RU2730146C1 - Axial-action cup packer - Google Patents

Abstract

FIELD: soil or rock drilling; mining.

SUBSTANCE: group of inventions relates to an axial-action cup packer and a method for its activation. Axial-action cup packer comprises mandrel with packer element arranged thereon to isolate annular space of the well. Packer element is bowl-shaped, fixed on mandrel with one end and open by other end to form appropriate cavity closed on the side of open end of packer element by clamping ring. Pressure ring is installed on mandrel with possibility of movement and compression of packer element by axial force. On the mandrel in the cavity a spacer is installed, which is made with the possibility of limitation of the clamping ring mobility. Spacer is fixed on mandrel with thrust ring. Upper end of hold-down ring interacting with packer element has holes with possibility of fluid flow from outer surface of hold-down ring into cavity, performing additional hydraulic pressure of liquid flow for compression of packer element, and other lower end of clamping ring is connected by means of thread with lower branch pipe. Locking ring with teeth engaged with mandrel mating surface in packer transport position is installed on mandrel, locking ring is made with possibility of protection against early activation of packer, locking ring by one lower end contacts with support surface of lower branch pipe, and by other upper end - with lower end of fixing semi-rings. Hold-down ring and the lower branch pipe are installed on the mandrel by means of fixing semi-rings and locking ring so that the semi-rings are installed between the ends of the hold-down ring and the locking ring and are made with possibility of limited axial movement relative to the mandrel in its profile.

EFFECT: technical result is improved reliability of packer and entire layout for repeated hydraulic fracturing of formation, as well as increased number of stages of hydraulic fracturing of formation without lifting assembly to surface.

11 cl, 5 dwg

Description

FIELD OF TECHNOLOGY

[001] This technical solution relates generally to the oil and gas industry, and in particular to devices for isolation of reservoirs in wells.

LEVEL OF TECHNOLOGY

[002] There are many situations in which downhole tools must be selectively actuated. For example, for hydraulic fracturing, where there are wells with completions in several reservoirs, each zone is equipped with one or more tools, and each tool requires such an actuation in which the fluid is diverted from the tool to the outer part of the wellbore for fracturing oil and gas bearing formation. Actuation is often required in a sequence to provide progressive fracturing along the wellbore without leaking fracturing fluid through the previously fractured zones.

[003] Currently, all packers, or in other words, packers of various types are designed to separate the annulus and in-tubular space of inter-formation zones in order to limit the flow of fluid between the zones. Despite the fact that the constituent parts of the design of various solutions may be present in different quantities and shapes, all determine the only type of functioning - this is the expansion of the packer element due to hydraulic or mechanical pressure.

[004] From the prior art patent US 5217077 A "Resettable packer", patentee: Baker Hughes Inc, publication date: 06/08/1993 is known. This solution considers a drop-hole packer. Circulation from the surface creates back pressure behind the seal member, which expands the seal member in contact with the wellbore or casing. The tool can be moved to hold pressure behind the element to keep it in contact with the wellbore or casing while allowing flow through the packer for procedures such as injection or stimulation. The tool includes a release mechanism to facilitate retrieval of the tubing string if the tool gets stuck for any reason. Arrangements are included to keep the packer in a retracted position for running and retrieval operations to avoid damage to the packer.

[005] Analysis of technical solutions, selected from the patent and scientific and technical literature, showed that the known mechanical packer (see "Reference manual on the gas-lift method of well operation". Yu.V. Zaitsev, R.A. Maksutov, O.V. Chubanov et al. M .: Nedra, 1984, p. 76). The packer consists of a wellbore connected to a tubing string. An expanding cone and sealing collars between the last and upper stops are freely installed on the barrel.

[006] To transmit torque to the packer bore, when it is seated, a spring lantern is used; there is a shaped bayonet groove in which the pin moves when the packer is seated. It is possible to disconnect the tubing string, if necessary, from the packer by left rotation. If it is necessary to reattach the tubing to the tubing packer, it can rotate within the production casing.

[007] A mechanical packer is also known from the prior art (see RF patent No. 2204427, IPC E21B 33/12, publ. 10.02.2004). The packer contains a barrel, a coupling, an anchor unit with dies and expanding cones, and a seal. The packer is equipped with an adapter and an extension, connected to each other and the barrel with carved elements, spring-loaded rusks in the barrel bore. It is also known to connect, by means of a thread, the lower expansion cone with the barrel.

[008] Based on the foregoing and the conducted patent studies, it can be concluded that there are no technical solutions in the prior art based on features that coincide with all the essential features of the proposed technical solution.

[009] All existing cup packers require a high load to set, have a high risk of cup damage during installation, are dependent on well integrity, and are limited to withstand high pressures after activation.

[0010] The oil and gas industry has every reason to improve the efficiency and reliability of packers that are deployed and operated in a downhole environment. This should ensure that the packers are operated with maximum efficiency, minimal risk of failure or inaccurate operation, possible flexibility according to operator requirements, and minimization of any repairs associated with time delays and costs.

ESSENCE OF THE TECHNICAL SOLUTION

[0011] The technical problem or technical problem in this technical solution is the creation of an axial cup packer.

[0012] This solution discloses an axially acting cup packer that includes a mandrel on which is mounted a rubber and / or rubber-metal packer element that is used to seal the annulus of the well. In some embodiments, material such as HNBR, Viton, Afflas, and the like may be used, but not limited to. The design of the packer element allows it to pass through the constrictions of the string when running the assembly due to the small value of the outer diameter in the deactivated position. To activate the packer element, a pressure ring is used, which is made in the form of a thin-walled cylinder with through oval holes along the surface and is designed to compress the packer element when axial force is applied. In some embodiments, the pressure ring may be made of steel. The pressure ring has holes (for example, circular) through which the fluid flow passes, which creates additional pressure on the packer element from the inside for more reliable isolation. To restrict the movement of the pressure ring, a spacer, for example made of steel, is used, which protects the packer element from excessive compression and damage. Also, in the activated position, this design allows the axial force to be transmitted to the lower packer of the two-packer assembly.

[0013] Also, the packer includes a resistor (retaining) ring that is used to protect against premature activation of the packer element.

[0014] The technical result of the invention, manifested when solving the above technical problem, is to increase the reliability of the packer and the entire assembly for re-fracturing, as well as increasing the number of stages of hydraulic fracturing without lifting the assembly to the surface.

[0015] An additional technical result is an increase in the stability of shutting down active formation zones during hydraulic fracturing and improving the quality of cleaning the well with chemical reagents.

[0016] In some embodiments, the mandrel has mating threads for connection to the rest of the two-packer assembly tools.

[0017] In some embodiments, the mandrel is made in one single piece, without connections.

[0018] In some embodiments, the pressure ring includes holes through which fluid flows.

[0019] In some embodiments, the packer element is made of rubber or rubber metal.

[0020] In some embodiments, the packer is activated by axial force and hydraulic pressure of the incoming fluid.

[0021] In some embodiments, the compression of the packer element is exerted by the hydraulic pressure of the fluid flow over the outer surface of the pressure ring, where the pressure ring is axially displaced towards the packer element.

[0022] In some embodiments, the packer element passes through the constrictions of the string without damage.

[0023] In some embodiments, the packer element, when activated, forms a small area of contact with the casing wall.

[0024] In some embodiments, the retaining ring is threadedly screwed to the lower port.

[0025] In some embodiments, a thrust washer is used to secure the spacer.

[0026] In some embodiments, the resistor ring is reusable.

[0027] In some embodiments, a retaining ring is used to attach the clamping ring and the lower branch pipe to the mandrel, which consists of two half rings that are installed in a profile.

[0028] In some embodiments, when the cup packer is run down the well, the teeth of the retaining ring are in profile.

[0029] In some embodiments, an axial force is applied to the axial cup packer to activate the packer element, causing the teeth to protrude out of the profile and the pressure ring compressing the packer element.

[0030] In some embodiments, the retaining ring includes teeth that are made of steel.

BRIEF DESCRIPTION OF DRAWINGS

[0031] The features and advantages of the present technical solution will become apparent from the following detailed description and the accompanying construction drawings, in which:

[0032] FIG. 1 shows the components of an axial cup packer in an exploded view.

[0033] FIG. 2 shows an axial cup packer assembled in longitudinal section.

[0034] FIG. 3 shows a cup packer of axial action located in the in-line space of the siege pipe string at the well site.

[0035] FIG. 4 shows an enlarged view of the packer element 102 during activation prior to the start of shear of the pressure ring 103.

[0036] FIG. 5 is an enlarged view of the activation of the packer element 102.

DETAILED DESCRIPTION OF THE INVENTION

[0037] Below will be discussed in detail the terms and their definitions used in the description of the technical solution, helping to understand the essence of the technical solution.

[0038] A packer is a device in a borehole for shutting off and sealing separate zones of the wells (the space between the tubing and the casing during hydraulic fracturing of the formation with a selective packer assembly). The axial cup packer is part of the downhole assembly for re-fracturing.

[0039] The axial cup packer is part of a downhole selective packer assembly for re-fracturing.

[0040] Hydraulic fracturing is a method for stimulating the production of oil and gas wells and increasing the injectivity of injection wells. Hydraulic fracturing is performed to create a highly conductive fracture in the target formation under the action of a fluid pumped under pressure. Hydraulic fracturing technology allows the commissioning of inactive wells, in which production by traditional methods is impossible or unprofitable.

[0041] The mandrel is a base tube that serves as a base for attaching various auxiliary parts that make up the assembly of the equipment structure.

[0042] The very technical solution in the complex for hydraulic fracturing works functionally as follows.

[0043] First, the entire assembly is run into the well, which contains the cup packer, to the required depth (depth from the earth's surface to areas of the oil-saturated reservoir, represented as a vertical line, the value of which depends on the depth of the formation. The depth can vary from 1 km to 5 km and more.). The installation of the packer on the casing is carried out by the drilling crew, immediately before running into the well. In some embodiments, this arrangement is two-packer. The upper packer is this technical solution, i.e. a cup packer of axial action, and the bottom is a packer that is generally known in the art. The design of the (upper) claimed packer is designed to transmit the thrust force to the lower packer to activate it, even if the upper packer is already activated. The two-packer assembly provides complete isolation of the leaky section of the casing. In some embodiments, the upper and lower packers may be connected together by tubing.

[0044] Then, the lower packer is activated by transferring a load to it (after activation of the lower packer, the two-packer assembly is fixed with built-in wedges at a given depth without the possibility of movement). An axial load is created on the packer tool due to the increased movement of the pipe string down the well.

[0045] With a further increase in the load in the inventive packer, the teeth of the retaining ring 106 emerge from the profile on the mandrel 100. The teeth are triggered when the value of the axial load is sufficient for the teeth of the retaining ring 106 to exit, i.e. a mechanical way of activation is carried out (application of force). The load is increased by the self-weight of the pipe string. The pipe connections (pipe string) are heavy, much of which is held back on the outer earth's surface. The string is held by wedges, to increase the load on the claimed packer, the wedges are slightly expanded and the weight increases.

[001] Next, the left side of the axially acting cup packer (items 100, 102, 107, 108, 109 in Fig. 1) begins to move to the right. The packer element 102 begins to be caught by the pressure ring 103.

[0046] Once the thrust collar 103 reaches the thrust collar 108, no further compression is possible, an increase in weight will be recorded at the wellhead, which will signal the activation of this cup packer. A way to ensure that the elements are activated is to check the column weight. Since one element clings to another, the result will be an increase in the weight of the entire pipe string.

[0047] At Fis. 1-2 shows the design of an axial cup packer. FIG. 3-5 design features are shown.

[0048] The axially acting cup packer includes a mandrel 100 on which all other parts are mounted. In some embodiments, the mandrel 100 can be made in one single piece, without additional connections, which increases its strength. Mandrel 100 is the basis of the cup packer design. Mandrel 100 can have a mating thread for connection with the rest of the two-packer assembly tools. An O-ring 109 is inserted into the profile to seal off the space between the packer 102 and the mandrel 100, as shown in FIG. 2. Packing element 102 is installed on mandrel 100 and serves to isolate the annulus in the well. In some embodiments, the packer element 102 may be configured with an inwardly inserted spacer to achieve better sealing performance. The specified packer element 102 in its principle of operation is not only hydraulic, but also mechanical, since it is deformed from both overpressure and axial compressive force. In some embodiments, the mechanical compression packer element 102 is composed of two sections. The upper section is made of soft rubber (hardness, for example, 65 - 80 units) and is intended for sealing the well, and the lower section, which serves to partially bridle the gap between the packer and the well, is made of harder rubber (hardness, for example, 90 - 95 units).

[0049] To activate the packing element 102, compression is necessary, which is performed by the pressure ring 103. The compression is carried out due to the hydraulic pressure of the fluid flow along the outer surface of the pressure ring 103, where the pressure ring 103 is shifted axially towards the packer element 102, thereby deforming it so that the element touches the casing 110. Fluid is supplied from the surface from the pumps to the well. Moving along the depth of the well through the inner space of the pipes and reaching the holes, the liquid comes out of them and begins to move towards the packer element along the outer surface of the pipes or well walls, as a result of which pressure is generated. Also, compression of the packer element 102 touches the element with the casing 110 with a small contact area due to the optimized profile of the section of the rubber element, which allows the transfer of axial force to the lower packer of the two-packer assembly without damaging the packer element 102, as shown in FIG. 5. Casing string 110 is designed for casing of boreholes, as well as isolation of productive horizons during operation. Casing 110 is made up of casing by making up (sometimes welded) in succession. Casing pipes used in drilling oil and gas wells are made mainly of steel with two threaded ends and a screwed sleeve at one end (sometimes sleeveless with a bell end). In some embodiments, a surface casing or intermediate casing or production casing may be used.

The design of the pressure ring 103 provides holes (for example, circular) through which the fluid flow passes, which provides a more reliable pressing of the packer element 102 against the wall of the casing string 110 due to the ingress of the liquid flow into the inner space of the packer element from the open end, fixed by the pressure ring 103. In some embodiments, fluid flow refers to the working fluid that is used to set the cup packer and fracture operations. The working fluid can be either plain water with impurities or various emulsions. To limit the compression ratio of the packer element 102 by the clamping ring 103, a spacer 107 is used. To fix the spacer 107, a thrust ring 108 is used. The clamping ring 103 is screwed with a threaded connection to the lower branch pipe 104. To securely attach the clamping ring 103 and the lower branch pipe 104 to the mandrel 100 fixing ring 105, which consists of two half rings that are installed in the profile. To protect against premature activation of the packer element 102, a resistor ring 106 is used. When the cup packer is run down the well, the teeth of the resistor ring 106 are in profile. To activate the packer element 102, an axial force must be applied to the axial cup packer, as a result of which the teeth come out of the profile, and the pressure ring 103 compresses the packer element 102. In some embodiments, the teeth can be made of steel and are part of the resistor ring 106, for example , in a trapezoidal shape. The load applied to the pipe string along the axis (along the length) is carried out by its own weight. Even if this weight is significant, the load it creates can be limited for various technical reasons, for example. large depth of the well, the complexity of the trajectory, limited expansion of the wedges that hold it, etc. Therefore, the fluid pressure is added in order to increase the load for activation.

[0050] While the above description has discussed some embodiments of a cup packer and methods of handling it, various improvements will be apparent to those skilled in the art. All such improvements that fall within the scope of the appended claims are intended to be included in the foregoing description.

Claims (15)

1. Cup packer of axial action, containing a mandrel, on which a packer element is installed, made with the possibility of isolating the annulus of the well, while the packer element is made of a cup-shaped form with one end fixed to the mandrel and an open other end with the formation of a corresponding cavity, closed from the open the end of the packer element with a clamping ring, while the clamping ring is installed on the mandrel with the ability to move and compress the packing element by axial force, a spacer is installed on the mandrel in the cavity, made with the ability to limit the mobility of the clamping ring, while the spacer is fixed on the mandrel with a thrust ring, and the upper end the pressure ring interacting with the packer element has openings with the possibility of fluid flow from the outer surface of the pressure ring into the cavity, providing additional hydraulic pressure of the fluid flow to compress the packer element , and the other lower end of the clamping ring is threaded with the lower branch pipe, while a retaining ring is installed on the mandrel with teeth engaging with the counter surface of the mandrel in the transport position of the packer, the retaining ring is configured to protect against premature activation of the packer element, retaining the ring with one lower end contacts the supporting surface of the lower pipe, and the other upper end with the lower end of the retaining half rings, while the pressure ring and the lower pipe are installed on the mandrel by means of the locking half rings and the retaining ring so that the half rings are installed between the ends of the pressure ring and the retaining ring and are made with the possibility of limited axial movement relative to the mandrel in its profile. 2. Cup packer of axial action according to claim 1, characterized in that the mandrel has a mating thread for connection with the rest of the two-packer assembly tools. 3. A cup packer of axial action according to claim 1, characterized in that the mandrel is made as one single element, without connections. 4. Cup packer of axial action according to claim 1, characterized in that the packer element is made of rubber or rubber-metal. 5. An axial cup packer according to claim 1, characterized in that the packer is activated by axial force and hydraulic pressure of the incoming fluid. 6. A cup packer of axial action according to claim 1, characterized in that the compression of the packer element is carried out due to the hydraulic pressure of the fluid flow along the outer surface of the clamping ring, where the clamping ring is shifted axially towards the packing element. 7. A cup packer of axial action according to claim 1, characterized in that the retaining ring is reusable. 8. Cup packer of axial action according to claim 1, characterized in that when the cup packer is run into the borehole, the teeth of the retaining ring are in the profile. 9. An axial cup packer according to claim 1, characterized in that to activate the packing element, an axial force is applied to the axial cup packer, as a result of which the teeth come out of the profile and the clamping ring compresses the packer element. 10. A cup packer of axial action according to claim 1, characterized in that the retaining ring contains teeth that are made of steel. 11. A method for activating an axial cup packer according to claim 1, including the following steps: lowering a two-packer assembly containing a cup packer of axial action according to claim 1, which is upper, into the well to a predetermined depth; activating the lower packer by transferring a load to it, and the teeth of the retaining ring of the upper cup packer come out of the profile; pressing the packer element of the upper cup packer with the pressure ring, and after the pressure ring reaches the stop ring, an increase in weight is recorded on the surface, which signals the activation of the cup packer and further transfer of the load to the lower elements of the assembly; with further pressure build-up, the fluid flow enters through the holes in the clamping ring into the cavity of the packer element.

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