等井径膨胀套管系统研制与试验

为了解决深井超深井钻遇复杂地层时实现无内径损失的机械封堵难题，通过优选大膨胀率管材、设计大变形膨胀螺纹和变径膨胀工具，研制了?219.1 mm等井径膨胀套管系统。通过室内试验，评价了?219.1 mm等井径膨胀套管系统的机械性能、膨胀性能，试验结果显示:?219.1 mm等井径膨胀套管系统膨胀后的抗外挤强度为15.1 MPa，抗内压强度为29.3 MPa，连接强度为1 850 kN，满足等井径膨胀套管作为“应急套管”临时封堵的要求；膨胀压力18～20 MPa，膨胀过程顺利，膨胀后整个系统性能良好。在测试?219.1 mm等井径膨胀套管系统井下功能性和裸眼下入性的基础上，进行了井下全过程试验，?219.1 mm等井径膨胀套管系统膨胀顺利，膨胀后内径为245.0 mm，满足?241.3 mm工具下入要求，达到了等径膨胀和无内径损失钻进的目的。研究和试验结果表明，?219.1 mm等井径膨胀套管系统可实现等径膨胀，可满足等井径膨胀及封堵作业要求，为等井径膨胀套管系统现场应用奠定了基础。 

Development and Test of a MonoHole Expandable Casing System

In order to achieve mechanical plugging without inner diameter loss while drilling deep and ultra-deep wells in complex formations, a MonoHole expandable casing system with a size of ?219.1 mm was developed by selecting tubes with a large expansion rate, and by designing the expandable screws with a large deformation and adjustable expansion tools. The mechanical and expansion properties of the system were evaluated through laboratory tests. The results indicated that the system was characterized by a collapse resistance of 15.1 MPa, a burst strength of 29.3 MPa, and a connection strength of 1 850 kN, which met the requirement of using the system as emergency casing for temporary plugging. The expansion pressure was 18-20 MPa. The expansion was smooth, and the system performs well after expansion. After the downhole functionality and open-hole running of the system were tested, a downhole whole-process expansion test was conducted. The system expanded smoothly, and its inner diameter after the expansion was ?245.0 mm, which met the running requirement of tools with a size of ?241.3 mm. The results achieved the research objectives to bring about the same-diameter expansion and drilling without inner diameter loss. The research and test results revealed that the MonoHole expandable casing system with a size of ?219.1mm could accomplish the same-diameter expansion and meet the requirements of MonoHole expansion and plugging operation. The research results lay a foundation for the field application of the MonoHole expandable casing system.