| 摘要 |
<p>The present invention provides a downhole cutting tool (20) for cutting materials at a worksite in a wellbore (22). The cutting tool includes a cutting end (32) that is adapted to discharge a high pressure fluid therefrom. A power unit (34) in the tool includes a plurality of serially arranged pressure stages, wherein each such stage increases the fluid pressure above its preceding stage. The high pressure fluid is discharged through the cutting end as a jet stream. A pulsar (35) in the tool is provided to pulse the fluid before it is discharged through the cutting end. A control unit (36) controls the position and orientation of the cutting end relative to the material. The downhole cutting tool can be programmed to cut materials according to predetermined patterns. The cutting tool may be utilized to cut support members of offshore structures, either from the inside or the outside of such support members. In a preferred method, the cutting tool is utilized to remove the earthen material from around the embedded support members and then to cut the support members below the sea bed. The cutting tool may be utilized in cutting nested pipes after pulling a selected length of such nested pipes from the wellbore.</p> |
