Special fishing neck for coiled tubing velocity string

Abstract

The invention relates to the technical field of petroleum and natural gas coiled tubing speed tubular column construction, in particular to a special fishing neck for a coiled tubing speed tubular column, and aims to solve the technical problems that no special fishing tool is provided for fishing a hanger with the diameter of 176 mm, the hanger cannot be centered in an inner cavity of a blowout preventer during butt joint, and the fishing efficiency is high in the prior art. The problems that the butt joint efficiency of the hanger is low, the sealing part of the hanger is difficult to protect in the fishing and butt joint process, the hanger is damaged, and when pressure exists in the coiled tubing, the pressure cannot be released quickly and safely are solved. The invention provides a special fishing neck for a coiled tubing speed string. The special fishing neck comprises a fishing neck piece, a reverse check valve, a centralizer, a central working barrel and a connecting piece, the fishing neck piece is connected with the central working barrel, and the central working barrel is connected with the connecting piece; the centralizer is sleeved outside the central working barrel; the end, away from the reverse check valve, of the connecting piece is used for being connected with a hanger. When pressure exists in the pipe, liquid or gas flows in from the connecting piece, passes through the reverse check valve and flows out from the fishing neck piece.

Description

Technical Field

[0001] The present invention relates to the technical field of coiled tubing velocity string construction in oil and gas, and particularly relates to a special fishing neck for coiled tubing velocity string. Background Art

[0002] With the in-depth development of Changqing Oilfield, the proportion of tight gas business in the total volume of well testing (oil testing) gas has been increasing year by year, and there are more quantity requirements and faster process requirements for the coiled tubing velocity string completion process construction. The coiled tubing velocity string tight gas operation occupies an important proportion in the company's business. At the same time, the company is in urgent need of developing new technologies, exploring new markets, and strengthening the development of the velocity string business under the original well Φ176mm hanger. There is an urgent need to develop a special fishing neck for coiled tubing velocity string construction, keep an eye on the cutting-edge technology of coiled tubing operations, adhere to independent innovation, and be guided by the tight gas market in Changqing Oilfield to help the company's well testing (oil testing) gas business move forward to a more refined and deeper level.

[0003] The coiled tubing velocity string completion process is a well testing operation process that uses coiled tubing to replace conventional coupling tubing, and completes the well under the conditions of not killing the well and not moving the downhole string. It has unique advantages such as fast operation, low cost, high efficiency, and less formation damage, and belongs to a new method and new process in the company's well testing operations.

[0004] When carrying out the coiled tubing velocity string completion construction, there are relatively large operation risks and process risks. The main problems existing at the coiled tubing velocity string construction site are as follows:

[0005] (1) When the GS fishing spear is docked with the Φ176mm hanger, there is no special fishing tool, and relying on the existing downhole operation fishing tools, it requires the cooperation of multiple people and long-time operation to complete the fishing;

[0006] (2) When docking, it is impossible to center and straighten the Φ176mm hanger in the inner cavity of the blowout preventer, and it is necessary to adjust the docking angle multiple times and repeatedly dock, resulting in low docking efficiency of the hanger;

[0007] (3) It is difficult to protect the sealing part of the Φ176mm hanger during the fishing and docking process, and it is easy to cause the tool and the hanger to collide and wear unevenly in the inner cavity of the blowout preventer due to repeated docking, resulting in problems such as loose sealing and unstable pressure during pressure testing;

[0008] (4) When there is pressure in the coiled tubing, it is impossible to quickly and safely relieve the pressure;

[0009] The above problems have had a great impact on the current coiled tubing velocity string construction. Summary of the Invention

[0010] The object of the present invention is to provide a special fishing neck for coiled tubing velocity string, so as to solve the problems existing in the prior art that there is no special fishing tool for fishing a Φ176mm hanger, the hanger cannot be centered and straightened in the inner cavity of the blowout preventer during docking, resulting in low docking efficiency of the hanger, it is difficult to protect the sealing part of the hanger during fishing and docking, resulting in damage to the hanger, and when there is pressure in the coiled tubing, it is impossible to quickly and safely release the pressure.

[0011] In order to solve the above technical problems, the technical solution provided by the present invention lies in:

[0012] The present invention provides a special fishing neck for coiled tubing velocity string, including: a fishing neck part, a reverse check valve, a centralizer, a central working barrel and a connecting piece;

[0013] The fishing neck part is connected to the central working barrel, and the central working barrel is connected to the connecting piece;

[0014] The fishing neck part is communicated with the connecting piece, and the reverse check valve is arranged between the fishing neck part and the connecting piece;

[0015] The centralizer is sleeved outside the central working barrel;

[0016] One end of the connecting piece away from the reverse check valve is used for connecting with the hanger;

[0017] When there is pressure in the pipe, liquid or gas flows in from the connecting piece, passes through the reverse check valve, and flows out from the fishing neck part.

[0018] Further,

[0019] The reverse check valve includes a valve body and a valve plate;

[0020] The valve body is arranged between the fishing neck part and the connecting piece, and the valve plate is rotatably connected to the valve body;

[0021] When there is pressure in the pipe, the valve plate can rotate in a direction away from the connecting piece, and at this time the reverse check valve is in an open state;

[0022] When the pressure is released completely, the valve plate can rotate in a direction close to the connecting piece, and at this time the reverse check valve is in a closed state.

[0023] Further,

[0024] The valve body is threadedly connected inside the central working barrel.

[0025] Further,

[0026] The centralizer is threadedly connected outside the central working barrel.

[0027] Further,

[0028] One end of the fishing neck part close to the reverse check valve extends into the central working barrel and is threadedly connected to the central working barrel.

[0029] Further,

[0030] One end of the connecting part close to the reverse check valve extends into the central working barrel and is connected to the central working barrel.

[0031] Further,

[0032] Threaded fasteners are provided at one end of the connecting part away from the reverse check valve.

[0033] Further,

[0034] The special fishing neck for coiled tubing velocity string further includes a fixing pin;

[0035] The fixing pin passes through the centralizer and extends into the central working barrel.

[0036] Further,

[0037] The special fishing neck for coiled tubing velocity string further includes a backstop pin;

[0038] The backstop pin passes through the central working barrel and extends into the connecting part.

[0039] Further,

[0040] The special fishing neck for coiled tubing velocity string further includes a sealing ring;

[0041] A sealing ring is provided between the reverse check valve and the central working barrel;

[0042] A sealing ring is provided between the connecting part and the central working barrel.

[0043] Further,

[0044] Based on the above technical solutions, the technical effects that can be achieved by the present invention are as follows:

[0045] The special fishing neck for coiled tubing velocity string provided by the present invention improves the docking efficiency of the GS fishing spear and the fishing neck by setting a centralizer outside the central working barrel to center and straighten the hanger when docking in the inner cavity of the blowout preventer. Due to the setting of the centralizer, the hanger is prevented from being bumped and eccentrically worn in the inner cavity of the blowout preventer, thereby avoiding problems such as poor sealing, unstable pressure during pressure testing, or leakage. By setting a reverse check valve between the fishing neck part and the connecting part, when there is pressure in the coiled tubing, the reverse check valve can be used to achieve rapid and safe pressure relief. Therefore, the special fishing neck for coiled tubing velocity string provided by the present invention can be used as a special fishing tool for fishing the hanger with a diameter of Φ176mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0047] Figure 1 FIG. 9 is a schematic structural diagram of the open state of the reverse check valve in the special fishing neck for coiled tubing velocity string provided by the embodiment of the present invention;

[0048] Figure 2 FIG. 13 is a schematic structural diagram of the closed state of the reverse check valve in the special fishing neck for coiled tubing velocity string provided by the embodiment of the present invention.

[0049] Reference numerals: 100 - fishing neck part; 200 - reverse check valve; 210 - valve plate; 300 - centralizer; 400 - central working barrel; 500 - connecting part; 600 - fixing pin; 700 - anti-back-off pin; 800 - sealing ring. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0050] In order to make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and illustrated herein can be arranged and designed in various different configurations.

[0051] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents the selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0052] The following will, in conjunction with the accompanying drawings, elaborate on some embodiments of the present invention. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0053] In view of this, the present invention provides a special fishing neck for coiled tubing velocity string, including: a fishing neck member 100, a reverse check valve 200, a centralizer 300, a central working cylinder 400, and a connecting member 500; the fishing neck member 100 is connected to the central working cylinder 400, and the central working cylinder 400 is connected to the connecting member 500; the fishing neck member 100 is in communication with the connecting member 500, and the reverse check valve 200 is arranged between the fishing neck member 100 and the connecting member 500; the centralizer 300 is sleeved outside the central working cylinder 400; one end of the connecting member 500 away from the reverse check valve 200 is used to connect with a hanger; when there is pressure in the pipe, liquid or gas flows in from the connecting member 500, passes through the reverse check valve 200, and flows out from the fishing neck member 100.

[0054] The special fishing neck for coiled tubing velocity string provided by the present invention, by arranging the centralizer 300 outside the central working cylinder 400, centers and straightens the hanger when docking in the inner cavity of the blowout preventer, improving the docking efficiency of the GS fishing spear and the fishing neck; due to the arrangement of the centralizer 300, it avoids the hanger from being knocked, rubbed against in the inner cavity of the blowout preventer, which may lead to problems such as poor sealing, unstable pressure holding during pressure testing, or leakage; by arranging the reverse check valve 200 between the fishing neck member 100 and the connecting member 500, when there is pressure in the coiled tubing, using the reverse check valve 200 can achieve rapid and safe pressure relief; therefore, the special fishing neck for coiled tubing velocity string provided by the present invention can be used as a special fishing tool for fishing a hanger with a diameter of Φ176mm.

[0055] The following will, in conjunction with Figure 1 - Figure 2 elaborate in detail on the structure and shape of the special fishing neck for coiled tubing velocity string provided in this embodiment.

[0056] Regarding the shape and structure of the fishing neck member 100, specifically:

[0057] Referring to Figure 1 , the fishing neck member 100 is specifically a special fishing neck, and the fishing neck member 100 is connected to the central working cylinder 400.

[0058] Specifically, one end of the fishing neck member 100 close to the reverse check valve 200 extends into the central working cylinder 400 and is threadedly connected to the central working cylinder 400

[0059] Regarding the shape and structure of the reverse check valve 200 and the connecting member 500, specifically:

[0060] The fishing neck piece 100 communicates with the connecting piece 500, and the reverse check valve 200 is arranged between the fishing neck piece 100 and the connecting piece 500. The reverse check valve 200 is arranged inside the central working barrel 400, and the connecting piece 500 is connected to the central working barrel 400. One end of the connecting piece 500 away from the reverse check valve 200 is used to connect with the hanger.

[0061] Specifically, the reverse check valve 200 includes a valve body and a valve plate 210. The valve body is threadedly connected to the inner wall of the central working barrel 400. The valve body is arranged between the fishing neck piece 100 and the connecting piece 500, and the valve plate 210 is rotatably connected to the valve body; Refer to Figure 1 and Figure 2 , when there is pressure in the pipe, the valve plate 210 can rotate in the direction away from the connecting piece 500. At this time, the reverse check valve 200 is in an open state. When there is pressure in the pipe, the liquid or gas flows in from the connecting piece 500, passes through the reverse check valve 200, and flows out from the fishing neck piece 100; When the pressure is released, the valve plate 210 can rotate in the direction close to the connecting piece 500. At this time, the reverse check valve 200 is in a closed state. The valve plate 210 in the closed state finally blocks the channel between the fishing neck piece 100 and the connecting piece 500 to prevent the liquid or gas in the channel from flowing continuously. Therefore, the liquid or gas can only flow in from the connecting piece 500 and flow out from the fishing neck piece 100. The reverse check valve 200 plays a role in the one-way flow of the liquid or gas.

[0062] In an alternative embodiment, one end of the connecting piece 500 close to the reverse check valve 200 extends into the central working barrel 400 and is connected to the central working barrel 400.

[0063] In an alternative embodiment, one end of the connecting piece 500 away from the reverse check valve 200 is provided with a thread. The connecting piece 500 can specifically be a nipple for connecting the hanger. The thread is 2 3 / 8" flush (NU) thread, and the nipple is connected to the hanger through 2 3 / 8" flush (NU) thread.

[0064] In this embodiment, the centralizer 300 is sleeved outside the central working barrel 400. Specifically, the centralizer 300 is threadedly connected to the outside of the central working barrel 400.

[0065] In order to strengthen the connection between the centralizer 300 and the central working barrel 400, a fixing pin 600 is also provided in this embodiment. The fixing pin 600 passes through the centralizer 300 and extends into the central working barrel 400.

[0066] In order to strengthen the connection between the central working cylinder 400 and the connecting member 500, the present embodiment is further provided with a back-stop pin 700, which passes through the central working cylinder 400 and extends into the connecting member 500. The stable connection between the central working cylinder 400 and the connecting member 500 also plays the role of positioning the reverse check valve 200 to prevent back-off.

[0067] In order to keep the pressure of the liquid column in the well stable and prevent leakage, the present embodiment is further provided with a sealing ring 800. A sealing ring 800 is provided between the reverse check valve 200 and the central working cylinder 400. Preferably, there are at least four sealing rings 800 between the reverse check valve 200 and the central working cylinder 400. A sealing ring 800 is also provided between the connecting member 500 and the central working cylinder 400.

[0068] During the construction process, if the bottom plug fails to seal, the bottom hole pressure cannot be directly observed on the ground, which brings great construction risks to the next step and safe production. In order to solve the problem that the bottom hole pressure cannot be directly observed on the ground when the bottom plug fails to seal, the end of the fishing neck 100 away from the reverse check valve 200 in this embodiment is connected to the pipeline, and a pressure gauge is provided on the pipeline for monitoring the pressure.

[0069] The special fishing neck for the coiled tubing velocity string provided in this embodiment is a GS fishing spear that has been redesigned and improved three times, and has been tried out in four well sites, including the Su 14-18-30X3 well and the Shuang 47-46C8 well, with good feedback. The special fishing neck for the coiled tubing velocity string provided in this embodiment uses a Φ178mm fishing neck with a centralizer 300 to centralize the Φ176mm hanger, ensuring that the hanger is centralized in the inner cavity of the blowout preventer, and preventing the fishing neck and the hanger from being worn eccentrically due to the bending of the coiled tubing.

[0070] The functions that can be realized by the dedicated fishing neck for the coiled tubing velocity string provided in this embodiment are:

[0071] (1) When the GS salvage spear is docked with the Φ176mm hanger, a special salvage tool can be used;

[0072] (2) When docking the BOP cavity, center and straighten the Φ176mm hanger to improve the docking efficiency of the GS salvage spear and salvage neck;

[0073] (3) Protect the sealing part of the Φ176mm hanger during the salvage and docking process to avoid collision and eccentric wear of the tools and hanger in the inner cavity of the BOP, which may lead to problems such as poor sealing, failure to maintain pressure during pressure test, or leakage;

[0074] (4) When there is pressure in the coiled tubing, the reverse check valve 200 can be used to quickly and safely release the pressure;

[0075] (5) In the case where the bottom plug is unsealed, the bottom hole pressure can be visually observed on the ground.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A special fishing neck for coiled tubing velocity string, characterized in that, Comprising: A fishing neck piece (100), a reverse check valve (200), a centralizer (300), a central working barrel (400) and a connecting piece (500); The fishing neck piece (100) is connected to the central working barrel (400), and the central working barrel (400) is connected to the connecting piece (500); The fishing neck piece (100) communicates with the connecting piece (500), and the reverse check valve (200) is arranged between the fishing neck piece (100) and the connecting piece (500); The centralizer (300) is sleeved outside the central working barrel (400); One end of the connecting piece (500) away from the reverse check valve (200) is used for connecting with a hanger; When there is pressure in the pipe, liquid or gas flows in from the connecting piece (500), passes through the reverse check valve (200), and flows out from the fishing neck piece (100).

2. The special fishing neck for coiled tubing velocity string according to claim 1, characterized in that The reverse check valve (200) includes a valve body and a valve plate (210); The valve body is arranged between the fishing neck piece (100) and the connecting piece (500), and the valve plate (210) is rotatably connected to the valve body; When there is pressure in the pipe, the valve plate (210) can rotate in a direction away from the connecting piece (500), and at this time the reverse check valve (200) is in an open state; When the pressure is released, the valve plate (210) can rotate in a direction close to the connecting piece (500), and at this time the reverse check valve (200) is in a closed state.

3. The special fishing neck for coiled tubing velocity string according to claim 2, characterized in that The valve body is threadedly connected inside the central working barrel (400).

4. The special fishing neck for coiled tubing velocity string according to claim 1, characterized in that The centralizer (300) is threadedly connected outside the central working barrel (400).

5. The special fishing neck for coiled tubing velocity string according to claim 1, characterized in that One end of the fishing neck piece (100) close to the reverse check valve (200) extends into the central working barrel (400) and is threadedly connected to the central working barrel (400).

6. The special fishing neck for coiled tubing velocity string according to claim 1, characterized in that One end of the connecting piece (500) close to the reverse check valve (200) extends into the central working barrel (400) and is connected to the central working barrel (400).

7. The special fishing neck for coiled tubing velocity string according to claim 1, characterized in that One end of the connecting piece (500) away from the reverse check valve (200) is provided with a thread.

8. The special fishing neck for coiled tubing velocity string according to claim 1, characterized in that It further includes a fixing pin (600); The fixing pin (600) passes through the centralizer (300) and extends into the central working barrel (400).

9. The special fishing neck for the coiled tubing velocity string according to claim 1, characterized in that, it further comprises a backstop pin (700); the backstop pin (700) passes through the central working cylinder (400) and extends into the connecting member (500).

10. The special fishing neck for the coiled tubing velocity string according to claim 1, characterized in that, it further comprises a sealing ring (800); a sealing ring (800) is arranged between the reverse check valve (200) and the central working cylinder (400); a sealing ring (800) is arranged between the connecting member (500) and the central working cylinder (400).

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