EA036974B1 - Method of plugging and abandoning a well - Google Patents

Abstract

A method of plugging and abandoning a well (1), comprising the following steps: (A) lowering a perforation tool (31) into a pipe string (5) onto a longitudinal section (L1); (B) with the perforation tool (31), forming perforations (51) along said longitudinal section (L1); (C) with a flushing tool (33) attached to a work string (3) and lowered onto said longitudinal section (L1), pumping a flushing fluid (35) through the work string (3), out through at least one flushing outlet (331) in the flushing tool (33), into the pipe string (5) and into said annulus (8) via the perforations (51), wherein an outlet axis (b) of said flushing outlet (331) is non-perpendicular to a longitudinal axis (a) of the flushing tool (33); (D) pumping a fluidized plugging material (37) through the work string (3) and into the pipe string (5) at said longitudinal section (L1); (E) placing the fluidized plugging material (37) in the pipe string (5) along at least said longitudinal section (L1), thereby also placing the fluidized plugging material (37) in said annulus (8) via the perforations (51); (F) pulling the work string (3) out of the well (1); and (G) abandoning the well (1).

Description

The present invention relates to a method for plugging and abandoning a subterranean well. In this regard, the present method can be used for temporary or permanent plugging and abandonment of such a well. In addition, the present method can be applied to any type of subterranean well, including oil and gas wells, such as production wells and injection wells.

The present method includes perforating, cleaning and plugging a longitudinal section of a well located at a desired depth interval in the well. More specifically, the invention relates to a method that provides hydraulic isolation in the form of a plug in a well along the entire cross-section of the well along at least its longitudinal interval. The plug provides pressure isolation in both horizontal and vertical directions along the specified longitudinal interval of the well. The well is also provided with a string of pipes, at least in the longitudinal interval of the well, where a plug is to be formed in the well to isolate the pressure.

A known method of installing a pressure-insulating barrier in a well by mechanical milling and removing a longitudinal section of the casing in the well. A cement slurry is then placed in the milled section of the well so as to form, after solidification, a pressure insulating cement barrier over the entire cross section of this milled section of the well. This technique, commonly referred to as cutting a piece of casing with a cutter, has been used for plugging and abandoning wells for decades. Such operations to remove part of the casing with a cutter are very time consuming and very costly for the well operator. The operations of removing a portion of the casing with a milling cutter typically require surface installations to be able to separate metal filings, called metal shavings, from the wellbore fluids used in such milling operations. To enable such metal filings (metal shavings) to be transported to the surface of the well, various types of cleaning fluids are often required. In addition, such metal filings can become stuck in other equipment in the well, such as a blowout preventer (BOP), thus creating obstructions downhole. Such metal filings are also difficult to dispose of and are usually hazardous to handle.

There is also known a method of installing such a plug in a well using the method and flushing tool disclosed in WO 2012/096580 A1 (referred to as the HydraWash technology). This method is suitable for use in conjunction with the displacement apparatus and method disclosed in WO 2012/128644 A2 (referred to as Archimedes technology).

The object of the present invention is to eliminate or reduce at least one of the drawbacks of the prior art, which includes said technique of removing a portion of the casing with a cutter, or at least to provide a useful alternative to the prior art.

This object is achieved by means of the features disclosed in the following description and in the following claims.

The present invention relates to a method for plugging and abandoning (T&L) a well, temporarily or permanently. The method includes perforating, cleaning and plugging a longitudinal interval of a well, said longitudinal interval comprising a wellbore, a pipe string located inside the wellbore, and an annulus located between the wellbore and the pipe string.

This method includes the following steps:

(A) lowering the perforating device into the pipe string at a specified longitudinal interval of the well;

(B) perforating (i.e., through) holes in the pipe string along said longitudinal interval are made by the perforating device;

(C) by means of a flushing device attached to the lower end portion of the tubular working string, which is lowered into the tubular working string at a specified longitudinal interval, pumping the flushing fluid through the tubular working string, outward through at least one flushing outlet in the flushing device, into the column pipes and further outward into the specified annular space through perforations in the pipe string, thereby cleaning the pipe string and the annular space along the specified longitudinal interval, and the axis of at least one of the specified at least one flushing outlet in the flushing device is not perpendicular to the longitudinal axis of the flushing device whereby the corresponding flushing jet from the flushing device is also not perpendicular to the longitudinal axis of the flushing device;

(D) pumping the flowable grouting material through the tubular workstring into the tubing at a specified longitudinal interval;

(E) placing the flowable grouting material in the pipe string along at least a specified longitudinal interval, thereby also placing the flowable grouting material in the specified annular space through the perforations in the pipe string, resulting in the flowable plugging material

- 1 036974 the pressing material forms a plug that bridges a substantially full cross-section of the well along at least the specified longitudinal interval of the well;

(F) removing the tubular working string from the well; and (G) abandoning the well.

This non-perpendicular configuration of the at least one flushing outlet in the flushing device provides very efficient flushing and cleaning of both the pipe string and the annulus outside the pipe string. This, in turn, ensures good filling and good adhesion of the subsequent grouting material in the pipe string and in the annulus.

The specified string of pipes can be composed of well pipe of a well known type, for example, a casing or liner. In this connection, the pipe string can, respectively, extend completely or partially to the surface of the well.

Typically, the tubular workstring consists of a drill string or coiled tubing of a well known type.

In one embodiment, the flushing device is provided with a plurality of flushing outlets having corresponding axes of the outlets (i.e., longitudinal axes through the flushing outlets) inclined at an angle of ± 80 ° relative to a plane perpendicular to the longitudinal axis of the flushing device. In this case, the corresponding flushing jets from the flushing device are also inclined at an angle within ± 80 ° with respect to the specified perpendicular plane.

Each of the at least one flushing outlet can also be provided with a detachable nozzle insert. Thus, the nozzle insert can be detachably connected to the flushing device by means of a threaded connection or the like. Such a nozzle insert is suitably sized and shaped to produce a flush jet with the desired concentration and distribution. The disconnectability also allows for quick replacement of the nozzle insert if desired or necessary.

Thus, the specified nozzle insert can be radially telescopic relative to the flushing device, and the telescopic movement of the nozzle insert is selectively activated. This characteristic allows the nozzle insert to be selectively extended and retracted relative to the flushing device. In this case, the flushing device can be lowered into the well pipe string with at least one nozzle insert retracted into the flushing device. After being placed in the well, said nozzle insert can be selectively extended outward from the flushing device body. Such an embodiment of the flushing device may be advantageous in cases where the tubing string has one or more restrictions requiring the use of a smaller flushing device to allow access to the tubing string.

In addition, the flushing fluid may contain drilling fluid. This is generally a suitable flushing fluid given that drilling fluid is usually readily available and also functions as a pressure barrier in the well.

The flushing fluid may also contain a cleaning agent such as a suitable soap or acid.

In addition, the flowable grouting material may contain a grout to create a cement plug.

Alternatively or additionally, the flowable plugging material may contain a flowable mass of particles to form a plug of the mass of particles. Such a mass of particles, as a rule, is unconsolidated. A slightly different use of such a fluid mass of particles in a well is disclosed, for example, in WO 01/25594 A1 and WO 02/081861 A1.

Between steps (B) and (C), the method may also include the following steps:

removing the perforating device from the well and attaching the flushing device to the bottom of the tubular working string for the subsequent execution of step (C). In this case, perforation and flushing are performed in separate tripping operations in the well.

Alternatively, and before step (A), the method may also include the following steps: connect the perforating device and the flushing device to form an assembly, and attach this assembly to said lower part of the tubular working string. In this case, perforation and flushing are performed in the same round trip in the well. Naturally, these steps save time and costs when plugging and abandoning the well.

In addition to the last alternative, the method may also include the following steps:

detachably connect, before step (A), the perforating device to the lower end portion of the flushing device; and disconnect, between steps (B) and (C), the perforating device from the flushing device.

- 2 036974

In this case, the perforating device is dropped further down into the pipe string and is thus left in the well. This can facilitate further operation of the flushing device in the well and, therefore, can additionally save time and costs for performing this work.

In another embodiment, step (C) of the method includes rotating the tubular workstring during flushing. This rotation provides a larger area covered by the movement of the flushing fluid and thus allows better cleaning of the tubing string and annulus.

Alternatively or additionally, step (C) of the method may also include reciprocating movement of the tubular workstring during flushing. This reciprocating movement also provides a larger area covered by the movement of the flushing fluid and thus allows better cleaning of the tubing string and annulus.

Step (E) of the method may also include moving the tubular workstring within the tubular while placing the flowable grouting material therein. In this regard, the tubular working string can be moved in a suitable manner along the perforated longitudinal interval of the pipe string for efficient placement of the grouting material in the well.

Before step (C), the method may include adding an abrasive agent to the flushing fluid. This option is especially suitable if the annulus is filled with, for example, cement residues (or some other casting material) and / or solid particles deposited within the annulus, such as barite particles precipitated from the drilling fluid in the annulus. Removal of such solid materials from the annulus can be difficult if the flushing fluid is devoid of such abrasive agent.

In one embodiment, the method includes adding an abrasive agent to the flushing fluid in an amount of 0.05 to 1.00 wt%. The abrasive agent may contain sand particles. Therefore, by way of example, the addition of about 0.1 wt% sand to the flushing fluid appears to be a suitable mixture.

In addition, the method may include discharging a flushing fluid from said at least one flushing outlet in the flushing device at an outlet speed of at least 15 m / s. The applicant of the present invention has conducted tests showing that an exit speed of 15 m / s is the minimum speed necessary to ensure that the well can be adequately cleaned with a flush device.

In a preferred embodiment, the method thus includes discharging flushing fluid from said at least one flushing outlet at an outlet velocity of at least 50 m / s. The aforementioned tests have also demonstrated that an exit velocity of at least 50 m / s provides a particularly effective in-hole cleaning result.

The optimum outlet rates for the flushing fluid, as well as the optimum amounts of abrasive added thereto, depend on the type of flushing fluid used, especially with regard to the viscosity of the flushing fluid. High viscosity flushing fluids generally require higher exit velocities from the flushing device than low viscosity flushing fluids. This is for the simple reason that high-viscosity flushing fluids experience more internal friction and therefore decelerate faster than low-viscosity flushing fluids.

Another embodiment of the method includes discharging flushing fluid from at least one flushing outlet in the form of a substantially non-rotating flushing jet. If such a wash jet exits from a nozzle insert located in the wash outlet, the nozzle insert requires less support space in the wash device than an alternative nozzle insert designed to give a pivoting / rotating effect to the wash jet.

Prior to step (D), the method may also include placing and securing the base of the plug in the tubing below the longitudinal interval of the wellbore. Such a plug base may comprise an artificial plug, a packer element and / or at least one cup-shaped element, for example a pumping piston collar of a well known type. The purpose of such a plug base is to maintain flowable grouting material after placement in the well. Typically, such a plug base (for example, an artificial plug) is lowered into the tubing string on a so-called auxiliary line or on a tubular working string, for example a drill string or coiled tubing string, reaching the surface of the well.

Alternatively, a column of viscous fluid, i. E. a so-called viscous plug can be pumped into the tubing string below the longitudinal interval of the well to support said flowable grouting material.

In addition, if the specified longitudinal spacing is located at a relatively small distance from the bottom of the pipe string, it may not be necessary to install such a plug base in the pipe string. Instead, a flowable grouting material is poured from the bottom of the pipe string upward until the grouting material closes the longitudinal interval of the well.

In yet another embodiment, and between steps (C) and (D), the method also includes the following steps:

take out the tubular working string and the flushing device from the well;

disconnect the flushing device from the tubular working column; and lowering the open-ended tubular workstring into the tubing at a longitudinal interval for subsequent steps (D) and (E) of the method. In this case, flushing with flushing fluid and displacement (squeezing) of flowable plugging material is performed in separate tripping operations in the well.

Steps (D) and (E) of the method may also include pumping the flowable grouting material into the tubing string through at least one spray outlet in the flushing device to discharge the flushing device in a suitable spray jet. In this case, flushing with a flushing fluid and spraying of a flowable plugging material are performed in the same round-trip operation in the well. Naturally, these steps save time and costs when plugging and abandoning the well. By realizing the flowable grouting material in the form of a spray from the flushing device, the grouting material also becomes directional and somewhat concentrated. This provides the advantage that the spray jet reaches a greater distance from the flushing device and can thus engage with the rock wall in the borehole, engulfing the borehole more fully and intensively. Such a spray also gains better access to potential voids in said annulus surrounding the tubing string along the longitudinal interval of the wellbore.

In one embodiment of the last embodiment of this method, the flushing device comprises a first section for discharging, in step (C), flushing fluid through said at least one flushing outlet and a second section for spraying, in steps (D) and (E) , flowable plugging material through the specified at least one spray outlet in the flushing device.

In this regard, the diameter of said spray jet of flowable grouting material discharged from said second flushing device section may be larger than the diameter of said flushing jet of flushing fluid discharged from said first flushing device section. At the same time, in contrast to the usual placement and displacement of the flowable plugging material in the well, the plugging material can adhere to the rock wall in the well more fully and intensively. The flowable grouting material will also gain better access to potential voids in the annulus along the longitudinal interval of the well. The smaller diameter of said flushing jet of flushing fluid, however, provides a more concentrated jet for grinding and flushing solids and particles along its flow path in the well.

In the latter context, the method may also include discharging said spray jet of flowable grouting material at an exit velocity of the order of 15-25 m / s and preferably of the order of 18-22 m / s. This range of output speeds is preferred to achieve the spray effect of the flowable grouting material.

In another embodiment of said last variant of the method, said at least one flushing outlet and said at least one spray outlet in the flushing device are one and the same hole, whereby both the flushing fluid and the flowable plugging material will be discharged through the specified at least one outlet in the flushing device; and wherein the method includes discharging said flushing jet of flushing fluid at a higher output velocity than the output velocity of said subsequent spray jet of fluid cementing material. Variations in the outlet velocity of the respective fluids can be achieved by varying the injection rate of a particular fluid.

In this regard, the method may include discharging the flushing fluid at an exit speed of at least 50 m / s and then discharging the subsequent flowable grouting material at an exit speed of about 15-25 m / s.

Apart from this, the method can also include the following steps:

attach, before step (D), the displacement body to the tubular working string near the flushing device and use, in step (E), the displacement body to further displace and distribute the flowable grouting material in the pipe string and further into the specified annular space through the indicated perforations in the pipe string along the longitudinal interval of the well. This promotes the displacement and distribution of the flowable plugging material within the specified longitudinal interval of the shaft. A displacement body suitable for this purpose is disclosed in WO 2012/128644 A2 (the so-called Archimedes technology), as mentioned at the outset.

Next, an exemplary embodiment of the present invention is disclosed and illustrated in the accompanying drawings.

FIG. 1 shows a side view of a well containing a casing string.

FIG. 2 shows a side view of a well after removing a longer portion of the casing in accordance with the prior art plugging method (ie, removing a portion with a cutter).

FIG. 3 is a side view of the well of FIG. 2, after the plug is installed in the well according to this plugging method by removing a portion with a cutter known in the art.

FIG. 4 shows a side view of a well as used in the context of the present method after lowering the perforating tool into the casing.

FIG. 5 shows a side view of a well after perforating the casing with a perforating tool and after pulling the perforating tool out of the well.

FIG. 6 shows a side view of a well after lowering the washer into the casing and while using the wash to flush and remove, for example, solids from the well.

FIG. 7 shows a side view of a well while filling and thus placing the flowable grouting material in a portion of the longitudinal interval of the well, whereby substantially the entire cross-section of the well is filled with grouting material along the longitudinal interval.

FIG. 8 shows a side view of a well after the well has been plugged along its longitudinal interval by the present method.

FIG. 9 shows a side view of a combined perforating and flushing device for use in one embodiment of the present method.

The drawings are schematic and simply show the steps, details and equipment essential to understanding the invention. In addition, the drawings are distorted in terms of the relative dimensions of the elements and parts shown in the drawings. The drawings are also somewhat simplified in terms of the shape and detail of such elements and details. Elements that are not key to the present invention may also not be shown in the drawings. In addition, the same, equivalent or equivalent parts shown in the drawings will be assigned substantially the same reference numbers.

FIG. 1 shows a well 1, which is to be plugged and abandoned after the extraction of a longer part of the pipe string, represented here as a single casing 5, in accordance with the plugging method known from the prior art (i.e., the so-called removal of a part with a cutter ). The drawing shows a casing string 5 located in a borehole 2 of a well 1. The enclosing rock 9 delimits the wellbore 2. There is also an annulus 8 between the wellbore 2 and the casing 5. Well 1 also contains typical wellbore fluids known to a person skilled in the art.

FIG. 2 shows a well 1 after removal of a long part / section of casing 5 in accordance with said prior art plugging method by removing a part with a cutter. A significant part of the length of the casing 5 is thus cut with a cutter.

FIG. 3, further, shows well 1 after grouting, i.e. flowable grouting material, into the milled section of well 1 so as to fill its entire cross-section T1. Once solidified, this slurry forms a cement plug 25 to isolate the pressure in the milled section of well 1, as shown in FIG. 3. This method of removing a part with a cutter has several disadvantages, as mentioned at the beginning.

FIG. 4 shows the first step of the present method in relation to a similar well 1. Also, a single casing 5 is located here in the borehole 2 of well 1, leaving an annular space 8 between the wellbore 2 and the casing 5. A tubular working string, here represented as a drill string 3 , was lowered into the casing 5 at the longitudinal interval L1 of the well 1, which is to be plugged and abandoned by the present method. A perforating device, here represented as a perforating gun 31 of a well-known type, has also been attached to the lower end of the drill string 3. Once positioned in the longitudinal interval L1 of the well 1, the perforator 31 is activated and makes a plurality of perforations 51 along the longitudinal interval L1 and through the casing wall 5 as shown in FIG. 5. In one embodiment, the perforating gun 31 can be pulled out of the well 1 and disconnected from the drill string 3 after the perforating operation.

FIG. 6 shows borehole 1 after lowering the flushing device 33 into the casing 5 at the longitudinal interval L1, while the flushing device is attached to the lower end of the drill string 3. This drill string may be the same drill string as

- 5,036974 was used in the previous perforation step, or may be another type of tubular workstring such as coiled tubing. This figure also shows the flushing device 33 during flushing and removal of, for example, solids (not shown in the figures) in the well 1 along its longitudinal interval L1. The curved arrow at the top of the drill string 3 indicates the rotation of the drill string 3 and hence the rotation of the flushing device 33 attached thereto during flushing and cleaning with the flushing device 33. In a further or alternative embodiment, the drill string 3 and therefore , the flushing device 33 can be moved in a reciprocating motion during flushing and cleaning of the longitudinal interval L1 by means of the flushing device 33. The rotation and / or reciprocating movement of the flushing device 33 along the longitudinal interval L1 during flushing provides a large and possibly repeatedly covered area to allow better cleaning of the casing 5 and the surrounding annulus 8 along the longitudinal interval L1 of well 1.

In this particular embodiment, the flushing device 33 is provided with a plurality of flushing outlets 331 distributed in a predetermined order around the flushing device 33. These flushing outlets 331 have corresponding outlet axes b, inclined at an angle of ± 80 ° with respect to plane c perpendicular to the longitudinal axis a of the flushing device 33. The corresponding flushing jets discharged from the flushing device 33 are also inclined at an angle within ± 80 ° relative to the perpendicular plane c. Longitudinal axis a, outlet axis b and perpendicular plane c are also shown in FIG. 9.

FIG. 6 also shows flushing fluid 35 in the form of flushing jets emitted at high speed and in substantially non-rotating jets from respective nozzle inserts 332 provided in the wash outlets 331 of the washer 33. These nozzle inserts 332 provide the desired concentration and the distribution of the wash jets after being discharged from the wash outlets 331 of the wash device 33. The wash jets are discharged at different angles relative to said perpendicular plane c, pass through the corresponding perforations 51 and enter the annular space 8 at different angles. This allows better access to the areas of the annular space 8 located between the perforations 51, thereby allowing better flushing and cleaning of these intermediate areas of the annular space 8. These oblique flushing jets are depicted by straight arrows pointing outward from some of the flushing outlets 331, shown in FIG. 6. The direction of flow and potential flow paths of the discharged flushing fluid 35 are shown by curved arrows located around the flushing device 33 in FIG. 6. At a particular point in time, the outflowing flush fluid 35 thus flows out through the perforations 51 adjacent to the flush outlets 331, through the annular space 8 outside the casing 5, and then back into the casing 5 through the perforations 51, more remote from the flush outlets 331. Flushing device 33 is slowly moved along the longitudinal interval L1 while flushing the casing 5 and annulus 8, thereby continuously repeating this instant flush scenario along the longitudinal interval L1 of well 1. This movement of flushing fluid continues until until the entire longitudinal interval L1 is covered and cleaned sufficiently.

Before plugging the longitudinal interval L1 of the well 1, additional cleaning and conditioning (preparation) fluid is usually pumped in the open manner through the flushing device 33 into the casing 5 and the annular space 8, thereby further cleaning and preparing the wellbore 2 and the casing 5 in order to enable the introduction of cement slurry 37, i.e. flowable grouting material, at least in the longitudinal interval L1 thereafter (see Fig. 7 and 8). This additional cleaning and conditioning fluid may consist of a so-called buffer fluid, which is typically used to remove solids remaining in the wellbore 2 / annulus 8 and to wet and prepare the casing 5 and the surrounding rock. 9 (which delimits the wellbore 2) so as to provide adhesion of the wellbore to the subsequent cement slurry 37 to be injected therein. Such a spacer fluid is generally less dense than the slurry 37 used in the plugging steps (D) and (E) of the present method. Therefore, the slurry 37 easily displaces the buffer fluid during these plugging steps.

FIG. 7 shows well 1 during pumping and, accordingly, placement of cement slurry 37 in the lower portion of the longitudinal interval L1 of well 1, whereby substantially the entire cross-section T1 of well 1 is filled with cement slurry 37. FIG. 7 shows the slurry 37 flowing out of the lower end of the drill string 3 so as to fill the inner

- 6 036974 the lower part of the casing string 5, after which the cement slurry 37 flows further into the annular space 8 through the perforations 51 in the wall of the casing string 5. In this case, the denser cement slurry 37 easily displaces the less dense buffer fluid (or other less dense wellbore fluid), if any, upwardly inside the well 1 and thus removes the buffer fluid from the specified longitudinal interval L1. Due to the pumping and displacement of grout 37, the drill string 3 is slowly moved upward while pouring and placing grout 37 in the casing 5 along the entire longitudinal interval L1 of well 1. This step of pouring / filling and moving may also continue as long as cement slurry 37 will not be poured into the casing 5 to a certain required level above the longitudinal interval L1, as a result of which at least the longitudinal interval L1 of well 1 will be filled with cement 37. Before pumping the cement slurry 37 into the casing 5, artificial plug 38 was placed and secured within the casing 5 and below the longitudinal interval L1 to provide a support base for the slurry 37 placed in the casing 5.

In an alternative embodiment, not shown in the drawings, the flushing device 33 may remain attached to the drill string 3 after flushing and cleaning the longitudinal interval L1. The slurry 37 is then pumped into the drill string 3 and discharged from the nozzles 332 provided in the flush outlets 331 of the flush 33. In this case, the slurry 37 can be discharged from the flush 33 as spray jets at a significantly lower output speed than high output velocity of the previous flushing jets of flushing fluid 35.

FIG. 8 shows well 1 after grouting 37 into casing 5 and the surrounding annulus 8 as disclosed hereinabove, and after solidifying therein so as to form a pressure isolation cement plug 25 spanning substantially the entire wellbore cross section T1. 1 along at least its longitudinal interval L1.

After the slurry 37 has been placed inside and along at least the specified longitudinal interval L1 of the well 1, the drill string 3 is taken out of the well 1. The well 1 is then abandoned, temporarily or permanently.

FIG. 9 shows a selectively detachable perforating device 31 detachably connected to the lower end portion of the flushing device 33 to form an assembly 34. Assembly 34 is attached to the bottom of a drill string 3 (not shown in FIG. 9). Selectively disconnecting the perforating device 31 from the flushing device 33 can be accomplished using well known techniques and methods. The use of such an assembly 34 makes it possible to perform perforation and flushing on the same trip in well 1. In this case, the perforating device 31 is dropped further down into the pipe string 5 and, thus, is left in well 1. This can facilitate further operation. flushing device 33 in well 1 and, therefore, can additionally save time and costs for performing such a plugging operation.

Claims (19)

1. A method for abandoning a well (1), including perforating, cleaning and plugging a longitudinal interval (L1) of a well (1), while said longitudinal interval (L1) contains a wellbore (2), a pipe string (5) located inside the wellbore (2), and the annular space (8) located between the wellbore (2) and the pipe string (5), and the method includes the following steps: (A) lowering the perforating device (31) into the pipe string (5) at the specified longitudinal interval (L1) of the well (1); (B) by means of a perforating device (31), perforations (51) are made in the pipe string (5) along said longitudinal interval (L1); (C) by means of a flushing device (33) attached to the lower end section of the tubular working string (3), which is lowered into the tubular working string (5) for the specified longitudinal interval (L1), pumping the flushing fluid (35) through the tubular working string ( 3) outwardly through at least one flushing outlet (331) provided in the flushing device (33) and provided with a nozzle insert (332) to be discharged in the form of a flushing jet into the pipe string (5) and then outwardly into the said annular space ( 8) through the perforations (51) in the pipe string (5), thereby cleaning the pipe string (5) and the annular space (8) along the specified longitudinal interval (L1), and the axis (b) of at least one of the specified at least one flushing outlet (331) in the flushing device (33) is not perpendicular to the longitudinal axis (a) of the flushing device (33), as a result of which the corresponding flushing jet from the flushing device - 7 036974 (33) is also non-perpendicular to the longitudinal axis (a) of the flushing device (33); (D) pumping the fluid cementing material (37) through the tubular workstring (3) into the tubing (5) at the specified longitudinal interval (L1); (E) placing the fluid grouting material (37) in the pipe string (5) along at least the specified longitudinal interval (L1), thereby also placing the fluid grouting material (37) in the specified annular space (8) through the perforations ( 51) in the pipe string (5), as a result of which the flowable grouting material (37) forms a plug (25) covering substantially the entire cross-section (T1) of the well (1) along at least the specified longitudinal interval (L1 ) wells (1); and (F) removing the tubular working string (3) from the well (1); moreover, this method, in steps (D) and (E), includes pumping a fluid grouting material (37) into the pipe string (5) through at least one spray outlet provided in the flushing device (33) and provided with a nozzle insert (332) to discharge the flowable plugging material (37) in a corresponding jet. 2. The method of claim 1, wherein the flushing with flushing fluid (35) and spraying of the flowable grouting material (37) are performed in the same tripping operation in the well (1). 3. A method according to claim 1 or 2, wherein the flushing device (33) is provided with a plurality of flushing outlets (331) having corresponding outlet axes (b) inclined at an angle of ± 80 ° with respect to plane (c), perpendicular to the longitudinal axis (a) of the flushing device (33), as a result of which the corresponding flushing jets from the flushing device (33) are also inclined at an angle within ± 80 ° relative to the specified perpendicular plane (c). 4. A method according to any one of claims 1 to 3, wherein the method, between steps (B) and (C), also includes the following steps: removing the perforating device (31) from the well (1) and attaching the flushing device (33) to the specified lower end of the tubular working string (3) for the subsequent execution of step (C); as a result of which perforation and flushing are performed in separate trips in the well (1). 5. A method according to any one of claims 1 to 3, wherein the method, before step (A), also includes the following steps: connecting the perforating device (31) and the flushing device (33) to obtain an assembly (34) and attach the assembly (34) to the specified lower part of the tubular working string (3); in this case, perforation and flushing are performed on the same round trip in the well (1). 6. The method of claim 5, wherein the method also includes the following steps: detachably attaching the perforating device (31) to the lower end portion of the flushing device (33) before step (A) and disconnecting, between steps (B) and (C), the perforating device (31) from the flushing device (33); while the perforating device (31) is dropped further down into the pipe string (5) and left in the well (1). 7. A method according to any one of claims 1 to 6, wherein step (E) comprises moving the tubular workstring (3) within the tubing (5) while placing the flowable grouting material (37) therein. 8. A method according to any one of claims 1-7, wherein the method, prior to step (C), comprises adding an abrasive agent to the flushing fluid (35). 9. A method according to any one of claims 1 to 8, including discharging a flushing fluid (35) from a nozzle insert (332) provided in said at least one flushing outlet (331) in the flushing device (33), with an output speed of at least 15 m / s. 10. A method according to claim 9, including discharging a flushing fluid (35) from a nozzle insert (332) provided in said at least one flushing outlet (331) at an outlet speed of at least 50 m / from. 11. A method according to any one of claims 1-10, wherein the method, prior to step (D), also includes placing and securing the base (38) of the plug in the pipe string (5) below the longitudinal interval (L1) of the well (1 ). 12. A method according to claim 11, wherein the plug base (38) comprises at least one bowl-shaped element. 13. A method according to any one of claims 1-12, in which the flushing device (33) comprises a first section for discharging, in step (C), flushing fluid (35) through a nozzle insert (332), providing - 8 036974 seen in the specified at least one flushing outlet (331), and a second section for discharging, in steps (D) and (E), the flowable plugging material (37) through the nozzle insert (332) provided in the specified at least one spray outlet in the flushing device (33). 14. A method according to claim 13, wherein the diameter of said jet of flowable grouting material (37) discharged from said second section of the flushing device (33) is greater than the diameter of said flushing jet of flushing fluid (35) discharged from said first section flushing device (33). 15. A method according to claim 14, including discharging said jet of flowable grouting material (37) from the nozzle insert (332) at an exit speed of the order of 15-25 m / s. 16. A method according to claim 15, including discharging said jet of flowable grouting material (37) from the nozzle insert (332) at an exit speed of the order of 18-22 m / s. 17. A method according to any one of claims 1 to 12, wherein said at least one flushing outlet (331) and said at least one spray outlet in the flushing device (33) are the same opening, as a result whereby both the flushing fluid (35) and the flowable plugging material (37) will be discharged through a nozzle insert (332) provided in said at least one outlet (331) in the flushing device (33); and wherein the method includes discharging said flushing jet of flushing fluid (35) from the nozzle insert (332) at a higher outlet velocity than the outlet velocity of said subsequent spray jet of flowable grouting material (37). 18. A method according to claim 17, including discharging flushing fluid (35) from the nozzle insert (332) at an output speed of at least 50 m / s and then discharging subsequent flowable grouting material (37) from the nozzle insert (332) with an output speed of the order of 15-25 m / s. 19. A method according to any one of claims 1-18, wherein the method also includes the following steps: connect, before step (D), the displacing body to the tubular working string (3) near the flushing device (33) and use, in step (E), the displacing body to further displace and distribute the flowable grouting material (37) in the string (5 ) pipes and further into the specified annular space (8) through the specified perforations (51) in the pipe string (5) along the longitudinal interval (L1) of the well (1), thereby contributing to the displacement and distribution of flowable plugging material (37) within the specified longitudinal interval (L1).