RU2303121C2 - Hydraulic percussion means for sand plug removal from well - Google Patents

Abstract

FIELD: oil and gas industry, particularly well cleaning devices.

SUBSTANCE: device comprises hollow body connected to sub and provided with circulation orifices, seat, end valve, annular piston fixedly connected to hollow spring-loaded shaft and arranged in axial channel of hollow body, crown with end teeth, throttle and hydraulic monitor head. Seat is arranged between the body and the sub. Hollow shaft sliding in axial sub channel and axial seat channel is spring-loaded with respect to the sub. Crown is directly connected with annular piston, which defines end valve along with the seat. Piston is installed to close circulation orifices of the body. Annular space between the rod and the sub is permanently fluidly communicated with axial channel made in the shaft and the seat.

EFFECT: increased efficiency of sand plugs breakage.

2 dwg

Description

The invention relates to the operation and repair of a well and can be used in the destruction and removal of dense sand-clay plugs in the axial channel of the pipe tubing and the interval of perforation of the reservoir.

A device for cleaning wells from sand plugs, consisting of a hollow body with a hollow rod in the axial channel. The device has a common axial channel and radial channels hydraulically connecting this axial channel with an external cavity, which may be the annular channel of the pipe pipe lift.

The hollow rod in the lower part is equipped with a milling cutter with end teeth (AS No. 602669 from 09/23/76, Ml. E21B 21/00, published in OB14, 1978).

It is known "Device for cleaning wells from sand plugs", see US Pat. RF №2242585, MKI 7 Е21В 37/00; 21/00, publ. December 20, 2004 Bull. Number 35.

The device consists of an adapter with a saddle, a detachable hollow body connected by a coupling to a casing provided with end teeth.

The destruction mechanism consists of a detachable hollow rod associated with an annular piston.

The adapter with the destruction mechanism have a common hydraulic channel. The hollow rod is spring-loaded relative to the hollow body with a return spring and is connected through a coupling to a crown, which is equipped with end teeth, and has an axial throttling channel. The crown is equipped with a hydraulic nozzle on the outside.

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

The disadvantage of the design of a device for cleaning wells from sand plugs is:

- design complexity;

- low reliability, which consists in the fact that during the transportation of mechanical particles along the annular gap between the device body and the inner surface of the pipe tubing, sand may enter the device, which can lead to jamming of the ring piston and stop the process;

- with a small diameter of the pipe string, it is therefore necessary to have small dimensions of the device while maintaining the impact force on the crown of the rock cutting device and the force developed by the return spring, which is difficult to do with these small dimensions of the device according to the proposed design scheme;

- the presence of a retaining ring connecting the fracture mechanism with the hollow body, requires axial forces developed on the annular piston to ensure its deformation and the movement of the fracture mechanism in the direction of the surface of the sand-clay cork.

The technical result that can be obtained by carrying out the present invention is that the destruction efficiency of dense sand-clay plugs in the axial channel of the elevator string of small pipes, especially in the axial sea otter of the wellbore in the perforation interval due to the action of the tangentially directed working jet, is increased fluid to the periphery of the wellbore and impulse action on the surface of the sand-clay plug near the wall of the casing pipe;

- provides mechanical destruction of the sand-clay cork due to the impact of the teeth of the crown of the shock mechanism when the excess pressure is perceived by the cross-sectional area of the stepped piston under the saddle having a larger diameter;

- provides reciprocating movement of the crown of the percussion mechanism and a pulsed increase in the flow rate and speed of the upward flow of the working fluid, in the interval of perforation and the annular space of the borehole, when the teeth of the crown of the percussion mechanism interact with the surface of a dense sandy clay plug

The technical result is achieved using the proposed hydropercussion device, consisting of a hollow body, with circulation holes made in the body of the hollow body, under the seat, of a mechanical valve, at the end of the annular piston in the axial channel of the hollow body, supported by a spring and rigidly connected to the annular piston, equipped with a crown with end teeth and a hydraulic nozzle.

An analysis of technical solutions carried out according to well-known sources, scientific, technical and patent information showed that a device for cleaning wells is known, equipped with a hydraulic nozzle (nozzle made in the form of an annular nozzle) with tangential channels mounted for rotation (see a.c No. 1320382 dated 04.02.86, Mcl. E21B 21/00, published in OB No. 24, 1987), there is known a device for cleaning a well, consisting of a hollow body and a hollow rod installed in it, movable in the axial direction (see Pat. RF №2068078 from 02.27.96, Mkl. E 2 1 In 21/00, published in OB No. 29, 1996). Identified technical solutions have design features that coincide with some distinctive features of the proposed technical solution. The proposed solution does not explicitly follow from the prior art, i.e. meets the criterion of "inventive step".

The design and principle of operation of the device for the destruction and cleaning of the wellbore from dense sand and clay plugs is illustrated by drawings, where;

- figure 1 - device in section, in the initial position of the parts;

- figure 2 - the design of the device in the exit position of the crown of the impact mechanism, the impact on the surface of a dense sand-clay plug and the formation of additional hydrodynamic connection of the axial channel of the device with the cavity of the well and the axial channel of the pipe tubing.

The inventive device consists of a hollow body 1 connected by its upper end to a seat 2 on which an adapter 3 is mounted. An annular piston 5 is installed in the axial channel 4 of the hollow body 1, provided with a cone 6 facing the mating conical surface 7 of the seat 2. The annular piston 5 with a cone 6, a seat 2 form an end valve. In the hollow body 1, circulation holes 8 are made, which are blocked in the initial position by the body of the annular piston 5.

A hollow rod 10 is passed into the axial channel 9 of the seat 2, rigidly connected to the annular piston 5, which is supported by a spring 12 through the support washer 12. The annular gap 13, formed by the body of the hollow rod 10, with the adapter 3 is constantly hydraulically connected by radial channels 14 to the axial channel 15 of the hollow rod 10 and the saddle 2.

At the lower end of the annular piston 5, a crown 16 with teeth 17 is installed, on the outside of which there is a hydraulic monitor nozzle 18 with an annular chamber 19 hydraulically connected by radial channels 20 with an axial channel 21 of the crown 16. At the end of the hydraulic monitor nozzle 18 there are tangential channels 22 connecting the annular chamber 19 with the environment (well cavity).

The crown 16 is also equipped with a throttle 23 connecting the axial channel 21 with the cavity of the well.

In the initial position, the annular piston 5 with the cone 6 is pressed by the force of the spring 12 to the conical surface 7 of the seat 2 with the isolation of the annular gap 13 from the annular gap under the saddle 2.

The end surface of the hollow body 1, facing the surface of a dense sand-clay cork in the axial channel of the pipe tubing, is provided with teeth 24 for its destruction.

The pressing force of the cone 6 of the annular piston 5 to the conical surface 7 of the seat 2 is regulated by a nut 25 at the upper end of the hollow rod 10.

The upper end of the adapter 3 is provided with a connecting thread, with which the device will be connected to the lower end of the flexible pipe string before being lowered into the well.

A device for cleaning a well from a dense sand-clay plug is an integral part of a complex of equipment that provides for the repair of wells using a flexible pipe string.

The unit with flexible pipes does not allow the tool to rotate, which requires cleaning the axial channel of the pipe riser and bottom hole, as a rule, washing with various liquids on a water and oil basis, using nozzles of various designs.

All of them are based on the use of the hydro-monitor effect of a jet of working fluid flowing out of the throttle channel. Pressure losses during pumping of a working fluid through a flexible pipe string can reach 17-18 MPa. It should be noted that the destruction efficiency of dense sand-clay plugs decreases due to the uneven effect of the jet of working fluid in the peripheral areas. In its central part, a hole is formed in which the energy of the jet is extinguished.

The use of the device of the claimed design can significantly improve the destruction of the sand-clay cork due to the mechanical impact and the hydro-pulse impulse by a tangentially directed jet of working fluid, which makes a sinusoidal movement relative to the pipe wall during rotation of the nozzle.

A device for the destruction of dense sand-clay plugs works as follows.

The device through the adapter 3 is connected to the lower end of the flexible pipe string and lowered into the axial channel of the pipe pipe lift until the teeth 24 at the end of the hollow body 1 contact the surface of the sand-clay plug.

A working fluid with a predetermined flow rate and design pressure is supplied to the column of flexible pipes, which enters the axial channel of the adapter 3 and is fed into the annular gap 13, where it is fed through the radial channels 14 in the body of the hollow rod 10 into the axial channel of the annular piston 5 and then into the axial channel 21 crowns 16. Through radial holes 20, the working fluid from the axial channel 21 of the crown 16 is fed into the annular chamber 19 of the jet nozzle 18, which is rotated by the reaction of the jets flowing from the tangential channels 22, and acts on rhnost sandy-argillaceous tube around the perimeter of the axial passage of tubing pipe. Part of the total flow rate of the working fluid supplied to the flexible pipe string is continuously supplied to the throttle 23 with the center of the dense sand-clay plug exposed to the surface.

In this case, the total flow rate of the working fluid through the throttle 23 and the tangential channels 22 in the hydraulic nozzle 18 is taken to be less than the flow rate of the working fluid supplied from the surface along the string of flexible pipes, which leads to a smooth increase in the pressure drop in their axial channel.

With increasing pressure drop, the latter is perceived by the cross-sectional area of the annular piston 5, from the annular gap 13, which is pressed against the conical surface 7 of the seat 2 by the force of the compressed spring 12. When the force of the spring 12 is exceeded, the annular piston 5 is squeezed from the surface of the saddle 2 and the overpressure is perceived by the annular piston 5 for a larger diameter. This leads to a sharp movement of the annular piston 5 together with the crown 16 in the direction of the surface of the sand-clay plug with mechanical action of the teeth 17. When moving the annular piston 5 in the axial channel of the hollow body 1, the latter passes through the circulation holes 8 with additional compression of the spring 12, and a working fluid with an increased flow rate is supplied to the axial channel of the pipe tubing string, which contributes to the effective movement-lifting of mechanical particles from the well. The pressure of the working fluid in the axial channel of the flexible pipe string is reduced by the force of the compressed spring 12 assembly: the hollow rod 10, the annular piston 5 with the crown 16 and with the hydraulic nozzle 18 move upward relative to the circulation holes 8 of the hollow body 1 with the cessation of the flow of working fluid through them.

By the force of the compressed spring 12, the annular piston 5, with its cone 6, sits on the conical surface 7 of the seat 2. The pressure of the working fluid in the axial channel of the flexible pipe string and inside the device gradually increases and, after increasing the pressure to the calculated value, the hydromechanical effect on the surface of the sandy clay plug repeated.

When reciprocating movement of the annular piston 5 assembly with the crown 16 and rotation of the nozzle 18, the jet of working fluid flowing out of the tangential channels 22 makes a sinusoidal movement relative to the wall of the pipe string, which contributes to the intensification of the destruction of the dense sandy clay plug at the periphery.

The claimed technical destruction meets the criterion of patentability, namely the condition of novelty, inventive step and industrial applicability.

Claims (1)

A hydropercussion device for cleaning wells from sand plugs, including a hollow body connected to the adapter with circulation holes, a seat, an end valve, an annular piston rigidly mounted on a hollow spring-loaded rod and installed in the axial channel of the hollow body, a crown with end teeth, a throttle and a hydraulic nozzle characterized in that the saddle is installed between the housing and the adapter, relative to which a hollow rod springing passes in its axial channel and the axial channel of the saddle, moreover, the crown It is directly connected with an annular piston forming an end valve with a seat and installed with the possibility of overlapping the circulation holes of the hollow body, and the annular gap between the hollow rod and the adapter is constantly hydraulically connected to the axial channel of the hollow stem and saddle.

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