An expandable open hole packer

Abstract

The application provides an expandable bare hole packer, which comprises an outer sleeve and an inner tube body sleeved together, a first channel is defined in the inner tube body, a piston cavity is formed between the outer sleeve and the inner tube body, a piston is arranged in the piston cavity, a liquid inlet hole is arranged at a first end of the piston and communicates with the first channel and the piston cavity, and a rubber sleeve is arranged on an outer sleeve body at an end of the piston away from the liquid inlet hole and communicates with an inner cavity. A first through hole communicating with the rubber sleeve is arranged at an axial middle part of the piston, a second through hole connecting the first channel is arranged on an outer wall of the inner tube body, the first through hole and the second through hole can communicate to form a second channel capable of communicating the first channel and the inner cavity of the rubber sleeve. The piston can move in the piston cavity to have a first position for initially isolating the second channel, a second position for keeping the second channel unobstructed, and a third position for re-isolating the second channel.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of oilfield exploitation, in particular to an expansion type open hole packer. BACKGROUND

[0002] In the process of oil exploitation, open hole staged fracturing technology is one of the commonly used technologies. This technology can improve the single well production, and is one of the effective processes to realize the single well production. In the open hole staged fracturing process, the packer is one of the most commonly used downhole devices, which is mainly divided into compression type open hole packer and expansion type packer.

[0003] Compared with the compression type open hole packer, the expansion type packer has greater expansion ratio, longer sealing section and stronger adaptability to irregular wellbore, and has greater advantages in open hole layering. In order to avoid the expansion of the packer in advance and realize effective interlayer separation, the liquid injection valve must realize the opening and closing function. At the same time, it is also necessary to prevent the secondary expansion of the rubber tube, so as to ensure the sealing performance and reliability of the packer. SUMMARY

[0004] In view of the above technical problems, the present application aims to provide an expansion type open hole packer. The expansion type open hole packer of the present application can avoid the expansion of the packer in advance, realize effective interlayer separation, and prevent the secondary expansion of the rubber tube.

[0005] According to the present application, an expansion type open hole packer is provided, which comprises: an outer sleeve and an inner tube body sleeved together, a first channel for fluid flow is defined in the inner tube body, a piston cavity is provided between the outer sleeve and the inner tube body, a piston is arranged in the piston cavity, a liquid inlet hole communicating the first channel and the piston cavity is arranged at the first end of the piston, and a rubber tube is arranged on the outer wall of the outer sleeve. A first through hole communicating the rubber tube is arranged at the axial middle part of the piston, a second through hole connecting the first channel is arranged on the outer wall of the inner tube body, and the first through hole and the second through hole can be communicated to form a second channel capable of communicating the first channel and the inner cavity of the rubber tube.

[0006] The piston can move in the piston cavity so that the piston has a first position for initially blocking the second channel, a second position for keeping the second channel unblocked, and a third position for re-blocking the second channel.

[0007] In a preferred embodiment, first and second fixing members capable of fixing the piston at the first and second positions respectively are further arranged between the piston and the inner wall of the outer sleeve, and the first and second fixing members can be cut off.

[0008] In a preferred embodiment, a groove with a certain length is arranged on the piston, and the second fixing member extends into the groove, so that the second fixing member can move in the groove relative to the piston.

[0009] In a preferred embodiment, the first fixing member and the second fixing member are arranged as shear pins, and the shear force of the second fixing member is arranged to be greater than that of the first fixing member.

[0010] In a preferred embodiment, the second fixing member is arranged to abut against the side wall of the groove after the piston moves from the first position to the second position.

[0011] In a preferred embodiment, a first gap is arranged between the piston and the outer sleeve in the radial direction, and the first through hole and the rubber sleeve are connected through the first gap.

[0012] In a preferred embodiment, a snap spring is further arranged at the end of the piston away from the liquid inlet hole, for keeping the piston in the third position.

[0013] In a preferred embodiment, a second gap is further arranged between the piston and the outer sleeve, and the second gap is separated from the liquid inlet hole and the second channel, respectively, and a pressure relief hole is arranged on the inner wall of the outer sleeve and connected with the second gap.

[0014] In a preferred embodiment, a sealing member is further arranged on the inner wall of the piston close to the inner sleeve, and the sealing member is arranged to be between the axial directions of the first through hole and the second through hole when the piston is in the third position.

[0015] In a preferred embodiment, a plurality of first fixing members and second fixing members are arranged on the inner wall of the outer sleeve, and the plurality of first fixing members and second fixing members are arranged evenly and alternately on the inner wall of the outer sleeve. BRIEF DESCRIPTION OF DRAWINGS

[0016] The present application will be described below with reference to the accompanying drawings.

[0017] Figure 1 A schematic view of an expandable open hole packer according to an embodiment of the present application is shown.

[0018] Figure 2 A schematic view of an expandable open hole packer according to an embodiment of the present application is shown. Figure 1 A schematic view of an expandable open hole packer according to an embodiment of the present application is shown.

[0019] Figure 3 A schematic view of an expandable open hole packer according to an embodiment of the present application is shown. Figure 1 A schematic view of an expandable open hole packer according to an embodiment of the present application is shown.

[0020] Figure 4 A schematic view of an expandable open hole packer according to an embodiment of the present application is shown.Figure 1 The diagram shown is a schematic of the expanded naked-eye packer after setting.

[0021] In this application, all drawings are schematic and are used only to illustrate the principles of the invention, and are not drawn to scale. Detailed Implementation

[0022] The invention will now be described with reference to the accompanying drawings. In this document, the terms "left side" and "right side" refer to the side closer to the upper connector and the side farther from the upper connector, respectively.

[0023] Figure 1 An expandable naked-eye occluder 100 according to an embodiment of the present invention is shown. Figure 1 As shown, the expandable open-hole packer 100 includes an outer sleeve 10, with an upper connector 12 provided at the first end 11 of the outer sleeve 10. An inner cavity 15 is also defined within the outer sleeve 10, and an inner tube 20 is provided within the inner cavity 15. A first channel 25 for the flow of downhole fluid is defined within the tube 20.

[0024] like Figure 1 As shown, a piston chamber 30 is provided radially between the outer sleeve 10 and the inner tube 20, and a piston 35 is provided in the piston chamber 30. The piston 35 can move axially in the piston chamber 30 under the action of external force.

[0025] Meanwhile, an inlet hole 32 is also provided on the outer wall of the inner tube 20 near the first end 351 of the piston 35. The first channel 25 is connected to the piston chamber 30 through the inlet hole 32, so that high-pressure fluid can enter the piston chamber 30 through the inlet hole 32 and push the piston 35 to move in a first direction away from the first end 351.

[0026] like Figure 1 As shown, a first through hole 42 is provided at the axial center of the piston 35, and a second through hole 44 communicating with the first channel 25 is provided on the outer wall of the inner tube 20. The first through hole 42 and the second through hole 44 can communicate to form a second channel 40 that communicates with the first channel 25, so that the fluid in the first channel 25 can flow into the outer sleeve 10 through the second channel 40.

[0027] Meanwhile, a rubber sleeve (not shown) is arranged in the outer sleeve 10. The rubber sleeve is arranged on the side of the piston 35 away from the liquid inlet 32. A first gap 19 is arranged between the piston 35 and the outer sleeve 10 in the radial direction, and the first through hole 42 and the rubber sleeve are connected through the first gap 19. Thus, when the first through hole 42 and the second through hole 44 are connected, the high-pressure fluid in the first channel 25 can pass through the second through hole 44, the first through hole 42 and the first gap 19 in sequence to reach the inside of the rubber sleeve, thereby supporting the expansion of the rubber sleeve and generating a sealing effect.

[0028] As shown in Figure 1 When the expandable open-hole packer 100 of the present application is in the initial state, the first through hole 42 is located on the left side of the second through hole 44, thereby blocking the first through hole 42 and the second through hole 44. At this time, the piston 35 is in the first position that cuts off the second channel 40.

[0029] A first fixing member 52 and a second fixing member 54 are arranged on the inner wall of the outer sleeve 10. The first fixing member 52 and the second fixing member 54 can be shear pins, for example, and the shear force of the second fixing member 54 is greater than that of the first fixing member 52. Meanwhile, a recess 354 is arranged on the outer wall of the piston 35. The recess 354 has a certain length, so that the second fixing member 54 can move axially in the recess 354.

[0030] When the expandable open-hole packer 100 of the present application is in the initial state, the second fixing member 54 extends into the recess 354 and abuts against the side wall on the right side of the recess 354. It is easy to understand that the first fixing member 52 can fix the relative position of the piston 35 and the outer sleeve 10, so that the piston 35 is fixed at the first position. When the first fixing member 52 is sheared off, the piston can only move to the right side because the second fixing member 54 abuts against the side wall on the right side of the recess 354, until the second fixing member 54 abuts against the side wall on the left side of the recess 354, and then the second fixing member 54 can play a fixing role to prevent the piston 35 from continuing to move to the right.

[0031] Figure 2 As shown in Figure 1 The expandable open-hole packer 100 is shown in the cross-sectional view along the A-A' plane. As shown in Figure 2As shown, in a preferred embodiment, multiple first fasteners 52 and second fasteners 54 are provided. The multiple first fasteners 52 and second fasteners 54 are evenly and alternately arranged on the inner wall of the outer sleeve. This arrangement increases the stability and reliability of the first fasteners 52 and second fasteners 54. Simultaneously, the shearing force of the second fastener 54 is set to be greater than the shearing force of the first fastener 52, thereby preventing the second fastener 54 from being sheared along with the first fastener 52.

[0032] Figure 3 for Figure 1 The diagram shows the expanded-type open-eye packer 100 in the set position. Figure 3 As shown, when the first fixing member 52 is cut off and the piston 35 moves to the position where the second fixing member 54 abuts against the side wall on the left side of the groove 354, the second through hole 44 moves to the position corresponding to the first through hole 42. At this time, the high-pressure fluid in the first channel 25 can flow sequentially through the second through hole 44, the first through hole 42 and the first gap 19 to the rubber sleeve on the right side of the piston 35.

[0033] Subsequently, supported by the high-pressure fluid, the rubber sleeve expands, thereby sealing the annular space between the outer sleeve 10 and the well wall. At this time, with the second fixing member 54 fixed, the piston 35 is in a second position that keeps the second channel 40 unobstructed.

[0034] Figure 4 for Figure 1 The diagram shows the completed setting of the expanded-type open-eye packer 100. Figure 4 As shown, when the annular space is sealed by the rubber sleeve, the second fixing member 54 will be sheared as the pressure on the left side of the piston 35 continues to increase. At this time, under the fluid pressure on the left side of the piston 35, the piston 35 will continue to move to the right until it is located to the left of the first through hole 42. At this time, the connection between the first through hole 42 and the second through hole 44 is cut off, and the second channel 40 is resealed. At this time, the piston 35 is in the third position of cutting off the second channel 40.

[0035] like Figure 4 As shown, in a preferred embodiment, a retaining ring 60 is provided at the end of the piston 35 away from the liquid inlet 32 ​​to keep the piston 35 in a third position.

[0036] Specifically, a stepped portion (not shown) is constructed on the cavity at the end of the piston chamber 30 away from the liquid inlet 32, and the diameter of the cavity on the right side of the stepped portion is larger than the diameter of the cavity on the left side. When the piston 35 is in the first position, the third fixing member 60 is located in the piston chamber 30 on the left side of the stepped portion. When the piston 35 moves to the third position, the third fixing member 60 can reach the right side of the stepped portion, thereby causing the third fixing member 60 to spring open and form a constraint with the stepped portion, thereby fixing the piston 35 to continue moving.

[0037] The third fixing member 60 prevents the piston 35 from retracting to the left after the expansion-type open-eye packer 100 has completed sealing, thus preventing the second channel from reconnecting and causing secondary expansion or loss of seal in the rubber sleeve located on the outer wall of the outer sleeve 10. This helps improve the sealing stability of the expansion-type open-eye packer 100 of the present invention.

[0038] Meanwhile, a sealing element 358 is also provided on the inner wall of the piston 35 near the inner cylinder 20. The sealing element 358 can be, for example, a sealing ring. The sealing element 358 is configured such that when the piston 35 is in the third position, it is located between the first through hole 42 and the second through hole 44 in the axial direction. When the sealing element 358 is in this position, it can seal the tiny gap in the radial direction between the inner tube 20 and the piston 35, preventing fluid from flowing from the second through hole 44 through this tiny gap to the first through hole 42, thereby improving the reliability of the piston 35 in sealing the second channel.

[0039] Sealing elements 358 are also provided at other necessary locations of the expandable naked eye occluder 100 of the present invention, which will not be described in detail here.

[0040] In addition, such as Figure 1 As shown, a second gap 70 is also provided between the piston 35 and the outer sleeve 10. The second gap 70 is separated from the liquid inlet 32 ​​and the second channel 40. Simultaneously, a pressure relief hole 75 communicating with the second gap 70 is provided on the outer wall of the outer sleeve 10. During the movement of the piston 35 to the right, the pressure relief hole 75 enables fluid exchange between the piston cavity 30 and the external space of the outer sleeve 10, maintaining pressure balance throughout the piston cavity 30 and preventing the cavity between the outer sleeve 10 and the inner tube 20 from becoming a dead space. This design prevents the formation of localized high pressure within the piston cavity 30 during piston 35 movement, thus avoiding obstruction of normal piston 35 movement.

[0041] The working process of the expandable naked-eye occluder 100 according to the present invention is briefly described below.

[0042] The expansion type open hole packer 100 of the present application is used to connect between downhole tubing, and is lowered into the oil well along with the tubing. When open hole staged fracturing is performed, and the oil well needs to be sealed, first high pressure fluid is injected into the well, and then the fluid will pass through the downhole tubing, the first channel 25 and the liquid inlet hole 32 into the piston cavity 30 in sequence.

[0043] When the high pressure fluid enters the piston cavity 30, under the action of liquid pressure, the first fixing member 52 will be sheared, and then the piston 35 will move to the right until the piston 35 reaches the second position from the first position. At this time, the first through hole 42 moves to the position corresponding to the second through hole 44, and the second channel 40 is opened. When the second channel 40 is opened, the high pressure fluid in the first channel 25 can pass through the second channel 25 to the rubber sleeve, support the rubber sleeve to expand until the rubber sleeve seals the annular space outside the outer sleeve 10, and the rubber sleeve is set.

[0044] When the rubber sleeve is set, as the pressure on the left side of the piston 35 continues to increase, the second fixing member 54 will be sheared, and then the piston 35 will move to the right under the action of fluid pressure to the third position, at which time the second channel 40 will be resealed. When the piston 35 moves to the third position, the third fixing member 60 will be opened, thereby repositioning the piston 35. At this point, the sealing operation of the entire expansion type open hole packer 100 is completed.

[0045] Finally, it should be noted that the above only describes the preferred embodiments of the present application, and does not constitute any limitation on the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or make equivalent replacements to some technical features. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An expandable naked-eye occluder (100), comprising: An outer sleeve (10) and an inner tube (20) are fitted together. The inner tube defines a first fluid flow channel (25). A piston cavity (30) is provided between the outer sleeve and the inner tube. A piston (35) is disposed in the piston cavity. An inlet hole (32) communicating with the first channel and the piston cavity is provided on the outer wall of the inner tube (20) near the first end of the piston. A rubber sleeve is disposed on the outer sleeve at the end of the piston away from the inlet hole, which is connected to the inner cavity of the rubber sleeve. A first through hole (42) communicating with the inner cavity of the rubber tube is provided in the axial middle part of the piston, and a second through hole (44) communicating with the first channel is provided on the outer wall of the inner tube. The first through hole and the second through hole can communicate with each other to form a second channel (40) communicating with the first channel and the inner cavity of the rubber tube. The piston is movable within the piston chamber, thereby enabling it to have a first position that initially blocks the second channel, a second position that keeps the second channel open, and a third position that re-blocks the second channel. Among them, a first fixing member (52) and a second fixing member (54) that can be cut off are provided between the inner wall of the piston and the outer sleeve, which can fix the piston in a first position and a second position respectively. A groove (354) of a certain length is provided on the piston, and the second fixing member extends into the groove, so that the second fixing member can move relative to the piston in the groove. The first and second fixing members are configured as shear pins, and the shearing force of the second fixing member is set to be greater than that of the first fixing member.

2. The expandable naked-eye occluder (100) according to claim 1, characterized in that, The second fixing member is configured to abut against the sidewall of the groove after the piston moves from the first position to the second position.

3. The expandable naked-eye occluder (100) according to claim 1 or 2, characterized in that, There is a first gap (19) in the radial direction between the piston and the outer sleeve, and the first through hole and the rubber sleeve are connected through the first gap.

4. The expandable naked-eye occluder (100) according to claim 1 or 2, characterized in that, A retaining ring (60) is also provided at the end of the piston away from the liquid inlet to keep the piston in a third position.

5. The expandable naked-eye occluder (100) according to claim 1 or 2, characterized in that, There is a second gap (70) between the piston and the outer sleeve, which is separated from the liquid inlet and the second channel respectively. A pressure relief hole (75) connected to the second gap is provided on the outer wall of the outer sleeve.

6. The expandable naked-eye occluder according to claim 1 or 2, characterized in that, A sealing element (358) is also provided on the inner wall of the piston near the inner tube body. The sealing element is configured to be located between the first through hole and the second through hole in the axial direction when the piston is in the third position.

7. The expandable naked-eye occluder according to claim 1 or 2, characterized in that, Multiple first and second fasteners are provided on the inner wall of the outer sleeve, and the multiple first and second fasteners are evenly arranged alternately along the circumference.

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