US20020107562A1 - Technique of forming expandable devices from cells that may be transitioned between a contracted state and an expanded state - Google Patents

Abstract

An expandable device comprising a plurality of expandable cells. The cells may be bistable cells or other types of cells that are expanded from a contracted position towards an expanded position. Additionally, the cells may be combined with locking mechanisms to hold the structure in an expanded position.

Description

CROSS REFERENCE TO RELATED APPLICATIONS
• The following is based on and claims the priority of[0001]provisional application number 60/261,749 filed Jan. 16, 2001 andprovisional application number 60/296,875 filed Jun. 8, 2001.
FIELD OF THE INVENTION
• This invention relates generally to expandable-devices, and particularly to devices formed from one or more expandable cells that facilitate transition of the device from a contracted state to an expanded state.[0002]
BACKGROUND OF THE INVENTION
• In a variety of applications and environments, it would be beneficial to have a device able to transition from a contracted state to an expanded state. Such devices can comprise planar members, tubular members, rectangular members and a variety of other configurations. Exemplary applications include medical applications in which expandable devices, such as stents, are deployed at a desired location and then expanded. Another exemplary application comprises the use of expandables in the retrieval of various fluids, e.g. oil, from subterranean locations.[0003]
• For example, fluids such as oil, natural gas and water are obtained from subterranean geologic formations (a “reservoir”) by drilling a well that penetrates the fluid-bearing formation. Once a wellbore has been drilled to a certain depth, the borehole wall typically is supported to prevent collapse. During the drilling and use of a wellbore, various tubular members, such as liners, casings, sandscreens, etc. are deployed within the wellbore.[0004]
• Various methods have been developed for radially expanding tubulars by, for instance, pulling an expansion mandrel through the tubular to plastically deform the tubular in a radially outward direction. Such an approach, however, requires a large amount of force to achieve the desired expansion.[0005]
• The medical industry, oil industry and a variety of other industries utilize certain types of expandables or would benefit from the use of expandables in numerous applications. However, there are very few existing devices that are readily expandable at a desired location. Of the devices that do exist, substantial forces are required to create the expansion. Also, substantial plastic deformation often occurs which can limit the selection of available materials for a given expandable device. The present invention is directed to overcoming, or at least reducing, the effects of one or more of the problems set forth above.[0006]
SUMMARY OF THE INVENTION
• The present invention relates generally to expandable devices that may be used, for example, in subterranean environments. In one embodiment of the invention, the expandable device comprises one or more expandable cells that facilitate expansion of the device. By way of example, a tubular may be formed with a plurality of expandable cells that facilitate radial expansion of the device from a collapsed or contracted state to an expanded state. A variety of cell types and cell designs may be utilized depending on the application and desired parameters of the expandable device.[0007]
BRIEF DESCRIPTION OF THE DRAWINGS
• The invention will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements, and:[0008]
• FIGS. 1A and 1B are illustrations of the forces imposed to make a bistable structure;[0009]
• FIG. 2A and 2B show force-deflection curves of two bistable structures;[0010]
• FIGS.[0011]3A-3F illustrate expanded and collapsed states of three bistable cells with various thickness ratios;
• FIGS. 4A and 4B illustrate a bistable expandable tubular in its expanded and collapsed states;[0012]
• FIGS. 4C and 4D illustrate a bistable expandable tubular in collapsed and expanded states within a wellbore;[0013]
• FIGS. 5A and 5B illustrate an expandable packer type of deployment device;[0014]
• FIGS. 6A and 6B illustrate a mechanical packer type of deployment device;[0015]
• FIGS.[0016]7A-7D illustrate an expandable swage type of deployment device;
• FIGS.[0017]8A-8D illustrate a piston type of deployment device;
• FIGS. 9A and 9B illustrate a plug type of deployment device;[0018]
• FIGS. 10A and 10B illustrate a ball type of deployment device;[0019]
• FIG. 11 is a schematic of a wellbore utilizing an expandable bistable tubular;[0020]
• FIG. 12 illustrates a motor driven radial roller deployment device;[0021]
• FIG. 13 illustrates a hydraulically driven radial roller deployment device;[0022]
• FIG. 14 is a cross sectional view of one embodiment of the packer of the present invention;[0023]
• FIG. 15 is a cross sectional view of another embodiment of the packer of the present invention;[0024]
• FIG. 16 is a side elevation view of an embodiment of the present invention in a contracted state;[0025]
• FIG. 17 is a side elevation view of an embodiment of the present invention in an expanded state;[0026]
• FIGS.[0027]18A-C are schematic views of an alternative embodiment of the present invention;
• FIG. 19 is a perspective view of an alternative embodiment of the present invention;[0028]
• FIG. 20 is a schematic view of an alternative embodiment of the present invention;[0029]
• FIG. 21 is a schematic view of an alternative embodiment of the present invention;[0030]
• FIGS.[0031]22A-B are partial side elevational view of an embodiment of the present invention in the contracted and expanded positions respectively;
• FIGS.[0032]23A-B are partial side elevational views of an embodiment of the present invention in the contracted and expanded positions respectively;
• FIGS.[0033]24A-B are side elevational views of an alternate embodiment of an expandable cell in its contracted and expanded positions, respectively;
• FIGS.[0034]25A-B are side elevational views of a cell similar to that illustrated in FIGS.24A-B deployed in its contracted and expanded positions, respectively;
• FIGS.[0035]26A-B illustrate another embodiment of expandable cells displayed in their contracted and expanded positions, respectively;
• FIGS.[0036]27A-B illustrate another embodiment of expandable cells displayed in their contracted and expanded positions, respectively;
• FIGS.[0037]28A-B illustrate another embodiment of expandable cells displayed in their contracted and expanded positions, respectively;
• FIGS.[0038]29A-B illustrate another embodiment of expandable cells displayed in their contracted and expanded positions, respectively;
• FIGS.[0039]30A-B illustrate another embodiment of an expandable cell displayed in its contracted and expanded position, respectively;
• FIGS.[0040]31A-C illustrate a cell with energy storage members moving from a contracted state to an expanded state;
• FIGS.[0041]32A-32B illustrate another embodiment of the cell illustrated in FIGS.31A-C in a contracted position and expanded position, respectively;
• FIG. 33 illustrates another exemplary expandable cell design;[0042]
• FIG. 34 illustrates another exemplary expandable cell design;[0043]
• FIGS.[0044]35A-D illustrate an exemplary locking mechanism moving through various stages from a closed position to an open, locked position;
• FIGS.[0045]36A-D illustrate another embodiment of the locking mechanism of FIG. 35;
• FIG. 37 illustrates a locking mechanism combined with an expandable cell;[0046]
• FIG. 38A-B illustrate an expandable cell combined with a locking mechanism in a collapsed and expanded position, respectively;[0047]
• FIG. 39 illustrates an expandable cell with another embodiment of a locking mechanism;[0048]
• FIGS.[0049]40A-B illustrate an individual expandable cell and a plurality of expandable cells, respectively, combined with corresponding locking mechanisms;
• FIGS.[0050]41A-B illustrate another embodiment of combined expandable cells and locking mechanisms in collapsed and expanded positions, respectively; and
• FIG. 42 is a schematic representation of the combination of expandable cells having differing sizes and configurations in a single expandable device.[0051]
• While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.[0052]
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
• The following describes a variety of expandable devices that utilize expandable cells to facilitate expansion of the device from a contracted state to an expanded state. Various expansion techniques, expandable cell designs, and locking mechanisms are described, and typically the description is related to one or more exemplary applications. For example, the cells are described for use in tubular components, such as tubulars used in the oil production industry. However, this application is only an exemplary application to demonstrate the applicability of the various cells and locking mechanisms described herein. The description should not be construed as limiting the application of such expandable devices to the particular environments or applications described herein. Rather the techniques for formulating expandable devices can have a wide range of applications in other environments and industries.[0053]
• As described below, exemplary expandable devices may or may not comprise bistable cells. Whether bistable or not, the expandable cells facilitate expansion of a given device between a contracted state and an expanded state for a variety of operations or procedures. The selection of a particular type of expandable cell depends on a variety of factors including environment, degree of expansion, materials available, etc.[0054]
• Bistable devices used in the present invention can take advantage of a principle illustrated in FIGS. 1A and 1B. FIG. 1A shows a[0055]rod10 fixed at each end to rigid supports12. If therod10 is subjected to an axial force it begins to deform as shown in FIG. 1B. As the axial force is increasedrod10 ultimately reaches its Euler buckling limit and deflects to one of the two stable positions shown as14 and15. If the buckled rod is now clamped in the buckled position, a force at right angles to the long axis can cause the rod to move to either of the stable positions but to no other position. When the rod is subjected to a lateral force it must move through an angle β before deflecting to its new stable position.
• Bistable systems are characterized by a force deflection curve such as those shown in FIGS. 2A and 2B. The externally applied[0056]force16 causes therod10 of FIG. 1B to move in the direction X and reaches a maximum18 at the onset of shifting from one stable configuration to the other. Further deflection requires less force because the system now has a negative spring rate and when the force becomes zero the deflection to the second stable position is spontaneous.
• The force deflection curve for this example is symmetrical and is illustrated in FIG. 2A. By introducing either a precurvature to the rod or an asymmetric cross section the force deflection curve can be made asymmetric as shown in FIG. 2B. In this system the[0057]force19 required to cause the rod to assume one stable position is greater than theforce20 required to cause the reverse deflection. Theforce20 must be greater than zero for the system to have bistable characteristics.
• Bistable structures, sometimes referred to as toggle devices, have been used in industry for such devices as flexible discs, over center clamps, hold-down devices and quick release systems for tension cables (such as in sailboat rigging backstays).[0058]
• Instead of using the rigid supports as shown in FIGS. 1A and 1B, a cell can be constructed where the restraint is provided by curved struts connected at each end as shown in FIGS.[0059]3A-3F. If both struts21 and22 have the same thickness as shown in FIGS. 3A and 3B, the force deflection curve is linear and the cell lengthens when compressed from its open position FIG. 3B to its closed position FIG. 3A. If the cell struts have different thicknesses, as shown in FIGS.3C-3F, the cell has the force deflection characteristics shown in FIG. 2B, and does not change in length when it moves between its two stable positions. An expandable bistable tubular can thus be designed so that as the radial dimension expands, the axial length remains constant. In one example, if the thickness ratio is over approximately 2:1, the heavier strut resists longitudinal changes. By changing the ratio of thick-to-thin strut dimensions, the opening and closing forces can be changed. For example, FIGS. 3C and 3D illustrated a thickness ratio of approximately 3:1, and FIGS. 3E and 3F illustrate a thickness ratio of approximately 6:1.
• An expandable bore bistable tubular, such as casing, a tube, a patch, or pipe, can be constructed with a series of circumferential bistable[0060]connected cells23 as shown in FIGS. 4A and 4B, where eachthin strut21 is connected to athick strut22. The longitudinal flexibility of such a tubular can be modified by changing the length of the cells and by connecting each row of cells with a compliant link. Further, the force deflection characteristics and the longitudinal flexibility can also be altered by the design of the cell shape. FIG. 4A illustrates an expandable bistable tubular24 in its expanded configuration while FIG. 4B illustrates the expandable bistable tubular24 in its contracted or collapsed configuration. Within this application the term “collapsed” is used to identify the configuration of the bistable element or device in the stable state with the smallest diameter, it is not meant to imply that the element or device is damaged in any way. In the collapsed state,bistable tubular24 is readily introduced into awellbore29, as illustrated in FIG. 4C. Upon placement of the bistable tubular24 at a desired wellbore location, it is expanded, as illustrated in FIG. 4D.
• The geometry of the bistable cells is such that the tubular cross-section can be expanded in the radial direction to increase the overall diameter of the tubular. As the tubular expands radially, the bistable cells deform elastically until a specific geometry is reached. At this point the bistable cells move, e.g. snap, to a final expanded geometry. With some materials and/or bistable cell designs, enough energy can be released in the elastic deformation of the cell (as each bistable cell snaps past the specific geometry) that the expanding cells are able to initiate the expansion of adjoining bistable cells past the critical bistable cell geometry. Depending on the deflection curves, a portion or even an entire length of bistable expandable tubular can be expanded from a single point.[0061]
• In like manner if radial compressive forces are exerted on an expanded bistable tubular, it contracts radially and the bistable cells deform elastically until a critical geometry is reached. At this point the bistable cells snap to a final collapsed structure. In this way the expansion of the bistable tubular is reversible and repeatable. Therefore the bistable tubular can be a reusable tool that is selectively changed between the expanded state as shown in FIG. 4A and the collapsed state as shown in FIG. 4B.[0062]
• In the collapsed state, as in FIG. 4B, the bistable expandable tubular is easily inserted into the wellbore and placed into position. A deployment device is then used to change the configuration from the collapsed state to the expanded state.[0063]
• In the expanded state, as in FIG. 4A, design control of the elastic material properties of each bistable cell can be such that a constant radial force can be applied by the tubular wall to the constraining wellbore surface. The material properties and the geometric shape of the bistable cells can be designed to give certain desired results.[0064]
• One example of designing for certain desired results is an expandable bistable tubular string with more than one diameter throughout the length of the string. This can be useful in boreholes with varying diameters, whether designed that way or as a result of unplanned occurrences such as formation washouts or keyseats within the borehole. This also can be beneficial when it is desired to have a portion of the bistable expandable device located inside a cased section of the well while another portion is located in an uncased section of the well. FIG. 11 illustrates one example of this condition. A[0065]wellbore40 is drilled from thesurface42 and comprises a casedsection44 and anopenhole section46. An expandablebistable device48 havingsegments50,52 with various diameters is placed in the well. The segment with a larger diameter50 is used to stabilize theopenhole section46 of the well, while the segment having a reduceddiameter52 is located inside the casedsection44 of the well.
• Bistable collars or[0066]connectors24A (see FIG. 4C) can be designed to allow sections of the bistable expandable tubular to be joined together into a string of useful lengths using the same principle as illustrated in FIG. 4A and 4B. Thisbistable connector24A also incorporates a bistable cell design that allows it to expand radially using the same mechanism as for the bistable expandable tubular component. Exemplary bistable connectors have a diameter slightly larger than the expandable tubular sections that are being joined. The bistable connector is then placed over the ends of the two sections and mechanically attached to the expandable tubular sections. Mechanical fasteners such as screws, rivets or bands can be used to connect the connector to the tubular sections. The bistable connector typically is designed to have an expansion rate that is compatible with the expandable tubular sections, so that it continues to connect the two sections after the expansion of the two segments and the connector.
• Alternatively, the bistable connector can have a diameter smaller than the two expandable tubular sections joined. Then, the connector is inserted inside of the ends of the tubulars and mechanically fastened as discussed above. Another embodiment would involve the machining of the ends of the tubular sections on either their inner or outer surfaces to form an annular recess in which the connector is located. A connector designed to fit into the recess is placed in the recess. The connector would then be mechanically attached to the ends as described above. In this way the connector forms a relatively flush-type connection with the tubular sections.[0067]
• A[0068]conveyance device31 transports the bistable expandable tubular lengths and bistable connectors into the wellbore and to the correct position. (See FIGS. 4C and 4D). The conveyance device may utilize one or more mechanisms such as wireline cable, coiled tubing, coiled tubing with wireline conductor, drill pipe, tubing or casing.
• A[0069]deployment device33 can be incorporated into the overall assembly to expand the bistable expandable tubular and connectors. (See FIGS. 4C and 4D). Deployment devices can be of numerous types such as an inflatable packer element, a mechanical packer element, an expandable swage, a piston apparatus, a mechanical actuator, an electrical solenoid, a plug type apparatus, e.g. a conically shaped device pulled or pushed through the tubing, a ball type apparatus or a rotary type expander as further discussed below.
• An inflatable packer element is shown in FIGS. 5A and 5B and is a device with an inflatable bladder, element, or bellows incorporated into the bistable expandable tubular system bottom hole assembly. In the illustration of FIG. 5A, the[0070]inflatable packer element25 is located inside the entire length, or a portion, of the initial collapsed state bistable tubular24 and any bistable expandable connectors (not shown). Once the bistable expandable tubular system is at the correct deployment depth, theinflatable packer element25 is expanded radially by pumping fluid into the device as shown in FIG. 5B. The inflation fluid can be pumped from the surface through tubing or drill pipe, a mechanical pump, or via a downhole electrical pump which is powered via wireline cable. As theinflatable packer element25 expands, it forces the bistable expandable tubular24 to also expand radially. At a certain expansion diameter, the inflatable packer element causes the bistable cells in the tubular to reach a critical geometry where the bistable “snap” effect is initiated, and the bistable expandable tubular system expands to its final diameter. Finally theinflatable packer element25 is deflated and removed from the deployed bistableexpandable tubular24.
• A mechanical packer element is shown in FIGS. 6A and 6B and is a device with a deformable[0071]plastic element26 that expands radially when compressed in the axial direction. The force to compress the element can be provided through acompression mechanism27, such as a screw mechanism, cam, or a hydraulic piston. The mechanical packer element deploys the bistable expandable tubulars and connectors in the same way as the inflatable packer element. The deformableplastic element26 applies an outward radial force to the inner circumference of the bistable expandable tubulars and connectors, allowing them in turn to expand from a contracted position (see FIG. 6A) to a final deployment diameter (see FIG. 6B).
• An expandable swage is shown in FIGS.[0072]7A-7D and comprises a series offingers28 that are arranged radially around aconical mandrel30. FIGS. 7A and 7C show side and top views respectively. When themandrel30 is pushed or pulled through thefingers28 they expand radially outwards, as illustrated in FIGS. 7B and 7D. An expandable swage is used in the same manner as a mechanical packer element to deploy a bistable expandable tubular and connector.
• A piston type apparatus is shown in FIGS.[0073]8A-8D and comprises a series ofpistons32 facing radially outwardly and used as a mechanism to expand the bistable expandable tubulars and connectors. When energized, thepistons32 apply a radially directed force to deploy the bistable expandable tubular assembly as per the inflatable packer element. FIGS. 8A and 8C illustrate the pistons retracted while FIGS. 8B and 8D show the pistons extended. The piston type apparatus can be actuated hydraulically, mechanically or electrically.
• A plug type actuator is illustrated in FIGS. 9A and 9B and comprises a[0074]plug34 that is pushed or pulled through the bistableexpandable tubulars24 or connectors as shown in FIG. 9A. The plug is sized to expand the bistable cells past their critical point where they will snap to a final expanded diameter as shown in FIG. 9B.
• A ball type actuator is shown in FIGS. 10A and 10B and operates when an[0075]oversized ball36 is pumped through the middle of the bistableexpandable tubulars24 and connectors. To prevent fluid losses through the cell slots, an expandable elastomer basedliner38 is run inside the bistable expandable tubular system. Theliner38 acts as a seal and allows theball36 to be hydraulically pumped through thebistable tubular24 is and connectors. The effect of pumping theball36 through the bistableexpandable tubulars24 and connectors is to expand the cell geometry beyond the critical bistable point, allowing full expansion to take place as shown in FIG. 10B. Once the bistable expandable tubulars and connectors are expanded, theelastomer sleeve38 andball36 are withdrawn.
• Radial roller type actuators also can be used to expand the bistable tubular sections. FIG. 12 illustrates a motor driven expandable radial roller tool. The tool comprises one or more sets of[0076]arms58 that are expanded to a set diameter by means of a mechanism and pivot. On the end of each set of arms is aroller60.Centralizers62 can be attached to the tool to locate it correctly inside the wellbore and thebistable tubular24. Amotor64 provides the force to rotate the whole assembly, thus turning the roller(s) circumferentially inside the wellbore. The axis of the roller(s) is such as to allow the roller(s) to rotate freely when brought into contact with the inner surface of the tubular. Each roller can be conically-shaped in section to increase the contact area of roller surface to the inner wall of the tubular. The rollers are initially retracted and the tool is run inside the collapsed bistable tubular. The tool is then rotated by themotor64, androllers60 are moved outwardly to contact the inner surface of the bistable tubular. Once in contact with the tubular, the rollers are pivoted outwardly a greater distance to apply an outwardly radial force to the bistable tubular. The outward movement of the rollers can be accomplished via centrifugal force or an appropriate actuator mechanism coupled between themotor64 and therollers60.
• The final pivot position is adjusted to a point where the bistable tubular can be expanded to the final diameter. The tool is then longitudinally moved through the collapsed bistable tubular, while the motor continues to rotate the pivot arms and rollers. The rollers follow a shallow[0077]helical path66 inside the bistable tubular, expanding the bistable cells in their path. Once the bistable tubular is deployed, the tool rotation is stopped and the roller retracted. The tool is then withdrawn from the bistable tubular by aconveyance device68 that also can be used to insert the tool.
• FIG. 13 illustrates a hydraulically driven radial roller deployment device. The tool comprises one or[0078]more rollers60 that are brought into contact with the inner surface of the bistable tubular by means of ahydraulic piston70. The outward radial force applied by the rollers can be increased to a point where the bistable tubular expands to its final diameter.Centralizers62 can be attached to the tool to locate it correctly inside the wellbore andbistable tubular24. Therollers60 are initially retracted and the tool is run into the collapsedbistable tubular24. Therollers60 are then deployed and push against the inside wall of the bistable tubular24 to expand a portion of the tubular to its final diameter. The entire tool is then pushed or pulled longitudinally through the bistable tubular24 expanding the entire length ofbistable cells23. Once thebistable tubular24 is deployed in its expanded state, therollers60 are retracted and the tool is withdrawn from the wellbore by theconveyance device68 used to insert it. By altering the axis of therollers60, the tool can be rotated via a motor as it travels longitudinally through thebistable tubular24.
• Power to operate the deployment device can be drawn from one or a combination of sources such as: electrical power supplied either from the surface or stored in a battery arrangement along with the deployment device, hydraulic power provided by surface or downhole pumps, turbines or a fluid accumulator, and mechanical power supplied through an appropriate linkage actuated by movement applied at the surface or stored downhole such as in a spring mechanism.[0079]
• The bistable expandable tubular system is designed so the internal diameter of the deployed tubular is expanded to maintain a maximum cross-sectional area along the expandable tubular. This feature enables mono-bore wells to be constructed and facilitates elimination of problems associated with traditional wellbore casing systems where the casing outside diameter must be stepped down many times, restricting access, in long wellbores.[0080]
• The bistable expandable tubular system can be applied in numerous applications such as an expandable open hole liner where the bistable expandable tubular[0081]24 is used to support an open hole formation by exerting an external radial force on the wellbore surface. Asbistable tubular24 is radially expanded, the tubular moves into contact with thesurface forming wellbore29. These radial forces help stabilize the formations and allow the drilling of wells with fewer conventional casing strings. The open hole liner also can comprise a material, e.g. a wrapping, that reduces the rate of fluid loss from the wellbore into the formations. The wrapping can be made from a variety of materials including expandable metallic and/or elastomeric materials. By reducing fluid loss into the formations, the expense of drilling fluids can be reduced and the risk of losing circulation and/or borehole collapse can be minimized.
• Liners also can be used within wellbore tubulars for purposes such as corrosion protection. One example of a corrosive environment is the environment that results when carbon dioxide is used to enhance oil recovery from a producing formation. Carbon dioxide (CO[0082]₂) readily reacts with any water (H₂O) that is present to form carbonic acid (H₂CO₃). Other acids can also be generated, especially if sulfur compounds are present. Tubulars used to inject the carbon dioxide as well as those used in producing wells are subject to greatly elevated corrosion rates. The present invention can be used to place protective liners, e.g. abistable tubular24, within an existing tubular to minimize the corrosive effects and to extend the useful life of the wellbore tubulars.
• Another exemplary application involves use of the bistable tubular[0083]24 as an expandable perforated liner. The open bistable cells in the bistable expandable tubular allow unrestricted flow from the formation while providing a structure to stabilize the borehole.
• Still another application of the[0084]bistable tubular24 is as an expandable sand screen where the bistable cells are sized to act as a sand control screen. Also, a filter material can be combined with the bistable tubular as explained below. For example, an expandable screen element can be affixed to the bistable expandable tubular. The expandable screen element can be formed as a wrapping aroundbistable tubular24. It has been found that the imposition of hoop stress forces onto the wall of a borehole will in itself help stabilize the formation and reduce or eliminate the influx of sand from the producing zones, even if no additional screen element is used.
• The above described bistable expandable tubulars can be made in a variety of manners such as: cutting appropriately shaped paths through the wall of a tubular pipe thereby creating an expandable bistable device in its collapsed state; cutting patterns into a tubular pipe thereby creating an expandable bistable device in its expanded state and then compressing the device into its collapsed state; cutting appropriate paths through a sheet of material, rolling the material into a tubular shape and joining the ends to form an expandable bistable device in its collapsed state; or cutting patterns into a sheet of material, rolling the material into a tubular shape, joining the adjoining ends to form an expandable bistable device in its expanded state and then compressing the device into its collapsed state.[0085]
• The materials of construction for the bistable expandable tubulars can include those typically used within the oil and gas industry such as carbon steel. They can also be made of specialty alloys (such as a monel, inconel, hastelloy or tungsten-based alloys) if the application requires.[0086]
• The configurations shown for the bistable tubular[0087]24 are illustrative of the operation of a basic bistable cell. Other configurations may be suitable, but the concept presented is also valid for these other geometries.
• In FIGS. 14 and 15, a[0088]packer80 formed of bistable cells is illustrated. Thepacker80 has a tubular82 formed ofbistable cells83, such as those previously discussed. In addition, thepacker80 has at least oneseal84 along at least a portion of its length. Anexemplary seal84 may include one or more layers positioned internally, externally, or both with respect totubular82. Additionally, the layer(s) may be intermixed with the openings formed in the cells.
• FIG. 14 illustrates an embodiment having an internal and an[0089]external seal84. FIG. 15 illustrates apacker80 having only aninternal seal84. Theseal84 may be formed of an elastomer or other material. Further, the properties of theseal84 allow it to at least match the expansion ratio of the tubular82. Folds or other design characteristics of theseal84 may be used to facilitate the expansion.
• Also, a resin or[0090]catalyst85 may be used to allow theseal84 to harden after setting. In one alternative embodiment a resin or other flowable material is placed between the layers of seals84 (as in FIG. 14). Once thepacker80 is placed in the well and expanded, the flowable material may be hardened or otherwise altered to improve the sealing characteristics of thepacker80. In some applications, hardening of the resin or other material requires heating of the material by a service tool. Thepacker80 can be expanded as described herein, and may comprise a variety of bistable cells. In one embodiment of use, thepacker80 is deployed on a run-in tool that includes an expanding tool. Thepacker80 is positioned at the desired location and expanded to seal against the walls of the casing or other tubular. Typically, thepacker80 is connected to a tubing or other conduit that extends downhole below thepacker80. Thepacker80 provides a seal in the annulus to prevent or restrict fluid flow longitudinally in the well (the typical use for packers). The present invention also may act as a well anchor which includes or excludes theseal84.
• In FIG. 16, an alternative embodiment is illustrated in which the[0091]packer80 forms a portion of a conduit. In the embodiment shown, a well conduit90 (such as a tubing) has a portion (marked as the packer80) that is cut to form the bistable cells. Thepacker portion80 has aseal84 thereon as previously described. In FIG. 16, a portion of theseal material84 is illustrated as removed to reveal thebistable cells83 in theunderlying tubular82. In FIG. 17, thepacker portion80 is illustrated in its expanded state. It should be to noted that in typical applications thewell conduit90 which does not have bistable cells formed therein, does not expand. Thus, one embodiment for attaching the well conduit to thepacker80 is to form thepacker80 as an integral part of the well conduit90 (note that a welded connection resembles this embodiment and is an alternative method of forming the present invention). Other methods include conventional methods of non-integral connection.
• In alternative embodiments, the well conduit has a plurality of[0092]bistable cell packers80 formed thereon. In yet another alternative embodiment, a portion orportions91 of the well conduit in addition to thepacker portions80 are formed of bistable cells so that these other portions also undergo expansion (see FIG. 17). The other portions may or may not have a material applied thereto. For example, the other portion may have a screen or filter material applied thereto to provide a well sand screen.
• Referring to FIGS.[0093]18A-C, an alternative design of the present invention is illustrated in a schematic, partial cross-sectional view. The expandable packer is shown in the retracted and expanded states, respectively, and in partial side elevational view (FIG. 18C). The packer shown includes a base tubular82 formed ofthin struts21 andthick struts22 formingbistable cells23/83 as previously described.Slats92 are attached to thetubing82 at one edge and extend generally longitudinally in the embodiment shown (see FIG. 18C). Specifically, eachslat92 is attached to thetubing82 at thethick struts22, and the width of the slats is such that they overlap at least the adjacent slat when thetubing82 is in the expanded state. Although illustrated as having a slat attached to each of the thick struts, the packer may have a slat attached to alternatethick struts22 or in other configurations. Furthermore, the slats may extend in a direction other than the longitudinal direction. Theslats92 slide over one another during expansion so that the outside of thetubing82 is covered by the overlappingslats92.
• A[0094]seal84 may be attached to theslats92 to provide the seal for the packer. Although shown in the figures as folded, theseal84, may have other characteristics that facilitate its ability to expand with theslats92 andtubular82. Also, theseal84 may have other characteristics previously mentioned (e.g., resin, internal seal, etc).
• It should be noted that although described as a packer, the present invention may be used to provide isolation over a long length as opposed to a traditional packer or downhole tool which generally seals only a relatively short longitudinal distance. Thus, the present invention may be-used in a manner similar to a casing to provide isolation for an extended length.[0095]
• In FIG. 19, a perspective view of packer[0096]80 (or isolation device) having a plurality ofslats92 attached thereto is illustrated in an overlapping arrangement as previously described. Thetubing82 includesend extensions94 that extend longitudinally from the endmost cells. Theslats92 may be attached to theend extensions94, to certain portions of thethick struts22 and/or to certainthick struts22. In one embodiment, for example, thestruts92 are attached to the thick struts which are longitudinally aligned with theend extensions94. Although generally shown as attached at an edge of theslats92, the slats also may attach to thetubing82 at a position intermediate the edges.
• In FIG. 20, an expandable tubing (or conduit)[0097]90 is illustrated positioned in awell100. Theconduit90 includes a plurality of spacedpackers80 or expandable sealing devices. Theexpandable packers80 engage the wellbore wall preventing annular flow thereby. Therefore, any microannulus formed between theexpandable tubing90 and the well100 (which may include a casing) is sealed in the longitudinal direction to restrict or prevent unwanted flow thereby. Theconduit90 may include one or moresuch packers80, as desired, to control the flow. Further, thepackers80 may be spaced at regular intervals or at some other predetermined spacing to control the flow in the annulus as needed.
• In one example, illustrated schematically in FIG. 21, the individual joints of[0098]tubing90 are interconnected by apacker80 to compartmentalize each joint of conduit from the adjacent joint(s). Thepacker80 can be a separate connector as shown in FIG. 21 or it can be formed as part of the joint. Accordingly, thepacker80 can be positioned at an end of the joint90, in the middle of the joint90, or at any other location along its length. In one embodiment bothconduit90 andpackers80, of FIGS. 20 and 21, are formed of bistable cells.
• Referring generally to FIGS.[0099]22A-B, an alternative embodiment of the present invention is disclosed. The device shown in these figures may be used as a packer, hanger, casing patch, or other device requiring expansion and is generally referred to herein in reference to these figures as anexpandable tubular120 for ease of description. Theexpandable tubular120 comprises a series ofcells122 formed therein, such as by laser cutting, jet cutting, water jet cutting or other manufacturing methods. Thecells122 are oriented such that a number oflongitudinal struts24 are formed on theexpandable tubular120. Thus, as shown in the figures, thelongitudinal struts124 lie between longitudinal lengths ofcells122 with thecells122 having relativelythinner struts126 extending between adjacentlongitudinal struts124. As shown in the figures, as the adjacentlongitudinal struts124 are moved longitudinally relative to one another (e.g. in opposite directions), thecells122 open to expand the structure radially. Not all of thelongitudinal struts124 must move; alternatelongitudinal struts124 may be moved while the other struts remain stationary. The relative movement of thelongitudinal struts124 provides the expansion of thecells122 and theexpandable tubular120. This type of cell is an example of an expandable cell that is not bistable.
• A[0100]locking mechanism128 may be used to maintain the expanded position of theexpandable tubular120. As shown in FIGS.22A-B, the expandable tubular may comprise one ormore locking mechanisms128 spaced along the length of theexpandable tubular120 and spaced radially about theexpandable tubular120. One embodiment of the locking mechanism is shown in FIGS.23A-B. In the embodiment shown, thelocking mechanism128 comprises a detent (or finger)130 extending from onelongitudinal strut124 and cooperating with a set ofratchet teeth132 provided on anotherlongitudinal strut124. Theratchet teeth132 extend from aramp area134 of thelongitudinal strut124 to accommodate for the relative movement of thedetent130 to thelongitudinal strut124 having theratchet teeth132. Theratchet teeth132 generally allow movement of thedetent130 thereon in a first direction associated with the expansion of theexpandable tubular120, and prevent movement of thedetent130 in the opposite direction. Once in the expanded position, thedetent130 acts as a locked strut preventing retraction of theexpandable tubular120. To increase the structural integrity of the expandedtubular120 and to resist forces tending to move the expandable tubular120 from an expanded state or position to a reduced position. Theexpandable tubular120 may include a plurality of lockingmechanisms128.
• Although shown as a ratchet, as an alternative the locking mechanism may have fewer discrete positions, such as one, in which the detent locks in the fully expanded position only. In another embodiment the detent may comprise a resilient finger biased toward an extended position that snaps into a groove in an adjacent[0101]longitudinal strut124. Likewise, theadjacent struts124 may each have resilient detents that cooperate to lock the device in the expanded position only upon the tubular120 achieving the expanded position. These are only a few examples of the many possible alternatives for thelocking mechanism128.
• Also, various other tubular expansion mechanisms and expandable cells may be utilized such expandable tubulars and other devices. For example, details of one type of expandable cell are illustrated in FIGS. 24A, 24B,[0102]25A and25B. In this embodiment, as in other embodiments, the cell is transitioned from a compressed state to an expanded state.
• During movement from the compressed state to the expanded state and depending upon the environmental conditions as well as the materials used, material thickness and other design parameters of the cell and devices formed from the cell, some areas of the cell and struts may experience plastic deformation. In FIGS. 24A, 24B,[0103]25A and25B alternative embodiments of a cell are illustrated in compressed and expanded states. In these embodiments, one of the struts21 (shown as the thinner, upper strut) has thinnedportions140 that serve as flexible hinges or joints. The thinnedportions140 are preferably placed at areas where plastic deformation of the strut is likely to occur as the strut moves from a compressed to an expanded state. Thus, for example, the thinnedportions140 may be placed near the intersection of thestruts21,22 to provide an area that is less susceptible to plastic deformation. Although the figures show a plurality of thinnedportions140, the strut may include a single thinnedportion140, for example, at an area of increased plastic deformation. Also, the thinnedportions140 may be placed in other positions along thestruts21,22 for other purposes. The thinnedareas140 definelinkages142 therebetween that comprise portions which are generally thicker than the thinnedportions140. Placing a plurality of thinnedportions140 along the length of astrut21,22 produces a plurality oflinkages142.
• Another factor in determining the positioning of the thinned[0104]portions140 is the number, placement, and design of the linkages. Although shown in the figures as having a uniform thickness, thelinkages142 may also have a variation in thickness to further tailor the expansion, contraction, and other characteristics of the cell as desired. Therefore, in one broad aspect of the inventions, at least one of thestruts21,22 has a thickness that varies. Also, other factors may be considered in placement of the thinnedportions140 and the thickness variations of thestruts21,22. Also, the thinned portions may occur at the intersection of thestruts21,22.
• In FIGS. 24A and 24B a cell with three[0105]linkages142 is illustrated; and in FIGS. 25A and 25B a cell with two linkages is illustrated. Although FIGS.24A-25B disclose only a single cell, the cells may be incorporated into a tool, such as a tube, having a plurality of cells such as that shown in FIGS. 4A and 4B. The figures illustrate a single cell to more clearly show the basic concept and the cell design. The handles shown in the figures are not a part of the cell structure, but are merely used on test cells to facilitate testing of the cells.
• Referring generally to FIGS. 26A and 26B, another embodiment of expandable cells, labeled as[0106]expandable cells150, is illustrated. Eachexpandable cell150 comprises athick strut152 and one or morethin struts154, e.g. twothin struts154. In the embodiment illustrated, eachexpandable cell150 comprises a pair of thin struts, and eachthin strut154 has a pair ofends156 pivotably coupled to adjacent thick struts, respectively.Ends156 may comprise pins that are pivotably received in correspondingsockets158.
• As the plurality of[0107]expandable cells150 is moved from the contracted state illustrated in FIG. 26A to the expanded state illustrated in FIG. 26B,thin struts154 deform sufficiently to permit pivoting ofpins156 in theircorresponding sockets158. As illustrated best in FIG. 26B, the pairs ofthin struts154 that form eachcell150 haveoutlying ends156 pivotably coupled toupper attachment regions160 of the lowerthick strut152. The opposite ends of each pair ofthin struts154 are pivotably coupled to alower attachment region162 of the next upwardly adjacentthick strut152. It should be noted that positional terms such as upper and lower or merely used to facilitate explanation of the location of various features relative to the figures provided and should not be construed as limiting.
• In another embodiment illustrated in FIGS. 27A and 27B, a plurality of expandable cells, labeled with[0108]reference numeral164, each comprise athick strut166 and one or morethin struts168. Eachthick strut166 is generally arcuate and connected to a correspondingthin strut168 at afixed connection region170 disposed at a generally central location along the outer or convex portion of the arcuate thick strut. The outer ends of eachthin strut168 are pivotably coupled to the next adjacentthick strut166 via apivot connection172 that may comprise a ball and socket.
• As the plurality of cells are moved from the contracted state illustrated in FIG. 27A to the expanded state illustrated in FIG. 27B,[0109]thin struts168 flex or deform as their outer ends pivot at eachpivot connection172. As with many of the other cells described herein, when thethin struts168 move past their point of greatest flexure, the stored spring energy tends to force thecells164 to their stable expanded state illustrated in FIG. 27B. Thus, as with the bistable cells illustrated in FIGS. 26A and 26B,cells164 move between a stable contracted state and a stable expanded state.
• Another expandable cell embodiment is illustrated in FIGS. 28A and 28B. In this embodiment, each[0110]expandable cell174 is formed of athick strut176 and athin strut178. Eachthin strut178 has a pair ofends180 that are pivotably coupled to a thick strut. For example, a given thick strut may comprise a pair ofsockets182 to pivotably receive pin or ball shaped ends180. Additionally,thin strut178 is fixedly coupled to adjacentthick struts176 in an alternating pattern. For example, each cell in the illustrated embodiment comprises three fixedcouplings184 that alternate between adjacentthick struts176. With this design, theexpandable cells174 again are movable between a stable contracted state as illustrated in FIG. 28A and a stable expanded state as illustrated in FIG. 28B.
• With reference to FIGS. 29A and 29B, another expandable cell design is illustrated. In this embodiment, each of a plurality of[0111]expandable cells186 comprises athick strut188 and at least a pair of stackedthin struts190,192, respectively. Thin struts190,192 are generally disposed in a stacked orientation and connected by a linkingmember194.Thin strut192 comprises a pair ofends196 affixed to a correspondingthick strut188. Anintermediate connection region198 ofthin strut192 is affixed to the next adjacentthick strut188, as best illustrated in FIG. 29B.Thin strut190, on the other hand, has unattached ends200.Ends200 are captured in an abutting engagement with a notchedregion202 formed in the samethick strut188 to which ends196 are affixed. As the plurality ofexpandable cells186 are moved from the contracted state illustrated in FIG. 29A to the expanded state illustrated in FIG. 29B, each pair ofthin struts190 and192 deforms to a deflection point where stored energy in the thin struts is maximized. As the thin struts are moved past this deflection point, the stored energy is released to facilitate expansion of the cells to their expanded state.
• Of course, with any of these types of bistable cells, the degree of expansion may be limited by an external barrier. For example, if the bistable cells are used to form a tubular, the tubular may be expanded against a wellbore wall that prevents the cells from moving to their fully expanded condition. Typically, the size of the tubular is selected to permit expansion of the cells at least past the point of maximum deformation. Thus, depending on the material used, the cells may actually cooperate to apply an outwardly directed radial force against the wellbore wall.[0112]
• Referring generally to FIGS. 30A and 30B, another expandable cell design is illustrated. Each[0113]expandable cell204 comprises a pair of arcuatethin struts206 pivotably coupled to a correspondingthick strut208 at a generally centralized extended region210 via pivot ends212. Generally opposite pivot ends212,thin struts206 comprise outer pivot ends214 that are pivotably coupled to the next adjacentthick strut208. Pivot ends212 and214 can be formed in a variety of configurations, such as ball joints, pin joints, etc. Removal of eachthin strut206 is prevented byappropriate ligaments216 and218 disposed at pivot ends212 and214, respectively. Theligaments216 and218 are coupled between thethin strut206 and the corresponding thick struts208.
• In FIGS.[0114]31A-31C, a different type ofexpandable cell220 is illustrated. In this embodiment, athick strut222 is coupled to one or morethin struts224 by one ormore spring elements226. In the particular embodiment illustrated, twospring elements226 are formed generally in the shape of a horn, with the base of each horn connected tothick strut222 and the tip of each horn coupled to the adjacentthin strut224. In this embodiment, athin strut224 is connected to eachspring element226 by aflexible hinge228. The twothin struts224 are coupled to each other through acenter beam230 and a pair of flexible hinges232.
• As[0115]cells220 are expanded from a contracted state, illustrated in FIG. 31A, to an expanded state, illustrated in FIG. 31C,spring elements226 flex outwardly and store spring energy. With this design,thin struts224 typically do not undergo substantial deformation during movement from the contracted state to the expanded state. Rather,spring elements226 are elastically deformed as they are forced outwardly during movement ofcenter beam230 from the contracted state to the expanded state. Whenspring elements226 are flexed outwardly, they store spring energy at least to the point of maximum flexure illustrated in FIG. 31B wherethin struts224 are generally parallel withthick strut222. Oncecenter beam230 moves past this point of maximum stored spring energy,spring elements226 tend to release the stored energy and move inwardly, thereby forcingthin struts224 andcenter beam230 to the expanded position illustrated best in FIG. 31C. Deformation ofhinges228 and232 facilitates the pivoting ofthin struts224 from the contracted state to the expanded state.
• A double horn cell design is illustrated in FIGS. 32A and 32B. In this design, a plurality of[0116]thick struts236 are coupled together viathin struts238 andhorn spring members240. Specifically, eachthin strut238 is coupled to twohorn spring members240 to permit storage of a greater amount of energy. This greater energy storage provides added positive energy for openingcells234 to their expanded positions as illustrated in FIG. 32B.
• In the example illustrated, each[0117]double horn cell234 has two outerhorn spring members240, coupled to onethick strut236, and two innerhorn spring members240, coupled to the next adjacentthick strut236. Onethin strut238 is coupled to each cooperating pair of inner and outer horn spring members viaappropriate hinge regions242. Thus, as thedouble horn cells234 are moved from the contracted state illustrated in FIG. 32A to the expanded state illustrated in FIG. 32B, cooperating pairs of inner and outerhorn spring members240 are flexed outwardly to a point at which thethin struts238 are generally aligned. Subsequent to this point of expansion, thehorn spring members240 begin to release the stored spring energy and forcethin struts238 towards the fully expanded state.
• Other forms of spring elements also may be utilized in facilitating expansion of a variety of cell types. For example, in FIG. 33 an[0118]expandable cell244 is illustrated in which adjacentthick struts246 are coupled to athin strut248 by a different type ofspring members250.Spring members250 may be coiled, undulating or arranged along other paths that accommodate the transitioning ofthin strut248 from the contracted state illustrated in FIG. 33 to an expanded state.
• Another type of spring system is illustrated in FIG. 34 as an[0119]expandable cell252. A pair ofthick struts254 are coupled by a pair of undulatingthin struts256. The design ofthin struts256 incorporates a plurality ofspring elements258 that both accommodate flexure of thethin struts256 and expansion of thecell252 by storing and then releasing spring energy. The spring energy is released as the thin struts transition past a point of maximum flexure towards the fully expanded state.
• To secure the overall device, e.g. tubular, in the expanded position, a locking mechanism may be utilized to prevent the individual cells from contracting. Exemplary locking mechanisms may be associated with individual cells, or they may be located at one or more positions along the expandable device. In FIGS.[0120]35A-35D, one type oflocking mechanism258 is illustrated. In this embodiment, apost260 is slidably received in acorresponding recess262. Aratchet finger264 extends generally transversely towardspost260. Specifically, ratchetfinger264 comprises anengagement end266 that resides in a recessedarea268 ofpost260 when the overall device andlocking mechanism258 are in a contracted state, as illustrated in FIG. 35A.
• As the device, e.g. tubular, is expanded,[0121]ratchet finger264 is flexed away from anadjacent support surface270, as illustrated best in FIG. 35D. Theratchet finger264 continues to slide along the side ofpost260 as the device is expanded to a maximum degree illustrated in FIG. 35C. When the expansion force is relaxed, any substantial movement ofpost260 towards the contracted position is blocked byratchet finger264, as illustrated in FIG. 35D. Aspost260 attempts to move towards its contracted state,engagement end260 is pressed firmly into interfering engagement with the side ofpost260. Additionally,support surface270 limits the movement ofratchet lo finger264 in the contracting direction. The side wall ofpost260 may comprise teeth or other interfering features that aid in preventing movement ofpost260 back towards the contracted state.
• Another[0122]exemplary locking mechanism272 is illustrated in FIGS.36A-36D. In this embodiment, afork ratchet274 is formed in the expandable device, such as in the wall of an expandable tubular. Fork ratchet274 comprises a pair ofprongs276 that each have adivergent end278. In the contracted state, prongs276 are received in anopening280 having a generally hourglass shape profile. In other words, divergent ends278 reside in a divergent or expandedportion282 ofopening280 and must be pulled through a narrow orconstricted portion284 when the device is expanded.
• During expansion of the tubular or other device,[0123]divergent portions282 are drawn through constricted region284 (see FIGS. 36D and 36C.) Onceprongs276 are drawn clear ofopening280, thedivergent portions282 once again spring outwardly to their normal position. In this position,divergent portions282 are wider than the entrance to opening280, and fork ratchet274 is prevented from reenteringopening280. Thus, the overall device is held in its expanded state.
• Another[0124]exemplary locking mechanism284 is illustrated in FIG. 37.Locking mechanism284 is designed for use with horn style cells. In the specific example illustrated, aslot286 is formed between a pair ofspring member horns288 within athick strut290 of anexpandable cell292. Awedge294 extends from an adjacentthick strut296 intoslot286. Ascell292 is expanded,wedge294 is drawn outwardly throughslot286. The size of thewedge tip298 andslot outlet300 are selected to interfere whencell292 is in its expanded state. This prevents flexing ofhorns288 towardsslot286 and thereby inhibits collapse of the expanded cell.
• Referring generally to FIGS.[0125]38A-41B, a variety of expandable cell and locking mechanism combinations are illustrated. With specific reference to FIGS. 38A and 38B, one embodiment of anexpandable cell302 comprisesthick struts304 that are coupled together bythin struts306 viaspring members308. Eachthick strut304 comprises one or more, e.g. two, ratchetfingers310 that slide along a correspondingratchet surface312 formed on expanded regions of the thin struts306 (see FIG. 38B).
• [0126]Ratchet surface312 may incorporate ratchet teeth to engage the end of thecorresponding ratchet finger310. As theexpandable cell302 is transitioned from its contracted state, as illustrated in FIG. 38A, to an expanded state, as illustrated in FIG. 38B, ratchetfingers310 are flexed away from asupport surface314 while sliding along corresponding ratchet surfaces312. The ends of theratchet fingers310 do not allow sliding motion of corresponding ratchet surfaces312 back towards the contracted state. Furthermore, support surfaces314 may be relied on to limit any flexing offingers310 back towards the contracted position. Thus, when the expandable cell in its expanded state, each of theratchet fingers310 acts against a correspondingratchet surface312 to support the cell against collapse.
• Another embodiment of the system is illustrated in FIG. 39 and utilizes fingers in the form of[0127]ratchet pawls316. In this embodiment, each ratchet pawl is formed in an appropriatethick strut304 by creating anopen area318 configured to receive acorresponding portion320 ofthin strut306 when in the contracted position. Eachratchet pawl316 may comprise a plurality ofteeth322 positioned to engage correspondingteeth324 extending fromportion320. Additionally, arelief cut326 may be formed alongratchet pawl316 generally oppositeopen area318. Relief cut326 allowsratchet pawl316 to flex asteeth322 are draggedpast teeth324 during transition of the cell from a contracted state to an expanded state.Teeth322 and324 are designed to prevent closure of the cell once expansion begins. Thus, theratchet pawl316 effectively ratchets alongportion320 holding the cell at each additional degree of expansion. As an alternative to teeth, theratchet pawl316 and cooperatingportion320 may utilize other types of interfering features to prevent contraction of the cell.
• The locking mechanisms also may be used in cooperation with expandable cells that are not necessarily bistable cells. For example, in FIG. 40A an[0128]expandable cell330 comprises athin strut332 disposed in an expandable “wishbone” type configuration between thethick struts334 to which it is connected. Alocking mechanism336 cooperates with one or more of the expandablethin struts332 to hold theexpandable cells330, at an expanded position. As illustrated in FIG. 40B, alocking mechanism336 may be combined with eachexpandable cell330, or there may be multiple expandable cells for eachlocking mechanism336.
• In this embodiment,[0129]locking mechanism336 comprises apost338 havingexternal teeth340.Post338 is slidably received within anopening342 defined by one or moreflexible fingers344 havingengagement tips346 that engageteeth340.Fingers344 flex outwardly to allowteeth340 to slidepast engagement tips346 as the cell is expanded, butengagement tips346 preventpost338 from moving in a direction towards the contracted state. Thus, onceexpandable cell330 is expanded,locking mechanism336 prevents contraction of the cell.
• A similar design is illustrated in FIGS. 41A and 41B. This design combines the expandable cell described with reference to FIG. 40A and a locking mechanism of the type described in FIGS.[0130]36A-36D. Thus, as the plurality ofexpandable cells330 are moved from the contracted state illustrated in FIG. 41A to the expanded state illustrated in FIG. 41B, the wishbone style thin strut is expanded. Simultaneously, prongs276 are pulled from theircorresponding opening280 to a position that prevents reentry offork274 intoopening280. The locking mechanism may be designed such thatprongs276 are withdrawn from and blocked from reenteringopening280. Alternatively, prongs276 may be designed for interference with corresponding teeth or other interferingfeatures350 disposed along the outer limit of each opening280 to prevent return movement ofprongs276 intoopening280.
• It also should be noted that expandable devices, such as expandable tubulars, can be formed with a variety of cells and locking mechanisms having differing configurations, such as changes in size or type, as illustrated schematically in FIG. 42. For example, by stacking cells of different length or eccentric offset in a sheet or tube, it is possible to design an opening bias into the structure. The expandable device may be designed to allow certain rows of cells to open prior to other rows of cells or for the cells to open in a predetermined pattern or at a predetermined rate. In FIG. 42, for example, an[0131]expandable device352 comprises rows ofexpandable cells354. However,different rows354 have cells of differing lengths,e.g. cells356,358 and360. This allows certain rows of cells to open prior to adjoining rows of cells, because, at least with certain cell designs, the length of the cell affects the force required to expand the cell. Incorporating different rows of cells into an expandable device allows the user to know the rate of expansion for a given deployment force and facilitates the design of devices having cells which open in a predetermined sequence. Additionally, the use of different types of cells can improve compliance of the expandable device when the deployment force is not uniform along the length of the device.
• It will be understood that the foregoing description is of exemplary embodiments of this invention, and that the invention is not limited to the specific forms shown. For example, the expandable cells can be combined into a variety of tubulars and other expandable structures; the size and shape of the expandable cells and locking mechanisms can be adjusted; the types of material utilized can be changed depending on the specific application; and a variety of mechanisms may be used to expand the cells. Also, the various cells can be formed by a variety of techniques including laser cutting, jet cutting, water jet cutting and other formation techniques. These and other modifications may be made in the design and arrangement of the elements without departing from the scope of the invention as expressed in the appended claims.[0132]

Claims (38)

What is claimed is:

1. An expandable device, comprising:

an expansion member having a plurality of cells that are expandable from a closed position to an open position, each cell having a thin strut pivotably coupled to a thick strut.

2. The expandable device as recited inclaim 1, wherein the thin strut and the thick strut of each cell are pivotably coupled by a pin joint.

3. The expandable device as recited inclaim 1, wherein the thin strut and the thick strut of each cell are pivotably coupled by a ball and socket joint.

4. The expandable device as recited inclaim 1, wherein the thin strut is coupled between a fixed end and a pivotable end.

5. The expandable device as recited inclaim 1, wherein the expansion member comprises a tubular that undergoes radial expansion during expansion of the plurality of cells.

6. An expandable device, comprising:

an expansion member having a plurality of cells that are expandable from a closed position to an open position, each of the plurality of cells comprising a thick strut, a first thin strut and a second thin strut.

7. The expandable device as recited inclaim 6, wherein the first thin strut is physically connected to the second thick strut and the second thin strut is disposed in abutting engagement with the thick strut.

8. The expandable device as recited inclaim 6, wherein the first thin strut and the second thin strut are generally parallel.

9. The expandable device as recited inclaim 6, wherein the first thin strut is longer than the second thin strut.

10. The expandable device as recited inclaim 6, wherein the expansion member comprises a tubular.

11. An expandable device, comprising:

an expansion member having a plurality of cells that are expandable from a closed position to an open position, each of the plurality of cells comprising a spring member to hold the cell in the open position.

12. The expandable device as recited inclaim 11, wherein the spring member comprises a horn.

13. The expandable device as recited inclaim 11, wherein the spring member comprises a pair of horns.

14. The expandable device as recited inclaim 13, wherein a thin strut and a thick strut extend between the pair of horns.

15. The expandable device as recited inclaim 11, wherein each cell comprises a double horn cell.

16. The expandable device as recited inclaim 11, wherein each spring member comprises an undulating spring member.

17. The expandable device as recited inclaim 11, wherein the expandable member comprises a tubular that undergoes radial expansion during expansion of the plurality of cells.

18. An expandable device, comprising:

an expansion member having a plurality of cells that are expandable from a closed position to an open position, each of the plurality of cells comprising a thick strut and a thin strut, the thin strut having a plurality of flexible joints.

19. The expandable device as recited inclaim 18, wherein each flexible joint comprises a thinned region.

20. The expandable device as recited inclaim 19, wherein each thinned region undergoes plastic deformation during expansion from the closed position to the open position.

21. The expandable device as recited inclaim 18, wherein the expansion member comprises a tubular.

22. An expandable device, comprising:

an expansion member having a plurality of cells that are expandable from a closed position to an open position, each cell having a thin strut coupled to a thick strut by a ligament.

23. The expandable device as recited inclaim 21, wherein the thin strut and the thick strut of each cell are pivotably coupled by a pin joint.

24. The expandable device as recited inclaim 21, wherein the thin strut and the thick strut of each cell are pivotably coupled by a ball and socket joint.

25. The expandable device as recited inclaim 21, wherein the thin strut is coupled between a fixed end and a pivotable end.

26. A method of expanding a device, comprising:

creating a plurality of bistable cells in a wall of the device by coupling thin struts to corresponding thick struts through hinge joints; and

applying an expansion force to the wall in a direction that transitions the plurality of bistable cells from a contracted state to an expanded state.

27. The method as recited inclaim 26, further comprising forming a plurality of locking mechanisms in the wall.

28. The method as recited inclaim 26, wherein creating comprises coupling each thin strut to a corresponding thick strut through a pivotable hinge joint.

29. The method as recited inclaim 26, wherein creating comprises coupling each thin strut to a corresponding thick strut through a flexible hinge joint.

30. The method as recited inclaim 26, wherein creating comprises coupling each thin strut to a corresponding thick strut by a hinge joint having a plastically deformable thinned region.

31. The method as recited inclaim 26, wherein creating comprises creating the plurality of bistable cells in a tubular.

32. The method as recited inclaim 31, wherein applying comprises applying a force in a radially outward direction.

33. The method as recited inclaim 26, further comprising coupling at least one thin strut to the at least one thick strut by a spring member.

34. The method as recited inclaim 26, further comprising coupling at least one thin strut to the at least one thick strut by a horn spring member.

35. An apparatus, comprising:

an expandable member having a plurality of cells that are expandable from a closed position to an open position, the plurality of cells comprising cells of differing sizes.

36. The apparatus as recited inclaim 35, wherein the expandable member comprises a tubular.

37. An apparatus, comprising:

an expandable member having a plurality of cells that are expandable from a closed position to an open position, the plurality of cells comprising cells of differing configurations.

38. The apparatus ofclaim 37, wherein the expandable member comprises a tubular.

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