Patent Application
20070256827
The present invention relates to expandable compliant structures used in pipes or boreholes, and more particularly, to an anchoring system and an expandable support module that may be used, in one embodiment, to seal off sections in a pipe or well within an oil drilling system. The system can conform to any cross sectional topology and can expand to variable diameter ratios. Furthermore, the system can also collapse by itself due its capacity to store potential energy when it is expanded. In addition to anchoring, this system may be adapted to deploy tools for inspection of the drilled well bores or for exploratory robots.
In oil and natural gas exploration, after a borehole has been drilled and a casing or open hole has been cemented within the borehole, one or more sections of the casing or open hole adjacent pay zones (e.g., reservoirs containing valuable resources, such as oil or natural gas) are perforated to allow fluid from the surrounding formation to flow into the well for production to the surface. Perforating guns are lowered into the borehole and the guns are fired to create openings in the casing or open hole and to extend perforations into the surrounding formation.
A production tubing may be inserted into the borehole to recover the fluid. Sealing devices may be used to seal off or otherwise block the formation and borehole fluids from the annulus between the production tubing and the casing or open hole during recovery of the fluid. Such devices may also be used for performing other operations within the casing or open hole. One such device is known as a packer, which is used in combination with reinforcing material (e.g., wire mesh). The packer may include at least one inflatable element that is used to seal off the passageway defined by the casing or open hole. One of the shortcomings associated with the use of packers is that the inflatable element may be subject to being extruded through the reinforcing material when the device is exposed to increased axial pressures and/or temperatures caused by the fluid.
The present invention relates, in part, to systems and techniques used to seal off the borehole during production or other operations. Of course, such systems may be used to block or otherwise seal other passageways as well. The systems may relate to anchoring systems that can be used to hold other components, such as logging tools, in specific positions within the well. The systems may also relate to crawling systems used to convey tools in horizontal and deviated wells.
An aspect of the present invention is directed to an anchoring module adapted to be secured within a structure. In one embodiment, the anchoring module comprises at least one compliant ring adapted to radially expand from a substantially relaxed position, and an expandable device positioned within the at least one compliant ring to expand the at least one compliant ring from its substantially relaxed position to interface with the structure.
Embodiments of the anchoring module may include the at least one compliant ring comprising a plurality of structural segments circumferentially arranged around the at least one compliant ring. In certain embodiments, each structural segment may be generally wedge-shaped. Each structural segment may be connected to one another by at least one interconnecting compliant portion and may be adapted to move radially outwardly with respect to structural segments of an adjacent compliant ring. The arrangement is such that two or more compliant rings may be positioned adjacent one another along a common axis, wherein segments of adjacent compliant rings may be aligned with respect to each other by at least one pin. The at least one compliant ring may be configured to be expandable from the substantially relaxed position to an expanded position. The at least one compliant ring may be configured such that the maximum diameter of the at least one compliant ring in its expanded position is approximately 1.69 times greater than the diameter of the at least one compliant ring in its substantially relaxed position. In further embodiments, the expandable device may comprise an inflatable bladder.
The anchoring module may further comprise a shaft and a pair of end caps in which the at least one compliant ring and the inflatable bladder may be positioned on the shaft between the pair of end caps. A sealing element may be further provided to block an interior of the structure. The arrangement is such that the at least one compliant ring, the expandable device and the sealing element may be mounted on the shaft.
Another aspect of the invention is directed to an anchoring module adapted to be secured within a structure. The anchoring module comprises at least one compliant ring adapted to radially expand from a substantially relaxed position, and means for expanding the at least one compliant ring from its substantially relaxed position to interface with the structure.
Certain embodiments of the anchoring module may include the at least one compliant ring comprising a plurality of structural segments circumferentially arranged around the at least one compliant ring. Each structural segment may be connected to one another by at least one interconnecting compliant portion, and may be adapted to move radially outwardly with respect to structural segments of an adjacent compliant ring. The arrangement is such that two or more compliant rings may be positioned adjacent one another along a common axis, wherein segments of adjacent compliant rings may be aligned with respect to each other by at least one pin. The at least one compliant ring may be configured to be expandable from the substantially relaxed position to an expanded position. The at least one compliant ring may be configured such that the maximum diameter of the at least one compliant ring in its expanded position is approximately 1.69 times greater than the diameter of the at least one compliant ring in its substantially relaxed position. In further embodiments, the means for expanding the at least one compliant ring may comprise an inflatable bladder.
The anchoring module may further comprise a shaft and a sealing element adapted to block an interior of the structure. The arrangement is such that the at least one compliant ring, the means for expanding the at least one compliant ring, and the sealing element may be mounted on the shaft.
A further aspect of the invention is directed to a system for sealing a structure. In one embodiment, the system comprises an anchoring module adapted to interface with an interior surface of the structure, and a support module adapted to transfer a load to the anchoring module.
Embodiments of the system may include the support module comprising a base, and a plurality of support elements coupled to the base. The plurality of support elements may be moveable from a collapsed configuration to an operable configuration in which the plurality of support elements expand radially along a plane generally perpendicular to an axis of the structure. Adjacently positioned support elements may be connected to one another by compliant linkages. The support module may further comprise at least one compliant link to connect the base and the plurality of support elements.
The system may further comprise a sealing element adapted to block an interior of the structure with the plurality of support elements being adapted to interface with the sealing element. The anchoring module may comprise at least one compliant ring adapted to radially expand from a substantially relaxed position, and an expandable device positioned within the at least one compliant ring to expand the at least one compliant ring from its substantially relaxed position to interface with the structure. The at least one compliant ring may comprise a plurality of structural segments circumferentially arranged around the at least one compliant ring. Each structural segment may be connected to one another by at least one interconnecting portion, and adapted to move radially outwardly with respect to adjacent structural segments. The expandable device may comprise an inflatable bladder. A pair of end caps may be further provided wherein the at least one compliant ring and the inflatable bladder may be positioned between the pair of end caps. The system may further comprise a shaft and a sealing element adapted to block an interior of the structure. The support module may be adapted to interface with the sealing element. The anchoring module, the support module and the sealing element may be mounted on the shaft.
Yet another aspect of the present invention is directed to a method of sealing a structure comprising securing a compliant device to an interior surface of the structure, and supporting a sealing device with the compliant device. In certain embodiments, the sealing device may comprise a sealing element. The method may further comprise transferring a load provided by the sealing device on the anchoring module with a support module positioned between the anchoring module and the sealing device.
In the drawings, like reference characters refer to the same or similar parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating particular principles, discussed below.
For the purposes of illustration only, and not to limit the generality, the present invention will now be described in detail with reference to the accompanying figures. This invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” “having,” “containing,” “involving,” and variations thereof herein, is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.
Some embodiments of the present invention are directed to systems for blocking or sealing an interior of a generally tubular structure, such as a pipe or a borehole used to characterize and/or produce fluid, such as oil or natural gas. Other embodiments are directed crawling systems used to convey tools in horizontal or deviated wells. Additional embodiments are directed to apparatuses adapted to hold devices in specific positions inside the tubular structures. An example of such a tubular structure is shown in the drawings as being circular in cross-section; however, as will be discussed below in greater detail, each described system is capable of sealing pipes that are not circular in cross-section, but instead are elliptical or oblong or otherwise asymmetrical in cross-section, for example. Prior blocking devices are particularly suited for sealing pipes having uniform circular cross-sections, and in most instances, are incapable of sealing pipes that, for whatever reason, are not circular. In some embodiments, the tubular structure is in the form of a borehole, which in certain instances may further include a casing, and in other instances may define an open hole. When employing a casing, the casing may comprise a pipe cemented to the borehole structure that is provided to define a passageway for fluids to travel. As used herein, “borehole” shall describe any generally tubular structure or open hole in which a device is capable of being anchored or otherwise secured within the passageway of the tubular structure. For the purpose of this application, “borehole” is intended to include cased holes and open holes. One skilled in the art would appreciate that this invention may be used in pipes whether inside or outside of the oilfield industry.
Certain embodiments of the present invention utilize the advantages of compliant mechanisms that adapt their configuration to surfaces having varying shapes and contours. Specifically, certain embodiments of the invention include an expandable system that uses a compliant mechanism to conform to geometrical variations along an axis and cross section of the borehole and to anchor the system within the borehole. Such a system may be self-retracting for subsequent removal or relocation of the system from the borehole. The system may include several modules designed to interact with one another to block or seal the passageway of the borehole.
One module of the system may be designed to anchor the system to an interior surface of the borehole. Another module of the system, sometimes referred to as a back-up module, employs an expandable surface that is capable to expand to the diameter of the interior of the borehole. These modules may be combined in a variety of configurations to support a sealing device, such as an inflatable sealing element.
In one embodiment, the anchoring module is a set of compliant rings capable of expanding to conform to the interior surface of the borehole. The arrangement is such that several compliant rings are arranged in series along an axis of the borehole. When expanded, the compliant rings expand radially outwardly to engage and secure the anchoring module within the borehole. One advantage associated with such systems is that the modules may conform to boreholes having varying or asymmetrical cross sectional profiles.
Referring now to the drawings, and more particularly to
Still referring to
In one embodiment, the compliant ring 24 may be fabricated from any suitable polymeric or plastic material. Other materials include, and are not limited to, steel, beryllium copper, titanium, etc.
Referring to
Each compliant ring 24 includes a plurality (e.g., twelve) of generally triangular- or wedge-shaped structural segments, each indicated at 38, that are circumferentially arranged about the axis 16. Each structural segment 38 is attached to its adjacent structural segment 38 by interconnecting portions, each indicated at 40. As shown, the compliant ring has a series of slits or notches 42, 44 extending inwardly from its outer diameter (slits 42) and extending outwardly from the inner diameter (slits 44) that together define the structural segments 38 and the interconnecting portions 40. The compliant ring 24 may be molded to the configuration shown in
The arrangement is such that the outer surfaces 34 of the compliant rings 24 are adapted to engage the interior surface 36 of the borehole 14 and inner surfaces 46 of the compliant rings are adapted to engage the inflatable bladder 26. Specifically, each structural segment 38 is adapted to move radially outwardly with respect to its adjacent structural segments. This capability is particularly beneficial for boreholes that are not circular in cross section, but are oblong or otherwise imperfect in cross section, for example. The structural segments 38 of adjacent compliant rings 24 may be aligned with one another by a pin 48 that extends through openings 50 the structural segments in the manner shown in
In certain embodiments, pressurized fluid (e.g., air or hydraulic fluid) is delivered to the inflatable bladder 26 through the shaft 28 in the well known manner. When pressurized, the inflatable bladder 26 expands the compliant rings 24 toward the interior surface 36 of the borehole 14. Specifically, the interconnecting portions 40 allow the structural segments 38 to move apart from each other and therefore radially outwardly to expand the overall diameter of the compliant ring 24. The inflatable bladder 26 is expanded by introducing pressurized fluid through the shaft and into the inflatable bladder thereby expanding the diameter of the inflatable bladder. The inflatable bladder's dimensions and material properties may be selected based on certain factors, such as climate conditions and the pressure of fluid being delivered to the bladder. The inflatable bladder 26 is secured to the shaft 28 such as with clamps (not shown). The end caps 30, 32, assist in ensuring that the inflatable bladder 26 expands properly within the compliant rings 24 to transfer the radial load to the compliant rings and the axial load to the end caps. In certain embodiments, the compliant rings 24 are capable of expanding to a maximum diameter that is approximately 1.69 times greater than the diameter of the compliant rings when they are in their relaxed state. Of course, the compliant rings may be designed to expand to a larger or smaller diameter depending on the borehole and shaft diameters and the material they are made of.
The anchoring module 18 may generate large anchoring forces with small input pressure delivered to the inflatable bladder 26. Table 1 shows, for different internal inflatable bladder pressure levels, the axial load that can be exerted on an anchoring module 18 before it slips with respect to an elliptical cross section borehole. These values are obtained for compliant rings made from plastic material and with a system that is 0.5 ft long, e.g., approximately eleven rings.
As shown, the anchoring module 18 is capable of being solidly secured within the borehole 14 so as to support large axial loads. The benefits associated with this capability will become apparent as the description of the system 10 proceeds.
Thus, it should be observed that the anchoring module 18 may conform not only to any cross sectional profile, but also to any topology along the axis of the well or tubular environment in which it is deployed. In addition, the anchoring module 18 stores potential energy that allows it to retract to its collapsed state by itself without external forces.
Turning now to
Each triangular-shaped support element 54 is connected by a compliant hinge 66 to an adjacent rectangular-shaped support element 56, which in turn is attached to another rectangular-shaped support element 56 by another compliant hinge 66. The support elements are hingedly attached to one another by the compliant hinges 66 to create the array 58. The arrangement is such that each rectangular-shaped support elements 56 has another rectangular-shaped support element 56 and a triangular-shaped support element 54 attached to it by two separate compliant hinges 66. This configuration enables the movement of the support module 20 from its collapsed configuration to its operable configuration upon receiving an axial force applied to the support elements 54, 56. In particular, the disk 58 formed by the support elements 54, 56 expands radially along a plane generally perpendicular to the long axis extending through the anchoring module 18 and the borehole 14 as illustrated in
Referring back to
One characteristic of the support module 20 is its ability to transfer loads axially along axis 16 (
Referring to
In one embodiment, six pivoting links 72 are provided. Each pivoting link 72 is a scissor-type mechanism having the ends of one pair of arms 74 connected to the base 52 by linkage pins (not designated) and opposite ends of the pair of arms 74 connected to a support element 54 by another pair of linkage pins (not designated). For each pivoting link 72, the ends of another pair of arms 76 are similarly connected to the base 52, with their opposite ends being attached to an annular member 78. The pivot links 72 enable the support module 70 to rotate independently about an axis (e.g., axis 16 in
This motion is made possible by the movement of an intermediate pin 80 formed on one pair of arms 74 that slides within an elongated slot formed in the mating pair of arms 76. This construction enables the support elements 54, 56 to expand differently with respect to one another, thus enabling the disk 58 to open within boreholes that are oblong or elliptical, for example. Springs 84 may be provided to contract or bias the support module 70 to its collapsed configuration. As shown, the each spring 84 is connected to the linkage pin and the intermediate pin 80 so as to apply a collapsing force to the pair of arms 74. It should be noted that the compliant version of the support module, e.g., support module 20, operates in a similar manner to the non-compliant version in that the resilient links 60 are normally biased in their collapsed state and the provision of an axial force (e.g., by sealing element 22) expands the support module 20 to its operable configuration.
In certain embodiments, the provision of an intermediate support element 68 may be provided to fill a gap created by the disk 58 of the support elements 54, 56 as the support module (20 or 70) expands. In addition, shims 86, preferably fabricated from stainless steel, may be included to provide a restoring force to bring the support module 70 back to its collapsed configuration. The shims provide mechanical limits to the rotation of the opening arms, mechanical or compliant, with respect to the axis 16. This limit of the rotation of the arms takes place while the support element conforms to the cross sectional geometry of the borehole.
In operation, and with further reference back to
The arrangement is such that the anchoring module 18 and support modules 20 or 70 support the sealing element 22 to seal the passageway 12 of the borehole 14. Although shown as a separate element, the sealing element 22 in a certain embodiment embodies an inflatable element that may be designed to have the shaft 28 extend therethrough. Thus, the sealing element 22 may be configured similarly to the inflatable bladder 26 in that pressurized fluid delivered through the shaft 28 is used to expand the sealing element. In certain embodiments, the following sequence may be followed. First, the anchoring module is deployed. Next, the support element is deployed, with the inflatable sealing acting on the support element. Once deployed, the sealing element 22 seals the borehole 14 so that other operations, such as harvesting oil or natural gas, may take place downstream within the borehole. In certain embodiments, the sealing element 22 and the inflatable bladder 26 may be fabricated from any elastomeric material adapted to withstand the pressure, temperature, and chemical characteristics of the fluids inside the borehole.
Referring to
As shown, the anchoring module 88 includes a series of compliant rings 24 arranged along the support shaft 28. As disclosed above, any number of compliant rings 24 may be provided depending on the required holding force to be provided by the anchoring module 88. Compliant support elements 54, 56 arranged as a disk 58 are provided at each end of the anchoring module 88 so that a planar surface of the outer compliant ring 24 engages its respective support elements 54, 56. The support elements 54, 56 are arranged in a similar manner to the support elements of the support modules 20, 70 so that either end of the anchoring module 88 may be used to engage and provide a resistance force to a sealing element, for example. It should be understood that only one end of the anchoring module 88 may be configured to have a support element 54, 56 when placing only one sealing element 22 within the borehole 14.
A device may be positioned between the compliant rings 108 of the support module 106 and the shaft 28 to expand the compliant rings to their operable position. In one embodiment, the device may be in the form of an inflatable bladder (not shown). Pressurized fluid may be delivered to the inflatable element via the shaft 28 for sealing and subsequently sealing the passageway 12 of the borehole 14.
Thus, it should be observed that the anchoring systems described herein are modular in construction. One module of the system may be designed to anchor the system to an interior surface of the borehole. Another module of the system may be designed to support a sealing element. In one embodiment, the module is a support or back-up module that employs an expandable surface that is capable of expanding to the diameter of the interior of the borehole. These modules may be combined in a variety of configurations to support a sealing element, such as an inflatable sealing element. The self-conforming nature of the modules obviate the need for prior knowledge of the borehole topology or complex sensor systems used to chart this data.
In addition to anchoring, the system may be adapted to be employed as a crawling apparatus used to deploy tools for inspection of drilled well bores or for exploratory robots. For example, a method of conveying devices inside a structure may comprise securing at least two anchoring modules in series within the structure, and moving at least one of the two anchoring modules an incremental amount. Tools connected to the anchoring modules outside of the anchoring modules may be conveyed in this manner.
While this invention has been shown and described with references to particular embodiments thereof, those skilled in the art will understand that various changes in form and details may be made therein without departing from the scope of the invention, which is limited only to the following claims.
