Drilling tool and method for plug sweeping and milling of tie-back cylinder

Abstract

The invention provides a drilling tool and method for plug sweeping and milling of a tie-back cylinder. The drilling tool comprises a drill pipe, a telescoping rod assembly and a mill shoe, wherein the telescoping rod assembly comprises an outer telescoping rod, an inner telescoping rod and a limiting assembly. One end of the outer telescoping rod is provided with a removing cylinder, and a containing cavity is formed in the removing cylinder. The method for plug sweeping and milling comprises the steps that the drilling tool is lowered to the upper end of set cement on the top of the tie-backcylinder, the mill shoe is moved into the containing cavity of the removing cylinder so as to limit the position of the inner telescoping rod; the removing cylinder is moved downwards to scrape the set cement on the top of the tie-back cylinder off; when the removing cylinder moves to the top of an upper end opening of the tie-back cylinder, plug sweeping is stopped, the mill shoe is moved untilto stretch out of the containing cavity of the removing cylinder, and the position of the inner telescoping rod is limited; the mill shoe is moved downwards to mill and polish the inner wall of the tie-back cylinder, and when milling is conducted on the lower end opening of the tie-back cylinder, milling is stopped. The drilling tool has the advantages of being high in efficiency, saving cost andbeing high in working reliability and safety.

Description

technical field [0001] The invention relates to the field of petroleum drilling, in particular to a drilling tool and a method for plug cleaning and milling of a return barrel. Background technique [0002] The liner tie-back process refers to a process in which after the liner cementing is completed, a tie-back casing with a tie-back tool connected to the bottom end is lowered, and the tie-back sleeve is connected back to the wellhead from the position of the liner hanger. Usually, before running the tie-back casing, it is necessary to remove the cement stone remaining on the top of the tie-back barrel of the liner hanger, and to grind and polish the tie-back barrel to ensure a good connection between the tie-back tool and the tie-back barrel seal. [0003] In the prior art, "three-pass drilling" is usually used for plug cleaning and milling of the tie-back barrel. Specifically, in the first pass, a drill bit suitable for the inner diameter of the upper casing is used to r...

AI Technical Summary

Problems solved by technology

This method requires multiple drills to complete the plug sweeping and milling of the tie-back barrel, and its efficiency is low; at the same time, it is impossible to judge whether the first drill has drilled to the upper port of the tie-back barrel or whether the upper port has been damaged. If there is a cement ring on the top of the tie-back barrel or the upper port is deformed, it will affect the running of the milling shoe or the tie-back tool, and also increase the risk of seal failure of the tie-back tool. If the tool is run in to repair the tie-back barrel, it will Seriously affect the timeliness of the project and cause serious losses

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