RU2446269C1 - Hydrodynamic pulsator - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: proposed device comprises body with openings, seat, spring-loaded valve with bush, spring-loaded piston fitted in bush axial channel, lower cover and damping channel. Piston comprises hollow rod with restrictor arranged in axial channel. Said lower cover is furnished with needle to make movable joint with restrictor. Said body is provided with retainer. Piston spring is fitted in annular clearance between bush and hollow rod to rest upon bush inner annular ledge. Piston is fitted in bush axial channel to have face contact with additional mounting face on aforesaid seat. Body is arranged in axial channel of outlet pipeline provided with lateral outlet branch pipe to allow constant hydraulic communication between body axial channel above lower cover and outlet branch pipe inner chamber.

EFFECT: expanded operating performances, higher well production rate.

2 dwg

Description

The invention relates to the oil and gas industry and is intended to impact on the reservoir in order to clean the bottom-hole zone and increase well productivity.

Known hydraulic vibrator (see AS USSR No. 817219, Mcl. E21B 43/00, publ. 30.03.1981. Bull. No. 12).

The device includes a case with windows, a movable sleeve with a seat for a locking ball. The movable clutch is kinematically connected through a pin to the sleeve, which in turn is equipped with a spring-loaded locking sleeve.

The disadvantages of the design of the device include:

- the device has limited use, because it can generate ripple in the stream, in a fairly narrow frequency range;

- low amplitude of the ripple reduces the effectiveness of the impact;

- the efficiency of the vibrator significantly depends on the flow rate of the working fluid;

- the joint movement of the sleeve with the coupling in the axial direction leads to uncertainty in the process of generating hydraulic pulses, since the washing windows in the body of the housing are blocked by the body of the coupling when it is moved.

A device is known for influencing the bottom-hole zone of a well (see AS USSR No. 1535971, Mcl. E21B 43/00, publ. 15.01.1990. Bull. No. 2).

The device consists of a hollow body, in the axial channel of which a hollow pipe is installed, between which an annular gap is formed. The hollow pipe is provided with a perforated partition connected with a thread connected to the hollow body. The hollow pipe has a conical axial channel with a seat under the ball valve, pressed to it through the sleeve by a compression spring. The axial channel of the hollow pipe under the ball valve is constantly hydraulically connected to the well cavity. The annular gap between the hollow body and the hollow pipe also has a constant hydraulic connection through the holes in the body of the perforated septum with the cavity of the well.

The force of pressing the ball valve to the seat in the hollow pipe can be adjusted by changing the stiffness of the spring, which allows you to change the frequency and amplitude of the pulsation of the working fluid.

Design disadvantages:

- when pumping the working fluid through the device (in the position as shown in the figure), the generation of frequency oscillations is possible only in the axial channel of the hollow pipe.

In this case, the oscillation frequency will be high at a relatively low flow rate of the working fluid, which does not allow to effectively affect the reservoir and the flow of formation fluid. The pulsation frequency, according to a number of literary sources, should be in the range f = 0.05-0.01 Hz and directly depends on the depth of the well and the properties of the reservoir fluid.

With the opposite existence of the flow, the ball valve does not participate in the generation, since the flow through the holes in the perforation grate is fed through the annular gap with the opening of hydraulic communication when the spring-loaded piston moves from the end of the hollow pipe.

The pressure relief mode and the passage of a sufficiently large volume of the working fluid through the device will be quite problematic in this case, since the holes in the perforated grating have a sufficiently high hydraulic resistance, and in combination with the hydraulic resistance of the annular gap do not allow the generation of pulses of the required frequency.

As a prototype defined hydrodynamic pressure pulsator (see US Pat. RF №2.212.513, IPC 7 ЕВВ 28/00, publ. 09/20/2003).

The pulsator consists of a hollow body with overflow windows, spring-loaded and overlapping the overflow windows of the mechanical valve installed with the possibility of axial movement and separation of the high and low pressure region. The end valve rests on the seat and is pressed against the last spring resting on the bottom cover. A piston is mounted in the axial channel of the end valve, resting on a spring that enters end contact with the bottom of the bottom cover, in which a damping hole and calibrated holes are made, which are blocked from the outside by a spring-loaded bypass valve.

Construction work.

The device in the tubing string is located in the well at a predetermined depth and pumping the working fluid.

In this case, with increasing pressure, the latter is reported to the cross-sectional area of the saddle and the cross-sectional area of the spring-loaded piston.

In this case, the mechanical valve is spring-loaded against the seat and does not perceive the pressure drop from above. The device reflects the condition that makes it possible for the pulsator to work, namely, the stiffness of the spring, which compresses the mechanical valve to the seat, higher than the stiffness of the piston spring.

When moving the piston down and jointly moving the seat with the mechanical valve, fluid from the internal cavity of the body flows into the cavity of the well through a damping hole in the bottom cover, and additionally, in the presence of excessive pressure, calibrated holes can be opened to allow fluid to pass through.

According to the description of the design and the principle of operation, an end valve should open, which will lead to the formation of a hydraulic connection between the cavity of the pipe tubing and the annular space and the discharge of liquid through the bypass windows in the hollow body into the well cavity.

In this case, a pressure drop occurs and with the force of the pre-compressed springs, the end valve enters the end contact with the seat with the termination of this hydraulic connection. The piston also returns to its original position.

But according to the design description, there are no conditions under which the mechanical valve moves away from the seat. If we assume that the piston reaches the end contact with the inner protrusion on the end sleeve, then it is possible to detach from the seat and then in the case that the seat has a limiter of its axial movement.

In order for the internal cavity of the hollow body to have damping properties, it must have a volume comparable to at least a second flow rate of the working fluid supplied from the surface.

Based on the foregoing, we can conclude that the design is inoperative.

An analysis of technical solutions for similar developments in this industry showed that a technological solution is known (see US Pat. RF No. 2083084, MKI 6 ЕВВ 37/00, publ. 07/10/1977, "Method for preventing paraffin deposits"), in which for it it was proposed that a flow of liquid be passed through the fitting device, with a change in its speed pulse. In this case, the pressure drop in the range from 0.015 MPa to 0.035 MPa.

Those. it is necessary to adjust to a given technological mode, with appropriate provision for a sharp supply of working fluid.

A technical solution is known (see AS USSR No. 1661372, MKI E21B 33/14, publ. 07/07/1991. Bull. No. 25 "Casing shoe"), which implements the principle of forced separation of the ball valve from the seat when joint movement to interact with the stock, rigidly connected with the sub. This ensures the formation of a hydraulic connection of the axial channel of the drill pipe string with the cavity of the well.

A technical solution is known (see AS USSR No. 1624130, Mcl. E21B 34/16, publ. 01/30/1991. Bull. No. 4 "Valve device for controlling the operation of a gas and oil well"), which implements the principle of introducing a needle into an axial throttle channel for cleaning it, with a change in pressure drop across it.

We have not found a device in the patent and scientific literature that implements the principle of generating low-frequency pulses, with the supply of a working fluid with a high unit flow rate from a high-pressure chamber.

The technical result that can be obtained by implementing the invention is reduced to the following:

- the ability to change the ripple frequency by adjusting the stiffness of the spring, limiting the stroke length of the saddle;

- the ability to control the frequency of the pulsations, due to the controlled flow of the working fluid through the throttle;

- the possibility of supplying a working fluid with a maximum flow rate with the full opening of the bypass channel formed between the seat and the mechanical valve.

The technical result is achieved using a known device installed on the outlet pipe of the fountain valves.

The hydrodynamic pulsator includes a case with windows, in the axial channel of which there is a saddle with a spring-loaded end valve, equipped with a sleeve with an internal annular protrusion, a spring-loaded piston in the axial channel of the sleeve, equipped with a hollow rod, with a throttle in the axial channel, the lower cover is equipped with a needle that enters the axial throttle channel, with the possibility of the formation of a movable connection. The housing is equipped with a stopper located under the seat, the piston spring is installed in the annular gap between the sleeve and the hollow rod with support on the inner annular protrusion of the sleeve, and the piston is installed with the possibility of face contact with an additional seat on the seat.

The damping channel is made in the housing, which is installed in the axial channel of the outlet pipe, with a lateral outlet pipe, providing constant hydraulic communication of the axial channel of the housing above the lower cover with the cavity of the outlet pipe.

A hydraulic pulsator for influencing the flow of produced fluid by generating hydrodynamic flow and pressure pulses is shown in the drawings, where:

- figure 1 shows the design of the device in section in the initial position;

- figure 2 is a design of the device in the context at the time of opening the end valve and the formation of the hydrodynamic connection of the well with high pressure with the reservoir.

The inventive device consists of a housing 1 with a bypass window 2 provided with a lower cover 3. In the axial channel 4 of the housing 1, a seat 5 is installed in the upper part, to which the end valve 7 is pressed with a spring 6 with a sleeve 8 provided with an inner annular protrusion 9 on the lower cone. Inside the axial channel of the mechanical valve 7, an annular piston 10 is installed, which is pressed against the seat 11 on the saddle 5 by a spring 12, which rests on the inner annular protrusion 9 of the sleeve 8. The annular piston 10 is equipped with a hollow rod 13, the axial channel 14 of which contains a throttle 15. The bottom cover 3 is equipped with a needle 16, which is included in the axial channel of the throttle 15. The inner cavity of the axial channel 4 is constantly hydraulically connected by the bypass hole 17 in the body of the housing 1 with the cavity of the outlet pipe 18. The stroke of the saddle 5 in the axial channel 4 of the housing 1 is limited by a stop 19, rigidly connected with the latter.

The spring 6, which compresses the end valve 7 to the seat 5, is adopted in terms of stiffness more than the spring 12, which compresses the annular piston 10 to the seat 11 on the saddle 5.

The pulsator assembly is installed in the axial channel of the discharge pipe 20.

The rod 16, which is included in the axial channel of the throttle 15, on the outer side contains longitudinal grooves 21, which play the role of throttling channels, the total cross section of which is determined based on the production rate of the well and the required pulsation frequency.

The claimed device operates as follows.

The pulsator assembly is installed in the axial channel of the discharge pipe 20.

When the gate valve is opened on the well’s fountain armature, the flow of formation fluid is supplied to the axial channel 4 of the housing 1, from where it enters the axial channel 14 of the hollow rod 13 and through the longitudinal grooves 21 in the rod 13 and the annular gap between it and the throttle 15 is supplied with an adjustable flow rate to the axial channel 4 above the bottom cover 3 and then through the damping channel 17 is discharged into the cavity of the outlet pipe 18 and further into the fishing manifold.

Since the flow rate of the reservoir fluid through the throttle 15 and the longitudinal grooves 21 on the rod 16 is less than the well flow rate, a smooth increase in pressure occurs in the axial channel 4 above the saddle 5, which is perceived by the area of the saddle 5. The saddle 5 under pressure from this differential pressure together with the valve 7 and the annular piston 10 are moved in the axial channel 4 of the housing 1 with compression of the spring 6 and spring 12.

When the saddle 5 reaches the stopper 19, the latter stops. The annular piston 10 excess pressure out of interaction with the seat 11 on the saddle 5, with the inclusion of an additional area of pressure perception and the occurrence of additional axial force communicated to the spring 12.

In this case, an additional axial load is transmitted through the spring 12 to the annular protrusion 9 of the sleeve 8, which is rigidly connected to the end valve 7. Thereby, the end valve 7 abruptly breaks off from the seat 5 to form a hydraulic connection between the axial channel of the outlet pipe 20 through the bypass window 2 with the outlet a pipe 18 and further with a fishing collector. The throttle 15, moving relative to the rod 16, provides cleaning of the annular gap and the longitudinal grooves 21.

When a portion of the reservoir fluid is dumped, pressure is equalized inside the pulsator.

By the force of the pre-compressed spring 12 and spring 6, the annular piston 10 and the mechanical valve 7 returns to their original position with the mechanical valve 7 and the annular piston 10 with the seat 11 inserted into the mechanical contact with the seat 5.

The seat 5 in contact with the mechanical valve 7 and the annular piston returns to its original position. Further, the process is repeated many times during the operation of the well.

A sharp opening of the mechanical valve 7 leads to a sharp increase in the flow rate of the reservoir fluid and the speed of movement in the axial channel of the pipe tubing. This leads to a perturbation wave, which contributes to the creation of a barrier to the movement of paraffin molecules to the wall of the pipes of the elevator column and their absorption. With a high gas factor, a sharp opening of the end valve causes the dissolved gas to begin to be released from the oil, with its foaming, which leads to a decrease in the specific gravity of the mixture and, therefore, a decrease in the hydrostatic pressure in the pipe tubing string. This reduces the back pressure on the reservoir and there is a condition for increasing the total production rate of the well.

Claims (1)

A hydrodynamic pulsator comprising a case with windows, a seat, a spring-loaded mechanical valve with a sleeve having an internal annular protrusion, a spring-loaded piston in the axial channel of the sleeve, a lower cover, a damping channel, characterized in that the piston is equipped with a hollow rod, with a throttle in the axial channel, lower the cover is equipped with a needle installed with the possibility of forming a movable connection with the throttle, the housing is equipped with a stopper, the piston spring is installed in the annular gap between the sleeve and the hollow rod, with the possibility of support on the inside a lower annular protrusion of the sleeve, and the piston is installed in the axial channel of the sleeve, with the possibility of end contact with an additional seat on the saddle, and the housing is equipped with a damping channel of the pulsator and is installed in the axial channel of the outlet pipe provided with a lateral outlet pipe, with the possibility of constant hydraulic communication of the axial housing channel over the bottom cover with a cavity of the outlet pipe.

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