Mechanical expansion sealing returnable fishing spear blanking plug

Abstract

A mechanical expansion sealing returnable fishing spear blanking plug relates to the technical field of petroleum machinery and comprises an upper joint (1), a well sealing rubber piece (2), a fishing spear mandrel (3), a slip insert plate (4), a release ring (5) and a guide cone (6), the fishing spear mandrel (3) is provided with a protective ring table (7) behind the slip insert plate (4), a storage ring groove (8) is arranged behind the protective ring table (7), the well sealing rubber piece (2) is a cylindrical body sleeved on the fishing spear mandrel (3), and the release ring (5) is arranged in the storage ring groove (8). The inner wall of the front section of the well sealing rubber piece (2) is provided with an annular protruding part (9) which is arranged in the storage annular groove (8) and protrudes inwards, the diameter of the outer wall of the well sealing rubber piece (2) is smaller than that of the protection annular table (7), a pull sleeve (10) is fixed to the rear end of the well sealing rubber piece (2), the pull sleeve (10) is provided with a blocking part (11) with the diameter larger than the inner diameter of an oil pipe to be fished, and the pull sleeve (10) can pull the well sealing rubber piece (2) to slide on the fishing spear mandrel (3). The device has the advantages of being good in sealing effect, reliable in work, convenient to control and the like.

Description

technical field [0001] The invention relates to the technical field of petroleum machinery, in particular to a special tool for petroleum drilling and workover, and a mechanical expansion seal and retractable fishing spear plug. Background technique [0002] The same kind of tool products currently in use all adopt a self-sealing structure, that is, one or two self-sealing sealing rubber parts are connected in series on the upper or lower end of the retractable spear tooth plate, and the outer diameter of the sealing rubber parts is larger than the fishing string Inner diameter: After the tool is inserted into the salvaged string, the outer diameter surface of the rubber part is pressed against the inner diameter surface of the salvaged pipe string by virtue of the elasticity of the rubber part. At the same time, the pressure medium in the well acts on the inner cavity of the rubber part to compress the rubber part to achieve sealing. [0003] Under ideal conditions, this se...

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Problems solved by technology

[0003] Under ideal conditions, this self-sealing working method can also meet the sealing requirements; however, the workover environment and the conditions of the operating strings vary greatly, and ideal conditions are rare, and the salvaged strings generally have corrosion, scaling, and wax deposition In other cases, the upper end surface of the pipe string is often deformed, and the self-sealing rubber parts are often scratched, torn or cut when inserted into the salvaged pipe string, which cannot guarantee the sealing effect and cannot be used reliably

[0004] The snubbing operation, especially the snubbing operation of gas wells, is a high-risk operation project. The associated products of natural gas are often severely corrosive or highly toxic, and unreliable tools cannot be used; often only high-density mud can be used to kill the well-opening Well workover is carried out in the way of conventional operations. The killing fluid or high-density mud used in the killing operation can suppress the high-pressure gas in the well, but the killing fluid or mud will penetrate into the formation to seal micro-fractures, because most domestic gas fields are located in low-permeability, low production formation, so well killing operations have a particularly large damage to the productivity of natural gas wells, especially shale gas wells: After high-density mud well killing-after conventional workover operations, ordinary natural gas wells will lose more than 20% of their productivity, and shale gas wells may lose The production capacity is more than 50%, or even completely crushed to death and completely loses the gas production capacity

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