Downhole safety valve

Abstract

The invention discloses a downhole safety valve, wherein a central tube is arranged in a main body consisting of a top joint, a valve body, an outer cylinder and a tail joint connected sequentially; the upper end of the top joint and the lower end of the tail joint are respectively connected with an external oil tube; a corrugated tube assembly is arranged in the gap between the outer cylinder and the central tube, and the bottom end of the corrugated tube assembly is connected with a positioning ring fixed on the peripheral wall of the central tube; a boss is formed on the inner wall of the lower port of the outer cylinder, a pressure spring is sleeved on the periphery of the central tube between the lower side of the positioning ring and the boss, and a plate valve assembly is connected to the bottom end of the outer cylinder; the top joint is provided with a control line, the control line is embedded on the top joint through a control line connection assembly and communicated with a hydraulic oil passage formed in the valve body wall, and the bottom port of the hydraulic oil passage in the valve body wall is connected with the top end of the corrugated tube assembly. The downhole safety valve can be used in extreme environment with well conditions such as super high temperature steam thermal recovery, high gas tightness requirement, ultradeep installation, high sandiness environment and high corrosion.

Description

Technical field [0001] The invention relates to a safety valve. In particular, it relates to a downhole safety valve used for well control of oil and gas wells in ultra-high temperature environments or other extreme well conditions. Background technique [0002] In the oil extraction industry, during downhole operations, it often occurs that the flow rate of hydrocarbon fluids increases but cannot be controlled due to the failure of mining equipment. At this time, the passage must be closed in time to ensure operational safety and avoid greater accidents. In actual production, there must be a device (downhole safety valve) to close the fluid channel to achieve the blocking function. [0003] The downhole safety valve is a downhole equipment that prevents blowouts and ensures production safety. When an emergency occurs, the oil and gas well can be closed by the pressure relief closing valve plate of the control pipeline connected from the valve body to the ground. When it needs to...

AI Technical Summary

Problems solved by technology

[0008] 1) At present, the downhole safety valves in the world either adopt a piston structure or a sliding mandrel structure to push the valve plate to open and close. Both structures must be sealed by seals, which will bring the following disadvantages: a) Unable to withstand high temperature; b) Once the sand and dust in the well enters the sealing surface, it may cause jamming; c) Repeated opening and closing may cause damage to the seal, so the number of uses is limited

[0009] 2) Due to the limited spring force of the traditional downhole safety valve, and the cross-sectional area of ​​the piston or sliding mandrel cannot be too small due to the stability of the rod, the opening and closing pressure cannot be too high, so it is difficult to meet the requirements of ultra-deep installation.

This structure cannot get rid of the dependence on the tape, and the temperature will make the seal fail

[0011] 4) The static sealing problem of the body of the downhole safety valve at high temperature

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