Branch well window sealing method

Abstract

The invention discloses a branch well window sealing method for sealing branch well windows of oil and water wells. The method is implemented through a sealing device; the device consists of a main borehole under the window, a branch borehole and a main borehole above the window; the sealing device is made of a material which has certain elasticity, can expand and can recover deformation, and the sealing device is molded by die casting or tube welding; after the sealing device and a running tool are dropped to the branch well window, the sealing device is firstly expanded by hydraulic pressure, and simultaneously a drilling tool is dropped to make the sealing device descend till to the designed position; after the sealing device is completely expanded, a feeding pipe column is pressed down to shear a connecting dowel between the running tool and the sealing device so that the running tool and the sealing device are separated; the feeding pipe column and the running tool are extracted from the well; and an expanding tool is dropped to push an expanding cone by using hydraulic pressure to expand the sealing device so that the sealing device is expanded to the inner wall of a sleeve at the other window to be fully jointed and the communication between two branches are ensured. The method solves the problem that the window has no mechanical seal in the prior art. The method can be used for the sealing operation for the branch wells of the oil and water wells.

Description

Technical field: [0001] The invention relates to a branch well window sealing method for oil and water well branch well windows. Background technique: [0002] With its high single-well production and low crude oil production cost, branch well has become the leading technology of crude oil production in the world, and its window sealing is the main indicator of the degree of completion of branch well. At present, domestic branch well technology is only at level four, and there is no reliable mechanical seal at the window. In foreign countries, level six branch wells use reaming at the window opening position of the main wellbore, and lower the prefabricated downhole branching device to realize the window. Mechanical seal at the place. The running of this sealing device tends to reduce the size of each branch wellbore, and at the same time, because the drill bit often passes through the prefabricated device, it will cause wear of the device, thereby affecting the sealing at ...

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to provide a method for sealing the branch well window, which solves the problem that there is no reliable mechanical seal at the branch well window in the prior art

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