RU2644312C1 - Cutoff valve - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: cut-off valve consists of detachable body, in axial channel of which there is a saddle with a center hole with an inner groove, and a number of longitudinal holes on the periphery. In the central hole of the saddle, there is a pusher with a crown that passes into the internal groove of an end valve. A cup is placed in the axial channel of the detachable body. On the outer surface of the cup, there are protrusions passing to the corresponding longitudinal grooves made in the detachable body. The protrusions extend beyond it and are covered by a clip with a nut connected to the detachable body by a thread. In the axial channel of the cup a deflector is freely installed, resting on the spring which in its turn rests on the adjusting nut in which the axial holes are made.

EFFECT: allows precise adjustment and setting of the technological mode of operation during operation without shutdown of the well and device dismantling.

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Description

The invention relates to the oil industry, in particular to devices for regulating the flow of formation fluid, mainly in horizontal wells of oil fields developed by the mine method using thermal methods of exposure.

Known throttle control device (see US Pat. 2514328 Russian Federation. IPC F16K 3/02; F16K 47/14. No. 2012151736/06; claimed 03.12.2012; published on 04.27.2014. Bull. No. 12), consisting from the housing in which the saddle is placed, with channels intersecting each other at different angles for the flow of the medium, an adjustable body installed with the ability to change the area of the passage section of the channels in the saddle.

The invention allows you to change the hydraulic resistance of the channels in the saddle without changing the throughput of the device, reducing the flow rate of the fluid flow, which eliminates the activation of the corrosion process, cavitation and vibration, with an extension of the control range.

The disadvantages of the design of the device include:

- it is difficult to completely shut off the supply of working fluid;

- it is problematic to maintain the throughput of the working fluid when its flow over part of the channels is stopped.

With a decrease in the flow rate of the working fluid through the channels, the flow rate will invariably decrease.

In the case of switching to the supply of a working medium with other physical and mechanical properties, for example, a liquid or a vapor gas phase, the operation of the device must be adjusted, that is, it is necessary to carry out readjustment, which is quite problematic.

A known fluid flow regulator (see US Pat. No. 4,858,644. Fluid flow regulator. M class F16K 15/14; claimed 05/31/1988, publ. 08/22/1989). The device consists of a hollow body with a stepped axial channel, in which a spring-loaded piston is placed, equipped with a fitting resting on a spring, which plays the role of an adjustable flow limiter. At the other end, the spring rests on a seat in the adapter, in which circulation holes are made connecting the axial channel of the housing with the channel of the adapter.

Device operation

Through the axial channel of the nozzle, the working fluid is fed into the axial channel of the piston and further into the cavity bounded by the coil of the spring, from where it flows through the gaps into the chamber surrounding the spring, and then through the holes in the body of the adapter is fed into its axial channel. Thus, there is a restriction of fluid flow by reducing the gap between the turns. This limitation changes with the axial movement of the piston. When the clearance changes, the differential pressure changes. The regulator allows you to compensate for the fluid flow rate in automatic mode.

Design flaws

During the operation of the device, the flow of the working fluid is limited on one side by the fitting, and then by slotted gaps between the spring coils, the gaps between which vary depending on the presence of a pressure differential across the piston. In this case, the piston makes a reciprocating movement, superimposed on the stream of flow pulses and pressure. This determines the unstable flow rate of the fluid over time.

The design of the device does not allow to completely stop the flow of fluid.

The well-known design of the borehole shutoff valve (see AS 874993 USSR. M class. E21B 43/12; No. 2808769 / 22-02; declared. 15.06.1979; publ. 10/23/1981. Bull. No. 39), consisting from a cylinder with a piston inside. A sub with a coupling is attached to the cylinder. The sub is attached to the valve body, which is connected to the seat body. A poppet valve is installed in the casing, pressed against the seat by a spring. The piston is held in the upper position by a spring bounded along the pusher, in which channels are made for communicating the cavity between the pusher and the housing with the space above the poppet valve.

Shutoff Valve Operation

Under the influence of the pressure drop communicated through the hole in the conductor, the piston moves and compresses the spring. The seals located at the end of the pusher move away from contact with the coupling, which leads to the supply of fluid through the hole in the coupling, through the annular channel between the seat and the pusher, and then through the channels at the end of the pusher into the area above the poppet channel. This leads to equalization of pressure above and below the poppet channel. With further movement of the piston down, the plunger is brought to the stop in the poppet valve with equalization of pressure.

When the valve opens smoothly, the pusher rests on the seat body and, passing through the seal, the working surface of the valve and seat is isolated from erosion by the flow of working fluid.

When removing (lowering) the fluid pressure, which is communicated to the piston through an opening in the sub, the piston moves upward under the action of the spring and fluid pressure. In this case, the pusher releases the poppet valve, which, under the influence of the spring and fluid flow through the openings in the body of the body, closes the passage of the shutoff valve.

Design disadvantages:

- for the operation (opening and support in the open state) of the shut-off valve, a pressure supply exceeding the reservoir pressure is necessary, respectively, a source of this control pressure is needed - the device does not work automatically;

- the valve design does not provide for reconfiguration to a new mode of operation without removing it from the well and dismantling the device;

- the use of a pop-up valve flap with a torsion spring as a locking body will require an increase in the overall dimensions of the device or a significant reduction in the passage channel; in addition, the operation of a poppet valve of this design in an environment of formation fluid containing mechanical impurities causes low reliability of the complete closure of the channel.

Known shut-off valve (see US Pat. 2533394 Russian Federation. IPC F16K 3/04; 17/04. No. 2013136058/03; claimed. 08.18.2013; publ. 20.11.2014. Bull. No. 32), adopted as a prototype .

The shut-off valve is installed as part of the pipe tubing and consists of a detachable body with a seat in the axial channel. Below, under the saddle is a hollow plunger with an annular protrusion, resting on a spring with a nut. An emphasis is made in the axial channel of the hollow plunger, on which a sleeve is supported, provided with radial holes that connect the cavity above the plunger with the cavity under the saddle. A tube with a poppet valve is located in the axial channel of the sleeve. A hollow plunger with an annular protrusion together with a detachable body forms an annular chamber, which communicates through its radial hole in the hollow plunger and the hole in the body of the sleeve with its axial channel and the channel of the tube.

The sleeve is provided with a bottom in which a central hole is made and a bypass valve is installed with the possibility of blocking the bypass holes that connect the axial channel of the sleeve with the cavity of the axial channel of the detachable housing. Above the hollow plunger, the bypass valve travel is limited by a retaining ring. A thrust sleeve is installed in the axial channel of the split housing, forming a movable connection with the upper end of the hollow plunger. In this case, the cavity above the annular protrusion through the hole in the hollow plunger communicates with the axial channel above the sleeve. The detachable housing is provided with a connecting thread.

The principle of operation of the shutoff valve.

The mechanical valve is pressed by the force of a compressed spring to a seat located in the axial channel of the split housing. The pressure of the working fluid in the pipe string through the axial channel of the pipe, the radial holes in the body of the sleeve and the radial hole in the body of the hollow plunger acts on the annular protrusion from below, which ensures the contact of the poppet valve with the surface of the seat. The same pressure is perceived by the cross-sectional area of the same poppet valve.

The cross-sectional area of the annular protrusion is taken less than the cross-sectional area of the poppet valve, which ensures that it is pressed against the seat by a spring. When the overpressure above the end valve exceeds the pressure from the column of the working fluid, the poppet valve comes off the seat, with the formation of a hydraulic connection between the axial channel of the pipes and the axial channel of the split housing above the sleeve. The working fluid through the axial holes in the sleeve passes to the bottom of the well. Hollow plunger when the poppet valve is separated from the seat when exposed to excessive pressure moves to the stop in the ledge.

After the supply of the working fluid is stopped, the hollow plunger, together with the sleeve and the poppet valve, rises upward in the axial channel of the split housing with the poppet valve landing on the seat. This eliminates the ingress of working fluid into the reservoir, which is important for the operation of gas wells in underground gas storages.

The disadvantages of the design and operation of the device:

If the device is equipped with oil wells, the production of which is carried out using thermal methods of influence:

- while the pressure of the reservoir fluid may be insufficient to open the poppet valve and compress the spring, which determines the failure of the device;

- when installing the device in the composition of the pipes in the well, it is impossible to reconfigure to a new mode without dismantling from the place of use;

- to close the poppet valve with a small pressure drop, it is impossible to create sufficient axial force without the use of an additional power unit;

- restrictions on the diametrical dimensions of the device imposed by the well design affect the throughput of the device due to the low throughput of the reservoir fluid through the axial holes in the sleeve.

The technical result that can be obtained by implementing the invention is as follows:

- the ability to configure the device to the optimal operating mode in the process of passing formation fluid through the device with a small pressure drop;

- the possibility of increasing the throughput of the device in the presence of restrictions on the diametrical dimensions of the structure by reducing hydraulic resistance;

- the possibility of changing the axial force for additional compression of the return spring of the hollow rod due to the inclusion of an additional area of perception of the differential pressure;

- the possibility of damping the feed rate of the reservoir fluid through the device through the use of a spring-loaded reflector.

The technical result is achieved by the fact that the shutoff valve comprises a detachable body with a seat in the axial channel, a spring-loaded mechanical valve connected to the hollow tube, and an adjusting nut. A cup is provided in the axial channel of the detachable body, provided with protrusions on the outside that extend into through longitudinal grooves made in the body of the detachable body. The protrusions are covered by a ferrule connected to a nut connected by a thread to a detachable housing. The end valve is equipped with an internal bore and is connected with a hollow tube passed into the axial channel of the glass, with the formation of a movable joint. The saddle is equipped with a series of longitudinal holes and an internal groove facing the end valve, and a pusher with a crown located in the inner groove of the saddle, with access to the inner groove of the mechanical valve. A spring-loaded chipper with an adjustment shutter in which radial holes are made and an annular protrusion with a series of longitudinal grooves forming a movable connection with the body of the cup is installed in the axial channel of the cup. The pusher forms a movable connection with the seat and is equipped with an adjusting nut supported by a spring.

The design of the shutoff valve is illustrated by drawings, where:

- in figure 1 - cutoff valve in the context, in the initial closed position;

- in figure 2 - shutoff valve in the position of the parts at the time of opening;

- in figure 3 - shutoff valve at the maximum opening of the hydrodynamic connection of the cavity of the well with the collector;

- figure 4 is a flow diagram of the binding of the wellbore with a shutoff valve.

The shut-off valve consists of a detachable body 1, equipped with a connecting pipe 2, pressing the seat 3 installed in the bore of the detachable body 1. In the body of the saddle 3 there is a central hole 4 with an internal bore, in which the pusher 5 with a crown 6, supported through an adjusting nut, is placed 7 to the spring 8. On the periphery of the seat 3 is made a series of longitudinal holes 9.

In the axial channel 10 of the detachable housing 1, under the seat 3, an end valve 11 is installed with a hollow stem 12, which is pressed against the saddle 3 by a spring 13, the lower end of which forms a movable connection with the body of the canister 14 located in the axial channel 10 of the detachable housing 1 and forming with it movable connection. The end valve 11 has an internal groove 15, in which the crown 6 of the pusher 5 is placed with the possibility of end contact with its body. The glass 14 is equipped with several protrusions 16 on the outer side, extending into the corresponding longitudinal grooves 17 made in the body of the detachable housing 1. The protrusions 16 extend beyond the boundaries of the detachable housing 1 and are freely located in the bore 18 of the holder 19 between the inner annular protrusion 20 of the holder 19 and the end of the nut 21, which is connected to the hollow body 1 by a connecting thread 22, made on the outer surface of the detachable body 1. In the axial channel 23 of the cup 14, a bump 24 is freely mounted, resting through the spring 25 on the adjusting nut 26, s axial 27 and radial 28 holes connecting the axial channel 23 of the glass 14, with the axial channel 10 of the detachable housing 1 below the glass 14.

The fender 24 on the outside has an adjustment shutter 29 with perforations 30 and a number of longitudinal grooves 31 around the perimeter. When this fender 24 forms a movable connection with the body of the glass 14.

In the body of the seat 3, in the central hole 4, an annular bore 32 is provided, equipped with a sealing ring 33. The axial channel 10 of the detachable housing 1, over the body of the cup 14 is sealed with sealing rings 34 and 35 installed in the grooves in the body of the cup 14, to ensure sealing of the annular gaps with a detachable housing 1 and the body of the hollow rod 12, respectively.

In the working position, the crown 6 of the pusher 5 is pressed from the end of the mechanical valve 11 by the spring 13 and forms a gap.

The cross-sectional area of the body of the pusher 5 is taken to be greater than the difference between the cross-sectional areas of the mechanical valve 11 and the hollow rod 12.

Device operation

The shutoff valve is used to equip wells of high-viscosity oil fields developed by the mine method using thermal methods of stimulating the formation. The shutoff valve is mounted vertically on the horizontal wellbore, which extends into a prefabricated manifold located in the tunnel.

The shut-off valve assembly by connecting thread on the body of the connecting pipe 2 is connected with the horizontal wellbore.

When excess pressure is applied from the side of the well into the device, it acts on the cross-sectional area of the pusher 5 and the annular area of the mechanical valve 11. When the pre-compression force of the spring 8 is exceeded, the pusher 5 begins to move toward the mechanical valve 11, with the mechanical contact entering it (Fig. 2). With a further increase in pressure and the creation of the estimated axial force (opening pressure), the pusher 5 presses the end valve 11 from the seat 3, with the formation of a gap between them, where the formation fluid begins to flow from the axial channel 10 of the detachable body 1, with the upper impact on the inner end surface mechanical valve 11 along the inner groove 15. Excessive pressure is also perceived by the cross-sectional area of the body of the hollow rod 12, which leads to its movement down, with additional compression of the spring 13 and the opening of a larger gap between at the seat 3 and the end valve 11, for free passage of the formation fluid into the axial channel of the hollow rod 12. At the same time, the pusher 5 is returned to its original position by the force of the spring 8 (Fig. 3). The flow of formation fluid flowing from the axial channel of the hollow rod 12 is fed to the chipper 24, from where it flows through the perforations 30 in the adjustment shutter 29 to the axial channel 23 of the cup 14. Then it passes through the longitudinal grooves 31 of the chipper 24 to the axial holes 27, from where the radial holes 28 in the body of the adjusting nut 26 fall into the axial channel of the detachable housing 1 and then into the collection manifold. At the maximum dynamic head of the jet of formation fluid flowing from the axial channel of the hollow rod 12, the baffle 24 moves in the axial channel 23 of the cup 14, with compression of the spring 13 and a change in the gap between the baffle 24 and the end face of the hollow rod 12.

The installation of the baffle 24 softens the axial force transmitted to the spring 13 when the mechanical valve 11 is sharply separated from the seat 3, when the formation fluid at the maximum pressure drop acts on the mechanical valve 11 with the hollow rod 12. When the dynamic pressure is perceived from the side of the formation fluid stream, the baffle 24 compresses the spring 25 and performs oscillatory movements along the axis of the glass 14, which are superimposed on the flow of formation fluid flowing through the axial channel 10 of the detachable housing 1 into the collecting manifold.

The outflow of formation fluid through the device occurs with a decrease in pressure in the wellbore. When the calculated pressure drop (closing pressure), the force of the compressed spring 13, the end valve 11 together with the hollow stem 12 returns to its original position, landing on the saddle 3 and stopping the flow of formation fluid from the wellbore through the device into the collection manifold.

There is an accumulation of formation fluid in the wellbore with increasing pressure to the calculated opening value, at which the device is triggered with a repetition of the process.

The operation mode of the device is produced by: changing the pre-compression force of the spring 8, acting on the pusher 5 - by rotating the adjusting nut 7; change the pressure force of the mechanical valve 11 to the seat 3 by changing the pre-compression of the spring 13 by rotating the cage 19 together with the nut 21, acting on the protrusions 16 of the cup 14 and moving them in the longitudinal grooves 17 of the detachable body 1, moving the cup 14 in the axial channel 10 of the detachable body one; the rotation of the adjusting nut 26 carries out its axial movement together with the chipper 24 in the direction of the hollow rod 12 or back with the impact on the fluid flow.

Such a setting is carried out taking into account the well-known production parameters - maximum flow rate, differential pressure, flow rate, well depth, before installing the device on the wellbore.

In the process of changing the operating mode of the device by rotating the cage 19 together with the nut 21 through interaction with the protrusions 16 on the body of the glass 14, it is moved in the axial channel 10 of the detachable housing 1, with the spring 13 of the mechanical valve 11 pressed to the seat 3 - without removing the device from the installation site and stop work.

Calculation example of a shut-off valve:

We will calculate the shut-off valve for equipping a horizontal well of an oil field developed by a mine method using thermal methods of stimulating the formation (see the diagram in Fig. 4).

Baseline:

- the length of the horizontal section of the well is taken equal to: L = 250 m;

- angle of inclination towards the galleries: α = 5 °;

We determine the height H = L⋅tg (α) and the hydrostatic pressure (P _g ) of the column of reservoir fluid (oil):

where: ρ is the density of the reservoir fluid (oil), kg / m ³ ;

g is the acceleration of gravity, g = 9.81 m / s ² ;

N - the height of the liquid column in the well, m;

L is the horizontal length of the wellbore, m;

α is the angle of inclination of the wellbore to the horizon towards the galleries;

tg (α) is the slope of the wellbore.

Taking the average density of oil equal ρ = 850 kg / m ³ , we determine the hydrostatic pressure:

R _gs = ρ⋅g⋅L⋅tg (α) = 850⋅9.81⋅250⋅tg (5 °) ⋅10 ^-6 = 0.18 MPa,

The vapor pressure at the end of the wellbore above the fluid level will be equal to R _p = 0.15 MPa (1.5 kgf / cm ² ). Thus, when the wellbore is filled with oil and the vapor pressure above it is accepted, the total pressure on the shutoff valve will be:

P _open = P _gf + P _p = 0.18 + 0.15 = 0.33 MPa.

We take this pressure as the design pressure at which the shut-off valve will open with the release of formation fluid from the wellbore into the collection reservoir: P _open. - valve opening pressure, MPa.

The temperature of the steam from the steam generator is 150-160 ° C, the temperature in the wellbore is about 75-80 ° C. When the shut-off valve is opened, adiabatic expansion of the steam occurs with a decrease in pressure in the system. The valve closing pressure is assumed to be equal to P shut _. = 0.1 MPa (1 kgf / cm ² ).

For an example of calculation, we will take the following values of the geometric parameters of the shutoff valve (position numbers are shown in Figs. 1-3):

- body diameter of the follower 5: D _sense. = 35 mm (0.035 m);

- outer diameter of the hollow rod 12: D _pcs. = 60 mm (0.06 m);

- diameter of the axial channel of the hollow rod 12: d _pc. = 50 mm (0.05 m);

- the outer diameter of the mechanical valve 11: D CL _. = 65 mm (0.065 m).

Define the area:

- cross-sectional area of the pusher 5:

- the cross-sectional area of the body of the hollow rod 12:

- the cross-sectional area of the annular protrusion of the mechanical valve 11:

We will calculate the forces of preliminary compression of the springs to ensure the operation of the valve in the given technological parameters:

The force (F) acting on the structural elements from the pressure of the liquid (or gaseous) medium filling the device is equal to the product of pressure (P) (or differential pressure) by the area (S) through which the pressure acts:

To open the valve, the condition expressed by the equation must be satisfied:

where F _p.t. - the axial force of the fluid pressure on the pusher (5) at a given opening pressure of the shutoff valve, N, equal to the product of the opening pressure on the cross-sectional area of the body of the pusher:

F _rt = P _open ⋅S _good. ;

F _r.cl. - the axial force of the fluid pressure on the mechanical valve 11 at a given opening pressure of the shut-off valve, N, acting on the mechanical valve from the bottom up in the direction of its pressing against the seat 3 and equal to the product of the opening pressure by the cross-sectional area of the annular protrusion of the mechanical valve: F _{p. class} = P _open ⋅S _class ;

F _pr. - the force of pre-compression of the spring 8 of the pusher 5, N;

- the force of pre-compression of the spring 13 of the hollow rod 12, N.

The pre-compression force of the spring 13 of the hollow rod 12 F _pr. determines the pressure at which the shut-off valve closes, that is, P _clos.

Closing condition for shut-off valve:

where F _p. - the axial force of the fluid pressure on the body of the hollow rod 12 from the side of the well at a given closing pressure of the shutoff valve, N, and equal to the product of the closing pressure by the cross-sectional area of the body of the hollow rod 12:

F _r. = P _close ⋅S _pcs ;

From equation 3 we express and determine the pre-compression force of the spring 8 of the pusher 5, taking the pre-compression force of the spring 13 of the hollow rod 12 equal to F _pr. = P _close ⋅S _pcs :

F _pr. = F _r.t. -F _pr. -F _r.cl. = P _open ⋅S _good. -R _close ⋅S _pcs -R _open ⋅S _class = 0.33 × 10 ⁶ ⋅9.6 × 10 ^-4 -0.1 × 10 ⁶ ⋅8.6 × 10 ^-4 -0.33 × 10 ⁶ ⋅4.9 × 10 ^-4 = 69 N (7 kgf).

The pre-compression force of the spring 13 of the hollow rod 12:

F _pr. = P _close ⋅S _pcs = 0.1 × 10 ⁶ ⋅8.6 × 10 ^-4 = 86 N (8.8 kgf).

The pre-compression force of the spring 8 of the pusher 5 is set by rotating the adjusting nut 7 before mounting the device (“rough” setting), and then, after installation or directly during operation, the pre-compression force of the spring 13 of the hollow rod 12 is adjusted by rotating the nut 21 and the yoke 19 together with moving Cup 14 (fine tuning). Thus, the device allows precise adjustment and adjustment of the technological mode of operation (opening and closing pressure) during operation without stopping the well and without dismantling the device.

Claims (1)

A shut-off valve comprising a detachable body with a seat in the axial channel, a spring-loaded mechanical valve connected to the hollow tube, adjusting a nut, characterized in that a cup is provided in the axial channel of the detachable body, provided with protrusions on the outside that extend into through longitudinal grooves made in the body of the detachable body, the protrusions are covered by a ferrule connected to a nut, connected by a thread to the detachable body, the end valve is provided with an internal bore and connected with a hollow tube passed into the axial channel of the stack on with the formation of a movable connection, the seat is equipped with a series of longitudinal holes and an internal groove facing the end valve and a pusher with a crown located in the internal groove of the saddle with access to the internal groove of the mechanical valve, the glass is equipped with a spring-loaded chipper with an adjustment shutter with radial holes and an annular protrusion on which a series of longitudinal grooves is made, wherein the chipper annularly forms a movable connection with the body of the glass, and the pusher forms a movable connection a saddle and is provided with an adjusting nut bearing on the spring.

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