Hydraulically-controlled underground check valve capable of being opened/closed repeatedly

Abstract

The invention relates to a hydraulically-controlled underground check valve capbale of being opened / closed repeatedly, and belong to the field of petroleum underground operation tools. The underground check valve comprises an outer sleeve, an upper joint, a lower joint, a baffle valve and a piston; the upper joint is mounted at one end of the outer sleeve through threads; the lower joint is mounted at the other end of the outer sleeve through threads; the baffle valve is mounted in the lower joint through threads; the piston is movably mounted in the outer sleeve on one side of the baffle valve; the piston is in contact connection with the baffle valve. The underground check valve is simple in structure and high in practicability, and can realize the full bore of an operation test string when being in the open state in the operation process; pressure is applied after a ball is throw into, so that the opening and the closing of the check valve can be realized; the balance of pressures above and below a valve plate can be easily realized when the pressures above and below the valve plate are not equal; the check valve can be mounted at any desired position of a pipe column to meet needs of various operating environments; meanwhile, the check valve has the characteristics of being convenient to mount and wide in application range.

Description

technical field [0001] The invention relates to a hydraulically controlled downhole check valve which can be switched repeatedly, and belongs to the field of oil well operation tools. Background technique [0002] In the completion of conventional oil and gas wells, especially in coiled tubing operations or pressurized tubing operations, in order to ensure the continuity and safety of operations, check valves are usually installed in the completion string. Conventional check valves are pre-set flow direction, a ball is designed inside the product. Because the ball is fixed in the pipe string in a certain way, the diameter of the pipe string is affected, which limits the displacement during fracturing or oil production, thus affecting the production of oil and gas wells; and the liquid flow always has only one direction ( Forward, or reverse), unable to achieve two-way connectivity under specific operating conditions, there are greater limitations in use. Contents of the i...

AI Technical Summary

Problems solved by technology

Because the ball is fixed in the pipe string in a certain way, the diameter of the pipe string is affected, which limits the displacement during fracturing or oil production, thus affecting the production of oil and gas wells; and the liquid flow always has only one direction ( Forward, or reverse), unable to achieve two-way connectivity under specific operating conditions, there are greater limitations in use

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