Method of installing disconnecting bridge in well

Abstract

FIELD: oil and gas production industry.SUBSTANCE: invention relates in particular to well interval isolation technologies, and can be used in repair and insulation work. The method for installing an isolation bridge in a well involves lowering an actuator into the casing and forming an isolation barrier. The actuator is lowered on a geophysical cable through the tubing string to a specified depth below the tubing string. After this, using an actuator, a primary isolating bridge is formed by placing a sealing material in the well in the form of a polymer material placed in an elastic capsule. Upon contact with well fluid, the polymer material swells, and the capsule takes the shape of the casing, forming a supporting polymer bridge. After a time sufficient for the formation of the said polymer bridge, a secondary isolation bridge is installed above it, while the cement slurry is delivered using a geophysical bailer above the polymer bridge and a cement bridge is installed.EFFECT: reduction in the time and operating costs during installation of an isolation bridge by eliminating the need to lift the tubing string, as well as increase in the reliability of well interval isolation by forming a preliminary polymer support bridge followed by the creation of a cement isolation bridge.1 cl, 1 dwg

Description

[0001] The invention relates to the oil and gas production industry, in particular to well interval isolation technologies, and can be used in carrying out repair and isolation work, installing isolation bridges, eliminating absorption zones, isolating water inflows, as well as in major repairs and well conservation, including without lifting the tubing string using a geophysical cable.

[0002] A device is known for delivering a cement slurry to a specified area of ​​a well (SU1388544, IPC E21B 33 / 132, published 15.04.1988, bulletin No. 4), including a housing with a squeezing and limiting plugs and ampoules with cement material between them and an adapter in the upper part, characterized in that, in order to expand the scope of application and increase the reliability of isolating well intervals, it is equipped with a shut-off unit in the upper part of the housing above the squeezing plug and rubber bands on the ampoules made of an elastic material with open inlet openings directed towards the squeezing plug, wherein the rubber bands are fixed at the open inlet openings of the ampoules and connect them together and the upper ampoule with the housing.

[0003] The disadvantages of this solution are the need to lower equipment onto the tubing, the creation of excess pressure in the column, as well as limited technological flexibility during operations.

[0004] A cement mortar bailer is known (patents SU604965, IPC E21B 27 / 02, published 04 / 30 / 1978), lowered into a well on a cable, consisting of a body, a cover, a bottom and a piston, characterized in that, in order to increase the efficiency of its operation, the piston is made in the form of a glass, equipped with a nozzle with a plug and filled with a powder charge with an electric igniter.

[0005] A cement mortar bailer is known (patents SU976025, IPC E21B 33 / 132, published 23..1982), comprising a housing with windows in the upper part, a cover on shear elements, a charge with an electric igniter and a plug installed in the lower part of the housing, characterized in that, in order to increase its reliability in operation by preventing premature setting and ensuring uniform squeezing out of the cement slurry, it is equipped with a divider made in the form of a perforated disk installed under the charge and located in the flow section of the housing, and a piston-float installed under the perforated disk and forming with the latter a chamber filled with a neutral liquid, wherein the housing in the lower part is made with radial holes, and the plug is made spring-loaded with the possibility of closing the radial holes.

[0006] The disadvantages are that these solutions are characterized by the use of explosive or powder elements, and also do not provide the formation of a stable supporting base for the cement bridge, which can lead to erosion of the mortar and a decrease in the quality of insulation.

[0007] The closest one is a cementing tool (SU972048, IPC E21B 33 / 138, published 07.11.1981) for isolating absorption zones and installing bridges in wells, including a body, a piston installed in it, easily destructible containers with dry cementing material, placed under the piston, a shoe, in the axial pockets of which knives are installed, and a plug, characterized in that, in order to increase the reliability of control over the extrusion of containers from the tool, the piston is made with a through axial channel and is equipped with a check valve placed in this channel, spring-loaded relative to it, made in the form of a rod with longitudinal grooves along its length, a lock placed in the upper part of the rod, and a shut-off element interacting with the containers, the diameter of which is less than the diameter of the axial channel of the shoe.

[0008] The disadvantages include the need to run the tubing string and perform mechanical operations, including rotation, which complicates the process, increases the time required, and increases the risk of accidents. The device does not provide a stable support base, which can result in the cement slurry being washed out and failing to create a reliable isolation bridge. Furthermore, the lack of multi-stage isolation reduces the tightness and durability of the barrier created.

[0009] The technical objective of the invention is to create a method for installing an isolation bridge in a well, which makes it possible to carry out work without lifting the tubing string, increasing the reliability of isolating well intervals by forming a stable support base, and also reducing the time and operating costs for performing repair and isolation work.

[0010] The technical result of the invention is a reduction in the time and operating costs during the installation of an isolation bridge by eliminating the lifting of the tubing string, as well as an increase in the reliability of the isolation of well intervals by forming a preliminary polymer support bridge followed by the creation of a cement isolation bridge.

[0011] The technical result is achieved by installing an isolation bridge in a well, which includes lowering an actuator into the casing and forming an isolation barrier.

[0012] What is new is that the actuator is lowered on a geophysical cable through the tubing string to a specified depth below the tubing string, after which, with the help of the actuator, a primary isolation bridge is formed by placing in the well a sealing material in the form of a polymer hydrogel or a swelling sealant placed in an elastic capsule, wherein after contact with the well fluid, the said material swells, and the capsule takes the shape of a casing string with the formation of a supporting polymer bridge, then after a period of time sufficient for the formation of the said polymer bridge, a secondary isolation bridge is installed above it by delivering cement slurry using a geophysical bailer, wherein the polymer bridge acts as a supporting base for the formation of a cement bridge, ensuring an increase in the reliability of isolation.

[0013] What is also new is that the polymer material is made in the form of a hydrogel in the form of granules with a diameter of 2-3 mm.

[0014] What is also new is that the polymer material used is a swelling sealant.

[0015] What is also new is that the elastic capsule prevents premature swelling of the polymer material during deflating.

[0016] What is also new is that the polymer material is activated by the flow of well fluid into the actuator after the shear element is destroyed.

[0017] What is also new is that the destruction of the shear element is carried out by rotating the drive shaft of the actuator.

[0018] What is also new is that the polymer bridge formation time is up to 30 minutes.

[0019] What is also new is that the installation time of the cement bridge is up to 15 minutes.

[0020] What is also new is that the volume of polymer material and cement slurry is up to 10 liters.

[0021] What is also new is that the pressure when installing the bridge corresponds to the hydrostatic pressure in the well.

[0022] The figure shows a diagram of the implementation of the method, where:

[0023] 1 - casing;

[0024] 2 - tubing column;

[0025] 3 - geophysical cable;

[0026] 4 - actuator;

[0027] 5 - electric drive;

[0028] 6 - ​​shear element;

[0029] 7 - tip;

[0030] 8 - elastic capsule;

[0031] 9 - polymer hydrogel (or swelling sealant);

[0032] 10 - geophysical bailer;

[0033] 11 - cement slurry.

[0034] In a method for installing an isolation bridge in a well, including lowering an actuator 4 into a casing string 1 and forming an isolation barrier, according to the invention, the actuator 4 is lowered on a geophysical cable 3 through a tubing string 2 to a predetermined depth below the tubing string 2, after which a primary isolation bridge is formed, and then a secondary isolation bridge.

[0035] The actuator 4 is lowered on the geophysical cable 3 through the tubing string 2 into the casing string 1 to the specified bridge installation depth. Using the geophysical cable instead of the tubing string allows for the operation to be performed without retrieving pipe, which, in turn, reduces time and operating costs.

[0036] After reaching the set depth, electric power is supplied to the electric drive 5, as a result of which the shaft begins to rotate, and the tip 7 fixed to it destroys the shear element 6. The destruction of the shear element ensures communication between the internal cavity of the actuator and the well environment, as a result of which the well fluid enters the inside of the device.

[0037] Under the influence of incoming wellbore fluid, polymer material 9, housed in elastic capsule 8, begins to swell. The elastic capsule prevents premature swelling of the material during downhole operation and, once activated, ensures its targeted expansion.

[0038] Due to swelling of the polymer material, capsule 8 expands in volume and takes the shape of the inner surface of casing 1, thereby forming a primary polymer isolating bridge. Contact with the fluid causes swelling, an increase in volume, and a tight fit to the walls, forming a sealed support base.

[0039] After the primary bridge is formed, actuator 4 is lifted, breaking the capsule's fastening elements and leaving the capsule in the well. The resulting polymer bridge acts as a support base, preventing the subsequent cementing material from settling and washing away.

[0040] Next, after a period of time sufficient for the polymer bridge to stabilize, a geophysical bailer 10 with cement slurry 11 is lowered into the well using a geophysical cable. The slurry is placed above the formed polymer bridge.

[0041] The presence of a supporting polymer base prevents the cement mortar from eroding, holds it in place, and forms a secondary cement bridge. This ensures a sequential two-stage seal, in which the polymer bridge serves as an auxiliary support, while the cement bridge serves as the primary seal, resulting in increased seal reliability.

[0042] The method for installing a disconnecting bridge in a well is implemented using an actuator 4, lowered on a geophysical cable 3 through a column of tubing 2 into a casing string 1. The positions of the elements correspond to the designations given in the description.

[0043] Before descent, the actuator 4 is equipped with an elastic capsule 8 filled with a polymer material 9. The following is used as the polymer material:

[0044] hydrogel in the form of granules with a diameter of 2-3 mm, or

[0045] swelling sealant.

[0046] The weight and volume of the polymer material are selected based on the internal diameter of the casing string 1 and the required height of the primary bridge and, as a rule, amount to up to 10 l.

[0047] Capsule 8 hermetically isolates the polymer material from the well fluid during the lowering stage, thereby preventing its premature swelling and ensuring delivery of the material to the specified interval without loss of properties.

[0048] The actuator 4 is lowered on the geophysical cable 3 through the tubing string 2 to a predetermined depth, located below the lower end of the tubing string. Depth control is performed using standard geophysical methods (cable length, GC / KS, coupling locators).

[0049] Using geophysical cable instead of tubing eliminates the need for retrieving pipes, resulting in reduced operating time and lower operating costs.

[0050] After reaching the set depth, power is supplied to actuator 4. Electric drive 5 rotates the shaft to which tip 7 is attached. As tip 7 rotates, it destroys shear element 6.

[0051] The destruction of the shear element 6 causes communication between the internal cavity of the device 4 and the well environment, as a result of which the well fluid enters the inside of the device.

[0052] Under the influence of well fluid, polymer material 9 begins to swell. Depending on the type of material:

[0053] for hydrogel, liquid is absorbed and the volume of granules increases;

[0054] for swelling sealant - transition to a viscous-elastic state with an increase in volume.

[0055] The swelling of the material causes an increase in pressure inside the capsule 8, as a result of which the capsule expands and takes the shape of the inner surface of the casing string 1.

[0056] This is how the cause-and-effect chain is realized:

[0057] liquid influx → material activation → swelling → volume increase → pressing against walls → formation of a hermetic barrier.

[0058] As a result, a primary polymer isolating bridge is formed, which hermetically covers the cross-section of the column, is fixed due to contact pressure on the walls, and performs the function of a supporting base.

[0059] The formation time of the polymer bridge is usually up to 30 minutes and depends on the temperature and mineralization of the well fluid.

[0060] After the bridge is formed, actuator 4 is lifted. The capsule's fastening elements are destroyed, leaving the capsule containing the material within the installation area.

[0061] After the time required to stabilize the polymer bridge (usually 10-30 minutes), a geophysical bailer 10 with cement slurry 11 is lowered into the well.

[0062] The bailer 10 is positioned above the formed polymer bridge and the solution is unloaded.

[0063] The presence of a polymer bridge ensures the creation of an artificial face, preventing the leakage of cement mortar downwards, reducing the filtration of the mortar into the formation, and stabilizing the installation zone.

[0064] This keeps the cement mortar within the specified interval and forms a secondary isolating bridge.

[0065] The setting time of a cement bridge is usually up to 15 minutes (for quick-hardening compounds) and depends on the mortar formulation.

[0066] This way a two-stage scheme is implemented:

[0067] Polymer bridge → supporting function → cement retention → forming a strong barrier.

[0068] The method is implemented with the following typical parameters:

[0069] pressure - corresponds to the hydrostatic pressure of the liquid column in the well;

[0070] temperature - determined by depth (usually 20-120°C);

[0071] volume of materials - up to 10 l;

[0072] column diameter - standard for production wells;

[0073] Installation depth - not limited by the tubing design.

[0074] Execution options.

[0075] Option 1 - hydrogel

[0076] Uses a hydrogel in 2-3 mm granules with a high swelling rate. This ensures rapid bridge formation and good adaptation to column irregularities.

[0077] Option 2 - swelling sealant

[0078] Use a sealant with increased adhesion, providing additional tightness in the presence of cracks or cavities.

[0079] Option 3 - deep and inclined wells

[0080] Due to the descent on a geophysical cable, the method is applicable in directional and horizontal wells, where the use of a tubing string is difficult.

[0081] Option 4 - complicated conditions

[0082] In the presence of high mineralization or liquid influx, the polymer bridge prevents cement erosion, which increases the reliability of the insulation.

[0083] Example 1

[0084] The actuator 4 is lowered on the geophysical cable 3 through the tubing string 2 to a depth of 1500 m. After activation of the device, the hydrogel 9, made in the form of granules with a diameter of 2-3 mm, placed in the capsule 8, swells under the action of the well fluid for 20-30 minutes, forming a polymer bridge.

[0085] After a 20-minute soak, a 10-bar bailer with up to 10 liters of cement slurry is lowered into the borehole and placed above the polymer bridge. Due to the support base, the cement slurry forms a stable isolation bridge within 10-15 minutes.

[0086] Example 2 (with swelling sealant)

[0087] The polymer material used is a swelling sealant placed in an elastic capsule 8. After the shear element 6 is destroyed, the sealant is activated by the well fluid and increases in volume, forming a dense support bridge.

[0088] Next, similar to example 1, a cement bridge is installed to provide final insulation.

[0089] Example 3 (deep well)

[0090] In a well over 2,500 m deep, a bridge is installed without pulling the tubing string. The pressure corresponds to hydrostatic pressure. The use of a geophysical cable ensures installation accuracy, and the use of a polymer bridge prevents cement slurry washout, even in highly mineralized wellbore fluids.

[0091] Implementation of the method ensures that work can be performed without lifting the tubing string, reducing operation time, reducing costs, increasing the reliability of insulation, and the possibility of use in difficult conditions.

Claims

1. A method for installing an isolation bridge in a well, which includes lowering an actuator into a casing string and forming an isolation barrier, characterized in that the actuator is lowered on a geophysical cable through a tubing string to a predetermined depth below the tubing string, after which, using the actuator, a primary isolation bridge is formed by placing a sealing material in the well in the form of a polymer material placed in an elastic capsule, wherein after contact with the well fluid, the polymer material swells, and the capsule takes the shape of the casing string with the formation of a supporting polymer bridge, then, after a period of time sufficient for the formation of the said polymer bridge, a secondary isolation bridge is installed above it, while the cement slurry is delivered using a geophysical bailer above the polymer bridge and a cement bridge is installed.

2. The method according to paragraph 1, characterized in that the polymer material is made in the form of a hydrogel in the form of granules with a diameter of 2–3 mm.

3. The method according to paragraph 1, characterized in that a swelling sealant is used as the polymer material.

4. The method according to paragraph 1, characterized in that the activation of the polymer material is carried out by the flow of well fluid into the actuator after the destruction of the shear element.

5. The method according to paragraph 1, characterized in that the destruction of the shear element is carried out by rotating the drive shaft of the actuator.

6. The method according to paragraph 1, characterized in that the time for forming the polymer bridge is up to 30 minutes.

7. The method according to paragraph 1, characterized in that the installation time of the cement bridge is up to 15 minutes.

8. The method according to paragraph 1, characterized in that the volume of the polymer material and cement slurry is up to 10 liters.

9. The method according to paragraph 1, characterized in that the pressure during installation of the bridge corresponds to the hydrostatic pressure in the well.

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