Blocking method for perforation well sections of slim hole sidetracking well

Abstract

The invention provides a blocking method for perforation well sections of a slim hole sidetracking well. One of the blocking method comprises the step that S100, a wellhead well plugging device is opened, a workover fluid is filled in sleeves, and drafting process is conducted; S200, operation pipe columns are put in the well, blocking operation is successively conducted on each perforation well section from top to bottom, and the blocking operation is completed when the blocking operation is conducted on the lowermost perforation well section; and S300, the sleeves are cleaned through a drag bit to the position of an artificial well bottom, wherein the blocking operation comprises the steps that an impending cement plug is set in the position, below the corresponding perforation well section, of each operation pipe column; cement squeezing blocking operation is conducted; temporary cement plugs are formed above the impending cement plugs; the wellhead well plugging device is closed, and waiting on cement setting is conducted under pressure; and the wellhead well plugging device is opened, the downward-put drag bit successively drills through the temporary cement plugs and the impending cement plugs from top to bottom, and blocking operation is completed. The invention further provides the other blocking method for the perforation well sections of the slim hole sidetracking well. A packer is not needed, blocking is completed from top to bottom, the blocking method can be used for permanent well plugging or slim hole major repairing.

Description

technical field [0001] The invention relates to the technical field of oil and gas downhole operations, in particular to a plugging method for a perforated well section of a sidetracked well with a slim hole. Background technique [0002] With the increasing difficulty of oil field production and the development and application of new drilling technologies, the number of slim hole sidetracking wells (the inner diameter of the casing is less than or equal to 86 mm) in the oil field has been increasing. With these special Structural wells are put into production, and there are more and more phenomena of overhaul due to various factors, such as: due to layer adjustment or other production requirements, the original perforated well section needs to be plugged. The conventional plugging method is generally to lower the packer and squeeze cement from bottom to top. However, the inner diameter of the sidetracked section of the slim hole is too small, so it is difficult to find a su...

AI Technical Summary

Problems solved by technology

[0003] In order to solve the technical problem that it is inconvenient to use conventional packers for plugging in slimhole sidetracking wells, the plugging method for the perforated well section of slimhole sidetracking wells proposed by the present invention does not require packers, and follows the top-down sealing method. The blocking principle completes the blocking

Images