RU2277164C1 - Well cleaning and flushing device - Google Patents

Abstract

FIELD: well operation and repair, particularly to clean well of mud, sand and sludge deposits.

SUBSTANCE: well cleaning and flushing device comprises body with radial orifices and packer located above the orifices. Hollow rod is arranged in the body so that the rod is concentric to the body. The rod has perforated orifices and may perform limited downward movement. The body is rigidly connected with liner provided with check valve arranged from liner bottom. The check valve is made as a plate sealing liner interior. The plate may rotate upwards about its edge by means of hinge and is provided with opening-closing force regulator made as additional load. The liner is provided with partition having throttle channel located over check valve. The packer is formed as self-sealing collar to permit liquid flow in bottom-top direction. The body is provided with extensions formed on upper edge thereof and with cylindrical extension arranged below radial windows. The cylindrical extension is formed on inner surface. The body is fixed relatively hollow rod by shear members. The perforated rod orifices are grouped in two rows, namely in upper and lower ones. In initial position lower perforated orifices of the rod are closed with the cylindrical extension, upper orifices are closed with bush fixed relatively hollow rod by thread. The bush has depressions formed on lower edge thereof and adapted to cooperate with body extensions when lower perforated orifices are opened. The hollow rod is provided with sealing member arranged on rod outside between upper and lower perforated orifices above the body. The sealing member isolates body interior during lower perforated orifices opening. The hollow rod is connected with flow string from top thereof. The liner may cooperate with sludge and sand deposits present in well bore and with well bottom.

EFFECT: provision of controllable speed of sludge and sand deposits in pipe string and possibility of well flushing in single trip.

2 dwg

Description

The invention relates to the operation and repair of wells and can be used to clean the well from sludge, sand and sludge deposits.

A device for cleaning a well is known (see as.s. SU No. 2068078, MKI 7 E 21 V 37/00, 21/00, BI No. 29 dated 10/20/1996), comprising at least one housing connected to the pipe string one window for communicating the housing cavity with the external space, a shank connected to the housing and equipped with a working tip and a valve blocking the housing window, the device being provided with a hollow stem connected to the pipe string and installed in the housing with the possibility of limited axial movement, and a casing with inner annular upper and lower support ledges wherein the hollow rod has in the upper part a supporting outer annular protrusion corresponding to the upper annular supporting protrusion of the casing, and a section with perforation holes, the housing has in the upper part a supporting external annular protrusion responding to the inner annular lower supporting protrusion of the casing to provide relative relative axial movement the casing, the housing and the hollow rod, and the portion of the hollow rod with perforations is isolated from the cavity of the housing in the initial position of the device, and the covering window The valve body is spring-loaded. In addition, the device is equipped with an overlapping side hole made in the lower part of the pipe string, a sealing element mounted on a shear element and configured to interact with the waste organ, while the perforation holes of the hollow rod portion are located along a helical line.

The disadvantages of this device are

- firstly, for flushing it is necessary to use a waste body, which is discharged from the wellhead in order to bring down the sealing element, at the same time, achieving this goal is very doubtful, since the waste body may be stuck in the sludge and sand located in the pipe string above the sealing element without reaching it, and this eliminates the possibility of flushing the well, which is simply necessary for effective cleaning of the well;

secondly, it is necessary to initially (before lowering the device into the well) fill the cavity of the device casing with gas (air), and this can only be done in specialized workshops;

thirdly, the fact that it does not provide a sufficiently complete inflow and extraction of a large volume of slurry and sand deposits from a well in one run due to the absence of a packer in its design that isolates the bottom-hole zone of the well.

The closest in technical essence is a device for cleaning wells (see AS SU No. 2068079, MKI 7 E 21 B 37/00, 21/00, BI No. 29 dated 10/20/1996), including pipes connected to the string a housing with at least one window for communicating the cavity of the housing with external space and a hollow rod installed in the housing with limited axial movement, a shank associated with the housing and configured to interact with the bottom of the well, a spring-loaded valve placed in the housing to block it windows in initial position properties, and a packer mounted on the body, while the shank and the hollow rod have sections with perforation holes, the value of the limited axial movement of the hollow rod is equal to the length of its section with perforation holes, while the said section with perforation holes of the hollow rod is isolated from the cavity of the housing position.

The disadvantages of this device are

firstly, it is necessary initially (before the device is launched into the well) to fill the cavity of the device casing with gas or liquid and gas, and this can only be done in specialized workshops;

secondly, for flushing it is necessary to use a waste body that is discharged from the wellhead in order to knock down the sealing element, achieving this goal is very doubtful, since the waste body may get stuck in the sludge and sand located in the pipe string above the sealing element without reaching it , and this eliminates the possibility of flushing the well, which is simply necessary for effective cleaning of the well;

thirdly, the rate of entry of slurry deposits into the pipe string is controlled by the force of the valve spring, which is installed on the surface before the device is lowered into the well, based on the expected bottomhole pressure, which can vary and is selected individually for each well, and therefore it is not always possible to achieve adjustable effective well cleaning.

An object of the invention is to provide a device that is simple to manufacture and use with a controlled rate of entry into the pipe string of slurry and sand deposits and guaranteed further flushing of the well for one run of the device.

The technical problem is solved by the proposed device for cleaning and flushing a well, comprising a housing with radial windows and a packer located above, a hollow rod with perforated holes installed in the housing with the possibility of limited axial movement downward, the perforated holes being isolated in the initial position, the shank associated with the housing and configured to interact with the bottom of the well.

What is new is that the hollow rod is connected to the pipe string, and the packer is made in the form of a self-sealing cuff that passes from the bottom up, while the body is provided with protrusions along the upper edge and a cylindrical protrusion located below the radial windows on the inner surface and fixed relative to the hollow rod shear elements, and the perforated holes of the hollow rod are made in the form of two rows of upper and lower perforated holes, while the lower perforated holes of the hollow rod in the initial position They are formed by a cylindrical protrusion, and the upper ones by a sleeve fixed with a thread on top of the hollow stem and equipped with cavities along the lower edge that interact with the body protrusions when opening the lower perforated holes, and the hollow stem is equipped with a sealing element on the outside between the lower and upper perforated holes that insulates the inner the cavity of the body when opening the lower perforated holes, the shank from the bottom is additionally equipped with a check valve with a closing force regulator and a baffle located above the throttling passage.

Also new is the fact that the non-return valve is made in the form of a plate hermetically closing the cavity of the shank made with the possibility of rotation upward relative to the edge, and the opening force regulator is in the form of an additional load fixed on the plate.

The figure 1 shows a device for cleaning and flushing a well in a transport position.

The figure 2 shows a device for cleaning and flushing the well in the working position when cleaning the well.

A device for cleaning and flushing a well consists of a housing 1 with radial windows 2 (see FIG. 1) and a packer 3 located above. A hollow stem 4 with perforated holes is placed concentrically in the housing 1, with the possibility of limited axial downward movement. The bottom housing 1 is rigidly connected to the shank 5, which is equipped with a check valve 6 on the bottom, which is made in the form of a plate 7, hermetically overlapping the inner cavity of the shank 5. The plate 7 has the ability to rotate upward relative to the edge by means of a hinge 8 and is equipped with a fixed opening-force control closing made in the form of an additional load 9. Above the check valve 6, the shank 5 is equipped with a partition 10 with a throttle channel 11.

The packer 3 is made in the form of a self-sealing cuff 12, which passes from the bottom up, while the housing 1 is provided with protrusions 13 along the upper edge and a cylindrical protrusion 14 located below the radial windows 2. The housing 1 is fixed relative to the hollow stem 4 by shear elements 15. The perforated holes of the hollow rod 4 are made in two rows: the upper 16 and the lower 17. The lower perforated holes 17 of the hollow rod 4 in the initial position are overlapped by the cylindrical protrusion 14 of the housing 1, and the upper 16 by the sleeve 18 fixed to relative to the hollow rod 4 with a thread 19 and recesses 20 fitted along the lower edge, interacting with the protrusions 13 of the housing 1 when opening the lower perforated holes 17. The hollow rod 4 is external to the upper 16 and lower 17 perforated holes above the housing 1 and has a sealing element 21 that insulates the inner the cavity of the housing 1 when opening the lower perforated holes 17.

The hollow rod 4 on top is connected to the tubing string (tubing) 22.

The shank 5 is configured to interact with sludge and sand deposits 23 located in the wellbore and a bottom hole 24 of the well 25.

The necessary tightness during operation of the device is provided by O-rings 26, 27, 28.

The device operates as follows.

If it is necessary to clean the bottom-hole zone of the well, the device on the tubing string 22 (see Fig. 1) is lowered into the well 25. At the same time, during the descent, the liquid in the well 25 freely flows from bottom to top through the radial windows 2 of the housing 1 and the annular gap formed by the hollow rod 4 and the housing 1. The descent of the device is continued until the lower part of the shank 5 stops (for example, made in the form of a milling crown) into slurry and sand deposits 23.

Next, the tubing string 22 is unloaded onto the device, while the shear element 15 is destroyed (see figure 2), as evidenced by the indication of the weight indicator located on the wellhead (not shown) of the well 7. After that, the tubing string 22 is continued to descend, while the casing 1, rigidly connected with the shank 5, remains stationary due to the fact that it is abutted in the sludge and sand deposits 23. The hollow rod 4, rigidly connected to the tubing string 22, is lowered down to the interaction of the lower edge of the sleeve 18 with depressions 20 and protrusions 13 of the housing 1. The sealing element 21 is located nny on the outer surface of the hollow rod 4, sealingly closes the annular gap between the hollow stem 4 and the housing 1 except bypass wellbore fluid from the bottom up, at the same time open the lower perforations 17 of the hollow rod 4 that bypass inner cylindrical sample 12 of the housing 1.

At this moment, slurry and sand deposits 23 located under the shank 5 rush into its internal cavity, and as soon as the force from below on the plate 7 of the check valve 6 exceeds the weight of the additional load 9, the check valve 6 opens (the plate 7 is rotated upward relative to the edge by means of a hinge 8) and passes up the slurry and sand deposits 23, which fall on the baffle 10 and through its throttle channel 11, which regulates the flow rate of particles of slurry and sand deposits 23, enter the internal cavity p hollow rod 4 through its lower perforated holes 17 and further into the tubing string 22.

As filling the tubing string 22 and, accordingly, lowering the device downward, the tubing string 22 is expanded until the liner 5 rests on the bottom 24 of the well 25.

Then, the slurry and sand deposits 23 located in the tubing string 22 are washed out and the well 25 is washed. To this end, the tubing string 22 is rotated to the left, and the hollow rod 4 rigidly connected to it rotates, and since the lower edges of the sleeve 18 by depressions 20 interact with the protrusions 13 housing 1, the sleeve 18, due to the thread 19, remains stationary. At a certain point, when the thread 19 is completely turned away, the sleeve 18 will be freed from hard interaction with the hollow rod 4.

After that, the tubing string 22 is lifted upward, while the upper perforation holes 16 of the hollow rod 4 are opened, since the sleeve 18 with its troughs 20 remains in interaction with the protrusions 13 of the housing 1.

At this time, the lower perforation holes 17 of the hollow rod 4 are hermetically sealed with the help of the inner cylindrical sample 12 of the housing 1, hydraulically cutting off the bottomhole zone of the well 25 with the internal space of the hollow rod 4. At this moment, the check valve under the weight of the additional load 9 mounted on the plate 7 6 is hermetically closed (the plate 7 is rotated downward relative to the hinge 8, preventing the loss of slurry and sand deposits 23 at the bottom 24 of the well 25).

A flushing fluid is pumped into the annulus from the mouth (not shown) of the well 25, which flows through the upper perforations 16 into the tubing string 22, since the self-sealing sleeve 12 of the packer 3 is pressed against the inner wall of the well 25, eliminating the flushing fluid entering the space under the device.

Sludge and sand deposits 23 are washed out of the tubing string 22. After washing, the device is removed to the surface, and during the lifting process, due to the open upper perforation hole 16, liquid is not spilled from the tubing string 22 when it is unscrewed at the wellhead 25.

The proposed device is simple to manufacture and use and allows you to adjust the rate of input of sand and slurry deposits into the device, which increases the cleaning efficiency with the subsequent guaranteed washing of these deposits during one run of the device into the well, which reduces material and financial costs.

Claims (2)

1. A device for cleaning and flushing a well, comprising a housing with radial windows and an upstream packer, a hollow rod with perforated holes installed in the housing with limited axial movement downward, the perforated holes being insulated in the initial position, the shank associated with the housing and made with the ability to interact with the bottom of the well, characterized in that the hollow rod is connected to the pipe string, and the packer is made in the form of a self-sealing cuff with the ability to pass liquid from the bottom to the top, while the casing is provided with protrusions along the upper edge, and with a cylindrical protrusion located below the radial windows along the inner surface and fixed with shear elements relative to the hollow rod, the perforated holes of the hollow rod made in the form of two rows of upper and lower perforated holes, the lower perforated holes of the hollow rod in the initial position are blocked by a cylindrical protrusion, and the upper ones are covered with a sleeve fixed on top relative to the hollow rod and equipped along the lower edge with cavities interacting with the protrusions of the housing when opening the lower perforated holes, the hollow stem from the outside between the lower and upper perforated holes above the housing is equipped with a sealing element that insulates the internal cavity of the housing when opening the lower perforated holes, the shank from the bottom is additionally equipped with a check valve with a regulator closing forces and a throttling channel located above. 2. The device for cleaning and flushing a well according to claim 1, characterized in that the check valve is made in the form of a plate hermetically closing the cavity of the liner, made with the possibility of rotation upward relative to the edge, and the opening force regulator is in the form of an additional load fixed on the plate .

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