RU2587654C1 - Downhole valve unit - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: invention relates to equipment of wells equipped with downhole electrically driven pumps. Device includes housing with annular projection on inner surface, below which has drain channels, movable in axial direction of slide valve with upper and lower shanks of smaller diameter. In upper part of upper shank are drain openings and there is a limiting collar, while lower shank of spool is sealed relative to housing. Furthermore, spool is equipped with through axial channel where there is a check valve and installed in housing to make annular starting chamber, in which on upper shank is arranged axially moving two-stage piston upper step of which there is a hollow cylinder in walls of which there are collets and drain openings. Hollow cylinder is rigidly connected and combined outer side with upper step of axially moving two-diameter piston, and on inner side of upper step of axially moving two-diameter piston forms an annular setting projection made with possibility of tight fit limiting collar upper shank of spool. Furthermore, annular starting chamber communicates with axial channel of spool by holes in lower part of upper shank. Lower outer surface of larger diameter step of axially moving two-diameter piston has possibility of sealing relative to housing inner surface. And upper stage is designed to shut off drain channels of housing and to seal relative to housing annular projection in uppermost position of piston. Furthermore, collets are installed with possibility of interaction with annular projection of housing and with limiting collar. Area bounded by compacted sides stages of axially moving two-diameter piston is made with possibility of exceeding area bounded by outer diameter of lower shank of the spool. At lower shank of spool there is a pressure relief valve with spring-loaded shutoff member and configured to release pressure from launching chamber and axial channel of spool. Adjusting sleeve is installed on housing. Adjusting sleeve is installed with possibility of interacting with shutoff member pressure release valve when pressure pulse to open message inner cavity of tubing string with annular space.

EFFECT: technical result consists in improvement of reliability.

1 cl, 3 dwg

Description

The invention relates to the oil and gas industry, in particular to the equipment of wells equipped with electric submersible pumps, and can be used to improve the reliability and efficiency of technological operations.

A device is known - a valve assembly of the injection pipeline of a borehole pump (see the description of the invention to copyright certificate No. 1435836, F04D 15/02 of 01/13/1987). The device comprises a housing with an annular protrusion on the inner surface, below which drain channels are made in the housing. The device also contains an axially movable spool having a shank of a smaller diameter in the upper part, the spool having a through axial channel in which the check valve is placed and installed in the housing to form an annular launch chamber. The launch chamber is in communication with the axial channel of the valve by means of holes in the lower part of the shank, and in the upper part of the latter there are drain windows arranged to communicate with the drain channels of the housing at the lowermost position of the valve. An axial-movable two-stage piston is installed on the shank in the launch chamber, while the outer surface of the lower stage of a larger diameter is sealed relative to the inner surface of the housing, and the upper stage is installed with the possibility of overlapping drain channels of the housing at the extreme upper position of the piston.

The disadvantage of this device is that for technological operations it is necessary to create an increase in pressure in the annulus and fill it with liquid, and this can be problematic for wells with low reservoir pressure. In addition, when starting the pump, the spool can be ahead of the piston, and this can lead to the inability to move the piston to its highest position and supply fluid to the surface.

The closest to the achieved result and the combination of features is a downhole valve device (see patent specification 2455459, IPC E21B 34/08 of January 11, 2011), comprising a housing with an annular protrusion on the inner surface, below which drain channels are made in the housing, axially movable spool having upper and lower shanks of smaller diameter, a safety valve and restriction collar are installed in the upper part of the upper shank, drain windows are also made, and the lower shank of the spool sealed relative to the housing. The spool is provided with a through axial channel in which the check valve is located. The spool is installed in the housing with the formation of an annular launch chamber, in which an axially-movable two-stage piston is placed on the upper shank, a hollow cylinder is installed on the upper stage, in the walls of which collets and drain windows are placed. The hollow cylinder is rigidly connected and aligned with the outer side with the upper stage of the axial-movable two-stage piston, and on the inner side the upper stage of the axial-movable two-stage piston forms an annular landing protrusion made with the possibility of tight fit of the restrictive shoulder of the upper spool shank. In addition, the annular launch chamber is in communication with the axial channel of the valve by means of holes in the lower part of the upper shank. Also, the outer surface of the lower stage of the larger diameter of the axially movable two-stage piston is sealed with respect to the inner surface of the housing. The upper stage is made with the possibility of overlapping the drain channels of the housing and with the possibility of sealing relative to the annular protrusion of the housing at the extreme upper position of the piston, in addition, collets are installed with the possibility of interaction with the annular protrusion of the housing and with a restrictive collar. Moreover, the area limited by the sealed sides of the steps of the axially movable two-stage piston is made with the possibility of exceeding the area limited by the outer diameter of the lower shank of the spool.

The disadvantage of this device is that when you create a pressure pulse in the tubing to organize the communication of the internal cavity of the tubing with the annulus through the device and drain channels in the housing can only partially open, not fully. Since the movement of the piston and the spool will be hindered by the force arising from the increase in pressure in the start-up chamber and in the axial channel of the spool, therefore, the degree of opening of the drain channels of the housing depends on the elasticity of the fluid enclosed in the start-up chamber and the axial channel of the spool, isolated by this position of the device. In part, the incomplete opening of the drain channels creates a condition for creating additional pressure losses and reducing efficiency when flushing through the device.

The claimed invention solves the problem of a complete and almost instantaneous opening by the communication device of the tubing cavity and annulus by creating a pressure pulse in the tubing to conduct more efficient technological operations and increase the reliability of the device.

The problem is solved in that in a device containing a housing with an annular protrusion on the inner surface, below which drain channels are made in the housing, an axially movable spool having upper and lower shanks of a smaller diameter. Drain windows are made in the upper part of the upper shank and a restrictive collar is installed, and the lower spool shank is sealed relative to the housing. In addition, the spool is provided with a through axial channel in which the check valve is placed and installed in the housing with the formation of an annular launch chamber, in which an axially-movable two-stage piston is placed on the upper shank, on the upper stage of which there is a hollow cylinder with collets and drain windows. Moreover, the hollow cylinder is rigidly connected and aligned with the outer side with the upper stage of the axial-movable two-stage piston, and on the inner side the upper stage of the axial-movable two-stage piston forms an annular landing protrusion made with the possibility of tight fit of the restrictive shoulder of the upper spool shaft. In addition, the annular launch chamber is in communication with the axial channel of the spool by means of holes in the lower part of the upper shank, while the outer surface of the lower stage of the larger diameter of the axially movable two-stage piston is sealed with respect to the inner surface of the housing. And the upper stage is made with the possibility of overlapping the drain channels of the housing and with the possibility of sealing relative to the annular protrusion of the housing at the extreme upper position of the piston. In addition, the collets are installed with the possibility of interaction with the annular protrusion of the housing and with a restrictive shoulder, and the area limited by the sealed sides of the steps of the axial-movable two-stage piston is made with the possibility of exceeding the area limited by the outer diameter of the lower shaft of the spool.

According to the claimed invention, a pressure relief valve with a spring-loaded shut-off element and configured to relieve pressure from the starting chamber and the axial channel of the valve is placed on the lower shank of the spool. And on the case, an adjusting sleeve is installed, and the adjusting sleeve is installed with the possibility of interaction with the shut-off element of the pressure relief valve when creating a pressure pulse to open the message of the tubing internal cavity to the annulus.

When creating a pressure impulse, a pressure-relief valve located on the lower shank of the spool with a spring-loaded shut-off element, configured to relieve pressure from the starting chamber, as well as an adjustment sleeve mounted on the housing that is capable of interacting with the shut-off valve by the pressure-relief valve, allow almost instantly complete opening the drain channels of the housing. That is, they reliably provide the opening conditions of the device for organizing the communication of the inner tubing cavity with the annulus, which in turn makes it possible to conduct more efficient technological operations in the well.

The drawings illustrating the claimed solution are schematically represented:

in FIG. 1, the proposed device is shown in section when the electric centrifugal pump is running;

in FIG. 2 - the same, when the pump is stopped and the fluid is held in the discharge pipe;

in FIG. 3 - the same, with the open communication of the internal cavity of the tubing and the annulus for carrying out technological operations.

The downhole valve device comprises a housing 1 with an annular protrusion 2 on the inner surface, below which drain channels 3 are made in the housing 1, an axially movable spool 4 having upper 5 and lower 6 shanks of smaller diameter. In the upper part of the upper shank 5, drain windows 7 are made and a restrictive collar 8 is installed. And the lower shank 6 of the spool 4 is sealed relative to the housing 1 by a seal 9. In addition, the spool 4 is provided with a through axial channel 10 in which the check valve 11 is placed, the spool 4 is installed in the housing 1 with the formation of an annular launch chamber 12. In which on the upper shank 5 there is an axially movable two-stage piston 13, on the upper stage 14 of which a hollow cylinder 15 is installed, in the walls of which there are collets 16 and drain ok 17, and the hollow cylinder 15 is rigidly connected and aligned with the outer side with the upper stage 14 of the axially movable two-stage piston 13, and on the inner side the upper stage 14 of the axially-movable two-stage piston 13 forms an annular landing protrusion 18, made with the possibility of tight fit of the limit collar 8 of the upper shank 5 of the spool 4. In addition, the annular launch chamber 12 is in communication with the axial channel 10 of the spool 4 through holes 19 in the lower part of the upper shank 5. The outer surface the lower stage 20 of the larger diameter of the axially movable two-stage piston 13 is sealed with respect to the inner surface of the housing 1 by a seal 21. And the upper stage 14 is configured to overlap the drain channels 3 of the housing 1 and can be sealed relative to the annular protrusion 2 of the housing 1 with the axial end position a movable two-stage piston 13. In addition, the collets 16 are installed with the possibility of interaction with the annular protrusion 2 of the housing 1 and with a restrictive shoulder 8, and the area limited by the sealed sides of steps 14 and 20 of the axially movable two-stage piston 13 is configured to exceed the area limited by the outer diameter of the lower shank 6 of the spool 4. On the lower shank 6 of the spool 4 there is a pressure relief valve 22 with a spring-loaded shut-off element 23 and made with the possibility of depressurization from the launch chamber 12 and the axial channel 10 of the spool 4, and on the housing 1, an adjusting sleeve 24 is installed, and the adjusting sleeve 24 is installed with the possibility of interaction Via a working body 23, a pressure relief valve 22 to create a pressure pulse for the opening of the inner cavity messages tubing annulus.

Downhole valve device operates as follows. When the electric centrifugal pump is operating, the spool 4, the ball 25 of the non-return valve 11, and also the axially movable two-stage piston 13 and, accordingly, the hollow cylinder 15, are transferred by the fluid flow (Fig. 1) to the highest position. The fluid from the electric centrifugal pump enters through the adjusting sleeve 24 into the axial channel 10 and the drain windows 7 of the upper shank 5 of the spool 4 and the drain windows 17 (one window is shown) of the hollow cylinder 15. Next, the fluid through the cavity between the walls of the hollow cylinder 15 and the housing 1 enters the inner the tubing cavity, changing direction, which contributes to the separation of sludge from the liquid, and further at the wellhead. In this position, the collets 16 (one collet is shown) are pressed out by the restrictive shoulder 8 and securely fix the axially movable two-stage piston 13 in the housing 1. The seal 21 of the lower stage 20 relative to the housing 1 and the seal of the upper stage 14 relative to the annular protrusion 2 of the axial-movable two-stage piston 13 reliably block and prevent fluid leakage through the drain channels 3 of the housing 1. In the cavity 26 formed by the upper part of the hollow cylinder 15 and the upper part of the upper shank 5 of the spool 4, sludge can collect the other can come with the produced fluid, separating from it, as well as from the walls of the tubing, for example, as a result of corrosion wear. In this position, the working body 23 of the pressure relief valve 22 is held by the spring 27 in the closed state.

When the pump stops, the ball 25 ceases to be held by the fluid flow in the upper position and, under the action of its own weight, occupies the extreme lower position, thus the check valve 11 closes. The pressure under the lower end of the lower shank 6 of the spool 4 decreases in the cavity 28 and reaches the annular pressure. And under the influence of the pressure drop in the tubing and the cavity 28, the spool 4 is moved to a tight fit by the restrictive shoulder 8 of the spool 4 on the annular landing protrusion 18 of the upper stage 14 of the axial-movable two-stage piston 13 (Fig. 2). Since the area limited by the sealed sides of the steps 14 and 20 of the axially movable two-stage piston 13 is configured to exceed the cross-sectional area of the lower shank 6 of the spool 4, the force to move the spool 4 down will be less than the effort to hold the axial-movable two-stage piston 13 in the upper position . Therefore, the axially movable two-stage piston 13 will reliably overlap the drain channels 3 of the housing 1 and retain the fluid in the tubing cavity. Thus, in this position, the device acts as a check valve. In addition, in this position, when the restriction collar 8 is mounted on the annular landing protrusion 18, a sealed cavity 29 is created, represented by the cavity of the annular launch chamber 12 and the cavity of the axial channel 10 of the spool 4. From below, the tightness of the cavity 29 is provided by a check valve 11, a pressure relief valve 22, and a seal 9 and on top of the seal 21 and the tight fit of the restrictive shoulder 8 on the annular landing protrusion 18.

When a device is lowered into a well, it is usually filled with a degassed kill fluid. The small compressibility of the degassed fluid in the cavity 29 during pressure increase in the inner tubing cavity for crimping them may cause insufficient movement of the spool 4 and the axially movable two-stage piston 13 to communicate the inner tubing cavity with the annulus through the device, since this movement of the spool 4 is axial a movable two-stage piston 13 does not allow to achieve the possibility of interaction of the end face of the working body 23 of the pressure relief valve 22 with the adjusting sleeve 24 and drain channels respectively opening 3 of the housing 1. Thus, in this case, the device can function as the pressing valve.

When creating a pressure pulse in the tubing, when the latter are filled with a carbonated fluid, sufficient to exceed the force of holding the axially movable two-stage piston 13 in the upper position, at the first stage, the axially-movable two-stage piston 13 and spool 4 are moved and, accordingly, the carbonated well fluid is compressed in the cavity 29. Compression of carbonated borehole fluid in the cavity 29 and the movement of the spool 4 and the axially movable two-stage piston 13 to a distance Δh occurs mainly with but due to the elasticity of the gas. In this case, the pressure in the cavity 29 also increases by ΔP, in a first approximation, we assume that the entire volume of the annular launch chamber 12 is occupied by gas, and in the rest of the cavity 29 is liquid, then according to the Boyle-Mariotte law, you can make the equation:

where z is the compressibility of the gas;

P ₁ - pressure in the annular launch chamber 12, is practically considered equal to the pressure above the device and can be measured by the descent of the depth gauge;

F _p - the area of the annular launch chamber 12;

h is the length of the annular launch chamber 12;

ΔP is the planned pressure pulse;

Δh is the travel length of the spool 4 and the axially movable two-stage piston 13 due to gas compression of the annular launch chamber 12 when creating a pressure pulse.

From equation 1, we determine the length Δh of movement of the spool 4 and the axially movable two-stage piston 13, in addition, we introduce the coefficient K, taking into account that the actual volume of gas will be more or less than the volume of the annular launch chamber 12:

The K coefficient in formula 2 at the first descent of the device into the wells of a given field can be taken K = 1, in the future it can be clarified by recounting according to formula 2 with the known ΔP and Δh.

Before the device is lowered into the well in the position of the spool 4 and the axially movable two-stage piston 13 shown in FIG. 2, to achieve the planned pressure ΔP, the adjusting sleeve 24 is installed relative to the housing according to the calculation according to formula 2 at a distance Δh from the end face of the working body 23 of the pressure relief valve 22, which allows you to reliably establish the necessary pressure pulse to open the message of the internal tubing cavity and the annulus through the device.

Thus, at the first stage of creating a pressure pulse ΔP, the gas in the annular launch chamber 12 compresses the spool 4 and the axially movable two-stage piston 13 moves by a distance Δh, and at the second stage the end face of the working body 23 of the pressure relief valve 22 interacts with the adjusting sleeve 24 and the liquid flows from the cavity 29 through the pressure relief valve 22 into the cavity 28. It should be noted that opening the pressure relief valve 22 does not require much effort, since the diametrically area of its working body 23 is minimized. After opening the pressure relief valve 22, the pressure in the annular launch chamber 12 decreases to the annular and, accordingly, the force acting on the axially movable two-stage piston 13 from the pressure in the annular launch chamber 12 decreases. At the same time, the force to move the axial-movable two-stage piston 13 and the spool 4 down remains practically constant and the axially movable two-stage piston 13 and the spool 4 continue under the influence of the pressure difference to continue moving down the device until the spool 4 stops against the protrusion 30 in the housing 1. In this position (Fig. 3), the drain channels 3 of the housing 1 become completely open for draining the fluid from the tubing, which contributes to more efficient technological operations associated with performing direct and reverse flushing of the well. So to carry out the technological operation to remove deposits from the inner surface of the ESP, reagent is injected by direct washing through the tubing into the annulus at the pump intake. The full opening of the channels 3 of the housing 1 ensures the delivery of the reagent to the pump intake at high speed, reducing the possibility of reagent losses in the active component from the reaction with the well fluid and tubing, in addition, the time of the technological operation is reduced.

It should also be noted, since the volume of the annular launch chamber 12 is small, the expiration of this volume through the pressure relief valve 22 with an increased pressure difference in the cavities 29 and 28 will occur almost instantly. Given that the structurally drainage channels 3 of the housing 1 are made with a higher bore, and the fluid in the tubing above the dynamic level has a large accumulated potential energy. All this creates the condition that with the complete and almost instantaneous opening of the drain channels 3 of the housing 1, the generation of a powerful wave impulse that can effectively affect the bottom-hole zone (PZ) of the well. The effectiveness of this process was noted at well No. 7081 of the Prirazlomnoye field during the testing of the device. The oil production rate of the well increased from 15 tons / day to 16 tons / day, and the water cut decreased from 13% to 6%. Thus, the device can act as a generator of impulse effects on the bottomhole zone of the well and, given that the device was not designed for this purpose, it can be considered an “unexpected effect” in the use of this device. In addition, the increased instantaneous flow rate that occurs after the drain channels 3 of the housing 1 are fully opened, contributes to a more efficient erosion of accumulated deposits from the cavity 26 into the annulus of the well. This ensures more reliable operation of the device as a self-cleaning sludge trap.

When starting the electric centrifugal pump from the position shown in (Fig. 3), the ball 25 of the check valve 11, the spool 4 with the upper shank 5 and the lower shank 6, as well as the axially movable two-stage piston 13 move under pressure of the pump pumped liquid to the extreme upper position . At the same time, the spool 4 cannot be ahead of the axial-movable two-stage piston 13 until the drainage channels 3 of the housing 1 are blocked by the upper stage 14, since the restriction shoulder 8 abuts the collets 16 and cannot unclench them, since they interact with the annular protrusion 2 of the housing 1 Thus, the drain windows 7 of the upper shank 5 of the spool 4 are reliably blocked by an axially movable two-stage piston 13 until the drain windows 3 of the housing 1 overlap. This creates the effect of starting the electric centrifugal pump on the “closed valve” , which reduces the starting currents of the electric motor. After moving the axial-movable two-stage piston 13 to its highest position, the interaction of the collets 16 with the protrusion of the housing 2 ends, and the collets 16 are unclenched under the action of the restrictive shoulder 8. This makes it possible to slide 4 with the lower 6 and upper 5 shanks to move to the highest position. The movement of the spool 4 is resisted by the fluid in the starting chamber 12, which, merging through the holes 19 and the gap between the spool 4 and the housing 1, provides a smoother movement of the spool 4, continuing the effect of starting the electric centrifugal pump on the “closed valve”. In the process of moving the spool 4, the interaction of the adjusting sleeve 24 with the working body 23 of the pressure relief valve 22 ends and the working body 23 is held in the pressure relief valve 22 by the spring 27 in the closed state.

When the spool 4 reaches its upper position, the liquid, as shown above, from the electric centrifugal pump flows through the device into the internal cavity of the tubing (see Fig. 1).

Thus, when the electric centrifugal pump is operating, the injected fluid passes through the device, changing direction, and the device is used as a sludge trap, and the two-stage axially movable piston 13 is reliably fixed, blocking the message of the internal cavity of the tubing to the annulus. When the pump stops, similarly to the check valve, the fluid is held by the device in the tubing cavity. To carry out efficient technological operations, impulse effects on the bottom hole of the well, draining the liquid and effectively cleaning the sludge trap, a pressure impulse is created in the tubing. The magnitude of the pressure pulse is set before the descent of the device, setting the gap Δh, calculated by formula 2, between the end face of the working body 23 of the pressure relief valve 22 and the adjusting sleeve 24.

When running into the well of the pump, the device can be used as a pressure test valve.

Claims (1)

A downhole valve device comprising a housing with an annular protrusion on the inner surface, below which drain channels are made in the housing, an axially movable spool having an upper and lower shanks of smaller diameter, drain windows are made in the upper part of the upper shank and a restriction collar is installed, and the lower the spool shank is sealed relative to the housing, in addition, the spool is provided with a through axial channel in which the check valve is placed, the spool is installed in the housing with the formation of a the launch chamber, in which an axially movable two-stage piston is placed on the upper shank, a hollow cylinder is installed on the upper stage, collets and drain windows are placed in the walls of which the hollow cylinder is rigidly connected and aligned with the outer side with the upper stage of the axial-movable two-stage piston and on the inner side the upper stage of the axially movable two-stage piston forms an annular landing protrusion made with the possibility of tight fit of the restrictive drill and the upper shank of the spool, in addition, the annular launch chamber is in communication with the axial channel of the spool through holes in the lower part of the upper shank, while the outer surface of the lower stage of the larger diameter of the axially movable two-stage piston is sealed with respect to the inner surface of the housing, and the upper stage is made with the possibility of overlapping drain channels of the housing and is configured to seal relative to the annular protrusion of the housing at the extreme upper floor When the piston is raised, in addition, the collets are installed with the possibility of interaction with the annular protrusion of the housing and with a restrictive shoulder, and the area limited by the sealed sides of the steps of the axial-movable two-stage piston is made with the possibility of exceeding the area limited by the outer diameter of the lower shaft of the valve, characterized in that on the lower shank of the spool there is a pressure relief valve with a spring-loaded shut-off element and configured to relieve pressure from the launch chamber, and to rpuse mounted adjusting sleeve, the adjusting sleeve is arranged to interact with the locking body pressure relief valve to create a pressure pulse for the opening of the inner cavity messages tubing annulus.

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