Spherical Ball Skate for Continuous Well String Injectors

摘要

A skate for an injector apparatus in which gripper dies on a pair of endless chains driven around respective closed loop paths on different sides a continuous wellbore string are forced against the continuous string by forcing a set of the skates toward theretoward from inside the closed loop paths of the endless chains. The inventive skate features a skate body carrying a plurality of spherical balls that are exposed on a side of the skate that faces toward the continuous string in order to allow riding of endless chains over exposed surfaces of the spherical balls as the endless chains are driven through the respective closed-loop paths, whereby the gripper dies ride over the spherical balls of said skates under the forcing of said skates toward the continuous string.

主权项

1. An apparatus for injecting or withdrawing a continuous string into and from a wellbore, the apparatus comprising:
a plurality of endless drive conveyors positioned on different respective sides of a pathway in which a length of the continuous string is receivable, each endless drive conveyor comprising an endless chain and a plurality of gripper dies coupled to the endless chain, each gripping die having a gripping face that faces outwardly from the endless chain and is shaped to engage a periphery of the continuous string and a base surface that faces inwardly from the endless chain, the endless chains being arranged for driven movement around respective closed-loop paths on the different sides of the pathway such that the gripper dies of each endless chain are conveyed in a same direction along the pathway at the respective side thereof during a portion of the respective closed-loop path; a plurality of skates respectively residing on the different respective sides of the pathway with the closed-loop path of each endless chain closing around a respective one of the skates, each skate carrying a plurality of spherical balls that are exposed on a side of the skate that faces toward the pathway; and a force application mechanism operable to force the skates toward the pathway for clamping of the length of the continuous string between the gripping faces and rolling movement of the endless chains over the spherical balls exposed on the side of the skate that faces toward the pathway.