Completion pipe string for shaft bottom replacement and operation method

Abstract

The invention discloses a completion pipe string for shaft bottom replacement and an operation method. The upper end of an expansion pipe column is connected with an emergency release connecting sleeve; the emergency release connecting sleeve is disposed on the outer wall of an upper connecting pipe in a sleeving manner; the lower end of the expansion pipe column is connected with a tail pipe releasing connecting sleeve; the upper end of a tail pipe is connected with a tail pipe releasing connecting sleeve; the lower end of the tail pipe is connected with a bump-pressing ball seat; the upper end of the tail pipe releasing tool is connected with an expansion head; the lower end of the tail pipe releasing tool is connected with a central inner pipe; the upper end of the expansion head is connected with an emergency releasing spline shaft through a middle connecting pipe; the upper end of the emergency releasing spline shaft is connected with the lower end of the upper connecting pipe, the outer wall of the tail pipe releasing tool is in threaded connection with the inner wall of the tail pipe releasing connecting sleeve, the outer wall of the expansion head is provided with a curved-surface outer shoulder, and when the expansion head moves upwards, the curved-surface outer shoulder of the expansion head abuts against the curved-surface inner shoulder of the inner wall of the reducing section in an attached mode. According to the invention, the shaft bottom replacement of the large tail pipe is achieved, well cementation quality is guaranteed, a large channel is provided for follow-up operation procedures, shaft integrity is improved, and follow-up production requirements are met.

Description

technical field [0001] The invention relates to a secondary completion pipe string technology in oilfield oil production engineering, in particular to a bottom hole replacement completion pipe string and an operation method. Background technique [0002] After years of development in old oil fields, there are a large number of shut-down wells, scrapped wells, and low-efficiency wells with casing damage. It is a very effective measure to restore the oil and gas production of old wells by changing the bottom of the well, maintain the perfection of the development well pattern, improve the recovery rate, and save the cost of drilling and ground construction at the same time. [0003] At present, the existing technology of bottom hole replacement in China is that the size of the liner used is too small, and the top of the liner uses a hanger or a bell mouth. The prior art has the following deficiencies: [0004] 1) The size of the tail pipe used is too small and the inner diam...

AI Technical Summary

Problems solved by technology

[0004] 1) The size of the tailpipe used is small and the inner diameter is small, which brings a lot of inconvenience to the follow-up operations and measures

Such as: 51 / 2" casing, the tail pipe used for changing the bottom of the well is 33 / 4", the outer diameter the inside diameter of Unable to use conventional 73mm tubing;

[0005] 2) The top of the tail pipe uses a hanger or bell mouth, the hanger is not sealed, and the top of the tail pipe often leaks;

[0006] 3) When plugging is used for cementing displacement, it is often necessary to clean the top of the liner or the bottom of the liner wellbore, which increases the operating cost

At the same time, due to various reasons, the rubber plug cannot be bumped and pressed smoothly. stuck in the drill pipe;

[0007] 4) All operations of the existing expandable liner hanger after cement injection depend on the smooth bumping of the rubber plug, and the risk points are too concentrated on the smooth bumping of the rubber plug

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