RU2770966C1 - Hydraulic impact device - Google Patents

Abstract

FIELD: oil and gas industry.SUBSTANCE: invention relates to the oil and gas industry; it is intended for cleaning the bottom-hole zone of wells equipped with a packer, using coiled tubing installations. The device includes a detachable case, in an axial channel of which a seat is installed, on which an end valve mounted at the end of a hollow rod rests from below. The end valve contains a number of grooves on the outer side, and it is equipped with a shutter entering an axial channel of a spring-loaded pusher equipped with an annular piston and an annular protrusion pressed by a spring to the surface of the end valve. An annular chamber between the pusher and the inner surface of the detachable case is connected by a radial hole to the axial channel of the pusher, at the lower end of which a crown with a throttling channel is installed. An external crown is made at the lower end of the detachable case. When working fluid is supplied under pressure at the calculated pressure drop perceived by the end valve, it is detached from the seat, with the formation of a hydraulic connection of the axial channel of the device through longitudinal grooves on the body of the end valve. The pressure of working fluid is perceived by the area of the annular piston with the separation of the annular protrusion from the surface of the end valve, followed by the movement of the pusher relatively to the shutter and the formation of a hydraulic channel between longitudinal grooves and the axial channel of the pusher. The pusher with the inner crown acts on the surface of a sand plug with simultaneous supply of working fluid to its surface through the throttling channel of the inner crown.EFFECT: rational use of working fluid is ensured, eliminating its loss, and possibility of using a device for removing plugs in a sub-packer zone is ensured.1 cl, 3 dwg

Description

The invention relates to the oil and gas industry and is intended for cleaning the bottomhole zone of a well equipped with a packer.

A device for cleaning wells from sand plugs is known (US Pat. No. 2242585, IPC E21B 37/00, publ. 20.12.2004, Bull. No. 35). The device consists of an adapter with a seat, a detachable body connected by a coupling to a casing, on the ends of which teeth are made.

The destruction mechanism consists of a detachable hollow rod connected to an annular piston and having a common hydraulic channel. The hollow rod is spring-loaded relative to the hollow body by a compression spring and is connected through a coupling to a crown provided with teeth at the end and having a throttling channel. The crown on the outside is equipped with a jet nozzle.

The hollow rod with the inner surface of the hollow body forms an annular chamber, which is connected by a hydraulic channel with the axial channel of the device, and the cross-sectional area of the annular chamber is equal to the cross-sectional area of the hydraulic channel in the hollow rod.

The disadvantages of the design include:

- a sufficiently large outer diameter of the device, which does not allow it to be used for the destruction of sand-hydrate and sand-clay plugs in the under-packer zone, since the axial bore of the packer is small;

- low reliability of operation due to the fact that when mechanical particles move along the annular gap between the body of the device and the inner surface of the tubing string, sand may get inside the device, which can lead to clogging of the throttling channel of the jet nozzle, jamming of the annular piston, and stopping the process ;

- the presence of a retaining ring connecting the destruction mechanism with the hollow body requires the expenditure of axial force developed on the annular piston to deform it and move the destruction mechanism in the direction of the surface of the destruction plug.

A hydraulic percussion device for cleaning wells from sand plugs is known (US Pat. RF No. 2303121, IPC E21B 37/00, publ. 20.07.2007, Bull. No. 20).

The device consists of a hollow body with circulation holes, a seat, an end valve, an annular piston mounted on a hollow spring-loaded rod, installed in the axial channel of the hollow body, a crown with teeth at the end, a throttle and a jet nozzle. The seat is installed between the body and the adapter, against which a hollow rod is spring-loaded, passing into the axial channel of the adapter and the axial channel of the seat. The crown is connected to the annular piston, which forms a mechanical valve with the seat. The piston is installed with the possibility of overlapping the circulation holes of the hollow body. The annular gap between the stem and adapter is hydraulically connected to the axial channel of the hollow stem and seat.

On a flexible pipe string, the device is inserted into the axial channel of the pipes of the tubing string to the location of the sand plug.

Device operation

The liquid under pressure enters the axial channel of the body and through the circulation holes in the hollow stem is fed into the axial channel of the crown. Part of the flow rate of the working fluid is constantly fed to the surface of the sand plug. The main flow is fed into the annular chamber of the rotating nozzle, with ejection to the surface of the plug. With increasing pressure in the axial channel of the flexible pipe string, the latter is perceived by the annular piston, which leads to the separation of the annular piston from the seat, moving down the crown with teeth and affecting the sand plug. The annular piston passes the circulation holes in the hollow body, with a corresponding increase in flow. This leads to a pressure drop in the system, which allows the annular piston with the crown to return to its original position, with the termination of the free discharge of fluid into the well and the repetition of the working cycle.

The disadvantages of the design include:

- irrational constant flow of working fluid through the throttling channel of the bit and tangential channels of the rotating nozzle;

- The diametrical dimensions of the device do not allow it to be used in wells equipped with a packer, the axial bore of which has a diameter of d _article =50/55 mm, which makes it difficult to remove the sand plug under the packer.

A well-known design of a hydraulic percussion device, adopted by the authors as a prototype (Mashkov V.A. et al. Pilot tests of a hydraulic percussion device for the destruction and removal of dense proppant plugs in perforation intervals during ANPD. // Modern equipment and technology for completing wells and drilling sidetracks: collection of scientific papers / OAO NPO Burenie - Krasnodar, 2006, pp. 363-371).

The hydropercussion device consists of a housing connected through a hydraulic cylinder with a connecting pipe equipped with an annular piston inside the adapter. The adapter through the shank is connected to the lift column of pipes. Inside the hydraulic cylinder there is an annular piston with a hollow rod passed into the axial channel of the body.

At the lower end of the hollow rod, a split housing of the destruction mechanism is installed, in the axial channel of which a throttle washer is installed in series with the axial channel, blocked in the initial position, by a spring-loaded pusher. In the middle part of the split body, a seat is installed, to which a spring end valve is pressed, connected by branch pipes with an inner crown. The pressing force of the end valve to the seat is regulated by a nut. An external crown is installed at the lower end of the split body. A ball check valve is installed in the axial channel of the pusher. The axial channel of the hollow rod is connected to the throttle channel in the body of the throttle washer, with an annular chamber between the split housing and the pusher, which, in turn, is connected through longitudinal grooves in the body of the saddle with the chamber between the split housing and the branch pipe. Calibrated holes are made in the nut, connecting the annular chamber between the split body and the pusher, with the well cavity.

The axial channel of the pusher is constantly hydraulically connected with the axial channel of the branch pipe and the axial hole in the inner crown.

The annular chamber under the annular piston is permanently connected to the well cavity by a radial hole in the body of the hydraulic cylinder.

The cross-sectional area of the calibrated holes in the adjusting nut is taken to be less than the cross-sectional area of the throttle channel in the body of the throttle washer, and the total area of the calibrated holes in the body of the inner crown is taken to be greater than the cross-sectional area of the throttle channel in the body of the throttle washer.

Device operation

The device on the tubing string is lowered into the well to the level of the sand plug, with the outer bit resting on it. Serves under pressure and at a given flow rate of the working fluid. Through the axial channel of the connecting pipe and the hollow rod, the working fluid is supplied through the throttle channels in the body of the throttle washer and the longitudinal grooves in the body of the seat to the calibrated holes in the body of the adjusting nut, with the jet acting on the surface of the sand plug.

The flow rate of the working fluid supplied through the tubing string is greater than the total flow rate through the calibrated holes in the body of the adjusting nut, so there is a smooth increase in pressure in the axial channel of the tubing tubing and inside the device. At the calculated pressure drop, perceived by the area of the pusher, it is separated from the throttle, with the transfer of axial force to the end valve, with separation from the seat and the formation of a hydraulic connection of the annular channel between the split body and the pusher, with the axial channel of the branch pipe.

The working fluid, with an increased flow rate, is supplied through the axial channel in the inner bit to the surface of the sand plug. When the end valve is separated from the seat, it abruptly moves down, with compression of the return spring and mechanical impact by the teeth of the inner crown on the surface of the sand plug, with its destruction.

There is a pressure drop in the hydraulic channel of the device, which leads to the return of the end valve to the seat, and the pusher to the end of the throttle washer. The frequency of impacts of destruction mechanisms is within n=0.5-1 impact/sec. The absorption of the working fluid by the productive formation leads to an insufficient upward flow rate, in connection with this, the pumping unit is switched to backwash.

After flushing the bottomhole zone from mechanical particles with the reverse flow of the working fluid, the pumping unit is switched over again to the direct supply of the working fluid to the hydraulic percussion device, with the process of plug destruction being repeated.

The disadvantages of the design include:

- large diametrical dimensions of the structure, which does not allow it to be used in wells equipped with a packer;

- the complexity of the design, which makes it difficult to install, adjust and use;

- the constant consumption of part of the working fluid reduces the efficiency of the process.

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

- the possibility of using a device for the destruction and removal of sand plugs in the under-packer zone;

- rational use of the working fluid, excluding its loss during the period of pressure build-up.

The technical result is achieved by the fact that the hydropercussion device consists of a detachable body, in the axial channel of which a hollow rod, a seat, a spring-loaded pusher with an end valve and an annular piston are installed. The crown is installed at the lower end of the pusher and has a throttling channel, and the outer crown is made at the lower end of the split body. The device is equipped with a spring centralizer installed at the junction of the split body parts. The end valve is provided with longitudinal grooves, rests on a spring and is mounted on the lower end of the hollow stem with the possibility of resting on the seat from below, with a shutter entering the axial channel of the pusher, at the upper end of which an annular protrusion is made with the possibility of end contact with the body of the end valve.

An annular chamber is formed between the pusher and the inner surface of the split housing, hydraulically connected by a radial hole in the pusher body with its axial channel.

The design of the hydraulic impact device (hydraulic hammer) is illustrated by drawings where:

Figure 1 - General view of the device in section, in the original transport position;

Figure 2 shows the design of the device in the position of the parts at the beginning of the technological cycle (the centralizer is removed);

The figure 3 - the relative position of the parts during the implementation of the working cycle - hydromechanical impact of the jet of the working fluid and the crown on the surface of the sand plug.

In figures 2 and 3, the centralizer is not shown. The hydraulic hammer consists of a split housing 1, at the junction of the parts a spring centralizer 2 is fixed, the petals 3 of which interact with the outer surface of the split housing 1 at one end.

In the axial channel 4 of the split housing 1, a seat 5 is installed, on which the end valve 6 rests from below, connected with a hollow stem 7, equipped with an adjusting nut 8 and a perforated washer 9, which presses the spring 10 to the end of the seat 5. The end valve 6 is equipped with a shutter 11, which enters into the axial channel 12 of the pusher 13, equipped with an annular protrusion 14 and an annular piston 15.

End valve 6 forms a movable connection with a detachable body 1 and is provided with a number of longitudinal grooves 16.

The pusher 13 with its annular protrusion 14 is pressed against the body of the mechanical valve 6 from below. The annular protrusion 14 has a diameter less than the diameter of the end valve 6 along the contact patch on the seat 5.

The pusher 13, together with the annular piston 15, form a movable connection with a split housing 1.

At the lower end of the split housing 1, a nut 17 is installed, which raises the annular protrusion 14 to the end surface of the seat 5 with the spring 18. The annular piston 15 forms a movable connection with the split housing 1. At the lower end of the pusher 13, an inner crown 19 is fixed, with a throttling channel 20. Formed by the body of the pusher 13 and the inner surface of the split housing 1, the annular chamber 21 is constantly hydraulically connected by a radial hole 22 with the axial channel 12 of the pusher 13. On the end surface of the split housing, an external crown 23. The device is equipped with a connecting thread 24.

Operation of the hydraulic device.

The device is connected with the connecting thread 24 to the lower end of the flexible pipe string of the coiled tubing unit and is inserted into the axial channel of the pipes of the production string, with a passage through the axial channel of the packer shaft to the location of the sand plug. When passing through the axial channel of the packer barrel, the petals 3 of the spring centralizer 2 are compressed and stretched along the surface of the split housing 1, with the restoration of the shape behind the packer. The working fluid is supplied under pressure to the axial channel 4 of the device. With the calculated pressure difference perceived by the cross-sectional area of the hollow stem 7 and the body of the mechanical valve 6, it is separated from the seat 5 with the formation of a hydraulic connection of the axial channel 4 of the split housing 1 above the seat 5, through the longitudinal grooves 16, with the action of the working fluid on the area of the annular piston 15, limited by the annular protrusion 14.

This leads to the movement of the pusher 13 with the annular piston 15 down, with the exit from the interaction with the shutter 11 and the opening of the hydraulic connection, to supply the working fluid from the longitudinal grooves 16 of the end valve 6 into the axial channel 12 of the pusher 13.

From the axial channel 12 of the pusher 13, the working fluid flows through the throttling channel 20 in the inner crown 19, with the impact on the surface of the sand plug. With a sharp downward movement of the pusher 13, the inner crown 19 acts on the surface of the sand plug with its destruction.

The sharp movement of the pusher 13 down is due to the fact that when the annular protrusion 14 is separated from the surface of the end valve 6, an additional area is activated, which is affected by the pressure of the working fluid. When the working fluid is poured out through the throttling channel 20 in the inner crown 19, a pressure drop occurs in the system, which leads to the return of the end valve 6 to the seat 5, with the cessation of the supply of the working fluid to the axial channel 12 of the pusher 13 and landing by the annular protrusion 14 on the end valve 6. The outer crown 23, at the lower end of the detachable housing, the device rests on the surface of the sand plug. When the pressure is released, the length of the flexible pipe string is reduced, with the separation of the outer bit 23 from the surface of the sand plug. After the working fluid exits the throttling channel 20 and mechanical destruction of the sand plug surface, sand particles are fed into the annular gap between the inner surface of the pipes of the tubing string and the outer surface of the pipes of the flexible string, with the removal of particles to the surface.

Claims (1)

Hydropercussion device, consisting of a split housing, in the axial channel of which a hollow rod, a seat, a spring-loaded pusher with an end valve and an annular piston, a crown at the lower end of the pusher, with an axial throttling channel, an external crown at the lower end of the split housing, are installed, characterized in that the device is equipped with a spring centralizer installed at the junction of the split housing parts, the end valve rests on a spring and is installed on the lower end of the hollow stem with the possibility of resting on the seat from below, provided with longitudinal grooves and a shutter included in the axial channel of the pusher, at the upper end of which there is an annular a protrusion with the possibility of end contact with the body of the end valve, and between the pusher and the inner surface of the split housing, an annular chamber is formed, hydraulically connected by a radial hole in the body of the pusher with its axial channel.

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