ES2951962T3 - Apparatus and method of well regeneration - Google Patents

Abstract

A well regeneration apparatus comprising: a treatment device (41), arranged to regenerate a well filter (WS) in a treatment zone of the well filter (WS), at least one upper packer (31) and a lower packer (32) arranged to isolate the treatment zone between the upper packer (31) and the lower packer (32), characterized in that the well regeneration apparatus comprises a sliding sleeve (20), mobile between: - a position of elevation in which the sliding sleeve (20) is connected to both the upper packer (31) and the lower packer (32), - a treatment position, in which the sliding sleeve (20) is disconnected from at least one of the packer upper (31) and lower packer (32).), to allow the treatment device (41) to look directly at the well screen (WS). (Automatic translation with Google Translate, without legal value)

Description

DESCRIPTION

Apparatus and method of well regeneration

The present invention refers to the field of cutting tools, in particular water well maintenance, but is applicable to any type of extraction well, when it is necessary to intervene in a well to ensure a minimum production volume or an increase in production.

US7360596B2 describes an apparatus and method for regenerating the permeability of a well by using pressure pulses. However, this method generates particles that contaminate the surrounding liquid, so pumping/cleaning/filtration operations are necessary in any case and especially when used in a water well, and all these steps lead to increased costs and the time of said maintenance. Additionally, the pulse generator is not protected from rocks or debris that could fall on the pulse generator during use.

US9057232B2 describes an apparatus and method for regenerating the permeability of a well through the use of pressure pulses, with the use of packers to isolate specific portions of the well screen to regenerate. However, this document does not propose any efficient solution to deal with contamination or to protect the pulse generator from damage/blockage in the well. US7681654B1 describes an apparatus and method for isolating a portion of a well and providing pressurized fluid therein including an upper packer, a lower packer, and a sliding sleeve therebetween. A seat is defined at the lower open end of the lower sleeve and a sealing member is configured to seal the seat. A biasing force drives the sliding sleeve toward a closed position. The apparatus is moved along the hole and the bottom plug is placed at the desired location, and then an opening force is exerted on the pipe to move the sliding sleeve to the open position. After setting the lower packer and opening the sliding sleeve, the upper packer is configured to isolate a portion of the wellbore between the packers with the sliding sleeve in the open position to provide a flow path from the tubing string to the formation between the packers. shutters.

EP0778393 presents a procedure that maintains the production of new wells, or cleans and regenerates existing ones. The filter is subjected to ultrasound radiated from a transducer. The water, now full of loosened particles, is extracted. The filter and the gravel section connected to it are treated to achieve a degree of cleanliness, which is measured from the water extracted. The filter assembly is cleaned section by section with the stationary transducer, in the absence of mechanical or hydromechanical effects. A device to carry out the process is also claimed. This includes two height-adjustable packing units containing transducer and extraction pump (7) that move in the well. The pump is in the upper package (5), connected by a line (8) to the instrument (9) that performs the measurements.

US2003/079876A describes a system having a downhole membrane separator, including a membrane, that separates hydrocarbons, such as methane and oil, from other contaminants, such as CO ₂ and water. After the membrane becomes fouled with contaminants after removing a sufficient amount of raw material, the membrane is backwashed, or chemically treated, instead to assist in the removal of contaminants from the membrane. An explosive can be used to create a pressure wave that washes away the membrane. If not, the pressure differential across the membrane can be reversed to create the backwash action. Chemicals can be used to help remove scale. If not, a spray or bubbling system can be used to create turbulence to aid in the removal of a foulant. Methods to remove membrane fouling are also taught, including backwashing and chemical treatment of membranes to remove unwanted contaminants from the membrane.

The present invention aims to address the aforementioned drawbacks of the prior art and to first propose a well regeneration apparatus and method that provides efficient regeneration of a well and also provides protection to the pulse generator from being damaged. damage/block in the well. Well.

In this objective, a first aspect of the invention refers to a well regeneration apparatus comprising:

a treatment device, arranged to regenerate a well screen in a treatment zone of the well screen,

at least one upper obturator and one lower obturator arranged to isolate the treatment zone between the upper obturator and the lower obturator,

characterized in that the well regeneration apparatus comprises a sliding sleeve, movable between:

- a lifting position in which the sliding sleeve is connected to both the upper plug and the lower plug,

- a treatment position, in which the sliding sleeve is disconnected from at least one of the upper and lower shutters, to allow the treatment device to directly face the well filter.

The well regeneration apparatus according to the above embodiment comprises two expandable packers to isolate or confine a specific treatment zone of the well. Typically, packers are introduced and lifted into the treatment zone in a retracted state, and expand when positioned to the desired depth, to form a transverse septum to close the cross section of the well. Additionally, the well regeneration apparatus comprises a sliding sleeve (typically a tubular part or a hollow part) that is attached to the two packers during lifting of the packers through the wellbore up or down. In the present disclosure, the lower packer is the one intended to be located in the deepest position (closest to the bottom of the well) and the upper packer is the one intended to be located in the highest position (closest to the surface from the well). At this stage, the sliding sleeve is in the lifting position and provides a mechanical link between the two plugs. Once the plugs are deployed to isolate the treatment area, the sliding sleeve is at least partially removed from the treatment area. In other words, the sliding sleeve is separated from at least one of the obturators and moved at least partially away from the treatment area (typically by means of a sliding or translational movement). Consequently, the treatment device can directly access or be in front of the well filter to perform efficient treatment/regeneration of the well filter, being protected in the treatment zone by the two plugs from foreign debris or material coming from the rest of the well. . Specifically, in the treatment position, the sliding sleeve is disconnected from the lower packer, so that the treatment device can face directly into the well filter.

Typically, when the sliding sleeve is in the treatment position, the two obturators are still secured or linked by cables.

In other words:

- in the lifting position, the sliding sleeve completely crosses the treatment zone so that an efficient and robust link is provided between the two obturators, but meanwhile the sliding sleeve constitutes to a certain extent a "screen" or "shield" between the treatment device and at least a part of the well filter to be treated,

- in the treatment position, the packers are attached or fitted to the well filter, so that the sliding sleeve in lifting position providing mechanical linkage is no longer necessary and the sliding sleeve can be at least partially removed to place it in the position of treatment, thus eliminating the aforementioned "screen" or "protection" between the treatment device and at least a part of the well filter to be treated: the treatment device can look directly at the entire well filter to be treated, so that the treatment is totally effective. In the treatment position, there is no central pipe or central element connecting the upper and lower obturators. Only cables or wires are present to join and secure the two shutters together.

According to one embodiment, the well regeneration apparatus comprises at least one connector arranged to be reversibly placed in:

- a connection state in which the connector provides a connection between the sliding sleeve and at least the upper plug,

- a disconnection state in which the connector releases the connection between the sliding sleeve and the upper plug.

Such a connector provides the ability to repeatedly connect/disconnect the sliding sleeve and at least the upper packer as many times as necessary to treat multiple treatment zones in the well.

According to one embodiment,

In the connected state, the connector locks at least five degrees of freedom and preferably six degrees of freedom between the sliding sleeve and at least the upper plug,

- in the disconnected state, the connector releases at least one degree of freedom between the sliding sleeve and at least the upper plug, so that the upper plug can provide a sliding joint to the sliding sleeve, and preferably a sliding pivot joint.

In other words, in the connected state, there is no free relative rotation between the sliding sleeve and at least the upper plug so that a movement of the sliding sleeve is completely transmitted to the upper plug, and in the disconnected state, the relative movement, such as translation/rotation, between the sliding sleeve and the upper plug.

According to one embodiment, the lower plug is connected through a secondary connector with the sliding sleeve when the sliding sleeve is in the lifting position, and the lower plug is completely disengaged/separated from the sliding sleeve when the sliding sleeve is in the lifting position. the treatment position.

According to one embodiment, said connector comprises:

- at least one cam track provided on one of the upper gaskets or the sliding sleeve,

- at least one projection arranged on the other of the upper plug or the sliding sleeve and arranged to move along the cam track,

and wherein the cam track comprises:

- a locking part to receive the projection, to fix the sliding sleeve to the upper plug,

- an open end portion to release the boss, to separate the sliding sleeve from the upper plug.

Such a cam track provides a safe engagement, as it normally requires the protuberance to have axial movement to exit the locking portion, rotational movement to reach the open end portion, and axial motion to exit the open end portion. . As an example, to put the connector in the disconnected state, 50 mm lowering slide sleeve, plus 70 degrees to the right of rotation, plus 120 mm of vertical lift must be applied to allow full rotation movement and a vertical within the treatment window.

According to one embodiment, the well reclamation apparatus comprises a tubing string arranged to connect the upper packer to hoisting equipment located at the surface, wherein the sliding sleeve is attached to the tubing string or is part of the pipe string to form a distal part of the pipe string. In other words, the sliding sleeve is the terminal part or the deepest part of the pipe string, which facilitates imparting the movement of the sliding sleeve between the lifting position and the treatment position and vice versa: a piece of equipment located in the The wellbore surface can easily be used to move the sliding sleeve by an action on the tubing string. In the present disclosure, surface means the ground level, from where operators normally organize and control maintenance, which is often an outdoor location.

According to one embodiment, the well regeneration apparatus comprises at least one air supply connector:

- connected to the sliding sleeve and/or to the pipe string,

- located above the upper plug to generate an air lift in the sliding sleeve and in the pipe string, at least when the sliding sleeve is in the treatment position. Using the tubing string terminated by the sliding sleeve to drain liquid into the treatment zone with compressed air avoids any additional piping between the surface and the treatment zone. The tubing string communicating with the sliding sleeve advantageously provides a direct channel for pumping the liquid into the treatment zone, so that the limited amount of contaminated liquid can be easily and safely pumped to the surface. This prevents completely emptying the well filter. Preferably, the air supply connector is located in the pipe string, a few meters above the sliding sleeve.

According to one embodiment, the well regeneration apparatus comprises at least one permanent link such as a metal cable, attached to both the upper packer and the lower packer. Such a metal cable or wire provides a safety link that allows the two plugs to be removed, even if the sliding sleeve in the treatment position or the pipe string is only attached or linked to the upper plug.

According to one embodiment, the well regeneration apparatus comprises an inspection device, arranged to inspect the well filter in the treatment zone.

According to one embodiment, the well regeneration apparatus comprises a main lifting unit, arranged to move downwards and/or upwards and/or in rotation the sliding sleeve.

According to one embodiment, the well regeneration apparatus comprises a secondary lifting unit, arranged to move down or up the treatment device on the sliding sleeve. The channel provided by the sliding sleeve and tube string allows the treatment device to be raised or lowered safely through the inner side of the tube string/sliding sleeve: there is no risk of impact/blocking even if foreign material is present ( stones, damaged parts of the casing or well screen...) fall from above the treatment zone, as the treatment device is fed through the internal channel of the sliding sleeve and the tubing string.

According to one embodiment, the secondary lifting unit is arranged to move down or up the inspection device on the sliding sleeve. It is not necessary to remove the entire well regeneration apparatus: since the sliding sleeve is in the treatment position, the inspection device can easily inspect the well filter before/after treatment and through the internal space of the tubing string and as clear water has (immediately) replaced the contaminated liquid.

According to one embodiment, the treatment device is arranged to generate any physical or chemical treatment to develop/treat the well.

According to a particular embodiment, the treatment device is arranged to generate impulse waves or shock waves or pressure waves in the treatment area.

According to a particular embodiment, the treatment device is arranged to inject a treatment fluid into the treatment zone.

According to one embodiment, the upper plug and/or the lower plug are expandable or inflatable to be reversibly nested:

- a retracted state in which the upper plug and/or the lower plug can be freely inserted into the well, - an expanded state in which the upper plug and/or the lower plug are in contact with a wall of the well, such as the well filter.

According to one embodiment, the upper plug and/or the lower plug in the retracted state have an external dimension or diameter within ±30% and preferably ±20% of the external dimension or diameter of the pipe string.

According to one embodiment, the upper plug and/or the lower plug comprise a movable sleeve or adapter arranged to compensate for longitudinal shortening of the rubber wrap during lateral expansion.

According to one embodiment, the well regeneration apparatus comprises a pressure control unit, arranged to control and adjust an inflation pressure of an inflation fluid fed to the upper packer and/or the lower packer, to establish a difference of maximum pressure allowed between the treatment zone and the rest of the well, when the upper packer and/or the lower packer are in the expanded state. The packers are inflated to a certain pressure to ensure isolation of the treatment zone, but when air lift occurs in the tubing string, it may be necessary to allow liquid to enter the treatment zone to prevent collapse of the pipe. well screen or casing. In this objective, the pressure in the packers is set so that above a certain pressure difference between the treatment zone and the rest of the well, the packers will leak and allow liquid to enter the treatment zone.

According to a further or alternative embodiment, the well regeneration apparatus comprises a pressure control unit, arranged to control and adjust a contact pressure between the well wall and the upper packer and/or the lower packer, to establish a difference maximum pressure allowed between the treatment zone and the rest of the well, when the upper packer and/or the lower packer are in the expanded state.

According to one embodiment, the pressure control unit is arranged to be located on the surface, and a feed hose is provided between the pressure control unit and at least the upper plug.

According to one embodiment, the sliding sleeve is made of unitary pieces of tubing, to provide the ability to adjust the height or length of the treatment zone. In other words, the unitary pieces of pipe are provided with a certain length (such as 1 m) and can be connected/disconnected before being lifted into the well to define a suitable treatment zone, in connection with a preliminary inspection, for example . In practice, the length of the window treatment is adjusted taking into account the characteristics of the well and the obstruction situation. It can be defined from 1 m to whatever distance is considered to proceed with the process.

Another aspect of the invention relates to a method for regenerating a well, which comprises the steps of:

- insert at least one upper plug and one lower plug into the well,

- isolating a treatment zone of a well filter between the upper packer and the lower packer,

- introducing into the well a treatment device arranged to regenerate a well screen in a treatment zone,

- move a sliding sleeve between:

- a lifting position in which the sliding sleeve is connected to both the upper plug and the lower plug,

- a treatment position, in which the sliding sleeve is disconnected from at least one of the upper and lower shutters, to allow the treatment device to directly face the well filter,

wherein the step of introducing and locating the treatment device in the treatment area and the step of moving the sliding sleeve can be performed in any order. The packers are introduced into the well until they reach the treatment zone with the sliding sleeve in the lifting position, providing a robust and reliable mechanical link between the two packers. Once the obturators are isolating the treatment zone, typically after expansion, the sliding sleeve can be partially removed from the treatment zone to enter the treatment zone, so that the treatment device can be used efficiently. in the treatment area, free of the sliding sleeve. Specifically, in the treatment position, the sliding sleeve is disconnected from the lower packer, so that the treatment device can face directly into the well filter.

According to one embodiment, the treatment device is introduced and located in the treatment zone through a step of passing the treatment device through the sliding sleeve. This step of supplying the treatment device through the sliding sleeve provides full protection against collision or blockage due to falling rocks, debris around the sliding sleeve/pipe string.

According to one embodiment, the method for regenerating a well comprises, before the step of moving the sliding sleeve, a step of expanding the upper packer and/or lower packer until contact of at least a part of said upper packer and/or bottom packer with a well wall, such as the well screen.

According to one embodiment, the method for regenerating a well comprises a step of regenerating the well filter, generating with the treatment device impulse waves or shock waves or pressure waves in the treatment zone, and/or any process physical or chemical

According to one embodiment, the method of regenerating a well comprises a step of inspecting the well filter in the treatment zone, by a step of passing an inspection device through the sliding sleeve.

According to one embodiment, the method for regenerating a well comprises a step of pumping liquid into the treatment zone, with a step of generating a pumping flow with an air lift created in a tubing string connected to the sliding sleeve. , so that the pumping flow passes through the sliding sleeve.

According to one embodiment, the method for regenerating a well comprises a step for injecting or pumping additives and/or chemicals pumped from the surface through the air supply connector (and air extraction pipe) and the sliding sleeve to increase the regeneration capacity of the process. Therefore, the flow through the air supply connector (and air extraction pipe) can be from the well to the surface or to the treatment zone (aquifer formation) through the extraction pipe. air and screen area. The flow can work in two ways for maximum efficiency.

According to one embodiment, the method of regenerating a well comprises a step of allowing a leakage flow to pass into the treatment zone from the rest of the well, through a step of adjusting the contact pressure between the wall of the well and the upper packer and/or the lower packer to establish a maximum allowable pressure difference between the treatment zone and the rest of the well.

According to one embodiment, the method for regenerating a well comprises a step of injecting chemical and/or additive into the treatment zone through the sliding sleeve. The additional chemical or additive can improve the treatment process and is easily provided from the surface through the tubing string and sliding sleeve.

Other features and advantages of the present invention will appear more clearly from the following detailed description of particular non-limiting examples of the invention. illustrated by the attached drawings where:

- Figure 1 represents a simplified diagram of a well partially filled with liquid, and comprising a well screen that requires maintenance to be regenerated;

- Figure 2 represents the well of Figure 1, to show the installation of a well regeneration apparatus comprising two packers in a deflated state and rising into the well;

- Figure 3 represents the well of Figure 2, with the well regeneration apparatus with the packers located in a treatment zone, and being in an inflated state, a sliding sleeve coupled to the two packers, in a lifting position ;

- Figure 4 represents the well of Figure 3, with the well regeneration apparatus having the sliding sleeve in a treatment position, raised compared to Figure 3;

- Figure 5 represents the well of Figure 4, with a treatment device of the well regeneration apparatus placed in the treatment zone between the two plugs;

- Figure 6 represents the well of Figure 5, during a stage of treatment and/or pumping of liquid from the treatment area;

- Figure 7 represents a connector arranged to provide a removable or reversible connection between the sliding sleeve and at least one plug, in particular an upper plug.

Figure 1 represents a well drilled in soil 10. Soil 10 is composed of layers 11 and 12, layer 11 in this example is saturated with liquid L. Liquid L is typically water but the description is not limited to water . The well comprises a well screen WS which is porous to allow liquid L to pass from the saturated zones 11 into the well. for collection and pumping via a pump tube PT and a pump P. Of course, Figure 1 is very simplified, and the well could comprise a cemented area or a gravel pack...

During production, sand, fine particles, mud or corrosion can create areas of CA clogging of the WS well filter and reduce its porosity (ability to pass liquid through the WS well filter), so volumes production are affected.

For this reason, it may be necessary to regenerate the well filter (to remove and clean foreign material accumulated in the well filter WS), and the present disclosure proposes an advantageous method and apparatus for regenerating the well filter WS from the well.

Typical methods to remove foreign material that clogs or blocks the WS well filter are mechanical treatments (with generation of pressure waves or shock waves or pulse waves or any other physical process) or chemical treatments (with injection in the vicinity of the well filter). clogged area of a chemical substance (such as an acid) prepared to remove, transform, or dissolve the foreign material.

Figure 2 represents the well in Figure 1 where the usual production equipment (pump P and pumping tube PT) has been removed to facilitate regeneration maintenance.

For this purpose, a well regeneration apparatus is introduced into the well with a CA crane comprising a main lifting group 61 and is coupled to a truck, and comprises in particular:

- a pipe string 50 made of unitary pipe string tubes 51,

- an upper shutter 31,

- a sliding sleeve 20 made of unitary sliding sleeve tubes 22,

- a lower shutter 32.

The equipment is raised down the wellbore by progressively assembling the tubes of the unitary pipe string 51 from the top of the pipe string 50 located at the surface, to position the upper packer 31, Slide the sleeve 20 and the lower packer 32 at the level of the deepest obstruction zone CA, as shown in Figure 2,

The unitary pipe chain tubes 51 can be screwed together, through threaded ends, to form the pipe chain 50, and the unitary sliding sleeve tubes 22 can also be screwed together, through threaded ends, to form the sliding sleeve 20, also screwed to the pipe string 50. Other mounting techniques are possible, such as quick-lock joints, spring joints...

A preliminary inspection (with a camera) can be carried out to determine the height of this deeper obstructed area CA, to adjust, before the introduction of the well regeneration apparatus into the well, the number of unit sliding sleeves 22, to ensure that the upper plug 31 is located slightly above the deepest obstructed area CA and the lower plug 32 is located slightly below the deepest obstructed area CA.

The upper plug 31 and the lower plug 32 can be expanded to be placed in a deflated state as shown in Figure 2, and can be placed in an inflated state as shown in Figures 3, 4, 5 and 6. Pneumatic plugs or Hydraulic valves, comprising rubber containers can be used normally, but you can consider using any other solution to expand/retract the upper plug 31 and the lower plug 32.

As the tubing string 50 is raised down the wellbore, a choke hose 33 and an air lift hose 52 are deployed into the wellbore, out of the tubing string 50 and the tubes of the unit tubing string 51.

The upper plug 31 and the lower plug 32 are joined by metal cables 37 to secure the plugs to each other, as shown in Figure 7, and a secondary hose 34 joins the upper plug 31 and the lower plug 32 to distribute the pressure/ inflation fluid to the lower plug 32. The secondary hose 34 could be connected directly to the plug hose 33, or through a pressure regulator to set a specific pressure in the lower plug 32.

As an example, if the well casing ranges from approx. 205 mm to 305 mm (approx. 8" to 12"), the inner diameter of the tubing string and/or sliding sleeve can be approx. 80mm (approx. 3").

As an example, if the well casing ranges from approx. 305 mm to 405 mm (approx. 12" to 16"), the inner diameter of the tubing string and/or sliding sleeve can be approx. 100mm (approx. 4").

As an example, if the well casing ranges from approx. 405 mm to 505 mm (approx. 16" to 20"), the inner diameter of the tubing string and/or sliding sleeve can be approx. 120mm (approx. 5").

The upper plug 31 and the lower plug 32 can also be attached/disconnected from the sliding sleeve 20, and Figure 7 shows an example of a reversible connection between the parts.

The upper plug 31 is joined to the sliding sleeve through a connector 35 comprising:

- a cam track 35a provided on one of the upper shutter 31 or the sliding sleeve 20,

-a projection 35b provided on the other of the upper plug 31 or the sliding sleeve 20 and arranged to move along the cam track 35a,

and wherein the cam track 35a comprises:

- a locking portion where the boss 35b is shown in Figure 7, for attaching the sliding sleeve 20 to the upper packer 31 (for vertical displacement/lift in the well when the packers are retracted or deflated)

- an open end portion (located on the left side of Figure 7) for releasing the protrusion 35b, to separate the sliding sleeve 20 from the upper plug 31, typically in the inflated state.

In a preferred embodiment, only the upper plug 31 is attached to the sliding sleeve 20 by a connector 35, no connector is provided at the lower level of the plug 32.

However, the lower plug 32 could be joined to the sliding sleeve 20 through another connector 36 comprising:

- a secondary cam track 36a provided on one of the lower plugs 32 or the sliding sleeve 20, - a secondary projection 36b provided on the other of the lower plug 32 or the sliding sleeve 20 and arranged to travel on the secondary cam track 36a ,

and wherein the secondary cam track 36a comprises an open end portion (located on the left side of Figure 7) for releasing the secondary protrusion 36b, to separate the sliding sleeve 20 from the lower plug 32.

It should be noted that in this configuration in Figure 7, as the plugs are attached to the sliding sleeve 20, the length of the metal cables 37 and the secondary hose 34 is greater than the distance between the plugs. When the tubing string 50 is fully deployed and raised in the wellbore as shown in Figure 2, the packers can expand. As shown in Figure 3, at this stage, pressure is supplied to the upper packer 31 and the packer. lower 32 through choke hose 33 to upper choke 31 and secondary hose 34 to lower choke 32.

As a consequence of the pressure supply, the upper plug 31 and the lower plug 32 expand (their outer diameter increases), until their outer surface makes contact with the well filter WS, As shown in Figure 3, at the end of the expulsion stage; the deeper plugged area CA is confined or isolated from the rest of the well. That is to say, the liquid L located between the upper plug 31 and the lower plug 32 cannot (or very little) flow above the upper plug 31 or below the lower plug 32.

As will be explained later in relation to Figure 6, the upper plug 31 and lower plug 32 are inflated with a given pressure, which is determined in relation to the depth of the plugged area CA to be treated (the height of the liquid column is a parameter to be considered to determine the inflation pressure of the plugs, as will be explained in relation to figure 6).

In summary, in the situation of Figure 3, the well regeneration apparatus (the upper plug 31, lower plug 32, the sliding sleeve 20) is placed in the well with respect to the obstructed area CA to be treated, and the upper plug 31, the lower plug 32 isolates the liquid in this treatment zone and are mechanically joined by the sliding sleeve 20.

Next, as the upper plug 31 and the lower plug 32 are in an expanded or inflated state, in firm contact with the well filter WS, it is possible and proposed to at least partially remove the sliding sleeve 20 from the treatment zone.

This requires disconnecting the sliding sleeve 20 from the plugs, and as shown by the arrows drawn at the level of the truck in figure 3:

- in a step A, the pipe string 50 and the sliding sleeve 20 are raised downward or translated vertically a small distance downward (so that the protuberance 35b (embarked on the sliding sleeve 20) of Figure 7 is displaced towards the bottom and horizontal part of the cam track 35a),

- in a step B, the pipe string 50 and the sliding sleeve 20 rotate in front of the plugs (so that the boss 35b and the secondary boss 36b of Figure 7 travel to align respectively with the open end portion of the track of cam 35a and the open end portion of the secondary cam track 36a) so as to unlock the sliding sleeve 20 of the plugs.

Figure 4 shows a step C of removal or upward movement of the sliding sleeve 20, with an upward arrow drawn at the level of the truck. Indeed, after rotation step B, the protrusion 35b and the secondary protrusion 36b are aligned with the open end portion of the cam tracks 35a, 36a, so that vertical translation or lifting is possible to remove, as shown , the sliding sleeve 20 of the treatment zone defined between the obturators. In other words, the sliding sleeve has moved from a lifting position (in which the sliding sleeve 20 is located between the upper plug 31 and the lower plug 32, see Figures 2 and 3) to a treatment position (in wherein the sliding sleeve 20 is partially or totally removed from the area between the upper plug 31 and the lower plug 32, see Figures 5 and 6;

Therefore, when the sliding sleeve 20 has moved away from the lifting position to the treatment position, it can be said that a window has been opened in the treatment area.

As also shown in Figure 4, a treatment device 41 can be inserted into the pipe string 50 and can be lifted downward through a treatment line 42 and a secondary lifting unit 62 attached to the CA crane. . This operation can be performed before, in parallel or after the disconnection/movement of the sliding sleeve 20.

In summary, in the configuration of Figure 4, the well regeneration apparatus, after steps A, B and C of Figures 3 and 4, has been established in a configuration where the treatment zone is free of any tube central, since the sliding sleeve 20 is no longer located between the upper plug 31 and the lower plug 32. There is no longer a central link or tube joining the two plugs, which remain in position due to the pressure applied to the outer membrane in contact with the WS well filter.

Figure 5 shows the well regeneration apparatus operated to treat the WS well filter. Indeed, the secondary lifting unit 62 has raised the treatment device 41 to the treatment zone, that is, between the upper plug 31 and the lower plug 32, through the treatment line 42, and the treatment device 41 can be controlled to treat the obstructed AC area. The treatment will be effective since the treatment device 41 faces directly the well filter WS (there is no wall/sliding sleeve 20 between the treatment device 41 and the well filter WS)

It should be taken into account that the treatment device 41 moves within the tube string 50 and the sliding sleeve 20, so that it is completely protected throughout its journey in the well. Even if debris, rocks or foreign material falls from the well wall, such obstacles will remain outside the internal channel (pipe string 50) and the treatment device 41 can be safely and reliably placed in the treatment zone.

In detail in this example, the treatment device 41 is a pulse generator fed energy through the treatment line 42 to generate pressure or shock or pulse waves in the liquid L, so that particles, corrosion, fine, the mud will come off the WS well filter. However, other treatment methods can be used, such as chemical treatments for example. It should be noted in Figure 5 that the deeper clogged area has disappeared and that the liquid L in the treatment zone is now mixed with particles/foreign material.

After or during this treatment step, another advantage provided by the well regeneration apparatus is that only the liquid located in the treatment zone is contaminated by the material removed from the well screen. Likewise, it is proposed to pump only this contaminated liquid to minimize operation time and liquid waste.

In this objective, since the treatment zone is in direct communication with the internal channel of the pipe string 50 and the sliding sleeve 20, an air lift can be advantageously generated in the pipe string 50 and the sliding sleeve 20 with air supply provided by the air lift hose 52. As shown in Figure 6, an upward movement/pumping of the liquid L located in the treatment zone is generated in the pipe string 50 and the sliding sleeve 20.

Liquid L is easily supplied from the saturated layer 11, since the well filter WS is now regenerated. However, if the flow from the saturated layer 11 is not sufficient to compensate for the air lift flow, liquid L can be supplied from the rest of the well. In this objective, it is proposed to precisely adjust the pressure in the upper obturator 31 and/or in the lower obturator 32 to allow leaks in the treatment area. In fact, if the flow of the saturated layer 11 is not sufficient to compensate for the air lift flow, the pressure in the liquid located in the treatment zone will be less than the hydrostatic pressure in the liquid located just above the upper shutter 31 and/or that the hydrostatic pressure in the liquid located just below the lower plug 32.

It is proposed to inflate the upper plug 31 and/or the lower plug 32 with a pressure that does not exceed a maximum calculated pressure slightly greater than the hydrostatic pressure of the liquid located just above the upper plug 31 and/or of the liquid located just below the plug. lower 32. In any case, the maximum pressure that the plug can be inflated depends on the manufacturer of the rubber element or the type of plug used.

The maximum depression or maximum differential pressure between the treatment zone located between the packers in relation to the rest of the well may be a function of the following characteristics of the well:

Housing type (pvc, steel, stainless steel, etc);

Type of filter area (slats, wiring, bridges, drilling, slit, etc.);

Screen situation. corrosion, age, deformation, damaged, etc.;

Degree of screen obstruction;

Well flow;

And the differential pressure could be a function of the characteristics of the plug (rubber thickness, type...). As a non-limiting example, it is proposed to have:

PGarriba _ Ph1 k-|,

with

- PGaup is the inflation pressure supplied to the upper plug 31,

- PGh1 is the hydrostatic pressure of the liquid located just above the upper plug 31 (can be measured or calculated based on the height of the liquid column and the density or weight of the liquid),

- k1 is the maximum allowable pressure difference, with, for example,

2 bars ≤ k ≤ 8 bars with, for example, a preferred value of 5 bars for a 205 mm well casing, in PVC, when all pressures are in bars;

5 bars ≤ k1 ≤ 15 bars with, for example, a preferred value of 10 bars for a 305 mm well casing, in steel, when all pressures are in bars.

As a non-limiting example, it can also be proposed to have:

P ^lp - P ^h2 k ² ,

with

- PGlp is the inflation pressure supplied to the lower plug 32,

- PGh2 is the hydrostatic pressure of the liquid located just below the lower plug 32 (can be measured or calculated based on the height of the liquid column and the density or weight of the liquid),

- k2 is the maximum allowable pressure difference, with, for example,

2 bars ≤ k2 ≤ 8 bars with, for example, a preferred value of 5 bars for a 205 mm well casing, in PVC, when all pressures are in bars;

5 bars ≤ k2 ≤ 15 bars with, for example, a preferred value of 10 bars for a 305 mm well casing, in steel, when all pressures are in bars.

Alternatively, it could be proposed to set the same inflation pressure in both plugs (and the actual pressure inside the plugs will be slightly different, the difference being caused by the difference in altitude and the height of the liquid column).

This embodiment allows liquid L from the rest of the well to enter the treatment zone in case the saturated layer 11 cannot supply enough liquid to compensate for the air pumping. Additionally, this protects the well screen or well casing from being damaged/collapsed by too high a pressure difference between the outside of the casing and the treatment zone.

The inflation pressure in the plugs can be adjusted from the surface during maintenance, with, for example, a user-operated pressure control unit. The inflation pressure in the plug is regulated continuously from the surface and can be modified according to the results obtained.

As shown in Figure 6, the contaminated liquid PL from the treatment zone is pumped to the surface through the pipe string 50 to be collected in a reservoir 71, and a pumping device 72 can be used to assist in this operation. This operation could be simultaneous with the treatment operated by the treatment device.

The treatment device 41 is still in the treatment zone at this stage, but could be lifted independently if necessary. It is also possible to take advantage of the secondary lifting unit 62 to lift an inspection device (such as a camera) to verify whether the well filter WS in the treatment zone is in the expected state/shape. when the liquid L has been renewed and is clear enough for visual/camera inspection.

Once the deeper plugged area is treated, the wellbore WS filter is regenerated and the wellbore regeneration apparatus can be removed to treat another plugged area. in summary,

- the air lift stops, the tank 71 is disconnected from the pipe string 50,

- the treatment device 41 and/or the inspection device are removed from the pipe string 50,

- the sliding sleeve 20 moves from the treatment position of Figures 4, 5, 6 to the lifting position of Figure 2, 3 (through the pipe string 50 and steps C, B, a,

- the shutters are deflated to return them to the deflated/retracted state,

- the tubing string and the well regeneration apparatus are lifted to the second plugged area CA, through the main lifting unit 61 (and removing the unit tubing string tubes 51).

One must keep the following in mind:

- in case the coupling between the lower plug 32 and the sliding sleeve 20 is difficult/impossible, the metal wires 37 still allow the system to be lifted,

- in case the coupling between the upper plug 31 and the sliding sleeve 20 is difficult/impossible, or if the sliding sleeve is in the treatment position, a stop can be implemented (a stop collar or a shoulder on the sleeve sliding, for example) at the bottom of the sliding sleeve to abut the upper plug 31 and still lift the system,

- the number of unitary sliding sleeves 22 can be adjusted between two treatments,

- a production test can be implemented through air lift (or regular pumping equipment) to verify the production volume capacity of a given part of the well filter, after treatment and before replacing the sliding sleeve 20 in the lifting position.

In summary, the well regeneration device provides the following advantages:

- the height of the treatment zone can be easily adjusted before lowering the entire system into the well, with the unitary sliding sleeves 22,

- the treatment device 41 faces directly the well filter WS to treat when the sliding sleeve 20 has moved to the treatment position (outside the treatment zone),

- the treatment device 41 moves safely and independently from the surface to the treatment zone through the internal channel of the tube string 50/sliding sleeve 20, and vice versa,

- the liquid L of the treatment zone contaminated during/after the treatment does not spread to the rest of the well but is safely contained in the treatment zone thanks to the upper plug 31 and the lower plug 32 inflated and in contact with the well filter,

- the liquid L from the contaminated treatment zone during/after treatment is safely and easily pumped to the surface through the air impulse generated in the pipe string 50/sliding sleeve 20, - the well filter is protected against pressure damage even if the saturated layer 11 cannot supply liquid to compensate for air lift, thanks to the pressure management of the shutters,

- the secondary lifting unit can easily lift the treatment device and/or an inspection device to completely treat the treatment area.

Claims (19)

1. A well regeneration apparatus comprising: a treatment device (41), arranged to regenerate a well screen (WS) in a treatment zone of the well screen (WS), at least one upper obturator (31) and one lower obturator (32) arranged to isolate the treatment area between the upper obturator (31) and the lower obturator (32), characterized in that the well regeneration apparatus comprises a sliding sleeve (20), movable between: - a lifting position in which the sliding sleeve (20) is connected to both the upper plug (31) and the lower plug (32), - a treatment position, in which the sliding sleeve (20) is disconnected from at least one of the upper obturator (31) and the lower obturator (32), to allow the treatment device (41) to be oriented directly towards well filter (WS). 2. The well regeneration apparatus according to the preceding claim, comprising at least one connector (35) arranged to reversibly engage: - a connection state in which the connector (35) provides a connection between the sliding sleeve (20) and at least the upper plug (31), - a disconnection state in which the connector (35) releases the connection between the sliding sleeve (20) and the upper plug (31). 3. The well regeneration apparatus according to the preceding claim, wherein said cover (35) comprises: - at least one cam track (35a) provided on one of the upper shutter (31) or the sliding sleeve (20), - at least one projection (35b) provided on the other of the upper shutter (31) or the sliding sleeve ( 20) and arranged to move along the cam track (35a), and wherein the cam track (35a) comprises: - a locking part to receive the projection (35b), to fix the sliding sleeve (20) to the upper plug (31), - an open end part to release the projection (35b), to separate the sliding sleeve (20) from the upper plug (31). 4. The well regeneration apparatus according to any one of the preceding claims, comprising a string of tubing (50) arranged to connect the upper packer (31) to lifting or lifting equipment located on the surface, at wherein the sliding sleeve (20) is attached to the pipe string (50) or is part of the pipe string (50) to form a distal part of the pipe string (50). 5. The well regeneration apparatus according to the preceding claim, comprising at least one air supply connector: - connected to the sliding sleeve (20) and/or to the pipe string (50), - located above the upper plug (31) to generate an air lift in the sliding sleeve (20) and/or in the pipe string (50), at least when the sliding sleeve (20) is in the treatment position. 6. The well regeneration apparatus according to any one of the preceding claims, comprising at least one permanent link, such as a metal cable (37), attached to both the upper plug (31) and the lower plug (32). . 7. The well regeneration apparatus according to any one of the preceding claims, comprising a main lifting unit (61), arranged to move downwards and/or upwards and/or in rotation the sliding sleeve (20). . 8. The well regeneration apparatus according to any one of the preceding claims, comprising a secondary lifting unit (62), arranged to move down or up the treatment device (41) on the sliding sleeve (20). ). 9. The well regeneration apparatus according to any one of the preceding claims, wherein the treatment device (41) is arranged to generate a physical or chemical process such as impulse waves or shock waves or pressure waves in the treatment area. 10. The well regeneration apparatus according to any one of the preceding claims, wherein the upper plug (31) and/or the lower plug (32) are expandable or inflatable to be reversibly placed in: - a retracted state in which the upper plug (31) and/or the lower plug (32) can be inserted freely In the well, - an expanded state in which the upper plug (31) and/or the lower plug (32) are in contact with a wall of the well, such as the well filter (WS). 11. The well regeneration apparatus according to the preceding claim, comprising a pressure control unit, arranged to control and adjust an inflation pressure of an inflation fluid fed to the upper packer (31) and/or the lower packer ( 32), to establish a maximum allowable pressure difference between the treatment zone and the rest of the well, when the upper packer (31) and/or the lower packer (32) are in an expanded state. 12. The well regeneration apparatus according to any one of the preceding claims, wherein the sliding sleeve (20) is made of unitary pieces of pipe (22), to provide the ability to adjust the height or length of the zone of treatment. 13. Method to regenerate a well, which includes the stages of: - insert at least one upper plug (31) and one lower plug (32) into the well, - isolating a treatment zone of a well filter (WS) between the upper shutter (31) and the lower shutter (32), - introducing into the well a treatment device (41) arranged to regenerate a well filter (WS) in a treatment zone, - move a sliding sleeve (20) between: - a lifting position in which the sliding sleeve (20) is connected to both the upper plug (31) and the lower plug (32), - a treatment position, in which the sliding sleeve (20) is disconnected from at least one of the upper obturator (31) and the lower obturator (32), to allow the treatment device (41) to be oriented directly towards the filter well (WS), where the step of introducing and locating the treatment device (41) in the treatment area and the step of moving the sliding sleeve (20) can be performed in any order. 14. Method for regenerating a well according to claim 13, comprising, before the step of moving the sliding sleeve (20), a step of expanding the upper plug (31) and/or the lower plug (32) until the contact of at least a portion of said upper packer (31) and/or lower packer (32) with a well wall, such as the well filter (WS). 15. Method for regenerating a well according to any of claims 13 to 14, comprising a regeneration step of the well filter (WS), generating with the treatment device (41) a physical or chemical process such as impulse waves or shock waves or pressure waves in the treatment area. 16. Method for regenerating a well according to any of claims 13 to 15, comprising a step of inspecting the well screen (WS) in the treatment zone, by means of a step of passing an inspection device through the sliding sleeve ( twenty). 17. Method for regenerating a well according to any of claims 13 to 16, comprising a step of pumping liquid into the treatment zone, with a step of generating a pumping flow with an air lift created in a pipe string (50) connected to the sliding sleeve (20) so that the pumping flow passes through the sliding sleeve (20). 18. Method for regenerating a well according to the preceding claim, comprising a step of allowing a leakage flow to pass to the treatment zone from the rest of the well, through a step of adjusting a contact pressure between the wall of the well and the upper choke (31) and/or the lower choke (32) to establish a maximum allowable pressure difference between the treatment zone and the rest of the well. 19. Method for regenerating a well according to any of claims 13 to 18, which comprises a step of injecting a chemical and/or additive into the treatment zone through the sliding sleeve.