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.