| 摘要 |
<p>A safety system controls the activation of one or more downhole tools by providing selective transmission of an activation signal or an energy stream. In a preferred embodiment, transmission of the activation signal or the energy stream is allowed after the tool has passed below a known pre-determined depth. A preferred safety system includes a first device in fixed relationship with the downhole tool and a second device fixed at the stationary location. The first device permits, after reaching the pre-determined depth, either (a) an initiation signal to reach an initiation device associated with a downhole tool upon or (b) the energy stream to reach a downhole tool. The second device positively engages the first device to provide an indication that the specified depth has been reached.</p> |
