Patent ID: 7748473
Filing Date: 2010-07-06
Classification: E21B

Abstract:
1. A top drive system for wellbore operations, the top drive system comprising a main body, a motor apparatus, a main shaft extending from the main body, the main shaft having a top end and a bottom end, the main shaft having a main shaft flow bore therethrough from top to bottom through which drilling fluid is flowable, a quill connected to and around the main shaft, the quill having an exterior surface, a gear system interconnected with the quill, the gear system driven by the motor apparatus so that driving the gear system drives the quill and thereby drives the main shaft, the main shaft passing through the gear system, upper components connected to the main body above the top end of the main shaft, and the main shaft removable from the top drive system by disconnecting the main shaft from the quill, by disconnecting the upper components from the main body and moving the upper components from above the main shaft, and by lifting the main shaft from the quill, a sealing assembly adjacent the main shaft, the sealing assembly comprising a seal carrier adjacent the main shaft, a primary seal member on the seal carrier, the primary seal member sealingly contacting the exterior surface of the quill, at least one secondary seal on the seal carrier, the secondary seal initially not in sealing contact with the quill and movable to move the at least one secondary seal into sealing contact with the exterior surface of the quill wherein the seal carrier has a carrier threaded surface and part of the top drive system adjacent the main shaft has a mating threaded surface, the seal carrier rotatable with the carrier threaded surface threadedly engaging the mating threaded surface so that the seal carrier is movable to move the at least one secondary seal into sealing contact with the main shaft.