RU2194845C2 - Gas cutoff valve - Google Patents

Abstract

FIELD: mining industry, particularly, gas production. SUBSTANCE: gas cutoff valve includes gate and closed chamber located above gate. Movable bushing with circular piston is connected with gate with possible its switching over to closed position with piston movement in direction of chamber volume increase. Chamber has throttling holes communicating chamber space with cavity of string located above gate. Cutoff valve has float and the second gate connected with float. The second gate is installed for shutoff of fluid passage to closed chamber with float moving upward. EFFECT: autonomy of device and possibility of its installation in the immediate vicinity of bringing inflow zone; higher efficiency and operating reliability. 2 cl, 3 dwg

Description

 The invention relates to the mining industry, namely gas production, and can be used in gas production to cut off the bottomhole zone of a well in case of depressurization of tubing, wellhead equipment or a pipeline directly connected to the well. The valve can also be used as a remotely controlled depth shut-off device.

 Known shut-off valve, comprising a slide valve [patent of Russia 2007547, C1 class. 5 E 21 B 34/06, 1990], a shutter and traction drive connecting the shutter drive to a surface.

 The disadvantage of the valve is the need for a gate actuator in connection with the surface.

 Known gas shutoff valve, adopted as a prototype [Bukhalenko E.I. and other Oilfield equipment: Handbook. 2nd ed. - M.: Nedra, 1990, p. 46-47, fig. 1.15.b.], including the shutter and a closed chamber forming with the device body located above it, a movable sleeve with an annular piston, connected with the shutter with the possibility of moving it to the “closed” position when the piston moves in the direction of increasing the chamber volume.

 The disadvantage of the valve is that to close and open it requires equipment located on the surface, connected to the valve by means of a special pipeline, in addition, the use of the valve is impossible without the use of cable technology. These conditions significantly limit the depth of its installation, significantly complicate the effectiveness and the possibility of its application.

 The purpose of the invention is to eliminate these disadvantages.

 This goal is achieved by the fact that the chamber has throttle openings connecting its cavity with the cavity of the column located above the shutter.

 Another objective of the invention is to prevent liquid from entering the closed chamber if it fills the column in which the valve is installed.

 This goal is achieved in that the device is equipped with a float and a associated second shutter installed with the possibility of blocking the passage of liquid into a closed chamber when the float moves up.

 Thus, the claimed gas shutoff valve meets the criterion of "novelty."

 Analysis of the known technical solutions showed that the features described above meet the criterion of "significant differences".

 New features tell the valve completely new possibilities.

 Due to the connection of the valve through the throttle openings directly with the medium of the column, to the state of which it must respond, the valve becomes completely autonomous, free from the use of tubes and cable technology. What is especially important, the valve can now be installed directly in the bottom-hole zone where its application is most effective.

 Due to the possibility of overlapping the chamber from liquid ingress, the field of application of the valve expands and its reliability increases. The valve may be installed in a column filled with liquid.

 In FIG. 1, a gas shut-off valve is shown in its initial position, in an environment filled with liquid.

 Figure 2 - valve after well development, during the period of gas movement along the column.

 Figure 3 - valve after cutting off the bottom-hole zone.

 A gas shut-off valve including a shutter l (Fig. 1) and a movable sleeve 2 with an annular piston 3 located above it, forming a closed chamber 4 with an annular body made therein. The sleeve 2 is connected to the shutter 1 with the possibility of switching it into the position is “closed” when the piston 3 moves in the direction of increasing the volume of the chamber 4. The throttle holes 5 are made in the chamber, connecting its cavity with the cavity 6 of the column located above the shutter.

 A design variant is possible when the piston 3 will be located not from above, but under the annular bridge of the housing, then the piston stroke will be directed from top to bottom.

 The valve is also equipped with a float 7 and a associated second shutter 8.

 The shutter 8 is needle-shaped and installed with the possibility of blocking the passage of fluid into the closed chamber 4 when the float 7 moves up.

 The device operates as follows.

 The valve can be lowered both with an empty column (Fig. 2) and installed in a well filled with fluid (Fig. 1), i.e. before calling the gas inflow. When the valve enters the liquid, the float 7 pops up, and the shutter 8 blocks the entrance to the chamber 4 (figure 1). If the column is filled with gas (figure 2), the float is lowered and opens the gas inlet to the chamber 4. When gas enters the column, the pressure in the chamber 4 all the time remains below the pressure in the column. As long as the pressure in the chamber is lower than the pressure in the column, the piston 3 constantly experiences the effect of a pressure drop directed from the bottom up. In this case, the sleeve 2 is always in the lower position, and the shutter 1 remains open. Thus, the increase in pressure in the zone of the device does not change the position of the shutter.

 In the event of a pressure drop, for example, as a result of pipe depressurization (Fig. 3), the pressure in the column drops, and the pressure in the chamber is higher than the pressure in the column. The piston 3 experiences the action of a differential pressure directed from the bottom up, raises the sleeve 2 and the shutter 1 begins to cover the passage in the column. This further reduces the pressure above the valve and the valve closes. Gradually, the gas leaves the chamber 4 through the orifice 5 and the pressure in it is equalized with the pressure acting in the column 6 in the area located above the closed valve.

 After eliminating the cause of the pressure drop, the valve is opened. To do this, a small pressure (0.8-1 MPa) is supplied from the surface, for example, by connecting the column to a gas collection network. After that, the pressure in the column above the valve is higher than the pressure in the chamber 4. The piston 3 is affected by pressure directed from top to bottom. The piston moves with the sleeve 2 and opens the valve 1. The pressure in the column above the valve will rise sharply. Due to the resistance of the throttle holes 5, the pressure increase in the chamber 4 lags behind the pressure rise in the column. Therefore, the force continues to act on the piston 3, pushing it down. The sleeve 2 is lowered and fully opens the shutter 1 (figure 2). The circulation through the column is restored.

Technical and economic efficiency of the device is achieved by the fact that:
the valve is made completely autonomous, free from the use of tubes and cable technology, does not need equipment located on the surface;
the valve can be installed directly in the bottom-hole zone where its application is most effective;
the valve can be installed in a column filled with liquid.

Claims (2)

 1. The gas shutoff valve, comprising a shutter and a closed chamber located above it and forming a closed chamber with the device body, a movable sleeve with an annular piston, connected with the shutter with the possibility of moving it to the closed position when the piston moves in the direction of increasing the chamber volume, characterized in that in the chamber there are throttle openings connecting its cavity with the cavity of the column located above the shutter.  2. The device according to p. 1, characterized in that it is equipped with a float and a associated second shutter installed with the possibility of blocking the passage of fluid into a closed chamber when the float moves up.

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