RU2346145C1 - Device used for removing sand plug from low pressure wells - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention refers to oil and gas industry, and can be used for current and overhaul repairs of wells, which are related to washing of sand plugs, mud settlements, scale, etc. out of wells with intake beds. Device consists of a pipe string, a branch pipe plugged from above and installed concentrically in a hollow frame, a self-sealing packing with a clamping nut, and a location bushing with a central channel. Location bushing is installed concentrically in the hollow frame outside the branch pipe whereto it is connected by means of branches which connect internal space of the hollow frame to the sand plug formation area. Location bushing is made with the possibility of restricted axial movement relative to the hollow frame. Besides, the latter is equipped with a seat at the top, and with short and long axial grooves connected by means of a radial groove from below - at the bottom. At the top, location bushing is rigidly connected to a hollow liner, and at the bottom - to a hollow tip which is tightly installed in the hollow frame and fixed in a transport position by means of a shear element with the possibility of axial and rotary movement in the operating position. Hollow tip is equipped with a pin which has the possibility of interacting with short and long axial and radial grooves of the hollow frame. In central channel of location bushing there installed above the branch pipe is a hollow cylinder with the possibility of restricted axial movement and tight covering of the central channel when interacting with upper part of the branch pipe. Hollow tip is equipped with a valve communicating with the seat of hollow frame, at the location of hollow tip pin in upper part of the long axial groove - transport position. At the top, hollow tip is connected in a movable manner to the bushing rigidly connected to the pipe string, and equipped with radial channels made so that they can be covered with a hollow tip when it moves upwards. Into the top end of the hollow frame seat there screwed is the extension piece of the hollow frame, in the upper part of which there outside located is a self-sealing packing, and a clamping nut is screwed into the top end of the adjusting branch pipe.

EFFECT: enlarging functional capabilities of the device.

2 cl, 3 dwg

Description

The invention relates to the oil industry and can be used in the routine and overhaul of wells associated with flushing wells with absorbing formations from sand plugs, mud sediments, scale, etc. in the presence of several exposed layers and a significant distance from the roof of the upper layer to the bottom of the well.

A device for washing sand plugs (ed. St. SU No. 857428, IPC 7 ЕВВ 21/00, published in BI No. 31 of 08/23/1981), comprising a housing with a concentrically placed tubing connected to a tubing string in it a pipe forming an annular cavity with it.

The disadvantage of this device is that it does not prevent the absorption of washing liquid when cleaning the perforation holes of the filter from sand plugs. Therefore, as the plug is removed from the bottom and the filter is cleaned, the absorption rate of the washing liquid increases and the circulation and the removal of sand pulp to the surface cease. In this case, suspended particles of sand and dirt are deposited in the wellbore, which leads to severe emergency situations: pipe sticking, prolonged shutdown of wells for overhaul. The cessation of flushing due to absorption of the liquid leads to the fact that the well remains not cleaned from the plug and is put into operation with a low flow rate, an increased content of mechanical impurities in the produced products, which leads to premature failure of the pumping equipment or standstill of the well due to the impossibility removing plugs by flushing.

A device for washing sand plugs (ed. St. SU No. 1081334, IPC 7 Е21В 21/00, published in BI No. 11 of 03/23/1984), comprising a housing with a concentrically placed tubing connected to a tubing string in it a pipe forming an annular cavity with it, two elastic cuffs installed in the upper and lower parts of the housing, and the coupling has radial channels for communicating the annular cavity formed by the housing and the pipe with the annulus.

The disadvantages of this device are:

firstly, during the descent of the device into the well, the cuffs are in constant contact with the walls of the well, resulting in friction, which leads to gradual wear of the cuffs during the descent of the device to the sand plug, especially in deep wells, which leads to a decrease in tightness in the process of flushing sand plugs and, as a result, to increasing the flow rate of flushing fluid in absorbing wells;

secondly, in paraffin wells during the descent process due to tight contact, the cuff can break, which reduces the efficiency of the device.

The closest in technical essence is a device for cleaning wells from sand plugs (patent RU No. 33600, IPC 7 ЕВВ 37/00, 21/00, published in BI No. 30 dated 10.27.2003), containing a pipe concentrically installed in a hollow body on which a self-sealing sleeve is installed, while it is provided with a hollow cylindrical nozzle connected to the lower part of the hollow body, provided with an installation sleeve on which the self-sealing sleeve is located, and a clamping nut mounted on the outer surface of the body, in addition, the hollow the housing has the ability to axially move a certain length relative to the installation sleeve, which allows you to create a limited load when pressing the self-sealing cuff to the walls of the well, equipped with a tip having longitudinal grooves on the outer surface and installed in the upper part of the body, equipped with four bends located radially in the hollow body and communicating the inner space of the bottom plugged with a sand plug formation zone.

The disadvantage of this device is that in the process of cleaning a well from a sand plug, the pressure of the flushing fluid above and below the self-sealing cuff is approximately equal, as a result, as soon as the self-sealing cuff is below the reservoir having low reservoir pressure, penetration (washing out the sand plug at the mouth) will stop since the fluid supplied to the annular space will be absorbed by the formation having a low reservoir pressure, while the sand plug will be removed from the well below the reservoir having a low e reservoir pressure, only to the height of the hollow body of the device, and this reduces the functionality of the device.

An object of the invention is to expand the functionality of the device, namely the possibility of washing the sand plug in the well with formations having low reservoir pressure, regardless of the height of the sand plug and the distance from the roof of the upper layer to the bottom of the well.

The technical problem is solved by a device for flushing a well with low reservoir pressure from a sand plug containing a pipe string, a hollow body, a plugged nozzle concentrically mounted in a hollow body, a self-sealing sleeve with a clamping nut, taps, an installation sleeve with a central channel, made with the possibility of limited axial displacement relative to the hollow body.

What is new is that the pipe is plugged at the top, the hollow body is additionally equipped with a saddle and a short and long axial grooves at the top inside the bottom and connected with a radial groove at the bottom, and a hollow body extension is screwed into the upper end of the hollow body seat, the upper part of which has a self-sealing sleeve, and the clamping nut is screwed into the upper end of the extension of the hollow body, and the installation sleeve is concentrically inserted into the hollow body outside the pipe and connected to it by taps that communicate in the morning space of the hollow body with a sand plug formation zone, while the installation sleeve is rigidly connected from above to the hollow end, and from below to the hollow tip, hermetically inserted into the hollow body and fixed in the transport position by a shear element with the possibility of axial and rotational movement in the working position, and equipped with a pin, which is made with the possibility of interaction with the grooves of the hollow body, and in the Central channel of the installation sleeve above the nozzle is a hollow glass with limited axial movement and tight overlap of the Central channel of the installation sleeve when interacting with the upper part of the pipe, while the hollow end is equipped with a valve that interacts with the seat of the hollow body when the pin is located in the upper part of the long radial groove - transport position, and the top of the hollow end is connected movably with a sleeve rigidly connected to the pipe string and equipped with radial channels configured to overlap with the hollow end when e about moving up.

Also new is the fact that the length of the extension of the hollow body should ensure the placement of the self-sealing cuff above the roof of the upper layer at any location of the device in the well.

The figure 1 shows the proposed device in longitudinal section in the working position.

The figure 2 shows a section aa of the proposed device.

The figure 3 shows a scan of grooves made on a hollow body.

A device for flushing a well with low reservoir pressure from a sand plug includes a pipe string 1 (see FIG. 1), a top plugged pipe 2, concentrically mounted in a hollow body 3, a self-sealing collar 4 with a clamping nut 5, an installation sleeve 6 with a central channel 7 .

The installation sleeve 6 (see figure 2) is concentrically inserted into the hollow body 3 on the outside of the pipe 2, to which it is connected by taps 8 connecting the inner space 9 of the hollow body 3 with the sand plug formation zone (not shown in Figs. 1, 2, 3) . The installation sleeve 6 is made with the possibility of limited axial movement relative to the hollow body 3.

The hollow body 3 is additionally equipped with a saddle 10 at the top and a short 11 (see Fig. 3) and a long 12 axial grooves connected at the bottom by a radial groove 13. The mounting sleeve 6 (see Fig. 1) is rigidly connected to the hollow end 14 from the top and from the bottom - with a hollow tip 15, hermetically inserted into the hollow body 3 and fixed in the transport position by a shear element 16 with the possibility of axial and rotational movement in the working position. The hollow tip 15 is equipped with a pin 17, which has the ability to interact with a short 11 (see figure 3), a long 12 axial and radial 13 grooves of the hollow body 3. In the Central channel 7 (see figure 1) of the installation sleeve 6 above the pipe 2 a hollow glass 18 is located with the possibility of limited axial movement and tight shutoff of the Central channel 7 when interacting with the upper part of the pipe 2.

The hollow trailer 14 is equipped with a valve 19, interacting with the seat 10 of the hollow body 3 when the pin 16 of the hollow tip 15 is located in the upper part of the long axial groove 12 — transport position. On top of the hollow end 14 is movably connected to the sleeve 20, rigidly connected to the pipe string 1 and equipped with radial channels 21, configured to overlap the hollow end 15 when moving up.

An extension cord 22 of the hollow body 3 is screwed into the upper end of the seat 10 of the hollow body 3, in the upper part of which a self-sealing sleeve 4 is placed outside, and a clamping nut 5 is screwed into the upper end of the extension 22 of the hollow body 3.

The length of the extension cord 22 of the hollow body 3 should ensure that the self-sealing cuff 5 is placed above the roof of the upper layer (not shown in FIGS. 1, 2, 3) at any location of the device in the well.

The device operates as follows.

Before the device is lowered into the well, it is assembled, while the length of the extender 22 of the hollow body 3 is selected so that it ensures that the self-sealing cuff 4 is placed above the roof of the upper formation (in the case of a multilayer well) at any location of the device in the well or above the roof of the formation (at the presence of one layer in the well).

Then, a hollow end 14 is screwed into the upper end of the valve 19, which is movably connected to the sleeve 20 from the top.

Next, the device is installed in the transport position, that is, the pin 17 (see figure 3) of the hollow tip 15 (see figure 1) is located in the upper part of the long axial groove 12, and the valve 19 is open, that is, between the valve 19 and the seat 10 there is an annular gap due to the shear element 16, which fixes the hollow tip 15 relative to the hollow body 3.

After that, the device assembly (see figure 1) on the pipe string 1 (for example, the tubing string), which is screwed into the upper end of the sleeve 20, is lowered into the well until the lower end interacts (for example, made in the form of a gear crown) hollow body 3 with the sand plug to be cleaned, while monitoring is carried out by the weight indicator installed at the wellhead. During the descent of the device, the borehole fluid from the space above the self-sealing cuff 4 enters the hollow body 3 due to the fact that the valve 19 is open, and this eliminates the outflow of the borehole fluid at the wellhead.

After the interaction of the lower end of the hollow body 3 with the sand plug, the device is unloaded to the sand plug, the shear element 16 is first destroyed, and then the hollow end 14 hermetically seals the radial channels 21 of the sleeve 20 with the upper end, after which the pin 17 moves downward by length (cm figure 3) a long axial groove 12, and the valve 19 is closed, that is, hermetically enters the seat 10, after which a weight drop is observed on the weight indicator. The hollow body 3 bottom end is fixed from turning in a sand cork.

Next, the device is rotated counterclockwise by the length of the radial groove 13. As a result of the operation, the pin 17 moves along the radial groove 13 to the lower part of the short axial groove 11, while all the parts of the device except the hollow body 3 (see figure 1), fixed with their lower end in the sand cork, and saddles rigidly connected from above with the hollow body 3, the extension 10 of the hollow body 22, the self-sealing cuff 4 with the clamping nut 5, which remain stationary, are rotated counterclockwise by a length adial groove 13. Unloading of the device onto the sand plug continues, while the pin 17 can only move along the short axial groove 11 (see Fig. 3), which allows the valve 19 to be fixed (see Fig. 1) in the open position, i.e. an annular gap between the seat 10 and the valve 19. Next, the erosion of the sand plug begins. For this, the flushing fluid is pumped into the annular space of the well (not shown in FIGS. 1, 2, 3).

The flow of flushing fluid through the annular space (not shown in FIGS. 1, 2, 3) of the well drops to a self-sealing collar 4, which is hermetically pressed against the walls of the well, after which it enters the seat 10 and then through the annular gap formed between the seat 10 and the valve 19, into the interior of the hollow body 3, from where it passes through the branch 8 (see FIG. 2) into the nozzle 2. The flushing fluid flows down the nozzle 2 (see FIG. 1) and acts on the sand plug, eroding it. The pressure drop above and below the self-sealing sleeve 4 additionally pressurizes the well walls, hermetically separating the annulus of the well.

Further, the sand plug in the form of a water-sand mixture washed out by the fluid flow rises from the zone of formation of the sand plug and along the annular space 23 formed by the pipe 2 and the hollow tip 15, acts from below on the end face of the hollow glass 18, raising the latter. The hollow glass 18 moves upward, forming an annular gap (not shown in FIGS. 1, 2, 3) between the pipe 2 muffled from above and the hollow glass 18.

As a result, the washed-out water-sand mixture rushes into the central channel 7 of the installation sleeve 6 and then passes through the hollow end 14 into the pipe string 1, which rises upward, since the radial channels 21 of the sleeve 20 are hermetically closed by the upper end of the hollow end 14.

As the sand plug is eroded, the pipe string 1 is lowered downward, and if necessary (depending on the height of the sand plug) they increase, while the pumping of the flushing fluid into the annular space of the well continues. The erosion of the sand plug in the well continues until it is completely eliminated or until the planned interval, after which the supply of flushing fluid to the annulus of the well is stopped, while the hollow cup 18 returns to its original position, since the flow of the washed-out sandy mixture ceases to affect its lower end and it with its own weight, it seals tightly on the pipe 2 plugged from above, preventing the return of the washed-out water-sand mixture into the sand cork zone. To remove the water-sand mixture located inside the pipe string 1 above the sleeve 20, the pipe string 1 is lifted up by about 2-3 meters, while the upper end of the hollow end 14 first goes out of contact with the sleeve 20, as a result of which its radial channels 21 open, and then the pin 17 moves to the upper part of the short axial groove 11 until it abuts against the upper end of the latter. Then, by supplying washing liquid to the annulus of the well (since the self-sealing collar 4 is pressed against the walls of the well), the sandy mixture located in the pipe string 1 is washed through the radial channels 21 of the sleeve 20 into a chute or barn. At the end of the flushing, the device is removed from the well.

The proposed device allows washing the sand plug in the well with formations having a low reservoir pressure, regardless of the height of the sand plug and the distance from the roof of the upper stratum to the current bottom due to cutting off these seams from the top with a self-sealing cuff, followed by washing the sandy mixture from the pipe string, due to what reduces the time for flushing the well and saves money.

Claims (2)

1. A device for flushing a well with low reservoir pressure from a sand plug, comprising a pipe string, a hollow body, a plugged pipe, concentrically mounted in a hollow body, a self-sealing cuff with a clamping nut, taps, an installation sleeve with a central channel, made with the possibility of limited axial movement relatively hollow body, characterized in that the pipe is plugged at the top, the hollow body is additionally equipped with a saddle at the top inside and a short and long axial grooves connected at the bottom from the bottom with a radial groove, and a hollow body extension is screwed into the upper end of the hollow body seat, a self-sealing sleeve is placed on the upper part of the hollow, and a clamping nut is screwed into the upper end of the hollow body extension, the installation sleeve is concentrically inserted into the hollow body and connected to it bends that communicate the internal space of the hollow body with the zone of formation of the sand plug, while the installation sleeve is rigidly connected to the hollow end and from the bottom to the hollow a tip sealed into the hollow body and fixed in the transport position by a shear element with the possibility of axial and rotational movement in the working position, and equipped with a pin that is designed to interact with the grooves of the hollow body, and in the central channel of the installation sleeve above the nozzle there is a hollow glass with the possibility of limited axial movement and tight overlap of the Central channel of the installation sleeve when interacting with the upper part of the pipe, when the hollow end is equipped with a valve that interacts with the seat of the hollow body when the pin of the hollow tip is located in the upper part of the long axial groove - the transport position, and on top the hollow end is movably connected to the sleeve rigidly connected to the pipe string and equipped with radial channels made with the possibility of overlapping hollow limit switch when moving it up. 2. A device for flushing a well with low reservoir pressure from a sand plug according to claim 1, characterized in that the length of the extension of the hollow body allows the self-sealing cuff to be placed above the roof of the upper formation at any location of the device in the well.

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