RU2466268C1 - Valve to balance pressure in valve equipment - Google Patents

Abstract

FIELD: oil and gas production.

SUBSTANCE: valve comprises a body with the main channel, communicated on top with process pipes, and at the bottom - with well equipment, a piston installed in the main channel, spring-loaded upwards and closing communication of the main channel and the well equipment in the upper position. The body is equipped with an additional channel that communicates the main channel with used equipment and arranged as capable of closure with the piston in its lower position, and the main channel below the piston is communicated with the well space. The piston spring may be arranged as capable of control of its compression extent. The main channel may be equipped with a seat made as capable of tight interaction with the piston in its upper position.

EFFECT: invention provides for quick reduction of pressure in equipment down to hydrostatic one and reduction of time to prepare to the next cycle in case of cyclic operation.

3 cl, 3 dwg

Description

The invention relates to the oil industry, in particular to the repair and operation of wells.

In the practice of operating and repairing wells, work is often carried out related to the repeated injection of fluid into technological pipes and subsequent equalization of pressure in the underground equipment with hydrostatic in the well after each cycle. To do this, it is necessary to drain fluid from process pipes through some hole or valve to the liquid level in the well, which can be hundreds of meters from the wellhead. To avoid this, valves are used that allow, without draining fluids from the pipes, to equalize the pressure in the equipment with hydrostatic.

A device for perforating a wellbore (patent RU No. 2105137, IPC E21B 43/114, publ. 02.20.1998), which includes an equalizing valve in the form of a spring-loaded spool.

The disadvantages of this valve are the design complexity, the ability to use only in the device for perforation.

Closest in technical essence to the proposed valve used in the design of the device for creating perforation channels in the casing of the well (patent RU No. 2395671, IPC E21B 43/112, published on July 27, 2010).

The valve is made in the form of a spring-loaded spool communicating the cavity of the process pipes with the cavity of the equipment used when liquid is pumped into them. And after the injection is stopped, it holds a column of liquid in the process pipes and opens a hole to reduce the pressure inside the equipment. The use of such valves in wells with a low static level is especially relevant.

The disadvantage of this valve is that when the valve is open during injection, with a decrease in fluid flow, the pressure above and below the valve is almost equalized and the spring closes the valve. As a result, the valve operates in a reduction mode, reducing the injection pressure in the equipment in accordance with the spring setting by a value corresponding to approximately the hydrostatic pressure of the fluid column held by the valve, which is equal in height to the level of the fluid in the well.

The technical problem solved by the invention is to eliminate the pressure reduction of the injected fluid by the valve.

The problem is solved by a valve for equalizing the pressure in the downhole equipment without draining the fluid from the process pipes, comprising a housing with a main channel communicated from above with the process pipes and from below with downhole equipment, a piston installed in the main channel, spring-loaded upward and blocking the communication of the main channel with downhole equipment in the upper position.

New is that the housing is equipped with an additional channel communicating with the main channel with the equipment used and configured to overlap the piston in its lower position, and the main channel below the piston is in communication with the borehole space.

Also new is the fact that the spring is configured to control its compression ratio.

Also new is the fact that the main channel is equipped with a seat made with the possibility of tight interaction with the piston in its upper position.

The essence of the invention lies in the fact that during the injection of fluid into the downhole equipment, the injection piston acts on top of the spool piston with injection pressure, and below the hydrostatic pressure of the fluid column in the well, and not the operating pressure in the equipment.

1 shows a diagram of a valve in the closed position.

Figure 2 shows a diagram of the valve in the open position.

Figure 3 shows the diagram of the valve in the closed position when making the upper end in the form of a valve.

The valve (figure 1) contains a housing 1 connected from below to the equipment 2 used, and from above to a column of process pipes 3. Housing 1 contains a cylindrical channel 4 communicated from above with a cavity of the process pipes 2, and from below with a channel 5 with a well cavity. Channel 4, the upper hole 6 and the bottom 7 is communicated by channel 8 with the cavity of the equipment used 3.

Inside the channel 4 there is a piston 9 containing an upper rod 10 with a thread 11 that interacts through a washer 12 and a nut 13 with a compression spring 14. Below the piston 9 has a lower rod 15 with a stopper 16, and the channel 4 has a bore 17 in the lower part. Rods 10 and 15 have a smaller diameter than the piston 9 and channel 4, and the limiter grooves 18 for the flow of fluid.

Figure 3 shows an embodiment when the piston 9 is made in the upper part in the form of a conical or spherical valve 19, and the channel 4 with a constriction 20 having a seat 21 in the lower part. The restrictor 16 is not needed in this design, the valve 19 plays its role .

The valve operates as follows.

In the absence of fluid injection into the process pipes 2 (Fig. 1), the valve is in the closed position, i.e. the piston 9 blocks the hole 6, and the cavity of the equipment 3 through the channel 8, holes 7 and channel 5 is in communication with the well. In this position, the spring 14, abutting the washer 12 and the nut 13, pulls the piston 9 along the upper rod 10 together with the lower rod 15 and the stopper 16, which abuts against the ledge at the transition of the channel 4 into the bores 17. The hole 6 is blocked by the piston 9, and the equipment cavity 3 is communicated through channel 8, hole 7, channel 4, bore 17 and channel 5 with the well cavity. The force acts on the piston from the difference in hydrostatic pressures of the process pipes and the well, which is overcome by the spring holding the piston 9 in the upper closed position.

When working with equipment 3 (figure 2) into the process pipes 2, fluid is injected under a pressure exceeding the hydrostatic pressure in the well. The pressure differential acting on the piston 9 overcomes the compression force of the spring 14 and moves it down until the rod 15 with the stopper 16 reaches the bottom of the bore 17. In this position, the piston 9 blocks the hole 7, interrupting the communication of the equipment cavity 3 with the well, and channel 5 remains open, communicating the cavity of the bore 17 with the well and providing a pressure under the piston 9 equal to the borehole hydrostatic. As a result, the pressure in the equipment 3 rises to the necessary, and it carries out the work for which, for example, as in the prototype, perforation of the production casing is intended. At the same time, a pressure differential is constantly acting on the piston 9, equal in magnitude to the difference from the sum of the injection pressures with hydrostatic in the process pipes and hydrostatic in the well. Therefore, as long as there is excess fluid pressure, the valve is in the open position without any decrease in the injection pressure, even in the complete absence of movement of the injected fluid.

After the completion of work or a cycle, the injection of liquid is stopped and the pressure at the mouth is equalized with atmospheric. The pressure drop across the piston 9 is equalized or simply reduced (if the static level in the well is lower than in the process pipes) and the spring 14 puts the piston 9 in the upper position, as in figure 1. In this case, the piston 9 blocks the channel 5, preventing leakage of fluid from the process pipes 2 and opens the fluid outlet from the equipment 3 through channel 8, hole 7, channel 4, bore 17 and hole 5 into the well. The pressure in equipment 3 is equalized with hydrostatic in the well, and it is ready for the next cycle of work. Technological pipes 2 remain filled and ready for the next cycle of work without waiting for their filling.

The pre-compression force of the spring 14, which is regulated by the position of the nut 13 and the washer 12 on the threaded rod 10, determines the valve opening pressure and the height of the fluid column held. The adjustment allows you to adjust the spring 14 depending on the actual liquid level in the well.

As for the operation of the valve with the seat 21 (Fig.3), its operation differs only in that in the closed position, when the piston 9 is in the upper position, while the piston 9 with the upper end, made in the form of the valve 19, sits on the seat 21 constriction 20. This ensures better tightness than the piston 9 and reduces leakage from the pipes 3 while waiting for the next cycle.

The spring 14 can be placed under the stop 16 (not shown in FIGS. 1, 2 and 3), but in this case its size will be limited and adjustment will become more difficult.

Thus, the proposed valve provides a quick reduction in pressure in the equipment to hydrostatic and a reduction in the preparation time for the next cycle during cyclic operation. At the same time, during valve injection, closing of the valve and loss of part of the pressure are excluded, since a constant pressure drop is maintained on the piston during the cycle. Especially effective is the use of the valve in wells with a low static level, where it takes a lot of time to level the levels in the process pipes and the well, and then fill them.

The valve can be used when working with a downhole hydromechanical jack and perforator, hydraulic anchors and other equipment requiring multiple injections of fluid to work, followed by pressure equalization with hydrostatic in the well.

Claims (3)

1. Valve for equalizing the pressure in the downhole equipment without draining the fluid from the process pipes, comprising a body with a main channel communicated from above with the process pipes and below with downhole equipment, a piston installed in the main channel, spring-loaded upward and blocking the communication of the main channel with downhole equipment in the upper position, characterized in that the housing is equipped with an additional channel communicating the main channel with the equipment used and configured to overlap the piston in its lower position, and the main channel below the piston communicates with the downhole space. 2. The valve according to claim 1, characterized in that the piston spring is configured to control its compression ratio. 3. The valve according to claim 1 or 2, characterized in that the main channel is equipped with a seat made with the possibility of tight interaction with the piston in its upper position.

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