Tool and method for preventing fall in well

Abstract

The invention discloses a tool and a method for preventing fall in a well. The tool comprises an upper connecting head having an oil pipe internal thread and a dovetail groove conical surface, one-way blocks accommodated in the dovetail groove conical surface and capable of relatively moving along the dovetail groove conical surface, a block base capable of pushing the one-way blocks to upwards move, an intermediate connecting head positioned below the upper connecting head, a mandrel arranged between the upper connecting head and the intermediate connecting head and used for bridging the upper connecting head and the intermediate connecting head, an outer barrel connected with the intermediate connecting head at the upper end and used for accommodating counterweight steels inside, and a lower connecting head connected with the lower end of the outer barrel. When a pipe column is normally produced, the tool dose not anchor a casing; only when the pipe column suddenly falls in the well, the anchoring is started to prevent the continuous descending of the pipe column, and the casing and the pipe column are effectively protected; the weightlessness and the hydraulic power are dually started; the mechanical structure is simple, and is not invalid for a long time in the well; and when the pipe column is out of control to fall in the well, the starting is rapid, and the support is reliable, so that the anchoring is easily relieved.

Description

technical field [0001] The invention relates to a well-fall prevention tool and method. Background technique [0002] With the rapid development of oilfield production technology, there are more and more horizontal wells and highly deviated wells. Because it is difficult to overhaul horizontal wells and highly deviated wells in highly deviated well sections, the requirements for the fall prevention of pipe strings are getting higher and higher. Most of the current anchor-type fall prevention tools are tubing anchor tools, which have been anchored when the production string is working, and have the following defects in use: 1. They have been anchored when the production string is working, and the casing has been damaged to a certain extent. 2. After the anchoring mechanism has been working for a long time in the well, there is a risk of difficulty in unblocking or being stuck; 3. After the pipe string is broken, the anchoring mechanism is easily damaged and stuck, resulting i...

AI Technical Summary

Problems solved by technology

[0002] With the rapid development of oilfield production technology, there are more and more horizontal wells and highly deviated wells. Because it is difficult to overhaul horizontal wells and highly deviated wells in highly deviated well sections, the requirements for the fall prevention of pipe strings are getting higher and higher. Most of the current anchor-type fall prevention tools are tubing anchor tools, which have been anchored when the production string is working, and have the following defects in use: 1. They have been anchored when the production string is working, and the casing has been damaged to a certain extent. 2. After the anchoring mechanism has been working for a long time in the well, there is a risk of difficulty in unblocking or being stuck; 3. After the pipe string is broken, the anchoring mechanism is easily damaged and stuck, resulting in the failure of the pipe string to be raised.

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