封隔器K341基本坐封后,在封隔器Y241坐封过程中封隔器K341将产生0.3～0.6 m的蠕变量,直接导致了封隔器K341的破坏。针对该问题,制定了超深裸眼分层注水管柱防蠕动技术对策,优化了相应的注水管柱结构:安装伸缩节、优化封隔器K341结构使其与封隔器Y241启封压力一致、封隔器K341两端安装扶正器以在入井过程中保护胶筒。

The particularity of the deep separate flood layer, the formation high temperature and the open hole completion in Tahe Oilfield＇s Ordovician carbonate reservoir, the failure of open hole packer K341 in pre-injection test well cause the injection test failure. To analyze the reasons for the failure, the paper established the mechanical model of the ultra-deep pipe string of separate zone water injection and calculated the K341 ＇s creeping quantitative relative to the casing packer with hydraulic anchor in different working conditions of the injection test pipe string and under the combined action of the mechanical effects. The results show that the K341 will produce 0.3-0.6 m creep variable when the Y241 packer is in the process of setting after the K431 packer is worked and this directly causes the damage of the K341 packer. To solve the problem, we draw up the creep preventing technical measure of the ultra-deep open hole separate zone water injection pipe string and optimize structure of injection string. That is installation of bumper sub, optimization structure of packer K341 to keep the working pressure with packer Y241, installation of centralizers at both end of packer K341 to protect element when down to the wellbore.