| 摘要 |
A method for controlling the ascent and descent of a tubular member passing through a pipe or casing slip into a well bore. A float control member is affixed beneath the top surface of the pipe or casing slip. The control member is activated to control the raising or lowering of the tubular member. A piston within a cylinder housing is positioned below the top surface of the slip. As the tubular member is lowered, but before there is significant weight on the supporting structure, the piston is moved to its maximum height extension. Once the slips are set and the weight of the tubular member is applied to the slips, the piston begins to descend in the cylinder housing floating the final descent of the string. The string may be raised by activating a pump to force fluid within the housing chamber, raising the piston and thereby raising or lifting the string.
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