| 摘要 |
<p>A shifting tool is disclosed which allows movement of a shifting sleeve, to be followed by an additional force applied to ensure complete stroking of the shifting sleeve. This is accomplished by a shifting key to normally shift the shifting sleeve, followed by an overpull key which engages while the shifting key is still engaged. Once a predetermined force has been applied to the overpull key, the force applied from the surface is removed so that the tool may disengage from the sleeve. Subsequent manipulation, without necessarily any removal from the wellbore, if it does not result in a reengagement, provides feedback that the shifting sleeve has, in fact, shifted its full stroke. An emergency release is available which actuated by an overpull force beyond a predetermined level, applied while the overpull key is engaged for an emergency release from the shifting sleeve.</p> |
