Under-pressure rotary pumping device for fracturing string

Abstract

The invention provides a fracturing string pressure transfer pumping device which comprises a series connection device and a transfer pumping device, the series connection device is fixedly connected to a fracturing string in series, the transfer pumping device extends into the series connection device, the transfer pumping device comprises a pipe shell, the pipe shell and the series connection device are coaxially arranged on the series connection device in a penetrating mode, and the pipe shell and the series connection device are axially locked and limited; the outer wall of the tube shell and the inner hole wall of the series connector are arranged in a sealed mode. The plug is arranged in the tube shell and used for plugging the first circulation opening in the tube shell, and the plug is connected with the tube shell through a shear pin; and the valve element is arranged in the pipe shell and used for blocking or opening a second circulation opening in the pipe shell, and when the first circulation opening and the second circulation opening are both opened, the pipe shell can communicate the inside and the outside. According to the under-pressure rotary pumping device for the fracturing pipe column, the fracturing pipe does not need to be taken out after fracturing, and the working procedures are few; in addition, the rotary pumping device can be put down after fracturing is completed, and blowout cannot occur in the process of putting down the rotary pumping device.

Description

Technical Field

[0001] This invention relates to the field of oilfield fracturing and pumping equipment technology, and particularly to a fracturing tubing string with pressurized pumping device. Background Technology

[0002] For oil wells with low formation permeability, fracturing is usually required before oil extraction. The current fracturing and pumping procedure involves running a fracturing tubing string before fracturing, and then removing the fracturing tubing string before running a pumping string for oil extraction.

[0003] The above construction method has the following problems: First, it involves many procedures; Second, the formation has good connectivity and high wellhead pressure immediately after fracturing. If the fracturing tubing is removed immediately, it will lead to a blowout. Therefore, it is necessary to release the pressure until no fluid is produced at the wellhead before oil can be produced, resulting in a long construction period; Third, after fracturing, the wellhead is in a fluid-producing state, and oily wastewater in and around the wellhead continues to accumulate and overflow, which can easily cause serious pollution to the work site environment. Summary of the Invention

[0004] This invention provides a live-line pumping device for fracturing tubing, which is used to change the working conditions of oil wells, reduce procedures, and enable rapid and safe live-line pumping after oil well fracturing, effectively shortening the construction period and preventing blowouts.

[0005] This invention provides a live-line extraction device for fracturing tubing, comprising a series connector and an extraction device. The series connector is fixedly connected in series with the fracturing tubing, and the extraction device extends into the series connector. The extraction device includes:

[0006] The tube shell is coaxially inserted into the series connector and the two are axially locked and limited. The outer wall of the tube shell is sealed to the inner wall of the series connector.

[0007] A plug, disposed within the casing and used to seal a first flow port within the casing, the plug being connected to the casing via a shear pin; and

[0008] The valve core is disposed inside the tube shell and is used to block or open the second flow port inside the tube shell. When both the first flow port and the second flow port are open, the tube shell can achieve internal and external communication.

[0009] In one embodiment, one end of the tubing is the oil inlet end, the other end of the tubing is the oil outlet end, the valve core is disposed near the oil outlet end, and the plug is located on the side of the valve core away from the oil outlet end.

[0010] In one embodiment, a locking member is provided on the tubing, and a first limiting step is provided on the inner wall of the series connector, with the limiting end face on the first limiting step facing the oil inlet end on the tubing.

[0011] The locking component is configured such that when it engages with the first limiting step, the first limiting step restricts the displacement of the shell in the upward direction.

[0012] In one embodiment, the locking member is installed at the oil inlet end of the pipe shell, and the locking member includes an elastic locking claw. The elastic locking claw can expand outward along its own radial direction under the action of its own elastic force to stop and limit itself on the limiting step.

[0013] In one embodiment, a second limiting step is provided on the inner wall of the series connector toward the oil outlet end on the tube shell, and a limiting engagement step is formed on the tube shell;

[0014] When the limiting step abuts against the second limiting step, the second limiting step restricts the displacement of the shell in the downward direction.

[0015] In one embodiment, the axial distance between the second limiting step and the first limiting step is equal to the axial distance between the elastic locking claw and the limiting mating step.

[0016] In one embodiment, the second limiting step is disposed on one side of the oil outlet end of the first limiting step.

[0017] In one embodiment, an elastic reset member is provided inside the casing, which applies an elastic force to the valve core in the direction of the oil outlet to block the second flow port.

[0018] In one embodiment, a mounting portion is formed on the side of the valve core near the oil inlet end on the pipe shell, and the valve core includes a rod that is axially telescopically inserted through the mounting portion and a spherical plug formed at the end of the rod.

[0019] The elastic reset component is a spring sleeved on the rod body, with one end of the spring abutting against the mounting part and the other end abutting against the valve core.

[0020] In one embodiment, the fracturing string pumping device further includes:

[0021] The inner tube extends into the casing from the oil outlet end of the casing at one end, and is connected to the oil pump at the other end. The outer wall of the inner tube is sealed to the inner wall of the casing.

[0022] A push rod is provided at one end on the inner tube and at the other end for pushing the valve core to open the second flow port inside the tube shell.

[0023] Compared with the prior art, the advantages of the present invention are as follows:

[0024] The basic operating principle of the fracturing tubing string pumping device in this embodiment of the invention is as follows:

[0025] Before fracturing, the tandem connector is fixedly connected to the fracturing tubing string. Then, the end of the fracturing tubing string with the tandem connector is inserted into the pre-set depth at the wellhead. During fracturing, the fracturing fluid flows from top to bottom through the upper fracturing tubing and the inner hole of the tandem connector before flowing out. After fracturing, the rotary extractor is inserted into the inner hole of the tandem connector, and the tubing shell on the rotary extractor is locked and limited on the tandem connector. Since the valve core inside the tubing shell is in a closed state and the plug is in a sealed state, a blowout can be effectively avoided during the deployment of the rotary extractor, that is, the high-pressure oil located below the rotary extractor is prevented from spraying out of the rotary extractor.

[0026] Once the rotary extractor is lowered into the series connector and locked axially, it cannot move axially relative to the series connector. Then, high pressure is pumped into the rotary extractor from top to bottom for a pressure test. After the pressure test is passed, the pressure is increased further. The high-pressure liquid pushes the valve core downwards and opens the second flow port. As the high-pressure liquid flows through the blockage, it applies downward pressure. When the pressure reaches a preset value, the shear pin breaks, and the blockage moves axially downwards along the pipe shell, opening the first flow port. Then, the pressurization is stopped, and the valve core closes automatically.

[0027] Finally, the oil pumping assembly is lowered into the rotary pump. After the oil pumping assembly opens the valve core inside the tubing, the tubing is connected from top to bottom, and the oil pumping assembly can then be used to extract oil.

[0028] In this embodiment, the fracturing tubing with pressurized transfer device does not require the fracturing tubing to be removed after fracturing, thus reducing the number of procedures. In addition, the transfer device can be lowered immediately after fracturing is completed, and no blowout will occur during the lowering of the transfer device. Attached Figure Description

[0029] The invention will now be described in more detail with reference to embodiments and the accompanying drawings.

[0030] Figure 1 This is a half-section view of a series connector;

[0031] Figure 2 This is a schematic diagram of the structure of the pressurized rotary extraction device for fracturing tubing before the shear pins break after the rotary extraction device is lowered into the series unit.

[0032] Figure 3 This is a schematic diagram of the structure of the rotary extractor and the series connector after the shear pin breaks;

[0033] Figure 4This is a schematic diagram of the structure of the fracturing tubing with pressure-driven rotary pumping device after the oil pumping assembly is lowered into the rotary pumping unit.

[0034] Figure 5 This is a structural schematic diagram of the locking mechanism;

[0035] Figure 6 This is a schematic diagram of fracturing operations carried out from below the tandem unit down into the well.

[0036] Figure 7 This is a schematic diagram of the oil production process after fracturing is completed.

[0037] Figure label:

[0038] 1. Serial connector; 11. First limiting step; 12. Second limiting step;

[0039] 2. Rotary pump;

[0040] 21. Tube shell;

[0041] 211. Extension pipe; 212. Valve body;

[0042] 213. Transfer pipe; 2131. Limiting and fitting step; 2132. Mounting part; 2133. Third through hole;

[0043] 22. Blockage; 221. Plugging plunger; 222. Sealing section;

[0044] 23. Valve core; 231. Stem; 232. Ball plug;

[0045] 24. Cut the nails;

[0046] 25. Locking components;

[0047] 251. Elastic locking claw; 2511. Locking protrusion;

[0048] 252. Installation pipe;

[0049] 253. Install the stop wall; 2531. First through hole;

[0050] 26. Spring;

[0051] 27. Sheath;

[0052] 281. Sealing ring; 282. Sealing ring;

[0053] 3. Oil extraction assembly;

[0054] 31. Inner tube; 32. Push rod; 321. Fourth through hole;

[0055] 33. Oil pump; 34. Sealing limit device;

[0056] 100. Fracturing tubing. Detailed Implementation

[0057] The invention will now be further described with reference to the accompanying drawings.

[0058] This invention provides a fracturing string live-line extraction device, which includes a series connector 1 and an extraction device 2. The series connector 1 is fixedly connected in series with the fracturing string 100, and the extraction device 2 includes a casing 21, a plug 22 and a valve core 23 disposed in the casing 21.

[0059] The series connector 1 is a tubular structure. Inside the series connector 1, there is an inner hole that extends along its own axis. This inner hole can serve as a flow channel for fracturing fluid during the fracturing process. During the oil pumping process after fracturing, this inner hole can be used to install the rotary pump 2.

[0060] The inner diameter of the series connector 1 is similar to that of the fracturing tube to ensure that the series connector 1 does not affect the flow rate of the fracturing fluid during fracturing.

[0061] The tube shell 21 is coaxially inserted into the series connector 1, and the two are axially locked and limited. The outer wall of the tube shell 21 is sealed to the inner wall of the series connector 1. The tube shell 21 has a first flow port and a second flow port formed sequentially along the axial direction.

[0062] The plug 22 is used to block the first flow port and is connected to the shell 21 by the shear pin 24; the valve core 23 is used to block or open the second flow port inside the shell 21. When both the first and second flow ports are open, the shell 21 can achieve internal and external communication.

[0063] The lower end of the casing 21 is the oil inlet, and the upper end of the casing 21 is the oil outlet. The valve core 23 is located near the oil outlet, and the plug 22 is located on the side of the valve core 23 away from the oil outlet. The valve core 23 is located above the plug 22.

[0064] It should be noted that, in this embodiment, "above" and "below" refer to... Figure 1 Above and below.

[0065] The basic operating principle of the fracturing tubing string pumping device in this embodiment of the invention is as follows:

[0066] like Figure 1 and Figure 6 As shown, before fracturing, the connector 1 is fixedly connected in series to the fracturing tubing 100, and then the end of the fracturing tubing 100 with the connector 1 installed is inserted into the preset depth at the wellhead; during the fracturing process, the fracturing fluid can flow from top to bottom through the upper fracturing tubing and the inner hole of the connector 1 and then out.

[0067] like Figure 2 and Figure 7As shown, after fracturing is completed, the rotary pump 2 is inserted into the inner hole of the series connector 1 and the casing 21 on the rotary pump 2 is locked and limited on the series connector 1. Since the valve core 23 inside the casing 21 is in a closed state and the plug 22 is in a blocked state, a blowout can be effectively avoided during the deployment of the rotary pump 2, that is, the high-pressure oil located below the rotary pump 2 is prevented from being ejected from the rotary pump 2.

[0068] After the rotary extractor 2 is lowered into the series connector 1 and axially locked in place, the rotary extractor 2 cannot move axially relative to the series connector 1. Then, high pressure is charged into the rotary extractor 2 from top to bottom for a pressure test. After the pressure test is passed, the pressure is increased further, and the high-pressure liquid pushes the valve core 23 downwards, opening the second flow port. When the high-pressure liquid flows through the plug 22, it applies downward pressure to the plug 22. When the pressure reaches a preset value, the shear pin 24 breaks, and the plug 22 will move axially downwards along the pipe shell 21, opening the first flow port. Then, the pressurization is stopped, and the valve core 23 will close automatically. Figure 3 As shown.

[0069] Finally, as Figure 4 As shown, the oil extraction assembly 3 is lowered into the rotary pump 2. After the oil extraction assembly 3 opens the valve core 23 in the casing 21, the casing 21 is connected from top to bottom, and the oil extraction assembly 3 can then extract oil.

[0070] In this embodiment, the fracturing tubing with pressurized transfer device does not require the fracturing tubing to be removed after fracturing, thus reducing the number of procedures. In addition, the transfer device 2 can be lowered immediately after fracturing is completed, and no blowout will occur during the lowering of the transfer device 2.

[0071] like Figure 2 and Figure 5 As shown, in one embodiment, a locking member 25 is provided on the shell 21, and a first limiting step 11 is provided on the inner wall of the series connector 1. The limiting end face on the first limiting step 11 faces the oil inlet end on the shell 21. The locking member 25 is configured such that when it cooperates with the first limiting step 11, the first limiting step 11 restricts the shell 21 from moving in the upward direction.

[0072] The locking member 25 is installed at the oil inlet end of the pipe shell 21. The locking member 25 includes an elastic locking claw 251. The elastic locking claw 251 can expand radially outward under its own elastic force to stop and limit on the first limiting step 11.

[0073] The inner wall of the series connector 1 is provided with a second limiting step 12 facing the oil outlet end of the tube shell 21, and a limiting engagement step 2131 is formed on the tube shell 21; when the limiting engagement step 2131 abuts against the second limiting step 12, the second limiting step 12 restricts the displacement of the tube shell 21 in the downward direction.

[0074] The second limiting step 12 is positioned above the first limiting step 11. The axial distance between the second limiting step 12 and the first limiting step 11 is equal to the axial distance between the elastic locking claw 251 and the limiting engagement step 2131.

[0075] In this embodiment, after fracturing is completed, the rotary extractor 2 is inserted into the inner hole of the series connector 1. When the rotary shaft extends into the preset position inside the series connector 1, the mating step on the casing 21 can abut against the second limiting step 12 to restrict the displacement of the casing 21 in the downward direction, ensuring that the casing 21 cannot continue to move downward during the continued pressurization process. In addition, the elastic locking claw 251 on the locking member 25 expands radially outward under its own elastic force and abuts against the limiting step. The first limiting step 11 restricts the displacement of the casing 21 in the upward direction, thereby ensuring that the axial position of the casing 21 on the series connector 1 is fixed during the oil production process.

[0076] In one embodiment, the locking member 25 includes a mounting tube 252, the outer wall of which is provided with an external thread, and the inner wall of the tube shell 21 is provided with an internal thread that mates with the mounting tube 252. The mounting tube 252 on the locking member 25 is threadedly connected to the tube shell 21.

[0077] The elastic locking claws 251 are strip-shaped and multiple of them are arranged at intervals along the circumference of the mounting tube 252. One end of each elastic locking claw 251 is formed on the axial end of the mounting tube 252, and the other end of the elastic locking claw 251 extends axially downward and protrudes outward in the circumferential direction at the end to form a locking protrusion 2511, which engages with the first limiting step 11 in an axial limiting fit.

[0078] like Figure 2 and Figure 3 As shown, the plug 22 includes a plug 221 and a sealing part 222 that are integrally formed and connected.

[0079] A sealing portion 222 is formed at one end of the plug 221, blocking the first flow port of the casing 21 and connecting it to the inner wall of the casing 21 via a shear pin 24. The outer wall of the sealing portion 222 mates with the inner wall of the sleeve and is sealed.

[0080] An installation stop wall 253 parallel to the cross-section is formed inside the installation tube 252, and the plug 221 extends axially along the tube shell 21 and passes through the installation hole of the installation stop wall 253.

[0081] The diameter of the plug 222 is larger than the diameter of the mounting hole on the mounting stop wall. When the shear pin 24 breaks and the plug 22 descends, the plug 222 can hook onto the mounting stop wall 253, preventing the plug 22 from falling into the well. Therefore, the plug 22 can be recycled and reused.

[0082] A check valve (not shown in the figure) is provided on the inner wall of the installation pipe 252. The check valve is used to block the top wall of the plug 222 after the plug 222 moves downward, so as to limit the upward movement of the plug 22 during the oil extraction process.

[0083] The check valve can be a baffle plate with one end formed on the mounting tube 252 and the other end radially inward and axially downward inclined.

[0084] The mounting stop 253 is provided with a first through hole 2531. When the sealing part 222 can be hooked on the mounting stop 253, the first flow port is connected to the first through hole 2531 on the mounting stop 253.

[0085] A sleeve 27 is fixedly connected to one end of the plug 221 away from the sealing part 222. The sleeve 27 is fitted onto the locking protrusion 2511 on the elastic locking claw 251 and applies radially inward pressure to the locking protrusion 2511, causing the elastic locking claw 251 to elastically contract radially inward.

[0086] like Figure 5 As shown, when the shear pin 24 breaks and the plug 22 moves downward, the sheath 27 can disengage from the locking protrusion 2511 and move downward together with the plug 221. The elastic locking claw 251 drives the locking protrusion 2511 to expand radially outward under its own elastic force, so that the locking protrusion 2511 stops against the first limiting step 11.

[0087] The sheath 27 is provided with a second through hole that communicates with the first through hole 2531.

[0088] like Figure 2 As shown, in this embodiment, the tube shell 21 of the rotary extractor 2 includes an extension tube 211, a valve body 212 and a transfer tube 213 connected sequentially along the axial direction.

[0089] A sealing ring 281 is provided between the outer wall of the extension tube 211 and the inner wall of the series connector 1. An installation groove is provided on the outer wall of the extension tube 211, and the sealing ring 281 is disposed in the sealing groove.

[0090] Adaptor pipe 213: The upper end of the adapter pipe 213 is connected to the lower end of the valve body 212 by a sealing thread.

[0091] The inner wall of the adapter pipe 213 matches the outer peripheral wall of the sealing part 222, and a sealing ring 282 is provided between the two. The shear pin 24 is arranged in a transverse direction, and the two ends of the shear pin 24 are fixedly connected to the adapter pipe 213 and the sealing part 222 respectively.

[0092] The lower end of the adapter pipe 213 is threadedly connected to the locking piece 25.

[0093] The limiting and matching step 2131 is set on the outer peripheral wall of the transfer pipe 213.

[0094] Specifically, the transfer pipe 213 includes a first pipe section and a second pipe section integrally formed and connected. The first pipe section is located above the second pipe section, and the outer diameter of the first pipe section is larger than the outer diameter of the second pipe section. The limiting and fitting step 2131 is formed by connecting the first pipe section and the second pipe section.

[0095] like Figure 1 and Figure 2 As shown, the inner hole of the series connector 1 is a stepped shaft hole. The inner hole of the series connector 1, from top to bottom, consists of a first inner hole section, a second inner hole section, and a third inner hole section. The diameters of the first and third inner hole sections are both smaller than the diameter of the second inner hole section.

[0096] The first limiting step 11 is formed by connecting the second inner hole section and the third inner hole section; the second limiting step 12 is formed by connecting the first inner hole section and the second inner hole section. The inner diameter of the second inner hole section is smaller than the outer diameter of the first pipe section.

[0097] Valve body 212: Valve core 23 is installed inside valve body 212. An elastic reset member is also provided inside valve body 212. The elastic reset member applies an elastic force to valve core 23 in the direction of oil outlet so that valve core 23 blocks the second flow port.

[0098] A mounting portion 2132 is formed on the housing 21 below the valve core 23. The mounting portion 2132 can be formed on the upper port of the adapter pipe 213. A third through hole 2133 communicating with the inner cavity of the valve body 212 is formed on the mounting portion 2132.

[0099] The valve core 23 includes a rod 231 that is axially telescopically inserted through the mounting portion 2132, and a spherical plug 232 formed on the upper end of the rod 231.

[0100] The second flow port is defined by the valve port at the upper end of the valve body 212, and the diameter of the ball plug 232 is larger than the diameter of the valve port.

[0101] The elastic reset element can be a spring 26 sleeved on the rod 231, with one end of the spring 26 abutting against the mounting part 2132 and the other end abutting against the valve core 23.

[0102] The valve core 23, valve body 212, and spring 26 together form a check valve. The valve core 23 can only be pushed down to open the valve port when it is subjected to a downward external force; when the valve core 23 is subjected to the action of the elastic reset element or an upward force, the ball plug 232 abuts against the valve port to block the valve port, which can ensure that the valve core 23 is closed after the shear pin 24 breaks and before the oil pumping assembly 3 is installed, thus avoiding a blowout during this period.

[0103] like Figure 4As shown, in one embodiment, the fracturing tubing string pumping device also includes a pumping assembly 3 for triggering the valve core 23 to open for oil production. The pumping assembly 3 includes an inner tube 31 and a push rod 32.

[0104] One end of the inner tube 31 extends into the extension tube 211 from the oil outlet end of the extension tube 211, and the outer wall of the inner tube 31 is sealed to the inner wall of the extension tube 211 and is axially limited. The other end of the inner tube 31 is connected to the oil pump 33. The oil pump 33 is a rod pump. A fourth through hole 321 is provided on the push rod 32.

[0105] A sealing and limiting device 34 is provided between the outer wall of the inner tube 31 and the inner wall of the extension tube 211 for sealing and axial limiting of the two. One end of the push rod 32 is mounted on the sealing and limiting device 34, and the push rod 32 and the inner tube 31 are connected in series through the sealing and limiting device 34. The other end of the push rod 32 is used to push the valve core 23 downward to open the second flow port in the tube shell 21.

[0106] Although the invention has been described with reference to preferred embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner as long as there is no structural conflict. The invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A device for switching a fracturing tubing string to pump under pressure, characterized in that, It includes a series connection device and a rotary extraction device, wherein the series connection device is fixedly connected in series with the fracturing tubing string, and the rotary extraction device includes: The tube shell is coaxially inserted into the series connector and the two are axially locked and limited. The outer wall of the tube shell is sealed to the inner wall of the series connector. The tube shell has a first flow port and a second flow port formed sequentially along the axial direction. A plug, used to seal the first flow port, the plug being connected to the tube shell via a shear pin; and The valve core is used to block or open the second flow port. When both the first and second flow ports are open, the tube shell can achieve internal and external communication.

2. The fracturing tubing string pumping device according to claim 1, characterized in that, One end of the tubing is the oil inlet, and the other end is the oil outlet. The valve core is located near the oil outlet, and the blockage is located on the side of the valve core away from the oil outlet.

3. The fracturing tubing string pumping device according to claim 2, characterized in that, The tube shell is provided with a locking component, and the inner wall of the series connector is provided with a first limiting step, the limiting end face of the first limiting step facing the oil inlet end of the tube shell; The locking component is configured such that when it engages with the first limiting step, the first limiting step restricts the displacement of the shell in the upward direction.

4. The fracturing tubing string pumping device according to claim 3, characterized in that, The locking member is installed at the oil inlet end of the pipe shell. The locking member includes an elastic locking claw. The elastic locking claw can expand outward along its own radial direction under the action of its own elastic force to stop and limit itself on the limiting step.

5. The fracturing tubing string pumping device according to claim 4, characterized in that, The inner wall of the series connector is provided with a second limiting step facing the oil outlet end on the tube shell, and a limiting mating step is formed on the tube shell; When the limiting step abuts against the second limiting step, the second limiting step restricts the displacement of the shell in the downward direction.

6. The fracturing tubing string pumping device according to claim 5, characterized in that, The axial distance between the second limiting step and the first limiting step is equal to the axial distance between the elastic locking claw and the limiting mating step.

7. The fracturing tubing string pumping device according to claim 5, characterized in that, The second limiting step is located on the side of the first limiting step near the oil outlet end.

8. The fracturing tubing string pumping device according to any one of claims 2-7, characterized in that, An elastic reset element is provided inside the tube shell. The elastic reset element applies an elastic force to the valve core in the direction of the oil outlet so that the valve core blocks the second flow port.

9. The fracturing tubing string pumping device according to claim 8, characterized in that, The valve core has a mounting portion formed on the side of the casing near the oil inlet end. The valve core includes a rod that can be axially telescopically inserted through the mounting portion and a spherical plug rod formed at the end of the rod. The elastic reset component is a spring sleeved on the rod body, with one end of the spring abutting against the mounting part and the other end abutting against the valve core.

10. The fracturing tubing string pumping device according to claim 1 or 9, characterized in that, Also includes: The inner tube extends into the casing from the oil outlet end of the casing at one end, and is connected to the oil pump at the other end. The outer wall of the inner tube is sealed to the inner wall of the casing. A push rod is provided at one end on the inner tube and at the other end for pushing the valve core to open the second flow port inside the tube shell.

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