Tool set for changing downhole damaged casing and cementing

Abstract

The invention relates to a tool set for changing a downhole damaged casing and cementing. The tool set comprises a hydraulic internal cutter, a downhole junk fishing tool, a remaining casing milling tool and an external insertion butt joint cementing tool, an external insertion guiding shoe is arranged at the lower end of the external insertion butt joint cementing tool, an extension cylinder is rotatably connected at the upper end of the external insertion guiding shoe, a circulating cylinder is rotatably connected at the upper end of the extension cylinder, a plurality of rows of ash injection holes are arranged on the peripheral wall on the middle section of the circulating cylinder, a sealing cylinder is rotatably connected at the upper end of the circulating cylinder, an R-shaped sealring is embedded at the upper part of a female thread at the lower end of the sealing cylinder, a barb faces upwards, a butt joint is rotatably connected in the female thread at the upper end of thesealing cylinder, a conical female thread is arranged at the upper end of the butt joint, an inner chamfer of the butt joint is arranged on a lower port of the butt joint, the upper part of the innerchamfer is narrow, and the lower part of the inner chamfer is wide; and the inner diameters of the sealing cylinder, the circulating cylinder, the extension cylinder and the external insertion guidingshoe are adaptive to the outer diameter of the casing. The tool set for changing the downhole damaged casing and cementing is simple in structure and is convenient to operate, the production cost andthe downhole risk are low, the operations of butt jointing and setting are simple, and the sealing reliability is high.

Description

technical field [0001] The invention relates to an underground damaged casing replacement and well cementing tool set, which is used for butt cementing of the newly replaced casing string in the wellbore and the original remaining casing in the wellbore during the replacement of the damaged casing in the wellbore. It belongs to the technical field of wellbore overhaul tools. Background technique [0002] Oil and natural gas are exploited through the wellbore formed by drilling. The wellbore casing string in the wellbore is formed by screwing the casing one by one through the thread. With the increase of oil and gas well production time, the downhole environment is getting worse and it is easy Breakage of casing. Usually, the cemented casing outside the casing is not easy to be damaged. The bare pipe section above the cemented section is more likely to be damaged due to double-sided corrosion, and sometimes it can be broken into several pieces. In this case, it is necessary ...

AI Technical Summary

Problems solved by technology

There are many construction steps and complex procedures for undercutting and casing replacement operations, which require the use of undercut drilling tools, which are not suitable for deep well casing replacement operations

This is because during casing undercutting operations, the undercut drilling tool is usually inserted into the casing for undercutting. Due to the small size and low strength of the inserted undercut drilling tool, the backing-off depth is limited

If conventional reverse thread drilling tools are used for reverse threading, the reverse thread position cannot be accurately determined, and it may be reversed into several pieces

If a large casing is inserted and docked, the sealing reliability of the casing butt joint will be poor

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