TAIL PIPE FOR SIDE HOLE ATTACHMENT Russian patent published in 2015 - IPC E21B7/08 

FIELD: oil and gas industry.

SUBSTANCE: invention refers to the oil and gas production industry, namely to a tail pipe for side hole attachment in a multi-lateral horizontal well. The tail pipe comprises a casing pipe of an effective length, a drive shoe with an end face displaced to an outer diameter, connected through an operating connection pipe to a body of a drive shoe clamper, forming a hinge fitting with an inner connection pipe in an articulating hub; beside the fitting, the articulating hub also comprises a back-pressure valve with a rod-opened retainer when lowering into the well; a stop assembly body is provided with a displacement plug casing; the lower displacement plug is provided on the connection pipe of the fitting, which is attached through the bore to the body of the removed tail pipe assembly; the body accommodate a crown hub with a put-on top of a profile partition, while a lower side seats on a lock connected to the hinge through an inner left thread to form a closed cavity inside the partition. The closed cavity of the partition is closed with the valve and additionally with a collet gate to protect from pressure jumps in a hydraulic canal of the tail pipe; the cavity has two sealing canals to be filled with water and de-aerated; corrugations of the partition are put on crown flanges of the hub and sealed, while a lower side is mated with the lock which comprises a seat for a foundation cutter; along the left thread, the lock is connected to the hinge to form a detachment assembly; the hinge fitting from the drive shoe, connection pipe and drive shoe clamper are configured to move in the axially symmetrical and radial direction along the well bore.

EFFECT: provided considerable reduction of the non-productive time required to attach the horizontal side hole during the multi-lateral well construction.

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