INDEXING DART

摘要

In order to overcome the limitation of being able to utilize a limited number of sliding sleeves with progressively more restrictive internal diameters in a particular wellbore when selectively opening the sliding sleeve or tool with progressively smaller balls or darts, an indexing dart may be utilized. A wellbore dart or pill is provided such that each time the dart passes through a downhole tool having a seat and externally extending finger is forced radially inward into the dart. As the finger moves inward to its depressed position, the finger moves a ball or other placeholder from a first position to a second position. When the ball is moved to the second position it may be released into the interior of the wellbore or it may be released into a chamber in the tool. In any event the ball is moved to a second position such that it may not return to the first position when the finger returns from its depressed position to its extended position. Once each of the balls have been released from the second position the finger is locked radially outward causing the dart to land and be locked in place at the next seat that is encountered by the dart.

主权项

1. A mechanically actuated dart system comprising:
a body, a seat, a finger,
wherein the finger is movable between a first position and a second position, at least one placeholder, wherein a placeholder is released when the finger moves from the first position to the second position, and a follower, wherein the follower moves to lock the finger into the first position after the last placeholder is released.