Abstract: A tubular handling assembly includes a mandrel; a plurality of gripping elements for gripping a tubular, the plurality of gripping elements coupled to and rotatable with the mandrel; one or more accumulators; a first actuator configured to supply fluid to the one or more accumulators; and a second actuator configured to receive fluid from at least one of the one or more accumulators and to actuate the plurality of gripping elements.

Abstract: A centralizer sub for cementing a tubular string in a wellbore includes: a tubular body; a centralizer disposed along an outer surface of the body and having a pair of collars and a plurality of bow springs connecting the collars; and a joint longitudinally coupling the centralizer to the body. The joint has a groove formed in and around the body outer surface, and a plurality of protrusions formed integrally with or mounted to one of the collars and configured to mate with the groove.

Abstract: A method of manufacturing a centralizer having a plurality of blades includes cutting the plurality of blades from a metal sheet; hardening the plurality of blades using a heat treatment process; and welding the plurality of blades to a tubular body. The blades may be welded to the tubular body using a plurality of weld seams.

Abstract: A tubular handling assembly includes a mandrel; a plurality of gripping elements for gripping a tubular, the plurality of gripping elements coupled to and rotatable with the mandrel; one or more accumulators; a first actuator configured to supply fluid to the one or more accumulators; and a second actuator configured to receive fluid from at least one of the one or more accumulators and to actuate the plurality of gripping elements.

Abstract: A centralizer sub for cementing a tubular string in a wellbore includes: a tubular body; a centralizer disposed along an outer surface of the body and having a pair of collars and a plurality of bow springs connecting the collars; and a joint longitudinally coupling the centralizer to the body. The joint has a groove formed in and around the body outer surface, and a plurality of protrusions formed integrally with or mounted to one of the collars and configured to mate with the groove.

Abstract: A centralizer sub for cementing a tubular string in a wellbore includes: a tubular body; a centralizer disposed along an outer surface of the body and having a pair of collars and a plurality of bow springs connecting the collars; and a joint longitudinally linking the centralizer to the body. The joint has: a groove formed in and around the body outer surface, and a plurality of protrusions formed integrally with or mounted to one of the collars and extending into the groove.

Abstract: A method and apparatus for centering a casing section in a wellbore. A centralizer includes a plurality of centralizer bow springs arranged between and around circumferences of end bands. The end bands are arranged over stop collars such that the end bands can rotate about and slide along the stop collars. At least one stop collar includes a radially-inward-extending lug that engages a groove in the stop collar. The groove limits the amount by which the end band can slide relative to the stop collar. When the centralizer is lowered into a wellbore, an interference between the lug in the end band and the groove in the stop collar can pull the centralizer into the wellbore. The pulling force can prevent the centralizer bow springs from expanding radially outward due to contact forces with edges of the wellbore.

Abstract: A modular top drive for construction of a wellbore includes a rail for connection to at least one of: a floor and a derrick of a drilling rig; and a motor unit. The motor unit includes: a first body; a drive motor having a stator connected to the first body; a trolley connecting the first body to the rail; and a first latch for selectively connecting either a drilling unit or a casing unit to the motor unit. The top drive further includes a bracket for holding any one of the drilling, casing, and cementing units and movable relative to the rail between a standby position and a connection position. The unit held by the bracket is aligned with the motor unit in the connection position and clear of the motor unit in the standby position.

Abstract: A method and apparatus for centering a casing section in a wellbore. A centralizer includes a plurality of centralizer bow springs arranged between and around circumferences of end bands. The end bands are arranged over stop collars such that the end bands can rotate about and slide along the stop collars. At least one stop collar includes a radially-inward-extending lug that engages a groove in the stop collar. The groove limits the amount by which the end band can slide relative to the stop collar. When the centralizer is lowered into a wellbore, an interference between the lug in the end band and the groove in the stop collar can pull the centralizer into the wellbore. The pulling force can prevent the centralizer bow springs from expanding radially outward due to contact forces with edges of the wellbore.

Abstract: A modular top drive for construction of a wellbore includes a rail for connection to at least one of: a floor and a derrick of a drilling rig; and a motor unit. The motor unit includes: a first body; a drive motor having a stator connected to the first body; a trolley connecting the first body to the rail; and a first latch for selectively connecting either a drilling unit or a casing unit to the motor unit. The top drive further includes a bracket for holding any one of the drilling, casing, and cementing units and movable relative to the rail between a standby position and a connection position. The unit held by the bracket is aligned with the motor unit in the connection position and clear of the motor unit in the standby position.

Abstract: A centralizer sub for cementing a tubular string in a wellbore includes: a tubular body; a centralizer disposed along an outer surface of the body and having a pair of collars and a plurality of bow springs connecting the collars; and a joint longitudinally linking the centralizer to the body. The joint has: a groove formed in and around the body outer surface, and a plurality of protrusions formed integrally with or mounted to one of the collars and extending into the groove.