LIGHT-WEIGHT SINGLE JOINT MANIPULATOR ARM

摘要

The present invention provides an apparatus and a method for making up tu bular strings in a well. The present invention provides a single joint manip ulator arm for manipulating and positioning tubing joints for coupling into a tubular string. In one embodiment, a string elevator is supported by a hoi st. A single joint elevator (22) is supported on a swing arm (18) that is pi votally secured to the sub-hoist assembly. An actuator (21) rotates the swin g arm to an initial position for securing to an add-on tubular joint whereby the single joint elevator engages a proximate end of the add-on tubular joi nt. As the hoist is lifted, a damper dampens rotation of the swing arm as it finds gravitational equilibrium with the single joint held in a substantial ly vertical orientation. A distal end of the tubular joint is aligned with a casing string supported by a spider, and the tubular joint is threadably co upled to the tubular string. The actuator may include provisions to power th e arm from the vertical orientation to a substantially horizontal orientatio n and also to dampen the movement of the arm as it moves from the substantia lly horizontal or an intermediate position to the vertical orientation once the single joint elevator engages the add-on tubular joint and the hoist sus pends the joint for rotation.