EA042913B1 - CENTRATOR - Google Patents

Description

The field of technology to which the invention belongs

The invention relates to a centralizer for use in centering a pipe in a shaft.

State of the art

In the oil and gas exploration and production industry, oil and gas formations are accessed by wellbores (wellbores) from the surface, the wellbore is usually then supported with metal pipes known as casing. Casing sections are usually screwed together to form a casing that is run into the wellbore, the annulus between the casing and the wellbore is then filled with a hardenable material such as cement that secures the casing and wellbore and provides a seal to prevent uncontrolled fluid flow from rising. environment in the annulus.

Given that securing the casing and/or wellbore and preventing controlled fluid flow up the annulus is critical to safe well operation, it should be recognized that poor cementing poses a significant operational risk to the operator.

One factor in poor quality cementing is unconstrained thickness of the cement in the annulus, caused by deviation or displacement of the casing from the central longitudinal axis of the well. To center the casing string in the wellbore, tools known as centralizers (commonly referred to as casing centralizers) are typically mounted around the casing string, used to maintain the casing in a generally central position in the wellbore until the cement sheath surrounding the casing solidifies.

Although centralizers are widely used, there are a number of problems and disadvantages when using conventional tools and equipment.

For example, rigid-body centralizers that have fixed radial vanes to move the casing away from the wellbore wall are not able to adapt to wellbore restrictions and therefore may prevent the casing from reaching the required depth in the wellbore.

As an alternative to rigid body centralizers, bow spring centralizers have been developed that have end sleeves hinged together by elongated spring elements in the form of bow springs. Although the spring elements are capable of deflecting radially inward to allow the casing string to pass through wellbore constrictions, in steep deviated or horizontal wellbores (which are generally referred to as horizontal wellbores), significant casing weight in the horizontal section of the wellbore can deform the spring elements beyond, where the elements are capable of holding the casing in position, with the casing resting on the underside of the wellbore and risking uneven wellbore cementing as described above.

The essence of the invention

According to the first aspect, a centralizer is proposed for use in centering a pipe in a wellbore, comprising a first end sleeve;

second end sleeve; and a plurality of retaining elements located between the first end sleeve and the second end sleeve, wherein at least one of the retaining elements contains the first end section;

second end section;

an intermediate section located between the first end section and the second end section; and one or more sections in the form of a wing protruding from the intermediate section and located at an angle inward relative to the intermediate section, wherein the first end sleeve, the second end sleeve and the supporting elements are made in one piece, and moreover, the sections in the form of a wing are made in one piece with an intermediate section, and sections in the form of a wing contain a curved or bent part of the intermediate section.

In use, the centralizer may be configured to be mounted on a pipe, wherein the centralizer is configured to cooperate with the wellbore to center the pipe in the wellbore.

The pipe may be a barrel-supporting pipe.

The pipe may be a shaft-supporting tubular string.

The pipe may be a casing pipe.

The pipe may be a casing string.

The pipe may be a liner.

The pipe may be a tool string, a work string, or the like.

- 1 042913

The pipe may contain a maintenance filter or the like.

Preferably, providing a centralizer having one or more wing-like sections angled to the intermediate section will move the intermediate section away from the pipe in use. Displacement of the intermediate portion away from the pipe can prevent or at least reduce the risk of damage to the retaining member that may otherwise occur if a force of sufficient absolute magnitude is applied to the intermediate portion to deform the otherwise retaining member to a flat position with respect to the end sleeves.

The intermediate section may have a stiffness greater than that of the first and second end sections of the supporting element.

Preferably, providing a centralizer having one or more bracing elements with an intermediate portion having a stiffness greater than that of the bracing element end portions allows the bracing member to flex at the end portions rather than at the intermediate portion. The preferred bending of the backing member at the end portions is provided by a centralizer having sufficient rigidity to maintain the tubular in a generally centered position in the wellbore, while also having sufficient flexibility to pass through restrictions in the wellbore and recover to the desired shape. Providing sections in the form of a wing improves the rigidity of the intermediate section.

In addition, providing a centralizer having sufficient rigidity to keep the pipe generally centered in the wellbore, as well as having sufficient flexibility to pass through the restrictions in the wellbore and recover to the desired shape, can reduce the number of supporting elements compared to a conventional centralizer. This, in turn, may reduce the force required to run the pipe into the wellbore, as the frictional forces generated in contact with the surrounding wellbore are reduced.

The ability to maintain the pipe in a generally centered position in the wellbore, as well as sufficient flexibility to pass through the restrictions of the wellbore and reshape, promotes improved cementing (or at least minimizes the possibility of poor cementing) with an increase in the ability to achieve the desired depth in the wellbore.

As described above, the centralizer can be configured to be located on the pipe, the centralizer is configured to cooperate with the wellbore to center the pipe in the wellbore.

In particular embodiments, the centralizer may be configured to be located on a wellbore pipe, such as a casing, and the wellbore may be a wellbore, the centralizer is configured to center the wellbore pipe in the wellbore.

However, the centralizer may have other forms. For example, in other cases, the centralizer may form all or part of a sub forming part of the holding tubular string. In other cases, the centralizer may be configured to be mounted on a tubular string, such as a tool string, a workstring, or the like, configured to run into the wellbore casing pipe, wherein the centralizer configured to center the tubing string in the wellbore casing pipe .

The first end and the second end may be configured, such as sized and/or shaped, to facilitate installation of the centralizer on the pipe.

The backing elements can be configured, for example, to be sized, shaped and/or flexible enough to facilitate interaction with the shaft.

As described above, the centralizer includes a first end sleeve, a second end sleeve and a plurality of supporting elements.

The centralizer is a single structure. Those. the first end sleeve, the second end sleeve and the supporting elements are made in one piece.

The centralizer can be made in the first larger diameter configuration.

In the first configuration, the centralizer may form an outer diameter that is larger than the outer diameter of the first and second end sleeves.

In the first configuration, the intermediate section may assume a radially extended position.

The centralizer can be made in a second smaller diameter configuration.

In the second configuration, the centralizer may form an outer diameter that is greater than the outer diameter of the first and second end sleeves, but less than the outer diameter in the first configuration.

In the second configuration, the intermediate portion may assume a radially retracted position with respect to the first configuration.

The centralizer can be reconfigured from a first larger diameter configuration to a second smaller diameter configuration.

The centralizer can be reconfigured from a second smaller diameter configuration to a first larger diameter configuration.

- 2 042913

The supporting elements may be configured to allow the centralizer to be reconfigured between the first configuration and the second configuration.

In use, the centralizer may be reconfigured from the first configuration to the second configuration upon encountering a restriction in the wellbore to allow passage of the centralizer through the restriction. The centralizer can be reconfigured from the second configuration to the first configuration when the centralizer has passed through the restriction in the wellbore.

The centralizer can be shifted to the first larger diameter configuration.

In use, the centralizer may normally form a first configuration, but it can be reconfigured into a second configuration when it encounters a restriction in the wellbore, with the centralizer returning to the first configuration when the restriction is passed.

Preferably, although the centralizer in the second configuration has an outer diameter smaller than the diameter in the first configuration, the backing elements in the second configuration are offset from the pipe, thereby preventing or at least reducing the risk of damage to the backing element that might otherwise occur.

As described above, at least one of the supporting elements includes one or more wing-like sections protruding from the intermediate section and angled to the intermediate section.

The wing-like portion protrudes inwards, i. e. in general to the pipe to be centered.

The wing portion may form any non-zero angle with the intermediate portion less than or equal to 180°. It will be understood that an angle of 180° means that the wing-like section is folded back towards the intermediate section and runs parallel to it.

The wing portion may form a non-zero angle with the intermediate portion less than or equal to 90° or about 90°.

In particular embodiments, the wing portion may form an angle of 90° or about 90° with the intermediate portion.

The wing portion may form a non-zero angle with the intermediate portion equal to or about 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, 100°, 110°, 120°, 130°, 140°, 150°, 160°, 170°.

In private embodiments, the implementation of the supporting element contains two sections in the form of a wing.

The wing sections form the same angle with the intermediate section.

However, the wing portions may alternatively form different angles.

Sections in the form of a wing are made in one piece with the intermediate section.

For example, the wing-like portions are formed as a curved or folded portion of the intermediate portion.

At least a portion of the wing-like portions may be curved.

The wing portions may be curved in a circumferential direction.

The wing portions may be curved in the axial direction.

As described above, the centralizer is reconfigured to and from the first configuration and the second configuration.

The first and second end portions of the backing members may be configured to reconfigure between a first larger diameter configuration and a second smaller diameter configuration.

The first and second end sections may be relatively more flexible than the intermediate section.

The first and second end sections may be relatively less rigid than the intermediate section.

The first and second end sections may contain at least one flexible section.

The end sections can be made with at least one of the following properties: flexible, bendable, twistable, deformable, or the like.

The end portions may be flexible, or configured to be flexible, bendable, twistable, deformable, or the like. in any suitable way.

It should be understood that the term bending may refer to bending, twisting, distortion, deformation and/or any other form of movement of the intermediate portion.

It should be understood that at least one element or component of the centralizer may be bent in one direction or in several directions.

At least a portion of the end portions may be curved.

The curved section may be formed in any direction relative to the centralizer.

The curved section may be formed in a direction along the element (for example, the direction may be given between one end sleeve and another end sleeve, or parallel to the axis of the centralizer).

The curved section may be formed in a direction across the element (for example, the direction

- 3 042913 can be set along a circle around the axis of the centralizer or can be taken perpendicular to the direction given between the end sleeves).

The end portions may comprise a non-curved section or a curved section forming a second radius of curvature.

A non-curved section or a curved section forming a second radius of curvature can be specified in the direction across the element.

A non-curved section or a curved section forming the second radius of curvature may be specified in the direction along the element.

The second radius of curvature may be greater than the first radius of curvature.

The non-curved section or the curved section defining the second radius of curvature can move the intermediate portion between the radially outward and inward positions.

Providing end sections having a larger radius of curvature than the intermediate section may provide a degree of flexibility for the end sections that is greater than the flexibility of the intermediate section (smaller radius of curvature).

As described above, the end sections can be made less rigid than the intermediate section.

The end sections may each contain at least two connectors for connecting the respective end section to the respective end sleeve.

The connectors of each end section may diverge from the intermediate section. The connectors can be positioned at a distance from each other on the terminations.

The location of the connectors of each end section at a distance from each other can help to more evenly distribute the load applied from the outside, for example, along the circumference of the end sleeve.

If an external load is applied to the intermediate section and can be transferred to the first and second end sections, the load can be transferred to the connectors. By spacing the connectors of each end portion from each other, the load on each connector can be reduced, which can reduce stress on each connector. Spaced apart connectors may help control bending, torsional, or any other forces at the end portions that could otherwise deform the end portions to the extent that the latter prevent or adversely affect recovery of the centralizer to a larger diameter configuration.

End sections may be bifurcated.

The connectors may form a fork-shaped or branched connector for transmitting force between the end portions and the end sleeves.

Connectors may contain or form curved edges.

As described above, the end sections can be made less rigid than the intermediate section.

The space between the connectors may form an aperture, which may have curved edges.

The aperture may be drop-shaped or triangular in shape, the width of which is greater closer to the end sleeve and further from the intermediate section.

The curved edges of the connectors can help distribute the load more evenly, for example, to reduce or relieve mechanical stress on the connectors.

The end portions may comprise a curved section which may be formed in at least one of the following directions: across and along the element.

The curved section may be proximate to the corresponding end sleeve and far from the intermediate section.

The curved section may provide the curved section with less flexibility than the other portion of the end portions.

The end sections may each form a transition section.

The transition section can be positioned between the curved section of the intermediate section and the curved section of the corresponding end sleeve. The transition section may have a larger radius of curvature than at least one of the following: the curved section of the intermediate section and the curved section of the corresponding end sleeve.

The transition section may comprise or form a flat, or relatively less curved section of the element, which may be relatively more flexible than at least one of the following: an intermediate section and an end sleeve.

The end sleeve and/or the intermediate section may be less flexible than the transition section.

The transition section may help distribute load or stress across the end section, or at least smooth the transition between relatively less flexible components so that loads or stress can be less concentrated on the end section.

- 4 042913 more flexible components.

If the end section contains a curved section to at least partially resist bending, twisting or deformation of the curved section of the end section, the transition between the end sleeve (which may be relatively rigid) and the end section (which may be relatively flexible) can be smoothed, which can help distribution load or mechanical stress on the end section.

The curved section of the end portion may be formed in a circumferential direction around the centralizer.

The intermediate portion may form or form a blade plate.

The intermediate portion may be relatively less flexible than the first and second end portions.

The intermediate section may contain at least one rigid section.

The intermediate portion may be configured to resist at least one of bending, bending, twisting, deforming, or the like.

The intermediate portion may be rigid or configured to resist bending, bending, twisting, deforming, or the like. in any suitable way.

At least a portion of the intermediate portion may be curved.

The intermediate section may include a curved section.

The curved section may be formed in a direction across the element.

The curved section may be formed in a direction along the element.

The curved section may have a first radius of curvature, which may correspond to a direction across the element and/or a direction along the element.

The curved section may provide an intermediate portion with relatively less flexibility than the end portions.

The intermediate portion may comprise or form a curved or convex outer surface. The curved or convex outer surface may be formed in the direction along the elements or may be formed between the end sleeves of the centralizer. The end portions may comprise or form a curved or concave outer surface which may be formed in the direction along the elements or may be formed in the direction between the end sleeves of the centralizer.

The transition portion may comprise a concave outer surface.

The intermediate portion may comprise or form a curved or convex outer surface which may be formed in a direction across the elements or may be formed in a direction given between adjacent centralizer elements.

The intermediate portion may include a ridge, rib, protrusion, or the like, which may reduce the area of contact between the intermediate portion and the wall of the wellbore.

As described above, the centralizer contains a plurality of supporting elements, at least one of which contains a first end section, a second end section, an intermediate section and one or more sections in the form of a wing.

Although in particular embodiments, the end portions and the intermediate portion may form portions of a different shape, for example, with different curved portions, in some cases, at least the support element may have end portions and an intermediate portion forming a generally common shape, for example, a curve .

At least one supporting element may be in the form of an arcuate spring element.

The supporting elements may form or form the blades of the centralizer.

Supporting elements can be arranged along the circumference around the first and second end sleeves.

The backing elements can be spaced along the circumference around the first and second end sleeves.

In private embodiments, the implementation of the supporting elements are bifurcated.

The backing elements may contain or form a convex outer surface along the length, for example along the entire length, between the end sleeves.

The backing elements may comprise at least one of the following: a convex, flat, or concave section along the length of the element.

The backing elements may comprise or form a convex outer surface for a portion of the length of the elements and may comprise or form at least one of the following: a flat and concave outer surface for another portion of the length of the element.

The direction formed between adjacent members of the centralizer may define a circumferential direction relative to the centralizer.

The end sleeves may be coaxial with respect to the axis of the centralizer, so that the circumferential direction may be given relative to the axis of the centralizer.

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The end sections may contain or form at least one of the following: a curved, convex, concave or flat outer surface in at least one of the directions given along and across the element.

At least one of the following: curved, convex, concave or flat outer surface - can be formed in the direction given between adjacent elements of the centralizer and/or between the end sleeves of the centralizer.

In an initial undeformed state, or at least a partially deformed state, the centralizer may assume a larger diameter configuration which may have a first radius of curvature.

The centralizer may enter the wellbore in an initially undeformed state and may then be partially deformed to assume a partially deformed configuration according to the diameter of the wellbore.

The first radius of curvature may be formed by the radius of the stem.

The curved or convex outer surface of the elements may define a second radius of curvature, which may be formed in a direction across the elements.

The second radius of curvature may be equal to or less than the first radius of curvature, such that at least in the undeformed state or at least partially deformed state has a centralizer.

The curved or convex outer surface of the elements may include a portion, such as a central portion or the like, which may be in contact with the barrel wall.

The curved or convex outer surface of the elements may include a portion, such as a rim portion or the like, that cannot contact the barrel wall in non-deformed or partially deformed configurations.

If the centralizer is deformed, in some circumstances the edge portions may come into contact with the borehole wall.

Providing edge portions that may not be in contact with the wellbore wall can reduce friction between the elements and the wellbore wall as the centralizer is moved through the wellbore.

The first radius of curvature may correspond to the radius of curvature of the stem. By providing the second radius of curvature equal to or less than the first radius of curvature, the convex outer surface can have a reduced area of contact between the intermediate portion and the wall of the wellbore. Reducing the area of contact may reduce friction and/or facilitate passage of the centralizer through the hole.

The centralizer can be configured to accept different diameters depending on the degree of deformation of the elements. The centralizer may contain at least one supporting element to limit bending or deformation of the elements. Narrowing, bending, or deformation of the members may prevent the centralizer from accepting a diameter that is less than a threshold diameter, which may allow the centralizer to at least partially recover to a diameter that is greater than the threshold diameter.

In the initial state, the centralizer may describe at least the first diameter, which may correspond to, be greater than or less than the value for the larger diameter configuration.

The centralizer can be reconfigured to a deformed state to describe a smaller second diameter to allow the centralizer to pass through the constriction.

The centralizer can be reconfigured to a restored state to describe the first diameter and center the pipe in the wellbore.

In the deformed configuration, the degree of deformation of the elements can be limited to ensure that the centralizer is restored to the first diameter.

The second diameter may be equal to or greater than the threshold diameter.

At least one support element can be configured to stop the pipe when at least one of the elements is bent or deformed.

At least one support element may be flexible or deformable.

At least one supporting element may be configured to support at least one of the following: intermediate section and end sections.

At least one supporting element may be configured to support the radially outermost portion of the elements from the axis.

At least one supporting element may be configured to support a section of elements containing a midpoint between the end sleeves.

The radially furthest part of the element from the axis may form the apex or highest point of the elements.

The elements may each comprise a convex outer surface formed along the circumference of the centralizer.

The outer surface may comprise a contact surface of the elements.

The contact surface may be in contact with the barrel wall.

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The convex outer surface may be formed at least partially along a segment of the length of the element.

The convex outer surface may be formed at least partially across the element in width.

The element length can be defined as the part of the element extending axially or downhole relative to the centralizer in the wellbore.

The width of the element can be defined as the portion of the element extending in a circumferential direction relative to the centralizer in the wellbore.

The thickness of the element can be set in the radial direction relative to the centralizer in the wellbore.

In the initial undeformed state, the centralizer can describe the first diameter, which forms the first radius of curvature.

The convex outer surface of the elements may each form a second radius of curvature.

The second radius of curvature may be equal to or less than the first radius of curvature.

The first radius of curvature may be formed along a circumference around the stem. The second radius of curvature may be formed along a circle around the centralizer.

By providing backing members with a second radius of curvature, friction between the centralizer and the wellbore can be reduced as the centralizer is moved through the wellbore. It is possible to reduce the wear of the elements due to this reduced friction.

The supporting elements may contain at least one end section for connecting the elements with the end couplings of the centralizer.

The supporting elements may contain at least two end sections for connecting the element with the end sleeve of the centralizer.

The end section may be bifurcated.

Providing more than one end portion for each end of the element can help distribute force evenly around the end sleeve.

The supporting elements may contain at least two end sections for connecting each end of each element with their respective end sleeves, while the connections between each adjacent end section on each end sleeve are located at an equal distance from each other along the circumference of the end sleeve. However, it is understood that, in the example, adjacent connections may not be equally spaced along the circumference of the end sleeve. Depending on the particular geometry of the centralizer, it may or may not be possible to distribute the end section connections equally spaced along the circumference of the end sleeve. For example, larger diameter centralizers or centralizers containing more than four, five, or six elements may provide sufficient space to accommodate equally spaced end section connections, while smaller diameter centralizers or centralizers containing fewer than four, five, or six elements may not provide enough space to accommodate equally spaced end section connections.

By providing an equal distance formed between the end sections, a uniform force distribution at least partially along the circumference of the end sleeves of the centralizer can take place. When used, for example, in a horizontal section of a wellbore, the centralizer elements on the underside of the wellbore may experience greater deformation than the centralizer elements on the upper side of the wellbore. The elements of the centralizer on the bottom side of the wellbore can apply a force to the end sleeves that is greater than the force applied to the end sleeves by the elements on the top side of the wellbore.

By providing end section connections that are equally spaced along the circumference of the end sleeves, the force applied to the end sleeves by the elements can be distributed more evenly than in the case where the end section connections are not equally spaced along the circumference of the end sleeves. couplings. Thus, it is possible to reduce excessive mechanical stress or permanent deformation created in some parts of the terminations or in fact in any other part of the centralizer.

At least one support element may comprise a concave outer surface. The outer surface of the support element may face the wall of the barrel. The outer surface of the support member may not normally be in contact with the barrel wall. The support element may comprise or have a curved shape.

The support element may include a convex inner surface. The convex inner surface may face the casing and may be moved to abut against the casing, for example, in response to passage through a constriction in the wellbore.

At least one supporting element may extend from one end section to the other end section of the elements. At least one support element can be configured to apply force between the first end and the second end of the elements.

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At least one supporting element can be configured to apply force to the elements or resist the force applied by the elements. At least one supporting element can be configured to provide support at the midpoint of the elements. The middle point can be formed between the end sleeves. At least one supporting element can be configured to support the intermediate section.

At least one support element can be centered or placed symmetrically about the midpoint of the elements.

At least one support element may be configured to apply force to the elements or resist force applied by the elements. At least one supporting element can be configured to provide support at the point of the elements located between the midpoint and the end section of the elements.

At least one supporting element can be installed along the length of the elements in place near one end of the centralizer and at a distance from the other end of the centralizer.

At least one support element may include at least one curved spring element. At least one supporting element may extend at least partially along the central section of at least one of the following: an intermediate section and end sections. At least one supporting element may extend at least partially along the central portion of the elements. At least one supporting element may extend at least partially along the edge of at least one of the following: intermediate section and end sections. At least one support element may extend at least partially along the edge of the support elements.

The supporting elements may comprise metal or may be made of metal.

The centralizer may include at least one contact surface for contact with the wall of the wellbore.

The contact surface may comprise a friction reducing coating.

The supporting elements may comprise a contact surface. The friction reducing coating may form part of the backing members.

The friction reducing coating may contain at least one of the following: polytetrafluoroethylene and graphene, or the like. material.

Any other suitable coating may be applied to the retaining members to reduce friction between the compressible members and the bore wall, or the retaining members may be made or modified to include a friction reducing coating. The supporting elements may contain metal.

By providing backing members with a friction reducing coating, friction between the centralizer and the wellbore can be reduced when the centralizer is moved through the wellbore. It is possible to reduce the wear of the backing member due to the reduced friction.

The contact surface may comprise a friction reducing coating forming part of the backing members.

The friction reducing coating may comprise at least one of the following: polytetrafluoroethylene and graphene or other suitable friction reducing coating.

According to a second aspect, a method is provided for centering a pipe in a wellbore using a centralizer of the first aspect.

The method may include providing a plurality of centralizers on the tubular string.

Centralizers may contain end sleeves connected by elements to ensure that the centralizer accepts different diameters depending on the degree of deformation of the supporting elements.

Supporting elements can be constrained to prevent the centralizer from accepting a diameter less than a threshold diameter.

The method may include running a pipe and centralizers into the well through a narrowing of the wellbore to radially deform the centralizers.

The method may include running pipe and centralizers from the narrowing into the wellbore section to at least partially restore the centralizers to a diameter greater than the threshold diameter.

The method may be of particular utility in running pipes, such as casing, deviated or horizontal wellbores, such as oil and/or gas wellbores, where the mass of the pipe tends to compress or deform centralizer members located between the pipe and the underside of the wellbore. . In the absence of limiting the degree of deformation of the retaining elements, the retaining elements between the tubular and the underside of the wellbore must certainly experience a greater degree of deformation than the retaining elements between the tubular and the upper side of the wellbore and may experience excessive or irreversible deformations when the centralizers pass through the narrowing of the wellbore. On a pipe extending into the wellbore section behind the narrowing, elements that have experienced excessive deformation may not recover sufficiently to provide

- 8 042913 description of the first diameter by a centralizer and retention of a coaxial pipe with a barrel.

With the proposed method, the degree of deformation of the individual elements can be limited, providing the compressible elements with a recovery sufficient to maintain a pipe essentially coaxial with the barrel. If the pipe and centralizers are run into the well through a horizontal pipe constriction, then there should be a situation for the elements of the centralizer between the pipe and the bottom side of the wellbore, in which the latter experience a greater degree of deformation, while limiting the degree of deformation of the individual elements, the deformation is probably more evenly distributed between compressible elements.

The threshold diameter may define a minimum centralizer diameter below which the retaining elements may experience excessive deformation to the extent that excessively deformed elements may not recover sufficiently to allow the centralizer to describe a larger design diameter when moved in the wellbore section after a narrowing of the wellbore. By limiting the backing members to prevent the centralizer from accepting a diameter smaller than the threshold diameter, the centralizer may be able to at least partially recover to a larger diameter than the threshold diameter to maintain the pipe substantially coaxial with the wellbore.

Those skilled in the art will appreciate that with a deformable centralizer there is always an unavoidable degree of deformation of the backing members on the underside of the pipe in deviated or horizontal wellbore applications, and this is covered, for example, in the American Petroleum Institute's Specification 10D for bow spring centralizers.

Centralizers may describe at least the first diameter in the initial state. The method may include radially deforming the centralizers to describe the smaller second diameter formed by the narrowing of the wellbore.

The centralizer may be in the initial state before entering the wellbore.

The barrel diameter may define the first diameter.

When entering the hole, the centralizers can be partially deformed to accept the first diameter.

The second diameter may be equal to or greater than the threshold diameter. When deformed in the narrowing of the wellbore, the centralizers may not be deformed to a diameter less than the threshold diameter.

By only deforming the centralizers to a diameter equal to or greater than the threshold diameter, the centralizers may not experience excessive deformation.

Imposing restrictions on the compressible elements to prevent the centralizer from acquiring a diameter that is less than a threshold diameter may comprise providing at least one support element between the compressible elements and the pipe.

At least one supporting element can be configured to prevent deformation of the supporting elements, which results in the centralizer describing a circle with a diameter less than the threshold diameter.

The method may comprise limiting the deformation of the bracing elements by abutting at least one supporting element against the pipe in response to radial compression of at least one of the bracing elements.

The method may include moving the centralizers through the narrowing of the wellbore in inclined or horizontal sections of the wellbore.

The method may comprise restricting the elements on the underside of the centralizer from excessive deformation in response to the weight applied to the supporting elements by the pipe as the centralizer passes through the narrowing of the wellbore.

The deformation-limiting elements on the underside of the centralizer may support the pipe such that the pipe assumes a substantially coaxial position in at least one of the following: the narrowing of the wellbore and the section of the wellbore.

The pipe support may comprise providing at least one support element to maintain the pipe in a substantially coaxial position. The at least one support element can resist deformation of the elements on the underside of the wellbore to keep the pipe at a minimum radial distance above the underside of the wellbore. The minimum radial distance can be set by a threshold diameter. The minimum radial distance can be set by the bore diameter. The minimum radial distance may be equal to, or approximately equal to, half the difference between the threshold diameter or the diameter of the borehole restriction and the diameter of the pipe.

Also described is a supporting element for the centralizer of the first aspect, and the supporting element contains the first end section;

second end section;

an intermediate section located between the first end section and the second end section; and one or more sections in the form of a wing protruding from the intermediate section and located

- 9 042913 at an angle to the intermediate section.

The intermediate section may have a stiffness greater than that of the first and second end sections.

According to the third aspect, a downhole assembly is provided, containing at least one centralizer of the first aspect.

The arrangement may comprise a plurality of centralizers of the first aspect.

The arrangement may include a pipe.

It is understood that any of the features described above or below may be used alone or in combination.

Brief description of the drawings

In FIG. 1 shows a centralizer for centering a pipe in a wellbore.

In FIG. 2 is an isometric view of the centralizer shown in FIG. 1.

In FIG. 3 is an enlarged view of the supporting element of the centralizer shown in FIG. 2, separately.

In FIG. 4 is an isometric view of an intermediate portion of the support element shown in FIG. 3, separately.

In FIG. 5 is a plan view of the intermediate section shown in FIG. 3.

In FIG. 6 is a side view of the intermediate section shown in FIG. 3.

In FIG. 7 shows a section A-A of the intermediate section shown in FIG. 6.

In FIG. 8 is an end view of the intermediate section shown in FIG. 3.

In FIG. 9 shows an alternative centralizer for centering pipe in a wellbore.

In FIG. 10 is an enlarged view of the supporting element of the centralizer shown in FIG. 9, separately.

In FIG. 11 shows an alternative centralizer for centering pipe in a wellbore.

In FIG. 12 is an enlarged view of the supporting element of the centralizer shown in FIG. 11, separately.

In FIG. 13 schematically shows a downhole assembly.

In FIG. 14 schematically shows an alternative well assembly.

Description of preferred embodiments of the invention

In FIG. 1 of the accompanying drawings schematically shows a centralizer 10 for use in centering pipe 12 in a wellbore W. As shown in FIG. 1, the pipe 12 is in the form of a casing string and the wellbore W is in the form of a wellbore, the annulus A between the pipe 12 and the wellbore W is filled with a hardenable material, such as cement, which secures the pipe 12 and the wellbore W and provides a seal to prevent the passage of uncontrolled fluid flow. along the annular space A.

For use as described further below, the centralizer 10 is configured to cooperate with the wall of the wellbore W to center the pipe 12 in the wellbore W.

In FIG. 2 of the accompanying drawings is an isometric view of the centralizer 10 shown in FIG. 1. As shown in FIG. 2, the centralizer 10 is a single structure having a first end sleeve 14, a second end sleeve 16 and a series of elongated support elements 18. The first and second end sleeves 14, 16 are generally cylindrical in shape and are configured to mount the centralizer 10 on the pipe 12. Supporting elements 18 are located between the first end sleeve 14 and the second end sleeve 16 and are located along the circumference and spaced around the first end sleeve 14 and the second end sleeve 16. The centralizer 10 shown has eight supporting elements 18. However, it should be recognized that the centralizer 10 can have any suitable number of supporting elements 18. The supporting elements 18 form the blades of the centralizer 10.

In FIG. 3 of the accompanying drawings, which shows one of the support elements 18 taken in isolation, it can be seen that the support element 18 has a first end section 20, a second end section 22, an intermediate section 24 and sections 26 in the form of a wing.

As shown in FIG. 3, the first end section 20 of the support member 18 is bifurcated, having two connecting sections 28 for connecting the first end section 20 to the first end sleeve 14. sleeve 14. The second end section 22 of the supporting element 18 is also bifurcated, having two connecting sections 32 for connecting the second end section 22 with the second end sleeve 16. An aperture 34, which in the centralizer 10 shown also has the form of a drop-shaped aperture, is formed between the connecting sections 32 and a second end sleeve 16. In the shown centralizer 10, the connecting sections 28, 32 diverge from the intermediate section 24 to be located at a distance from each other on the first and second end sleeves 14, 16.

In the centralizer 10 shown, the connecting portions 28, 32 each comprise a curved section 36, 38 near the respective end sleeves 14, 16 and a non-curved section 40, 42, the curved sections 36, 38 due to their shape having a stiffness greater than the non-curved sections 40, 42, while

- 10 042913 provides a transition between the end sleeves 14, 16 and the intermediate section 24.

In FIG. 4-8 of the attached drawings show an intermediate section 24 of one of the supporting elements 18 of the centralizer 10.

As shown, the intermediate portion 24 is curved in both directions, circumferentially and axially, and forms a convex, curved outer surface. The curved shape of the intermediate portion 24 provides a rigidity that is greater than that of the end portions 20, 22.

The wing sections 26 protrude from the intermediate section 24 and are angled to the intermediate section 24. In the centralizer 10 shown, the wing sections 26 form an angle of approximately 90° with the intermediate section 24. However, the wing sections 26 may form other angles. with an intermediate section 24.

As shown in FIG. 6, for example, the portions in the form of a wing 24 are also curved in the axial direction.

The wing sections 26 have been found to further improve the rigidity of the intermediate section 24 relative to the end sections 20, 22. In addition, providing the wing sections 26 at an angle to the intermediate section 24 moves the intermediate section 24 away from the pipe 12 in use.

Preferably, providing a centralizer 10 having one or more brace members 18 with an intermediate portion 24 having a stiffness that is greater than that of the end portions of the stem member allows for preferential bending of the stem member at the end portions rather than at the intermediate portion. The preferred bending of the retaining members 18 at the intermediate location is provided by a centralizer 10 having sufficient rigidity to maintain the pipe 12 generally in a central position in the wellbore W, but also having sufficient flexibility to pass through the restrictions in the wellbore and recover to the desired shape. It has been found that providing wing sections 26 further improves the rigidity of intermediate section 24 relative to end sections 20, 22. In addition, providing wing sections 28 at an angle to intermediate section 24 moves intermediate section 24 away from pipe 12 in use.

It should be recognized that various modifications can be made without departing from the scope of the invention as defined in the claims.

For example, in FIG. 9 of the accompanying drawings shows an alternative centralizer 110 for centering pipe 12 in wellbore W.

As shown in FIG. 9, the centralizer 110 is a single structure having a first end sleeve 114, a second end sleeve 116, and a series of elongated support members 118. The first and second end sleeves 114, 116 are generally cylindrical in shape and configured to mount the centralizer 110 to the pipe 12. Supporting elements 118 are located between the first end sleeve 114 and the second end sleeve 116 and are located along the circumference and spaced around the first end sleeve 114 and the second end sleeve 116. have any suitable number of support elements 118. The support elements 118 form the blades of the centralizer 110.

Also in FIG. 10 of the accompanying drawings, which shows an enlarged view of one of the brace elements 118 in isolation, it can be seen that the brace element 118 has a first end section 120, a second end section 122, an intermediate section 124, and sections 126 in the form of a wing.

As shown in FIG. 10, unlike the backing element 18 described above, the first end section 120 of the backing element 118 is not forked, has one connecting section 128 for connecting the first end section 120 with the first end sleeve 114 and a connecting section 132 for connecting the second end section 122 with a second end sleeve 116. In the centralizer 110 shown, the end sections form a convex outer surface.

In the centralizer 110 shown, the connecting portions 128, 132 each comprise a curved section 136, 138 adjacent to the respective end sleeves 114, 116 and a non-curved section 140, 142, the curved sections 136, 138 due to their shape having a stiffness that is greater than that of non-curved sections. sections 140,142, while providing a transition between the end sleeves 114, 116 and the intermediate section 124.

As shown in FIG. 9 and 10, intermediate portion 124 is curved in both directions, circumferentially and axially, and forms a convex, curved outer surface. The intermediate section 124 of the curved shape provides a rigidity that is greater than that of the end sections 120, 122.

The wing sections 126 extend from the intermediate section 124 and are angled to the intermediate section 124. In the centralizer 110 shown, the wing sections 126 form an angle of approximately 90° with the intermediate section 124. However, the wing sections 126 may form other angles. with an intermediate section 124.

As shown in FIG. 10, for example, the wing portions 124 are also axially curved.

- 11 042913 direction.

As described above, it has been found that the wing sections 126 further improve the rigidity of the intermediate section 124 relative to the end sections 120, 122. In addition, providing the wing sections 126 at an angle to the intermediate section 124 moves the intermediate section 124 away from the pipe 12 when applied.

In FIG. 9 of the accompanying drawings shows an alternative centralizer 110 for centering pipe 12 in wellbore W. Similar components of centralizers 10, 110 are represented by like reference numerals increased by 100.

As shown in FIG. 9, the centralizer 110 is a single structure having a first end sleeve 114, a second end sleeve 116, and a series of elongated support members 118. The first and second end sleeves 114, 116 are generally cylindrical in shape and configured to mount the centralizer 110 to the pipe 12. Supporting elements 118 are located between the first end sleeve 114 and the second end sleeve 116 and are located along the circumference and spaced around the first end sleeve 114 and the second end sleeve 116. have any suitable number of support elements 118. The support elements 118 form the blades of the centralizer 110.

Also in FIG. 10 of the accompanying drawings, which shows an enlarged view of one of the brace elements 118 in isolation, it can be seen that the brace element 118 has a first end section 120, a second end section 122, an intermediate section 124, and sections 126 in the form of a wing.

As shown in FIG. 10, unlike the backing member 18 described above, the first end section 20 has one connecting section 128 for connecting the first end section 120 to the first end sleeve 114 and a connecting section 132 for connecting the second end section 122 to the second end sleeve 116. In the shown centralizer 110 connecting sections 128, 132 each contains a curved section 136, 138 near the respective end sleeves 114, 116 and a non-curved section 140, 142, and the curved sections 136, 138 due to their shape have a rigidity that is greater than that of non-curved sections 140 , 142, while providing a transition between the end sleeves 114, 116 and the intermediate section 124.

As shown in FIG. 9 and 10, intermediate portion 124 is curved in both directions, circumferentially and axially, and forms a convex, curved outer surface. The intermediate section 124 of the curved shape provides a rigidity that is greater than that of the end sections 120, 122.

Wing portions 126 extend from intermediate portion 124 and form an angle with intermediate portion 124. In centralizer 110 shown, wing portions 126 form an angle of approximately 90° with intermediate portion 124. However, wing portions 126 may form other angles with intermediate section 124.

As shown in FIG. 10, for example, the wing portions 124 are also axially curved.

In use, the centralizer 110 may be configured to be mounted on the pipe 12, with the centralizer 110 configured to engage with the wall of the wellbore W to center the pipe 12 in the wellbore W. which is greater than the end sections 120, 122 of the backing element 118, provides preferential bending of the backing element 118 at the end sections 120, 122 and not at the intermediate section 124. The preferred bending of the backing element 118 at the intermediate section provides a centralizer 110 having sufficient rigidity to support pipe 12 generally in a central position in the wellbore W, and also having sufficient flexibility to pass through the restrictions of the wellbore and recover to the desired shape. It has been found that providing wing sections 126 further improves the stiffness of the intermediate section relative to the end sections 120, 122. In addition, providing wing sections 126 at an angle to the intermediate section 124 moves the intermediate section 124 away from the pipe 12 in use.

In FIG. 11 of the accompanying drawings shows another alternative centralizer 210 for centering pipe 12 in wellbore W. Similar components in centralizers 10, 210 are represented by like reference numerals increased by 200.

As shown in FIG. 11, the centralizer 210 is a single structure having a first end sleeve 214, a second end sleeve 216, and a series of elongated support members 218. The first and second end sleeves 214, 216 are generally cylindrical in shape and configured to mount the centralizer 210 to the pipe 12. Supporting elements 218 are located between the first end sleeve 214 and the second end sleeve 216 and are located along the circumference and spaced around the first end sleeve 214 and the second end sleeve 216. have any suitable number of bracing elements 218. The bracing elements 218 form the blades of the centralizer 210.

- 12 042913

Also in FIG. 12 of the accompanying drawings, which shows an enlarged view of one of the brace elements 218 in isolation, it can be seen that the brace element 218 has a first end section 220, a second end section 222, an intermediate section 224, and sections 226 in the form of a wing.

As shown in FIG. 12, similar to the centralizer 110, the first end section 220 has one connecting section 228 for connecting the first end section 220 to the first end sleeve 214 and a connecting section 232 for connecting the second end section 222 to the second end sleeve 216. In the centralizer 210 shown, the end sections form a concave outer surface.

In the centralizer 210 shown, the connecting portions 228, 232 each comprise a curved section 236, 238 adjacent to the respective end sleeves 214, 216 and a non-curved section 240, 242, the curved sections 236, 238 due to their shape having a stiffness that is greater than that of non-curved sections. sections 240, 242, while providing a transition between the end sleeves 214, 216 and the intermediate section 224.

As shown in FIG. 11 and 12, the intermediate portion 224 is curved in both directions, circumferentially and axially, and forms a convex, curved outer surface. The intermediate section 224 of the curved shape provides a rigidity that is greater than that of the end sections 220, 222.

Wing portions 226 extend from intermediate portion 224 and form an angle with intermediate portion 224. In centralizer 210 shown, wing portions 226 form an angle of approximately 90° with intermediate portion 224. However, wing portions 226 may form other angles with intermediate section 224.

As shown in FIG. 12, for example, wing portions 224 are also curved in the axial direction.

In use, centralizer 210 may be configured to be mounted on pipe 12, with centralizer 210 configured to engage with a wall of wellbore W to center pipe 12 in wellbore W. Providing a centralizer 210 having one or more supporting elements 218 with an intermediate section 224 having which is greater than the end sections 220, 222 of the backing element 218, provides a preferential bending of the backing element 218 at the end sections 220, 222, and not at the intermediate section 224. The preferred bending of the backing element 218 at the intermediate section provides a centralizer 210 having sufficient rigidity for maintaining the pipe 12 in a generally central position in the wellbore W, and also having sufficient flexibility to pass through the restrictions of the wellbore and recover to the desired shape. It has been found that providing wing sections 226 further improves the rigidity of the intermediate section relative to the end sections 220, 222. In addition, providing wing sections 226 at an angle to the intermediate section 224 moves the intermediate section 224 away from the pipe 12 in use.

In FIG. 13 of the accompanying drawings, a downhole assembly 1000 is shown comprising a plurality of centralizers 1010. In the arrangement 1000 shown, the centralizers 1010 are identical to the centralizer 10 shown in FIG. described above.

As shown in FIG. 13, centralizers 1010 are mounted on tubular 1012, which is in the form of a wellbore-supporting tubular string, more specifically a casing string, with tubular 1012 configured to be run into the wellbore W as a wellbore. The centralizers 1010 used center the pipe 1012 in the wellbore W as described above.

An alternative downhole assembly 2000 is shown in FIG. 14 attached drawings. In the arrangement 2000 shown, the centralizers 2010 are identical to the centralizer 10 shown in FIG. 1. However, it should be understood that one or more centralizers 2010 may be identical to the centralizer 110 or centralizer 210 described above.

As shown in FIG. 14, the centralizers 2010 are mounted on a pipe 2012 which is in the form of a tubular string, and more specifically a workstring, the pipe 2012 is configured to run into a wellbore W'' as a cased hole. The applied centralizers 2010 center the pipe 1012 in the wellbore W'' as described above.

Claims (20)

1. Centralizer for use when centering the pipe in the wellbore, containing the first end sleeve; second end sleeve; and a plurality of retaining elements located between the first end sleeve and the second end sleeve, wherein at least one of the retaining elements contains the first end section; second end section; an intermediate section located between the first end section and the second end section - 13 042913 area; and one or more sections in the form of a wing protruding from the intermediate section and located at an angle inward relative to the intermediate section, wherein the first end sleeve, the second end sleeve and the supporting elements are made in one piece, and moreover, the sections in the form of a wing are made in one piece with an intermediate section, and sections in the form of a wing contain a curved or bent part of the intermediate section. 2. Centralizer according to claim 1, in which the intermediate section has a stiffness that is greater than that of the first end section and the second end section. 3. Centralizer according to claim 1 or 2, configured to be configured in a first larger diameter configuration in which the intermediate section assumes a radially extended position, and in a second smaller diameter configuration in which the intermediate section assumes a radially retracted position. 4. The centralizer according to claim 3, configured to be reconfigured from a first configuration of a larger diameter to a second configuration of a smaller diameter. 5. Centralizer according to claim 3 or 4, configured to be reconfigured from a second smaller diameter configuration to a first larger diameter configuration. 6. The centralizer according to any preceding claim, wherein the end portions of the supporting elements are configured to be reconfigurable between a first larger diameter configuration and a second smaller diameter configuration. 7. Centralizer according to claim 6, in which the end sections are relatively less rigid than the intermediate section. 8. The centralizer according to any preceding claim, wherein at least a portion of each wing portion is curved. 9. The centralizer according to claim 8, wherein the wing-like portions are curved in a circumferential direction. 10. Centralizer according to claim 8 or 9, wherein the wing portions are curved in the axial direction. 11. The centralizer according to any of the preceding claims, wherein the supporting elements are bifurcated. 12. The centralizer according to any one of the preceding claims, wherein at least a portion of the intermediate portion is curved. 13. Centralizer according to claim 12, wherein the intermediate portion is curved in the circumferential direction. 14. Centralizer according to claim 12 or 13, in which the intermediate section is curved in the axial direction. 15. The centralizer according to any preceding claim, wherein one or more of the wing portions form a non-zero angle with the intermediate portion less than or equal to 180°. 16. The centralizer of claim 15, wherein one or more of the wing portions form a non-zero angle with the intermediate portion less than or equal to 90° or about 90°. 17. The centralizer according to any preceding claim, wherein one or more of the supporting elements comprise two wing-like sections. 18. The centralizer according to claim 17, wherein the wing-like portions form different angles with the intermediate portion. 19. A method for centering a pipe in a wellbore, comprising the use of a centralizer according to any one of claims 1-18. 20. A downhole assembly comprising at least one centralizer according to any one of claims 1-18.