1. Field of the Invention
This invention concerns a device for disconnecting a wireline. More specifically, it concerns a device that is particularly suitable for disconnecting a wireline from a wireline tool, for example after having stuck the wireline tool and possibly having damaged the wireline.
2. Discussion of the Prior Art
The wireline tool may become stuck during wireline operations in a borehole. Subsequently, when the wireline tool is to be released or otherwise during unfavourable conditions and when maneuvering erroneously, the wireline may be torn off, and a portion of the damaged wireline may be left in the borehole.
In order to access the wireline tool with a fishing tool, the wireline portion located in the borehole must first be removed. The operation of removing a wireline portion of this type may be time-consuming and costly.
According to prior art, a wireline, which is to be used in wireline operations, is provided with a weakened portion near its point of connection in the wireline tool. Normally, the weakening is provided by means of removing a portion of the wireline strands. The purpose of the weakening is to attribute a potential wireline breakage to the weakened portion, thereby allowing substantially all of the wireline to be retrieved to surface after breakage. Then, the wireline tool may be retrieved by means of a so-called fishing tool.
Obviously, said method considerably reduces the carrying capacity of the wireline and therefore may cause unnecessary wireline breakages.
The object of the invention is to remedy the disadvantages of prior art.