大位移水平井旋转自导式套管浮鞋的研制及应用

为了提高浮鞋引导能力，解决大位移水平井套管下入困难的问题，研制了一种旋转自导式浮鞋。利用偏头引鞋增强引导能力，利用双向螺旋槽实现自动调整引导状态，利用弹浮式回压密封结构来实现回压坐封。该工具引导机构可沿轴线360°自由旋转，耐温可达180 ℃，耐回压能力可达50 MPa，引导机构自动复位后偏转角度都在10°以内。室内试验及现场应用表明:旋转自导式浮鞋具有较强的自导向能力和反向承压能力，能够引导套管在井眼轨迹曲折的水平井眼内顺利下行，在固井作业后可靠坐封。由于页岩气井的开发多为大位移水平井，因此，可广泛应用于各类页岩气水平井下套管及固井施工作业。

Development of rotary self-guidance casing float shoe and its application in extended-reach horizontal wells

A kind of rotary self-guidance float shoe was researched and developed to improve the guidance capacity of float shoes so as to deal with the difficult casing job in extended-reach horizontal wells.An offset guide shoe is used to reinforce the guiding capacity, a bi-directional spiral groove is used to adjust the guiding state automatically and an elastic-floating backpressure sealing structure is used for the realization of backpressure setting.The guidance mechanism of this tool can rotate freely along the axial line by 360°, and it can resist the temperature of 180 ℃ and backpressure of 50 MPa.After the guidance mechanism resets automatically, its angle of deflection is within 10°.It is indicated from laboratory experiments and field application that this rotary self-guidance float shoe is stronger in terms of self-guidance capacity and reverse pressure bearing capacity.By virtue of this tool, casing job can be implemented smoothly in horizontal wells whose hole trajectory is zigzag and the setting after the cementing is reliable.Shale gas wells are mostly in the form of extended-reach horizontal wells, so this tool can be extensively applied to casing job and cementing operation in various shale-gas horizontal wells.