Packer

Abstract

The utility model belongs to the technical field of oil and gas exploitation, and discloses a packer which comprises a central pipe, an elastic cylinder, an expansion pipe and a sealing assembly. A first liquid transfer hole is formed in the pipe wall of the central pipe; the center pipe is sleeved with the elastic cylinder, the two ends, in the axial direction, of the elastic cylinder are connected with the center pipe in a sealed mode, a first elastic cavity is defined by the outer circumferential wall of the center pipe and the inner circumferential wall of the elastic cylinder, and liquid in the center pipe can enter the first elastic cavity through the first liquid conveying hole; the elastic cylinder is sleeved with the expansion pipe, the two ends of the expansion pipe in the axial direction are both connected with the elastic cylinder in a sealed mode, a second elastic cavity is defined by the outer circumferential wall of the elastic cylinder and the inner circumferential wall of the expansion pipe, a second liquid conveying hole is formed in the expansion pipe, and external liquid can enter the second elastic cavity through the second liquid conveying hole; the sealing assembly is arranged outside the expansion pipe. The packer has an internal and external pressure balancing function, can still keep reliable setting under high pressure, and reduces the difficulty of staged fracturing operation under high temperature and high pressure.

Description

TECHNICAL FIELD

[0001] The utility model relates to oil and gas exploitation technical field especially relates to a packer. BACKGROUND

[0002] The packer is a downhole tool commonly used for sealing the annular space between the oil pipe and the casing or the open hole wall of the oil and gas well.

[0003] In the open hole staged fracturing process, the packer not only bears the internal pressure, but also bears the external pressure. The traditional packer does not have the function of balancing the pressure, and combined with the irregular shape of the well wall structure, the packer is easy to lose sealing under the action of external pressure, making it difficult to carry out staged fracturing operation under high temperature and high pressure.

[0004] Therefore, it is urgent to propose a packer to solve the above technical problems. UTILITY MODEL CONTENT

[0005] The utility model provides a kind of packer, it has internal and external pressure balancing function, still can keep reliable setting under high pressure, reduce the difficulty of staged fracturing operation under high temperature and high pressure.

[0006] To achieve this purpose, the utility model adopts the following technical solutions:

[0007] The packer comprises:

[0008] A central pipe is provided with a first liquid transmission hole on the pipe wall thereof;

[0009] An elastic cylinder is sleeved outside the central pipe, and the two ends of the elastic cylinder in the axial direction are sealingly connected with the central pipe; the outer peripheral wall of the central pipe and the inner peripheral wall of the elastic cylinder form a first elastic cavity; and the liquid in the central pipe can enter the first elastic cavity through the first liquid transmission hole;

[0010] An expansion pipe is sleeved outside the elastic cylinder, and the two ends of the expansion pipe in the axial direction are sealingly connected with the elastic cylinder; the outer peripheral wall of the elastic cylinder and the inner peripheral wall of the expansion pipe form a second elastic cavity; the expansion pipe is provided with a second liquid transmission hole, and the liquid outside can enter the second elastic cavity through the second liquid transmission hole;

[0011] A sealing assembly is arranged outside the expansion pipe.

[0012] Optionally, the sealing assembly comprises a plurality of annular protrusions having elastic properties, and the plurality of annular protrusions are arranged at intervals along the axial direction of the expansion pipe.

[0013] Optionally, the material of the annular protrusion is rubber.

[0014] Optionally, a plurality of first annular grooves are arranged on the outer peripheral wall of the central pipe at both ends in the axial direction of the elastic cylinder, and a first sealing ring is arranged in each of the first annular grooves, and the part of the first sealing ring protruding from the first annular groove is attached to the inner peripheral wall of the elastic cylinder; or the two ends in the axial direction of the elastic cylinder are connected to the central pipe by welding.

[0015] Optionally, a plurality of second annular grooves are arranged on the inner peripheral wall of the expansion pipe at both ends in the axial direction of the expansion pipe, and a second sealing ring is arranged in each of the second annular grooves, and the part of the second sealing ring protruding from the second annular groove is attached to the outer peripheral wall of the elastic cylinder; or the two ends in the axial direction of the expansion pipe are connected to the elastic cylinder by welding.

[0016] Optionally, the packer further comprises a lower joint, one end of the lower joint is provided with a first connecting ring part and a second connecting ring part, the first connecting ring part is connected to the central pipe, and the second connecting ring part is connected to the expansion pipe.

[0017] Optionally, the first connecting ring part is provided with an internal thread, one end of the central pipe is provided with an external thread, and the first connecting ring part is connected to the central pipe provided with the external thread through the internal thread; and / or the second connecting ring part is connected to the expansion pipe by welding.

[0018] Optionally, the material of the elastic cylinder is spring steel.

[0019] Optionally, a plurality of first liquid transmission holes are arranged on the pipe wall of the central pipe and are arranged at intervals in the circumferential direction of the central pipe.

[0020] Optionally, a plurality of second liquid transmission holes are arranged on the expansion pipe and are arranged at intervals in the circumferential direction of the expansion pipe.

[0021] The packer has the following beneficial effects:

[0022] The utility model provides a packer, including central tube, elastic cylinder, expansion pipe and sealing assembly. When the liquid of pressing enters central tube, a part of liquid will enter first elastic cavity through first liquid hole, make elastic cylinder and expansion pipe receive internal pressure and expand outward together, and finally expansion pipe can be in accordance with the shape of well wall or stratum wall and its adhesion, sealing assembly is compressed and acts on well wall or stratum wall simultaneously, realizes setting. In the process of open hole staged fracturing, a part of liquid of pressing will flow into well wall or stratum wall and packer, and this part of liquid can enter second elastic cavity through second liquid hole, and will push elastic cylinder inward, and expansion pipe keeps invariant, namely through elastic cylinder can balance external pressure, has guaranteed the reliability of setting of expansion pipe. The packer can balance internal and external pressure, can avoid the influence of external pressure to setting, has guaranteed the reliability of setting, and, through expansion pipe and sealing assembly jointly realizes setting, and the sealing performance is higher, and then reduces the difficulty of staged fracturing operation under high temperature and high pressure. In addition, the packer simple structure, the inside diameter is bigger, is convenient for operation, and the cost is also lower. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical scheme in the embodiment of the utility model, the following will introduce the drawing needed to be used in the embodiment of the utility model briefly, obviously, the drawing in the following description only is some embodiments of the utility model, for ordinary skilled person in the art, under the premise of not paying the creative labor, can also obtain other drawings according to the content of the embodiment of the utility model and these drawings.

[0024] Figure 1 It is the schematic diagram of packer provided by the embodiment of the utility model;

[0025] Figure 2 It is Figure 1 The enlarged view at A;

[0026] Figure 3 It is the setting schematic diagram of packer provided by the embodiment of the utility model;

[0027] Figure 4 It is the schematic diagram of packer when bearing external pressure after setting provided by the embodiment of the utility model;

[0028] Figure 5 It is the fracturing process schematic diagram provided by the embodiment of the utility model

[0029] Figure 6 It is Figure 1 The enlarged view at B.

[0030] In the drawing:

[0031] 10, stratum wall;20, sliding sleeve assembly;

[0032] 100, central tube; 110, first liquid passage hole; 120, first sealing ring;

[0033] 200, elastic cylinder; 210, first elastic cavity; 220, second elastic cavity;

[0034] 300, expansion tube; 310, second liquid passage hole; 320, second sealing ring;

[0035] 400, sealing assembly; 410, annular protrusion;

[0036] 500, lower joint; 510, first connecting ring part; 520, second connecting ring part. DETAILED DESCRIPTION

[0037] The utility model will be described in further detail below in combination with the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the utility model, and not to limit the utility model. In addition, it should be noted that, in order to facilitate the description, only the part related to the utility model is shown in the drawings, not all structures.

[0038] In the description of the utility model, unless otherwise explicitly specified and limited, the terms "connected", "connected", "fixed" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral; It can be mechanical connection, or electrical connection; It can be directly connected, or indirectly connected through intermediate media, or the communication between two elements or the interaction between two elements. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0039] In the utility model, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can include the direct contact of the first and second features, or the contact of the first and second features through other features between them. Moreover, the first feature "on", "above" and "above" the second feature includes the first feature directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "under", "below" and "below" the second feature includes the first feature directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0040] In the description of the present embodiment, the terms "upper", "lower", "left", "right" and the like orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0041] The present embodiment provides a packer with internal and external pressure balancing function, which can still maintain reliable setting under high pressure, reducing the difficulty of staged fracturing operation under high temperature and high pressure.

[0042] Specifically, as shown in the drawings, Figures 1-4 The packer includes a central pipe 100, an elastic cylinder 200, an expansion pipe 300 and a sealing assembly 400. The central pipe 100 is provided with a first liquid transmission hole 110 on the pipe wall, the elastic cylinder 200 is sleeved outside the central pipe 100, the two ends of the elastic cylinder 200 in the axial direction are sealingly connected with the central pipe 100, the outer peripheral wall of the central pipe 100 and the inner peripheral wall of the elastic cylinder 200 form a first elastic cavity 210, and the liquid in the central pipe 100 can enter the first elastic cavity 210 through the first liquid transmission hole 110. The expansion pipe 300 is sleeved outside the elastic cylinder 200, the two ends of the expansion pipe 300 in the axial direction are sealingly connected with the elastic cylinder 200, the outer peripheral wall of the elastic cylinder 200 and the inner peripheral wall of the expansion pipe 300 form a second elastic cavity 220, the expansion pipe 300 is provided with a second liquid transmission hole 310, and the external liquid can enter the second elastic cavity 220 through the second liquid transmission hole 310. The sealing assembly 400 is arranged outside the expansion pipe 300.

[0043] It can be understood that the sealing assembly 400 mainly plays the functions of sealing and suspension, so as to ensure the reliable sealing of the packer and the stability of the position of the packer.

[0044] For the convenience of understanding, the use method and working principle of the packer will be briefly introduced by taking the packer used in the open hole staged fracturing process as an example:

[0045] It is worth noting that when the number of fracturing layers is N, the number of packers is 2N.

[0046] As shown in the drawings, Figure 5 In the present embodiment, the number of fracturing layers is set to 1, so two packers are needed, the lower end of one of the packers is connected with a first casing, then a sliding sleeve assembly 20 is connected on the first casing, then a second casing is connected on the sliding sleeve assembly 20, and finally the lower end of the second casing is connected with the upper end of the other packer, forming an equipment for open hole staged fracturing.

[0047] The specific fracturing steps are as follows:

[0048] Firstly, as shown in the figure, the device is lowered into the formation until reaching the position where fracturing is needed; Figure 5

[0049] Then, as shown in the figure, the pressurizing liquid is delivered into the device to realize the setting of the two packers. Specifically, the pressurizing liquid entering the center tube 100, part of it will enter the first elastic cavity 210 through the first liquid transmission hole 110, and the other part will continue to flow downward (indicated by the middle arrow). The liquid entering the first elastic cavity 210 makes the elastic cylinder 200 and the expansion tube 300 expand outward together with the internal pressure (i.e., the first elastic cavity 210 becomes larger), and finally the expansion tube 300 can conform to the shape of the formation wall 10 and seal the component 400 is compressed against the formation wall 10 to realize setting; Figure 3 Figure 3 After that, as shown in the figure, the soluble fracturing ball is put in and is stuck when it moves to the sliding sleeve assembly 20. Due to the blockage of the soluble fracturing ball, the pressurizing liquid will not enter the lower packer through the center tube 100.

[0050] Figure 5 Finally, as shown in the figure, the pressurizing liquid is continuously delivered to carry out fracturing operation. At this time, the sliding sleeve assembly 20 is opened, the pressurizing liquid is delivered from the upper packer to the sliding sleeve assembly 20, and flows into the formation wall 10 and the open hole staged fracturing device from the opening of the sliding sleeve assembly 20. Among them, part of the liquid flows to the outside of the upper packer to form an internal and external balance with the liquid inside the packer to ensure the reliable setting of the packer; the other part of the liquid flows to the outside of the lower packer, as shown in the figure, this part of the liquid will enter the second elastic cavity 220 through the second liquid transmission hole 310, and as the second elastic cavity 220 becomes larger, the liquid will push the elastic cylinder 200 inward to balance the external pressure and ensure that the expansion tube 300 does not change, ensuring the reliability of the setting of the expansion tube 300.

[0051] Figure 5 Figure 4

[0052] The packer provided by the embodiment can balance the internal and external pressure, avoid the influence of external pressure on setting, ensure the reliability of setting, and through the expansion tube 300 and the sealing component 400, the setting is realized, the sealing performance is higher, and the difficulty of staged fracturing operation under high temperature and high pressure is reduced. In addition, the packer has simple structure, large internal diameter, is convenient for operation, and has low cost.

[0053] The packer provided by the embodiment has good sealing performance, can be placed in the downhole for a long time, and is convenient to use.

[0054] ​​​​​​It is worth mentioning that the position of the second liquid transmission hole 310 should be set as required to ensure that the pressurized liquid can flow smoothly into the second elastic cavity 220. In the embodiment, the second liquid transmission hole 310 is arranged close to the upper end of the expansion pipe 300.

[0055] It can be understood that the elastic cylinder 200 expands outward under internal pressure and expands inward under external pressure. Alternatively, the material of the elastic cylinder 200 can be spring steel. Spring steel has a very high elastic limit (yield strength) and can withstand repeated elastic deformation without plastic deformation (permanent deformation), and has good functional stability. Moreover, spring steel has excellent fatigue resistance under long-term alternating load and can withstand millions of cycles of stress without breaking, and has a long service life.

[0056] It can be understood that the expansion pipe 300 expands outward under internal pressure. Alternatively, the material of the expansion pipe 300 can be alloy steel, such as 15CrMoG, etc., which needs to have a certain plastic deformation ability, which can be selected according to actual needs, and the present application does not make specific limitations.

[0057] Alternatively, a plurality of first liquid transmission holes 110 are arranged on the wall of the central pipe 100 and are arranged at intervals in the circumferential direction of the central pipe 100. By arranging a plurality of first liquid transmission holes 110, the speed of liquid entering the first elastic cavity 210 can be improved, thereby improving the setting efficiency.

[0058] Alternatively, a plurality of second liquid transmission holes 310 are arranged on the expansion pipe 300 and are arranged at intervals in the circumferential direction of the expansion pipe 300. By arranging a plurality of second liquid transmission holes 310, the speed of liquid entering the second elastic cavity 220 can be improved, which is beneficial to improve the performance of the packer in balancing external pressure.

[0059] Further, with reference to Figure 2 , the sealing assembly 400 comprises a plurality of annular protrusions 410 having elastic properties, and the plurality of annular protrusions 410 are arranged at intervals in the axial direction of the expansion pipe 300. The sealing is realized by the plurality of annular protrusions 410, which has a simple structure, and since the annular protrusions 410 have elastic properties, they can be elastically pressed against the well wall or the formation wall 10, and the sealing and hanging performance are both good.

[0060] Alternatively, the material of the annular protrusion 410 can be rubber. Rubber has good sealing and fitting properties and can fill gaps by deforming when under pressure, and has good sealing performance. Moreover, it is easy to process and has a relatively low cost.

[0061] Alternatively, the annular protrusion 410 can be arranged outside the expansion pipe 300 through a vulcanization process, which is simple and easy to process.

[0062] Alternatively, with reference toFigure 2 In one possible embodiment, a plurality of first annular grooves are arranged on the outer peripheral wall of the central tube 100 at both ends in the axial direction of the elastic cylinder 200, and a first sealing ring 120 is arranged in each first annular groove. The part of the first sealing ring 120 protruding out of the first annular groove is attached to the inner peripheral wall of the elastic cylinder 200. The sealing connection between the central tube 100 and the elastic cylinder 200 is achieved by the first sealing ring 120, which is simple in structure and easy to assemble.

[0063] It can be understood that the number of the first sealing ring 120 at each end in the axial direction of the elastic cylinder 200 can be one, two, three, etc., which can be set according to actual needs, and the present application does not make specific limitations.

[0064] In another possible embodiment, the two ends in the axial direction of the elastic cylinder 200 can also be sealingly connected to the central tube 100 by welding. In other possible embodiments, the sealing structure between the elastic cylinder 200 and the central tube 100 can also be set to other structures, which can be set according to actual needs, and the present application does not make specific limitations.

[0065] Optionally, continuing to refer to Figure 2 In one possible embodiment, a plurality of second annular grooves are arranged on the inner peripheral wall of the expansion tube 300 at both ends in the axial direction of the expansion tube 300, and a second sealing ring 320 is arranged in each second annular groove. The part of the second sealing ring 320 protruding out of the second annular groove is attached to the outer peripheral wall of the elastic cylinder 200. The sealing connection between the expansion tube 300 and the elastic cylinder 200 is achieved by the second sealing ring 320, which is simple in structure and easy to assemble.

[0066] It can be understood that the number of the second sealing ring 320 at each end in the axial direction of the expansion tube 300 can be one, two, three, etc., which can be set according to actual needs, and the present application does not make specific limitations.

[0067] In another possible embodiment, the two ends in the axial direction of the expansion tube 300 can also be sealingly connected to the elastic cylinder 200 by welding. In other possible embodiments, the sealing structure between the elastic cylinder 200 and the expansion tube 300 can also be set to other structures, which can be set according to actual needs, and the present application does not make specific limitations.

[0068] Further, as Figure 6 shown, the packer further includes a lower joint 500, one end of the lower joint 500 is provided with a first connecting ring part 510 and a second connecting ring part 520, the first connecting ring part 510 is connected to the central tube 100, and the second connecting ring part 520 is connected to the expansion tube 300. The lower joint 500 is used to connect the central tube 100 and the expansion tube 300, and to support the expansion tube 300.

[0069] Optionally, in a possible embodiment, the first connecting ring part 510 is provided with an internal thread, one end of the central pipe 100 is provided with an external thread, and the first connecting ring part 510 is connected to the central pipe 100 provided with the external thread through the internal thread. The connection between the lower joint 500 and the central pipe 100 is realized in the form of threaded connection, which is simple in structure and convenient to install. In other embodiments, the connection structure between the first connecting ring part 510 and the central pipe 100 can also be provided as other, which can be set according to actual needs, and the present application does not make specific limitation.

[0070] Optionally, in a possible embodiment, the second connecting ring part 520 is connected to the expansion pipe 300 in the form of welding. The welding process is simple and convenient to process.

[0071] It is worth noting that the strength of the lower joint 520 should be greater than that of the expansion pipe 300, so as to avoid that the lower joint 520 expands together with the expansion pipe 300.

[0072] In other embodiments, the lower joint 520 can also be of an integrated structure with the expansion pipe 300, and the lower joint 520 is subjected to local heat treatment to improve the strength of the lower joint 520.

[0073] Further, continuing to refer to Figure 6 In the present embodiment, the second connecting ring part 520 is connected to the expansion pipe 300 in the form of welding. Moreover, at the end of the expansion pipe 300 connected to the second connecting ring part 520, part of the elastic cylinder 200 is located between the second connecting ring part 520 and the central pipe 100. In this scheme, the second annular groove is provided on the inner peripheral wall of the second connecting ring part 520, and the second sealing ring 320 is arranged in the second annular groove, so that the lower joint 500 and the elastic cylinder 200 are sealed from each other by the second sealing ring 320. Since the lower joint 500 is connected to the expansion pipe 300 in the form of welding, the sealing between the end of the expansion pipe 300 and the elastic cylinder 200 can also be ensured by such arrangement.

[0074] Obviously, the above embodiments of the present application are only examples for clearly illustrating the present application, and are not a limitation on the embodiments of the present application. For those skilled in the art, various obvious changes, re-adjustments and substitutions can be made without departing from the protection scope of the present application. Here, it is not necessary and impossible to exhaust all the embodiments. Any modification, equivalent substitution and improvement made within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A packer, characterized by, The packer comprises: a center pipe (100) provided with a first liquid transmission hole (110) on the pipe wall of the center pipe (100); an elastic cylinder (200) sleeved outside the center pipe (100), both ends of the elastic cylinder (200) in the axial direction being in sealed connection with the center pipe (100), the outer peripheral wall of the center pipe (100) and the inner peripheral wall of the elastic cylinder (200) surrounding a first elastic cavity (210), liquid in the center pipe (100) being able to enter the first elastic cavity (210) through the first liquid transmission hole (110); an expansion pipe (300) sleeved outside the elastic cylinder (200), both ends of the expansion pipe (300) in the axial direction being in sealed connection with the elastic cylinder (200), the outer peripheral wall of the elastic cylinder (200) and the inner peripheral wall of the expansion pipe (300) surrounding a second elastic cavity (220), the expansion pipe (300) being provided with a second liquid transmission hole (310), external liquid being able to enter the second elastic cavity (220) through the second liquid transmission hole (310); a sealing assembly (400) arranged outside the expansion pipe (300).

2. The packer of claim 1, wherein, The sealing assembly (400) comprises a plurality of annular protrusions (410) having elastic properties, the plurality of annular protrusions (410) being arranged at intervals along the axial direction of the expansion pipe (300).

3. The packer of claim 2, wherein, The material of the annular protrusions (410) is rubber.

4. The packer of claim 1, wherein, On the outer peripheral wall of the center pipe (100), a plurality of first annular grooves are arranged at both ends in the axial direction of the elastic cylinder (200), and each first annular groove is provided with a first sealing ring (120), the part of the first sealing ring (120) protruding out of the first annular groove being attached to the inner peripheral wall of the elastic cylinder (200); or both ends of the elastic cylinder (200) in the axial direction are in sealed connection with the center pipe (100) by welding.

5. The packer of claim 1, wherein, On the inner peripheral wall of the expansion pipe (300), a plurality of second annular grooves are arranged at both ends in the axial direction of the expansion pipe (300), and each second annular groove is provided with a second sealing ring (320), the part of the second sealing ring (320) protruding out of the second annular groove being attached to the outer peripheral wall of the elastic cylinder (200); or both ends of the expansion pipe (300) in the axial direction are in sealed connection with the elastic cylinder (200) by welding.

6. The packer of claim 1, wherein, The packer further comprises a lower joint (500), one end of the lower joint (500) being provided with a first connecting ring portion (510) and a second connecting ring portion (520), the first connecting ring portion (510) being connected with the center pipe (100), and the second connecting ring portion (520) being connected with the expansion pipe (300).

7. The packer of claim 6, wherein, The first connecting ring part (510) is provided with an internal thread, one end of the central pipe (100) is provided with an external thread, and the first connecting ring part (510) is connected to the central pipe (100) provided with the external thread through the internal thread; and / or the second connecting ring part (520) is connected to the expansion pipe (300) by welding.

8. The packer of any one of claims 1-7, wherein, The material of the elastic cylinder (200) is spring steel.

9. The packer of any one of claims 1-7, wherein, The central pipe (100) is provided with a plurality of first liquid transmission holes (110) on the pipe wall, and the plurality of first liquid transmission holes (110) are arranged along the circumference of the central pipe (100) at intervals.

10. The packer of any one of claims 1-7, wherein, The expansion pipe (300) is provided with a plurality of second liquid transmission holes (310), and the plurality of second liquid transmission holes (310) are arranged along the circumference of the expansion pipe (300) at intervals. The material of the elastic cylinder (200) is spring steel. The central pipe (100) is provided with a plurality of first liquid transmission holes (110) on the pipe wall, and the plurality of first liquid transmission holes (110) are arranged along the circumference of the central pipe (100) at intervals. The expansion pipe (300) is provided with a plurality of second liquid transmission holes (310), and the plurality of second liquid transmission holes (310) are arranged along the circumference of the expansion pipe (300) at intervals.

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