| 摘要 |
<p>When a downhole tool 20 is in close proximity to a casing collar, it is sensed by a magnetic casing collar sensor (98, fig. 3) that then generates an electric signal causing a weight (70, fig. 4) to be released and strike a surface (90, fig. 4) to generate a tension pulse (24, fig. 2) in the slickline 21. This is achieved without requiring any physical connection with a downhole structure. A hydraulic strain head 41, with a pressure-responsive transducer (254, fig.11) is used to instruct the tool 20 to start and/or stop generating the tension pulses by accelerating and decelerating the tool assembly 44. A split collar (62, fig. 4) can selectively grab or release a threaded shaft which is attached to the weight, allowing the weight to be retracted in preparation for another pulse, and a solenoid (57, fig. 4) may be used to control these upward and downward movements. A coiled spring (68, fig. 4) may surround the threaded shaft 64 to increase the impact of the weight (70, fig. 4). The weight (70, fig. 4), can have a flat surface (71, fig. 4) or a conical point (90, fig. 4) for striking the housing (50, fig. 3). The different surfaces, as well as different distances (D, fig. 5) in which the weight (70, fig. 4) travels may be used to define different signatures for the tension signal (24, fig. 2). The slickline 21 is attached to a drum 33 of a slickline unit 28 at the surface of the well, which controls the depth of the tool assembly 44. The slickline is also passed through rollers (300, 302, fig. 10) with a tension sensor 26. Other arrangements, such as electrical or hydraulic, may also be used to generate tension pulses.</p> |
