COMBINED ACTUATION OF THE JAWS AND SEALING ELEMENT OF THE PACKER

Abstract

A technique facilitates the actuation of a packer into a sealing and clamping position along a bore. The packer includes a packing element structure mounted around a central structure. The packing element structure includes a sealing element mounted along an expandable base such that the sealing element can expand radially. The packer also includes an actuating element connected to a portion of the packing element structure via a release mechanism, for example, a shearing element. A plurality of jaws can be positioned on the actuating element such that the linear movement of the actuating element causes the successive movement of the packing element and then the jaws in a radially outward direction.The packer may be constructed in such a way that this sequential clamping motion creates a percussion effect to ensure that the jaws engage firmly with the surrounding wellbore surface, for example, the casing surface.

Description

COMBINED ACTUATION OF THE JAWS AND SEALING ELEMENT OF THE PACKER CROSS REFERENCE TO RELATED APPLICATION This document is based upon and claims priority from U.S. provisional patent application serial number 62 / 923,575, filed on October 20, 2019, and U.S. provisional patent application serial number 63 / 051,019, filed on July 13, 2020, which are incorporated herein in their entirety by reference. BACKGROUND In many well applications, packers are used along a well string to seal sections of a borehole. Typically, a packer comprises a sealing element that can expand radially outward to form a seal between a central mandrel of the packer and a surrounding borehole surface, such as the inside surface of the casing. The packer may also comprise, or work in conjunction with, jaws that have gripping elements designed to engage with the surrounding borehole surface. The jaws can also expand radially outward to engage with the surrounding borehole surface, securely positioning the packer at a desired location along the borehole. COMPENDIUM In general, a system and methodology are provided for actuating a packer into a sealing and securing position along a borehole. The packer can be positioned along a variety of well strings and may include a central structure, such as a mandrel, through which it passes. A packer element structure is mounted around the central structure and includes a sealing element mounted along an expandable base, allowing the sealing element to expand radially. The packer also includes an actuating element connected to a portion of the packer element structure via a release mechanism, such as a shearing element.A plurality of jaws may be positioned on the actuating element such that the linear movement of the actuating element causes the successive movement of the packer's sealing element and then the jaws in a radially outward direction. The packer may be constructed such that this sequential clamping motion creates a percussive effect to ensure that the jaws engage firmly with the surrounding wellbore surface, for example, the casing surface. However, many modifications are possible without materially departing from the principles of this description. Therefore, it is intended that such modifications be included within the scope of this description, as defined in the claims. BRIEF DESCRIPTION OF THE FIGURES The following describes certain modalities of the description with reference to the accompanying figures, where similar reference numbers describe similar elements. However, it is understood that the accompanying figures illustrate the various implementations described herein and are not intended to limit the scope of the various technologies described herein. Figure 1 is a schematic illustration of an example of a packer placed along a well string located in a borehole, according to one modality of the description; Figure 2 is a cross-sectional view of another example of a packer placed along a well string, according to one modality of the description; Figure 3 is a cross-sectional illustration of a part of the packer illustrated in Figure 2, according to one modality of the description; Figure 4 is a cross-sectional illustration showing the features of an example of a packing element structure, according to one modality of the description; Figure 5 is an illustration that demonstrates the operation of the packer illustrated in Figures 2 and 3, according to one modality of the description; Figure 6 shows a short casing top packer system according to one or more of the embodiments described herein; and Figures 7-8 show the comparative results of the forces experienced by the short casing top packer system during short casing top packer attachment. DETAILED DESCRIPTION The following description details several aspects to clarify certain modalities of this description. However, those skilled in the art will understand that the system and / or methodology can be implemented without these details and that numerous variations or modifications of the described modalities are possible. This disclosure generally relates to a system and methodology for actuating a packer into a sealing and clamping position along a borehole. The packer is constructed to allow sequential actuation of the sealing element and then the jaws via an actuation inlet, such as a mechanical actuator or a pressure inlet, along the annulus and / or inside the well string. The packer can be installed along a variety of well strings and in many types of boreholes, including vertical or deviated wells, and cased wells. According to one embodiment, the packer may comprise a central structure, for example, a mandrel structure, having a passage through it. A packing element structure is situated around the central structure and includes a sealing element mounted along an expandable base such that the sealing element can expand radially. The sealing element may be formed of a suitable elastomeric material, and the expandable base may comprise a plurality of metallic base elements that can be displaced radially outward. Further, the packer comprises an actuating element connected to a portion of the packing element structure via a release mechanism, for example, a shearing element. The shearing element may comprise a tab or a plurality of tabs extending between the expandable base and the actuating element.The shearing element effectively provides a shearing mechanism within a radially expanding packer structure, consisting of a sealing element and a metal substrate, to sequentially secure the packer. Sequential securing involves first securing the sealing element, followed by shearing the shearing element, which then allows the jaws to be secured. This sequential method creates a percussive effect, ensuring that the engaging elements, such as the teeth, of the jaws bite into the surrounding surface of the borehole or harder casing metals. Referring generally to Figure 1, an example of a well system 30 is illustrated. In this embodiment, the well system 30 comprises a well string 32 that includes at least one packer 34 having a packer element structure 36 with a sealing element 38. The packer 34 also comprises a jaw section 40 that may have a plurality of jaws 42. In this example, the well string 32 is set in a perforation 44, for example, a well, which has a perforation surface 46 against which the packer can be attached. MA / t / ZUZZ / UÓÓ l UO packer 34. In some applications, the well 44 may be lined with a casing 48 and the drill surface 46 may be an inner casing surface surrounding the packer 34. Referring generally to Figure 2, a packer 34 is shown according to one or more of the modalities of the present description. As shown, the packer 34 has a core structure 50 having an outer surface 54 that includes a conical / inclined section 56 inclined in an outward radial direction with respect to a longitudinal axis 58 of the packer 34. In this example, the conical / inclined surface 56 of the core structure 50 is created by a cone 88 mounted along a mandrel 90. The cone 88 can be attached to the mandrel 90 by various fastening mechanisms, such as fasteners 92. As also shown in Figure 2, the packer 34 also includes a packer element structure 36 having a packer sealing element 38, which is expandable and mounted on an expandable base 60 (Figures 3-4) located along the outer surface 54 of the core structure 50.The sealing element of the packer 38 may be made of a suitable elastomeric material, for example. With reference to Figures 2 and 3, the packer 34 may also include an actuating element 62 connected to the structure of the packer element 36. As shown in Figure 3, the actuating element 62 may be in the form of a push collar 64 in one or more of the embodiments of this disclosure, for example. As further shown in Figure 3, the actuating element 62 may be coupled to the expandable base 60 via a release mechanism 66. The release mechanism 66 may be in the form of a shearing element 68, for example, at least one shearing tongue. According to the embodiment illustrated in Figure 3, the shearing element 68 may include at least one shearing tongue extending from the expandable base 60 to a corresponding recess 70 in the actuating element.With further reference to Figure 2, it should be noted that one method for causing the linear drive movement of the actuating element 62 involves applying annular pressure to a sealed pressure chamber through the ports 94. The pressure is used to drive the actuating element 62 linearly along the mandrel 90. Also with reference to Figures 2 and 3, the packer 34 according to one or more embodiments of this description also includes a jaw structure 40 having a plurality of jaws 42. In one or more embodiments of this disclosure, the jaws 42 include engagement elements 76, for example, teeth, constructed to securely engage a surrounding surface of the borehole 46, for example, an internal surface of the casing, when the jaws 42 expand radially during the assembly of the packer 34. As shown in Figure 3, for example, the jaws 42 and the corresponding teeth 76 are located on the actuating element 62, for example, on the thrust collar 64, in one or more embodiments of this disclosure. Furthermore, as shown in Figure 3, part of the expanded base 60 is provided with an outwardly inclined surface 80, for example, a conical surface.In one or more embodiments of this disclosure, the actuating element 62 can move linearly to fix the sealing element of the packer 38 and then cut the shearing element 68. Once the shearing element 68 is cut, the continued linear motion of the actuating element 62 forces the radial expansion of the jaws 42 as they slide along the outwardly inclined surface 80 of the expandable base 60. More specifically, during a packer setting operation, the actuating element 62 is displaced linearly, for example, in a direction toward the packer sealing element 38 along axis 58. Displacement of the actuating element 62 can be achieved by applying pressure along the inner passage 52 and / or along the annular space between the well string 32 and the surrounding borehole surface 46. A variety of pressure piston actuation techniques and other pressure actuation techniques are known in the industry. In some applications, however, the actuating element 62 can be constructed to be displaced mechanically. The linear movement of the actuating element 62 causes a linear / axial movement of the packing element structure 36 along the inclined section 56 of the outer surface 54 because the actuating element 62 is coupled to the expanding body 60 through the shearing element 68. Due to the radially outward inclination of the section 56, the expanding body 60 and the sealing element of the packing element 38 are also forced in an outward radial direction until the sealing element of the packing element 38 moves into sealing engagement with the surrounding surface of the perforation 46. As the sealing element of the packer 38 is forced to engage with the surface 46, further linear movement is resisted. The continued linear movement of the actuating element 62 can then shear the shearing element 68 to release the actuating element 62 from the structure of the packer element 36. As a result, the actuating element 62 can slide along the inclined surface 80 of the expanding shell 60, forcing the jaws 42 in an outward radial direction until the engaging elements / teeth 76 are secured against / within the surrounding wall surface 46. The release due to the shearing of the shearing element 68 creates a percussive effect during the engagement of the jaws 42, resulting in improved engagement of the elements / teeth 76 with the surrounding wall surface 46.Therefore, the packer 34 can independently fix the sealing element of the packer 38, followed by the subsequent fixing of the jaws 42. Also with reference to Figure 3, the structure of the packer element 36, according to one or more embodiments of the present description, has the form of a deflection rib seal having ribs 82. The ribs 82 extend radially inward from a portion of the expandable base 60 so that they are arranged in the sealing element of the packer 38. The ribs 82 deflect during setting and when subjected to drilling pressure from either side, for example, above or below, the sealing element of the packer 38. The expandable base 60 and the sealing element of the packer 38 combine to provide an expandable bonded seal, which is energized when pressure is applied. Such a structure of the packer element 36 can be used in a variety of packers 34, including short casing top packers.In combination with the deflection ribs 82, the structure of the packing element 36 may comprise additional ribs 84, for example, vertical ribs, extending outwards into the sealing element of the packing element 38. In the illustrated example, the deflection ribs 82 are located on the upper and lower sides of the additional ribs 84. For example, the lower deflection rib 82 may be oriented in a generally outward and downward direction, and the upper deflection rib 82 may be oriented in a generally outward and upward direction. The centrally located ribs 84 may be oriented to project radially outward and serve to prevent the sealing element of the packer 38 from being unduly deformed and also serve as a hard stop that limits the amount of deflection of the deflection ribs 82. The deflection ribs 82 deflect when the packing element 38 is clamped into a sealing position against the surrounding surface of the bore 46 by the application of force. The deflection of the ribs 82 effectively stores clamping energy when the sealing element 38 is in the sealing position. Advantageously, the deflection rib seal design according to one or more embodiments of the present description may require only about 50,000 lbf or less of a clamping load, which is at least half of that required in prior art seal assemblies. In some embodiments, the elastomeric material of the packing element 38 may be shaped to a profile such that when pressure is applied, the elastomer MA / t / ZUZZ / UÓÓ l UO further pushes the deflected ribs 82 against the surrounding surface of the borehole 46, for example, the surrounding surface of the casing. This ensures that the sealing action with the surrounding borehole surface 46 is strong. Ribs 82, 84, and the packing element 38 work together to provide a self-energizing seal. For example, the deflection ribs 82 help energize the packing element 38 with applied pressure, forcing it to achieve an improved seal with the surrounding surface of the perforation 46. Features such as the deflection ribs 82 also help energize the sealing action with the applied annular pressure. For example, when pressure is applied from one or both directions (see the right side of Figure 5), the deflection ribs 82 help energize the seal on both the outer and inner diameters of the packing element 36 structure. This energization helps the sealing element 38 withstand the increased annular pressures acting on the packing element 34, for example, pressures exceeding 15,000 psi.In several applications, the 82 deflection ribs can tilt up and down to deflect when set and further energized when pressure is applied from above or below. In some embodiments, the expandable base 60 may also include internal metal protrusions 86 oriented to form an enhanced metal-to-metal seal with the corresponding outer surface 54 of the core structure 50. The internal metal protrusions 86 create high contact pressure when the packing element 38 seals against the surrounding bore wall surface 46. Such a metal-to-metal seal provides increased resistance to backlash. When pressure is applied from either side of the packing element 34, for example, the deflection ribs 82 and the metal protrusions 86 help maintain the seal along the outside and inside of the packing element structure 36.It should be noted that an internal seal 78, for example an O-ring style seal, can be placed between the outer surface 54 and the expandable base 60, such as between the internal metal protrusions 86, for example, to form a suitable seal along the inside of the element structure. According to one embodiment, the packing element 36 may be a stamped seal having an expandable base 60 in the form of a metallic substrate. The metallic substrate may comprise a ductile metal material, for example, 8620 steel or another suitable ductile steel. In this example, the sealing element of the packing element 38 may be in the form of a suitable elastomer, for example, HNBR, bonded to the expandable metallic base 60. Depending on the parameters of a given application and / or environment, the materials and configurations selected for the expandable base 60 and the sealing element of the packing element 38 may be adjusted accordingly. According to one example, the jaws 42 can be mounted or formed entirely with the actuating element 62, for example, the collar 64, and positioned for sliding engagement with a secondary ramp created by the inclined surface 80 of the expandable base 60 (see Figure 3). The secondary ramp / inclined surface 80 helps to energize the jaws 42 to improve jaw grip when pressure is applied, for example, on the sealing element of the packer 38. This type of construction effectively provides a high clamping load capacity with a relatively compact jaw length by enabling the jaws 42 to be energized when pressure is applied. As further shown in Figure 4, it should be noted that the structure of the packing element 36 can be similar to that described with reference to Figure 3, which has deflection ribs 82, centrally located ribs 84, the packing sealing element 38, and internal metal protrusions 86. This type of construction reduces backlash to improve sealing pressure, as previously described. For example, the configuration prevents backlash in the packing sealing element 38 when a lower annular pressure is applied and energizes the grip of the jaws 42 as the pressure increases (see Figure 5). Furthermore, with reference to Figure 5, a larger ramp angle or a composite ramp angle of the secondary ramp / inclined surface 80 can be used to reduce the radial load experienced by the casing pipe 48 and mandrel 90, thereby providing greater clamping capacity. In this example, the teeth 76 of the jaws 42 are fully supported by the secondary ramp / inclined surface 80 to assist each tooth in gripping the surrounding casing pipe 48. Similar to other embodiments, the jaws 42 are actuated sequentially by a shearing sequence, as described above, so that the jaws 42 are clamped after the sealing element of the packer 38 is fully clamped.The shearing sequence can be used to achieve the desired percussion effect which ensures that the jaws 42 bite into the harder metallurgies associated with certain types of casing pipes 48. It should be noted that the packer 34 can be constructed in various sizes and configurations. For example, the central structure 50, the packer element structure 36, the actuating element 62, and the jaws 42 can have a variety of sizes and configurations. In some embodiments, the jaws 42 are formed as a unitary part of the actuating element 60, while in other embodiments, the jaws 42 are formed as a friction ring or other structure separate from the actuating element 60. The packer element structure 36 can comprise various types of materials and configurations to form the sealing element of the packer 38, as well as the expandable base 60. In addition, various integral or separate components can be used to form the inclined surfaces 56 and / or 80. With reference to Figure 6, a short casing top packer system is shown, comprising a packer element 36, a cone 88, and a mandrel 90, according to one or more embodiments of this disclosure. In a typical short casing top packer system, the entire packer element is disposed on the cone in the unfixed position. This typical configuration reduces the packer element's cross-section because the inside diameter (ID) of the packer element is constrained by the outside diameter (OD) of the cone, and the OD of the packer element is constrained by the OD of the packer.Conversely, in the short casing top packer system according to one or more of the embodiments described herein, a notch 96 is added to the mandrel 90 below the cone tip, allowing the packer element ID to be smaller than the cone tip and restricted only by the mandrel OD. As further shown in Figure 6, the packer element 36 is partially outside the cone 88 in the unfixed state, increasing the packer element 36's cross-section. Furthermore, by adding a notch 96 to the mandrel 90, the packer element 36 can be fixed over the cone 88 without sagging. This increased cross-section of the packer element 36 allows the packer OD to be reduced and the packer bypass area to be increased. The notch in the mandrel 96 can take various shapes and configurations without departing from the scope of this description. With reference to Figures 7 and 8, comparative results of the forces experienced by the short casing top packer system during short casing top packer installation are shown. Specifically, Figure 7 shows the resulting forces experienced by a short casing top packer system without a mandrel notch, and Figure 8 shows the resulting forces experienced by a short casing top packer system with a mandrel notch, according to one or more of the modalities described herein. As shown in Figure 7, without the notch in the mandrel, excessively high forces are required for the packer element to pass over the cone tip edge, as evidenced by the maximum load (circled), for example. However, as a result of adding the notch in the mandrel according to one or more of the modalities described herein, the maximum load shown in Figure 7 is eliminated in Figure 8. Eliminating excessive loading forces during the setting of the short casing top packer in this manner is particularly useful when a shear event is present to initiate the setting of the short casing top packer, according to one or more of the modalities described herein. Although only some embodiments of the description have been described in detail above, those skilled in the art will readily understand that many modifications are possible without materially departing from the principles of the present description. Accordingly, it is intended that such modifications be included within the scope of the present description, as defined in the claims.

Claims

1. A system for use in a well comprising: a well string having a packer mounted along the well string, wherein the packer comprises: a central structure having an outer surface inclined in an outward radial direction with respect to a longitudinal axis of the packer; a packer element structure having a sealing element mounted around an expandable base positioned along the outer surface of the central structure; an actuating element connected to a portion of the expandable base of the packer element structure via a shearing element;and a plurality of jaws located on the actuating element, wherein the linear movement of the actuating element causes the movement of the packing element structure in an axial direction along the outer surface, such that the outer surface forces the expandable base and the sealing element to expand radially outwards until the shearing element is cut, wherein further linear movement of the actuating element causes the subsequent expansion of the plurality of jaws in an outward radial direction.

2. The system as described in claim 1, wherein the central structure comprises a mandrel having an internal passage through it, and wherein the outer surface of the central structure is a cone positioned around the mandrel.

3. The system as described in claim 2, wherein the mandrel comprises a notch.

4. The system as described in claim 3, wherein the notch in the mandrel is below the tip of the cone.

5. The system as described in claim 2, wherein the packing element structure is partially outside the cone in an unfixed position.

6. The system as described in claim 1, wherein the sealing element of the packing element structure is elastomeric.

7. The system as described in claim 6, wherein the expandable base of the packing element structure is formed from ductile metal.

8. The system as described in claim 7, wherein the structure of the packing element comprises a plurality of deflection ribs to facilitate self-energizing of the sealing element.

9. The system as described in claim 1, wherein the actuating element comprises a push collar.

10. The system as described in claim 1, wherein the shearing element comprises at least one shearing tongue extending from the expandable base to a recess in the actuating element.

11. The system as described in claim 1, wherein the plurality of jaws is positioned along an inclined surface of the expandable base, wherein the inclined surface creates a secondary ramp that forces the plurality of jaws in an outward radial direction during packer attachment.

12. The system as described in claim 1, further comprising a seal placed between the structure of the packing element and the outer surface.

13. The system as described in claim 1, wherein the cutting of the shearing element causes a percussion effect that helps to fix the plurality of jaws.

14. A system comprising: a packer that is fixed against the surface of a surrounding wall in a borehole, wherein the packer comprises: a central structure; a packer element structure mounted around the central structure, wherein the packer element structure has a sealing element mounted around an expandable base positioned along an outer surface of the central structure; an actuating element connected to the packer element structure via a shearing element; and jaws engaged with the actuating element such that linear movement of the actuating element causes the sequential fixing of the sealing element against the surface of the surrounding wall; the shearing of the shearing element; and then the fixing of the jaws against the surface of the surrounding wall.

15. The system as described in claim 14, wherein the cutting of the shearing element causes a percussion effect that helps to fix the jaws against the surrounding wall surface.

16. The system as described in claim 14, wherein the sealing element of the packing element structure is elastomeric.

17. The system as described in claim 14, wherein the expandable base is formed of metal and comprises deflection ribs extending into the interior of the sealing element.

18. The system as described in claim 14, wherein the shearing element comprises at least one shearing tongue extending from the expandable base to a recess in the actuating element.

19. The system as described in claim 14, wherein the jaws are arranged around an inclined surface of the packing element structure, wherein the inclined surface creates a secondary ramp that forces the jaws radially outwards during packing attachment.

20. The system as described in claim 19, wherein the secondary ramp energizes the jaws to improve the grip of the jaw on a surrounding wall surface when pressure acts on the packing element structure.

21. A method comprising: providing a packer with a radially expandable packer element structure; jaws; and an actuating element releasably attached to the packer element structure; moving the packer at the bottom of a borehole to a desired location; and physically displacing the actuating element to cause sequential attachment of the packer element structure; releasing the actuating element from the packer element structure; and then attaching the jaws.

22. The method as described in claim 21, further comprising releasably fixing the actuating element to the structure of the packing element with a shearing element.

23. A system for use in a well comprising: a packer structure having a sealing element mounted on a metal base, wherein the metal base has deflection ribs extending outward into the sealing element, wherein the deflection ribs have at least one upper deflection rib and at least one lower deflection rib such that when the packer structure is positioned in a generally vertical borehole, the at least one upper deflection rib is generally inclined outward and upward and the at least one lower deflection rib is generally inclined outward and downward, wherein the deflection ribs are oriented to deflect during the setting of the packer structure and to be energized when pressure is applied to the packer structure.

24. The system as described in claim 23, wherein the metal base further comprises ribs located in the center positioned between the at least one upper deviation rib and the at least one lower deviation rib.

25. The system as described in claim 24, wherein the ribs located in the center comprise a pair of radially oriented ribs.

26. The system as described in claim 24, wherein the metal base further comprises protrusions located on a radially inner side of the metal base and oriented to form a metal-to-metal seal with a corresponding metal surface.

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