【作者】 尚占魁；

【导师】 孙宝江；

【作者基本信息】 中国石油大学 ， 船舶与海洋结构物设计制造， 2011， 硕士

【摘要】 近年来,随着国民经济的快速发展和对能源需求的不断增长,海洋油气资源勘探开发越来越受到国家的重视。然而,钻井技术和装备的限制一直是困扰海洋石油开发的难题。例如,海洋深水油气开发效率较高的大位移井在钻进时无法有效的施加钻压、窄密度窗口导致的复杂井控等等都是深水钻井常遇的问题。因此,探索合理高效的深水钻完井方法和技术具有重要意义。海洋双通道钻杆反循环MPD(控制压力钻井)是一项利用双通道钻杆及相应配套设备实现钻井液反循环的钻井工艺。该钻井方法能实现井筒压力精确控制,井下水力钻压推进,膨胀工艺下尾管、更高的携岩效率。本文在总结了海洋双通道钻杆反循环MPD的工艺流程及技术特点的基础上,针对正常钻进、海底表层钻进、危险井段钻进、起下钻等工况,分析了海洋双通道钻杆反循环MPD的技术优势。在此基础上,对顶部注入接头、流向转换器、双通道截止阀进行结构和关键尺寸的设计,并对其关键部位进行了强度校核。充分考虑“海洋双通道钻杆反循环MPD钻井技术”特殊的工艺,进行了水力参数计算方法的研究。总结了双通道钻杆环空和内管内压降计算公式、钻头压降公式。从传热学角度推导出了井筒温度场计算方法,总结了地层、套管、双通道钻杆以及流体对流传热热阻的计算方法。从携岩角度出发得出钻井液最小排量计算方法,从井壁稳定角度出发得出钻井液最大排量计算方法。对井筒压力控制进行分析,得出钻井过程中更反映灵敏、操作简单、更适合实时控制的方法是调节钻井立压和回压,其次是调节钻井液排量。更多还原

【Abstract】 Due to shortage of oil and gas resources and cutbacks of many maturing oil-fields, the supply of crude oil and gas can’t meet the demands of national economy development. Oil and gas exploration and development will focus on offshore. However, offshore drilling is a daunting task. The precise downhole pressure control to keep the wellbore safe, exerting hydraulic weight on bit in extended reach drilling, the high day-rate of the floating rig, so a advanced offshore drilling method is needed to answer these challenges of offshore drilling.A new drilling method called "Deep-water Reverse Circulation MPD" is introdued which uses dual concentric strings. The closed circulation system can makes the pressure control more precisely. The piston attached on drilling string can exert sufficient hydraulic WOB. The expansion liner drilling and the well cleaning devices can extend the ERD’s range.The technique features and the advantages of this drilling method are summarized. On this basis, the structure of some relevant key equipments are designed, which include the top injecter, the flow switcher, the automatic non-return valve and the manul controll non-return valve.The well temperature field model and wellbore pressure field model are established based on the the principle of energy and momentum conversation. The method to calculate the parameters of pressure loss and temperature is summarized, The circulation rate selection of this method is based on the hole cleaning and stabilization of wellbore.By analyzing the pressure control methods, it is found that to adjust the back pressure first, and change the circulation rate next.更多还原