Self-balancing downhole safety valve

Abstract

The invention belongs to the field of oil-gas field development, and particularly relates to a self-balancing downhole safety valve. The self-balancing downhole safety valve is of a columnar annular structure and comprises an upper joint, a piston sleeve, a spring sleeve, a connecting joint, a lower joint, a drive pipe, a center pipe, a spring and a valve base structure. The self-balancing downhole safety valve is characterized in that the upper joint, the piston sleeve, the spring sleeve, the connecting joint and the lower joint are sequentially fixedly connected to form a hollow shell, the drive pipe, the center pipe, the spring and the valve base structure are arranged in the shell formed by the upper joint, the piston sleeve, the spring sleeve, the connecting joint and the lower joint, the drive pipe is fixedly connected with the center pipe, the spring is arranged on the center pipe, the top end and the bottom end of the spring abut against the bottom of the drive pipe and the top of the connecting joint respectively, and the valve base structure is arranged at the lower end of the connecting joint. According to the self-balancing downhole safety valve, the opening and closing actions of an oil well in a normal work state can be excellently finished, the reliable later-period repair function is designed, and therefore reliability of a well mouth safety system is greatly improved.

Description

technical field [0001] The invention belongs to the field of oil and gas field development, and in particular relates to a self-balancing downhole safety valve. Background technique [0002] The downhole safety valve is an important part of the wellhead safety system, and its development has gone through about 70 years. The working principle of a common safety valve is as follows: During normal operation, the ground control fluid acts on the piston rod, the piston rod pushes the drive tube and the center tube, and at the same time the spring is compressed, the valve plate opens to maintain the pressure supply of the ground control fluid, The valve plate is normally open, and the oil well is connected up and down; when an emergency occurs and the oil well needs to be shut down, the control fluid on the ground is unloaded, the center pipe and the drive pipe move upward under the action of the spring force, and the force acting on the valve plate by the center pipe disappears. ...

AI Technical Summary

Problems solved by technology

[0003] At present, the downhole safety valve has the following problems: when the safety valve is used in some ultra-deep wells, the control pipeline or sealing ring is prone to leakage, causing the high-pressure oil in the oil jacket space to enter the piston chamber

Then the force on the piston remains high, even if the control fluid on the ground is unloaded, the center pipe cannot go up under the action of the spring force, resulting in the situation that the valve plate cannot be closed; when the downhole safety valve opens and closes frequently or the operating pressure When it is too high, it is easy to cause the failure of the sealing ring, which will cause the leakage of the downhole safety valve body. When the safety valve is closed due to the loss of pressure in the system, the oil well cannot work normally

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