RU2539087C2 - Downhole pulsator - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil and gas industry, in particular, to devices used for formation simulation. Device for hydropercussion simulation of the formation included into the assembly of flow string comprises a hydraulic cylinder with crossover shoe, a plunger with radial openings, a spring-actuated pusher with circular bore and a ring piston. At that the hydraulic cylinder is fixed rigidly to a chamber with a landing ring installed in it and longitudinal grooves at its outer side. The pusher is equipped with outside protrusion, a saddle and a ball valve in the axial channel. The pusher lower end is passed to the axial channel of the landing ring and equipped with a locking ring interconnected with the pusher by a shear pin. The chamber axial channel is covered from below by a thrust ring and equipped with a hollow rod with the end valve pressed by a spring to the landing ring. At that in the end valve body there is a bore with a loose locking ring installed in it and the plunger is equipped with a ring piston thus forming an annular gap with the hydraulic cylinder coupled hydraulically to annular space by bypass ports.

EFFECT: improved efficiency of hydropercussion simulation of the formation.

4 dwg

Description

The invention relates to the oil and gas industry, in particular to devices for increasing productive strata of wells.

Known downhole pressure pulsator (I) (see and.with. No. 939.737 Ml. E21B 43/25, publ. 06/30/82, bull. No. 24).

The device consists of a cylindrical body with a spring-loaded valve provided with support projections. Between the body and the rod, a sleeve with a pin is movably mounted. The outer surface of the rod is made with grooves for the pins of the sleeve, the inner surface of which is made with protrusions for interaction with the supporting protrusions of the valve. The cylindrical housing through the upper sub is connected to the tubing string.

Design disadvantages:

- the pulsator is operated at a low pressure drop and directly depends on the area of the valve receiving this pressure drop and the force of the spring holding the valve in the closed position. It is impossible to obtain a sharp change in pressure drop;

- the device can be brought into working condition by moving the tubing string with direct contact of the connecting sub with the bottom of the well;

- the ability to pass the reservoir fluid through the device without imposing hydrodynamic impulses on the flow has flow restrictions, since the annular gap area is small and is an obstacle to flow with large well flow rates.

Known hydraulic vibrator (see AS.№1.573.147 Mkl, EV 43/25, publ. 06/23/90, bull. No. 23).

The invention can be used for hydraulic and vibration treatment of wells. The device comprises a housing, with a hydraulic pulse generator, made in the form of a barrel and a self-rotating gate with a spring-loaded piston. The barrel and self-rotating gate are mounted in the housing axisymmetrically.

The housing is perforated in the area of the output channels of the gate. The piston is equipped with a blade located outside the housing, and is installed in the housing with the possibility of its return to its original position.

The operation of the device.

When pumping fluid, the gate rotates, which leads to periodic blocking of the fluid flow flowing out of the barrel, which leads to the creation of hydraulic shocks that affect the spring-loaded piston associated with the blade. This leads to the creation of standing waves. According to the authors, transverse hydrodynamic pulses are generated in the well from the action of a water hammer on the walls of the well with the excitation of local hydrodynamic vibrational vibrations due to the periodic outflow of fluid through perforations.

The frequency of hydrodynamic pulses is determined by the number of revolutions of the gate and the number of channels in it.

The intensity of the pulses is determined by the flow rate of the flowing fluid.

It is problematic to provide reciprocating movement of a spring-loaded piston with blades, since at a high frequency of pressure pulses acting on the piston, it is impossible to change the position of the piston due to the inertia of the system. At best, a piston with blades will tremble with low amplitude without generating standing waves.

The power of hydraulic pulses is small and their propagation deep into the reservoir for its processing cannot be effective.

After the formation has been processed, it is difficult to develop and launch the well into operation. It is necessary to lift the device from the well to the surface.

A device for hydroimpulse effects on the reservoir (see US Pat. RF No. 2.147.336, Mcl. E21B 43/25, publ. 10.04.2000, bull. No. 10), adopted by the authors for the prototype. The device is part of the tubing string and consists of an implosion chamber with pressure concentrators, a plunger with a drive in the chamber. The device is equipped with upper and lower sub and branch channels.

The plunger has slotted holes, a radial channel and a distribution mechanism consisting of a spring-loaded pusher with an annular groove, a seat and a spring-loaded locking element with a throttling hole, which forms a transition cavity with the plunger. The plunger drive is made in the form of a hydraulic cylinder with a hollow rod, on which a piston with a reversing switch is fixed.

The hydraulic cylinder is located between the upper and lower sub. The stem is installed in the sub with axial movement, the lower end of the rod is fixed in the plunger, and the upper is located in the axial channel of the tubing.

The operation of the device.

From the wellhead, working fluid is supplied under pressure, which enters the rod cavity and, through the channels of the reversing switch, enters the lower cavity of the hydraulic cylinder, from where it is supplied through the throttle hole to the cavity of the shut-off element. At the same time, annular fluid fills the upper cavity of the hydraulic cylinder and the upper cavity of the implosion chamber through the outlet channels. At the design pressure of the working fluid, the piston moves upward together with the stem and plunger with the formation of a low pressure zone between the plunger and the spring-loaded valve.

When moving the piston up, the lower cavity of the hydraulic cylinder is filled with well fluid with the release of the upper cavity of the implosion chamber and the upper hydraulic cylinder from the annular fluid along the outlet channels of the sub.

Design disadvantage:

- since the process of supplying the working fluid from the surface is continuous, when the spool is displaced in the plunger, at the first stage, it isolates the axial channel of the stem from the supply of the working fluid to the implosion chamber.

This leads to an increase in pressure in the axial channel of the pipe tubing string with an effect on the cross-sectional area of the rod from above. The flow of the borehole fluid under the piston through the spool cannot lead to its downward movement, since there are equal pressures above and below the piston, i.e. the device has low reliability.

It is doubtful that the device is operable when the spool is actuated in the plunger due to its end-face interaction with the sub, and then when the piston moves further, the spool switches in the piston due to the end-face interaction of the latter with the upper sub. It is more than problematic to synchronize the sequence of operation of the spools and the moves of the plunger movements.

If we assume that the device is operational, then at the end of the hydrodynamic impact on the reservoir, it is necessary to carry out work related to the development and commissioning of the well. To do this, you need to remove the device to the surface, which requires a fairly large investment of working time.

In the process of lowering the device into the well, it is necessary to refill the working fluid into the axial channel of the pipe riser.

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

- this is the possibility of generating hydroshock pulses at large pressure drops with a maximum flow rate of the working fluid supplied to the reservoir;

- the repetition of the process of generating hydroshock pulses;

- the ability to fill the tubing string with formation fluid when the device is lowered into the well;

- the possibility of development and launch of the well after hydrodynamic effects without lifting the tubing string with the device to the surface;

- the ability to ensure maximum flow rates of formation fluid and gas through the device by increasing the cross section of the passage channel by removing the pusher with cable or coiled tubing without killing the well.

The design of the downhole pulsator is illustrated by drawings, where:

- figure 1 - construction of the device in the context, in the initial transport position of the parts;

- figure 2 - the design of the device in the position of the parts when the working fluid is supplied under pressure to the pipe string and the axial channel of the device at the time of creating a hydrodynamic connection with the cavity of the well, its internal cavity;

- figure 3 - the relative position of the parts of the device with a maximum supply of working fluid into the well with the generation of shock pulses in the interval of the reservoir;

- figure 4 - the design of the device in the position of the parts during the development and launch of the well into operation.

The downhole pulsator consists of a hydraulic cylinder 1 connected to the chamber 2, the axial channel 3 of the hydraulic cylinder 1 is blocked from above by a sub 4.

Inside the axial channel 3 of the hydraulic cylinder 1, a plunger 5 is installed with an annular piston 6, forming a movable connection with the hydraulic cylinder 1. The cavity 7 above the annular piston 6 is connected bypass holes 8 to the external environment (annulus).

Between the hydraulic cylinder 1 and the plunger 5, an annular gap 9 is formed, which is connected by radial holes 10 with the axial channel 11 of the plunger 5.

The chamber 2 is provided with a landing ring 12, in which longitudinal grooves 13 are made around the perimeter, hydraulically connecting the axial channel 3 of the hydraulic cylinder 1 with the axial channel 14 of the chamber 2. A thrust ring 15 is installed at the bottom in the axial channel 14 of the chamber 2, through which a hollow rod 16 provided mechanical valve 17, pressed by a spring 18 to the end face of the seat ring 12. The plunger 5 is equipped with an internal protrusion 19, which is supported by the outer protrusion 20 of the pusher 21, the lower end of which is passed through the axial channel of the landing ring 12 with the formation rolling joint. At the lower end of the pusher 21 there is a retaining ring 22, freely entering the bore 23 in the body of the mechanical valve 13 and connected to the pusher 21 by a shear element 24.

A saddle 26 with a ball valve 27 is fixed in the axial channel 25 of the pusher 21. At the top, in the axial channel 25 of the pusher 21, an annular groove 28 is made.

The plunger 5 is supported by a spring 29.

The annular gap between the landing ring 12 and the pusher 21 is closed by the sealing ring 30.

The annular gap between the thrust ring 15 and the hollow rod 16 is closed by a seal 31, a nut 32 is installed at the lower end of the hollow rod 16.

The area of the annular piston 6 is determined from the condition:

$$F_{k.P}^{\Delta P}+F_{t.k}^{\Delta P}+QP{R}_{\mathrm{one}}+\mathrm{<figure-callout\; id="2"\; label="Q\; P\; R"\; filenames="00000003.png,00000004.png"\; state="\{\{state\}\}">Q\; </figure-callout>}P{R}_{}{}_2<F_t\Delta P$$

where: Fk.p - the area of the annular piston, m ² _;

Ft.k - cross-sectional area of the pusher, m ² _;

Qpr ₁ - spring force, pressed by the plunger, KN;

Qpr ₂ - spring force pushed by the end valve to the seat ring, KN;

ΔР - pressure of the working fluid supplied to the axial channel 11 of the plunger 5, MPa.

Face pulsator operation

By sub 4, the device is connected to the tubing string and inserted into the well with a location in the interval of the reservoir.

In the tubing pipe string, a working fluid is supplied under pressure. The pressure of the working fluid acts on the area of the annular piston 6 with pressing it to the end surface of the sub 4.

The pressure of the working fluid also affects the area of the mechanical valve 17 with its pressing against the end face of the seat ring 12.

The pressure of the working fluid also affects the cross-sectional area of the pusher 21, which moves with the retaining ring 22, with the external protrusion 20 acting on the inner annular protrusion 19 of the plunger 5 and moving it towards the seat ring 12,

With the calculated pressure difference, the pusher 21 moves the hollow rod 16. With the mechanical valve 17 separated from the seat ring 12 to form a hydraulic connection between the axial channel 14 and the chamber 2 with the axial channel of the hollow rod 16. The pressure of the working fluid acts on the area of the mechanical valve 17 from above, which leads to even greater downward movement of the hollow rod 16 with the passage under high pressure of the flow of working fluid into the axial drip of the hollow rod 16 with the flow into the axial channel of the well and hydropercussion on the reservoir.

At the same time, when the pressure is equalized in the axial channel 11 of the plunger 2 and the axial channel of the hollow rod 16, the pusher 21 is returned to its original position by the force of the compressed spring 29 with the plunger 5. When the pressure is equalized between the axial channel 14 of the chamber 2 and the axial channel of the hollow rod 16, the force is preliminarily of the compressed spring 18, the hollow rod 16 together with the end valve 17 returns to its original position with the end valve 17 landing on the seat ring 12, with the termination of the hydraulic connection of the axial channel 3 of the hydraulic cylinder 1 with the axial channel of the canopy about the rod 16. Again raise the pressure in the string with the appropriate set of pressure in the axial channel 11 of the plunger 5 with a repetition of the process of generating shock pulses in the well.

After the operation on hydroblow impact on a productive reservoir, without lifting the tubing string with the device to the surface, they call the inflow and development of the well. The formation fluid or gas is supplied to the axial channel of the hollow rod 16 and then with the extraction of the ball valve 27 from the seat 26 is fed to the axial drip 25 of the pusher 21 and the axial channel 11 of the plunger 5.

With a high flow rate of the well to reduce hydraulic resistance, the pusher 21 can be removed from the device by lowering into the axial channel of the elevator column the pipes of a known design catcher with its entry into the annular groove 28.

By pulling up the pusher 21, the shear element 24 is destroyed and the pusher 21 is removed to the surface.

The retaining ring 22 is located in the bore 23 and does not impede the flow of produced fluid.

A device for hydraulic impact on the reservoir as part of a tubing string, including a hydraulic cylinder with an adapter, a plunger with radial holes, a spring-loaded pusher with an annular groove, an annular piston, characterized in that the hydraulic cylinder is rigidly connected to the chamber, in the axial channel of which a seating ring is installed with longitudinal grooves on the outside, the pusher is provided with an external protrusion, a seat and a ball valve in the axial channel, the lower end of the pusher is passed into the axial channel of the seat ring and equipped with a locking ring connected to the pusher by a shear element, the axial channel of the chamber is blocked from below by a thrust ring and provided with a hollow stem with an end valve pressed by a spring to the seat ring, and a bore is made in the body of the end valve, in which the retaining ring is freely mounted, and the plunger is provided with an annular a piston with the formation of an annular gap with a hydraulic cylinder, hydraulically connected bypass holes with the annulus.

Claims (1)

A device for hydraulic impact on the reservoir as part of a tubing string, including a hydraulic cylinder with a sub, a plunger with radial holes, a spring-loaded pusher with an annular groove, an annular piston, characterized in that the hydraulic cylinder is rigidly connected to the chamber, in the axial channel of which a seating ring is installed with longitudinal grooves on the outside, the pusher is provided with an external protrusion, a seat and a ball valve in the axial channel, the lower end of the pusher is passed into the axial channel of the seat ring and equipped with a locking ring connected to the pusher by a shear element, the axial channel of the chamber is blocked from below by a thrust ring and provided with a hollow stem with an end valve pressed by a spring to the seat ring, and a bore is made in the body of the end valve, in which the retaining ring is freely mounted, and the plunger is provided with an annular a piston with the formation of an annular gap with a hydraulic cylinder, hydraulically connected bypass holes with the annulus.

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