ROTARY STEERABLE DRILLING SYSTEM

摘要

A rotary steerable drilling system includes a housing, a drive shaft passing through the housing, a shaft/housing locking mechanism disposed to selectively engage the drive shaft and the housing, and an anti-rotation mechanism disposed to engage a wellbore wall. Shaft/housing locking mechanism includes a first configuration in which rotation of the drive shaft is independent of the housing, and a second configuration in which rotation of the drive shaft causes rotation of the housing. Anti-rotation mechanism includes a first configuration in which the anti-rotation mechanism extends radially relative to the drive shaft, and a second configuration in which the anti-rotation mechanism retracts from engagement with the wellbore wall. A timing mechanism may be employed to transition the anti-rotation mechanism from the first configuration to the second configuration before the shaft/housing locking mechanism transitions from the first configuration to the second configuration.