Dart with changeable exterior profile

Abstract

A dart for effecting wellbore operations has an inactivated position and an activated position wherein the exterior profile of the dart is changed when the dart is activated. The change in profile may be achieved by moving (for example, rotating) a portion of the dart relative to the remaining portion. When inactivated, the exterior profile allows the dart to pass freely through a valve. When activated, the dart cannot pass through the valve because the changed exterior profile is caught by the interior profile of the valve. Once caught, the dart creates a seal to open the valve when fluid pressure above the seal is increased. The dart can thus be used in multiple stage applications with valves having seats of the same size so that the dart can be selectively activated to engage a desired valve seat.

Dependencies are inferred from the claim text.