A wellhead backflow material capturing device

Abstract

The present application provides a wellhead backflow material capturing device, comprising: an outer cylinder; a ball blocking plate which is arranged along the radial direction of the outer cylinder and connected to the inner wall of the outer cylinder; a screen pipe which is inserted into the outer cylinder and forms an annular space gap with the inner wall of the outer cylinder; wherein one end of the screen pipe is hermetically connected to one end of the outer cylinder, and the other end of the screen pipe is connected to the ball blocking plate; a plurality of first flow holes which are circumferentially and uniformly arranged are formed in the pipe wall of the screen pipe, and the plurality of first flow holes communicate with the annular space gap; a flow hole group is formed in the ball blocking plate, and the flow hole group communicates with the space between the screen pipe and the other end of the outer cylinder and the space between the annular space gap and the other end of the outer cylinder respectively. For the capturing device involved in the present application, the screen pipe is used as a captured material storage chamber, the backflow materials can be captured and accommodated in the screen pipe, and the backflow liquid can directly flow out through the flow hole group in the screen pipe or flow into the annular space gap through the screen pipe and then flow out. By arranging the screen pipe, the captured material storage chamber is separated from the backflow liquid channel, so as to achieve the anti-blocking function.

Description

Technical Field

[0001] This application relates to the technical field of oil wells, and particularly to a wellhead backflow material capturing device. Background Art

[0002] At present, for the stimulation and transformation of unconventional oil and gas wells such as low-permeability and tight oil and gas, shale gas, etc., processes such as staged ball-drop sliding sleeves + packers or casing + bridge plug perforation are mostly used. During the fracturing construction, it is necessary to input a plugging ball from the surface wellhead and pump it to the corresponding ball seat or bridge plug to block the next layer of reservoir, and then transform the upper layer of reservoir. After the stimulation and transformation construction is completed, a blowout is required. At this time, the input plugging ball and the residues of soluble fracturing tools will return to the surface wellhead along with the backflow fluid and gas, which will damage valves such as needle valves in the pipeline. Therefore, a capturing device is generally set between the outlet of the production tree and the pipeline. Since the plugging ball is generally made of resin ball or bakelite ball and will not dissolve in the fracturing fluid or backflow fluid, the commonly used capturing device is usually a ball catcher to collect and capture the plugging ball without affecting the blowout operation and damaging the valve.

[0003] In recent years, with the development of technology, soluble metal fracturing balls have been widely used for plugging balls. Since the dissolution of soluble balls requires a certain amount of time and corresponding liquid to dissolve, in some well conditions, the plugging balls cannot be completely dissolved. In the construction wells using soluble bridge plugs, the undissolved rubber cylinder or metal body will also return to the surface wellhead along with the backflow fluid and gas, and the undissolved plugging balls, metal fragments and powder rubber cylinder fragments generated by dissolution are very easy to gather in the ball catcher together, resulting in the blockage of the ball catcher and the inability to perform blowout operations.

[0004] Therefore, a wellhead backflow material capturing device is needed to solve the problem that the wellhead backflow materials such as soluble plugging balls or soluble materials are likely to cause the blockage of the ball catcher, resulting in the inability to perform blowout operations. Summary of the Invention

[0005] The main purpose of this application is to provide a wellhead backflow material capturing device to solve the problem that the wellhead backflow materials such as soluble plugging balls or soluble materials are likely to cause the blockage of the ball catcher, resulting in the inability to perform blowout operations.

[0006] To solve the above technical problems, this application provides the following technical solutions:

[0007] This application provides a wellhead backflow material capturing device, including:

[0008] An outer cylinder;

[0009] A ball blocking plate, which is arranged radially along the outer cylinder and connected to the inner wall of the outer cylinder;

[0010] A screen pipe, the screen pipe is inserted into the outer cylinder, and a annular space gap is formed between the screen pipe and the inner wall of the outer cylinder;

[0011] Wherein,

[0012] One end of the screen pipe is hermetically connected to one end of the outer cylinder, and the other end of the screen pipe is connected to the ball blocking plate;

[0013] A plurality of first flow holes are arranged on the pipe wall of the screen pipe and are circumferentially distributed, and the plurality of first flow holes communicate with the annular space gap;

[0014] The ball blocking plate is provided with a flow hole group, and the flow hole group communicates between the screen pipe and the other end of the outer cylinder, and between the annular space gap and the other end of the outer cylinder respectively.

[0015] Preferably, it further includes a first joint and a second joint. The outer cylinder includes a first end and a second end. The first end of the outer cylinder is located upstream of the second end. The first joint is connected to the first end, and the second joint is connected to the second end.

[0016] Preferably, it further includes a transition joint and a check valve device. Wherein,

[0017] The transition joint is connected between the first joint and the first end of the outer cylinder, and the transition joint is connected between the first end of the outer cylinder and the screen pipe, and the check valve device is arranged in the transition joint.

[0018] Preferably, the check valve device includes a plurality of check spring pieces, the plurality of check spring pieces are circumferentially distributed, and one end of each check spring piece is connected to the inner wall of the transition joint, and the other end extends axially towards the transition joint.

[0019] Preferably, the check spring piece includes a rectangular section and a triangular section connected to each other. A plurality of installation grooves are arranged on the inner wall of the transition joint and are circumferentially distributed. The rectangular section of each check spring piece is connected to one of the installation grooves, and the tips of the triangular sections of the plurality of check spring pieces are arranged close to each other.

[0020] Preferably, the transition joint includes a third end and a fourth end;

[0021] The third end is inserted into the first joint and is hermetically connected to the first joint;

[0022] The fourth end is inserted into the outer cylinder and is sleeved outside the screen pipe, and the fourth end is hermetically connected to the outer cylinder;

[0023] The second joint is inserted into the second end of the outer cylinder and is hermetically connected to the second end;

[0024] The third end of the transition joint is connected to the first joint, the fourth end of the transition joint is connected to the outer cylinder, and the outer cylinder is connected to the second joint through threads and set screws respectively. The fourth end of the transition joint is connected to the screen pipe through threads.

[0025] Preferably, the first flow holes on the screen pipe are distributed in multiple columns along the circumferential direction of the screen pipe, and each column includes a plurality of the first flow holes;

[0026] The aperture of the first flow hole is 3-8 mm, and / or the length of the screen pipe is not less than 350 mm.

[0027] Preferably, an annular groove is provided on one side of the ball blocking plate facing the first joint. The depth of the groove is 1-3 mm, and the other end of the screen pipe is inserted into the groove.

[0028] Preferably, the flow hole group includes a plurality of second flow holes, a plurality of third flow holes and a plurality of fourth flow holes that penetrate along the direction parallel to the axial direction. Among them,

[0029] The plurality of second flow holes are circumferentially and uniformly distributed outside the groove for communicating the annulus gap and the second joint;

[0030] The plurality of third flow holes and the plurality of fourth flow holes are circumferentially and uniformly distributed inside the groove for communicating the screen pipe and the second joint.

[0031] Preferably, the apertures of the second flow holes, the third flow holes and the fourth flow holes are all not less than 3 mm and not more than 8 mm, and the apertures of the third flow holes and the fourth flow holes are different.

[0032] Compared with the prior art, the wellhead backflow material capturing device provided by the present application has at least the following beneficial effects:

[0033] Taking the screen pipe as a capturing material storage chamber, the backflow materials can be captured and accommodated in the screen pipe. The backflow liquid can directly flow out from the screen pipe through the flow hole group, or enter the annulus gap through the screen pipe and then flow out through the flow hole group. By setting the screen pipe, the capturing material storage chamber is separated from the backflow liquid channel to play an anti-blocking function, thereby solving the problem that wellhead backflow materials such as soluble plugging balls or soluble materials are likely to cause the ball catcher to be blocked, resulting in the inability to perform blowout prevention operations;

[0034] The present application relates to a wellhead backflow material capturing device, which has a simple structure and can be directly installed horizontally on an oil / gas production tree and then connected to a blowout prevention pipeline, and can effectively capture particulate backflow materials to avoid damaging the valves of the blowout prevention pipeline;

[0035] This application relates to a wellhead backflow material capturing device, which can not only be used to capture plugging balls, but also be used to capture undissolved substances such as residues of various soluble tools, and has a wide range of applications.

[0036] The above description is only an overview of the technical solution of this application. In order to understand the technical means of this application more clearly and implement it according to the content of the specification, the following describes in detail with reference to the preferred embodiments of this application and the accompanying drawings. Brief Description of the Drawings

[0037] By reading the following detailed description with reference to the accompanying drawings, the above and other objects, features, and advantages of the exemplary embodiments of this application will become readily understood. In the drawings, several embodiments of this application are shown in an exemplary rather than restrictive manner, and the same or corresponding reference numerals represent the same or corresponding parts, where:

[0038] Figure 1 A cross-sectional view of the wellhead backflow material capturing device showing an exemplary embodiment of this application;

[0039] Figure 2a A schematic structural view of the screen pipe in the wellhead backflow material capturing device showing an exemplary embodiment of this application, Figure 2b Shows Figure 2a The A-A cross-sectional view of Figure 2c Shows Figure 2a The B-B cross-sectional view of

[0040] Figure 3a A schematic structural view of the transition joint in the wellhead backflow material capturing device showing an exemplary embodiment of this application, Figure 3b Shows Figure 3a The A-A cross-sectional view of Figure 3c Shows Figure 3a The side view of

[0041] Figure 4a A schematic structural view of the anti-rebound sheet in the wellhead backflow material capturing device showing an exemplary embodiment of this application, Figure 4b Shows Figure 4a The A-A cross-sectional view of

[0042] Figure 5a A schematic structural view of the ball blocking plate in the wellhead backflow material capturing device showing an exemplary embodiment of this application, Figure 5b Shows the cross-sectional view of the ball blocking plate, Figure 5c Shows Figure 5b The enlarged view at A in

[0043] Figure 6 A schematic diagram showing the flow direction of the backflow liquid and backflow materials when the capturing device of an exemplary embodiment of this application is in use;

[0044] Figure 7 Shows a schematic diagram of the installation position of the wellhead backflow material capturing device according to an exemplary embodiment of the present application.

[0045] Explanation of the reference numerals in the drawings:

[0046] 1 First joint, 101 Chuck, 2 Transition joint, 201 Boss, 202 Installation groove, 203 Sealing groove, 3 Anti-rebound sheet, 4 Fixing member, 5 Outer cylinder, 6 Second joint, 7 Ball blocking plate, 701 Second flow hole, 702 Third flow hole, 703 Fourth flow hole, 704 Groove, 8 Screen pipe, 801 First flow hole, 9 Sealing member, 10 Set screw, 11 Annular space gap. Detailed implementation manners

[0047] The exemplary embodiments of the present application will be described in more detail below with reference to the drawings. Although the exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present application can be more thoroughly understood and the scope of the present application can be fully conveyed to those skilled in the art.

[0048] It should be noted that unless otherwise specified, the technical terms or scientific terms used in the present application should have the ordinary meanings understood by those skilled in the art to which the present application belongs.

[0049] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present application.

[0050] To solve the problems existing in the prior art, the present application provides a wellhead backflow material capturing device. Please refer to Figures 1 to 6 , the wellhead backflow material capturing device includes:

[0051] Outer cylinder 5;

[0052] Ball blocking plate 7, the ball blocking plate 7 is arranged along the radial direction of the outer cylinder 5 and is connected to the inner wall of the outer cylinder 5;

[0053] Screen pipe 8, the screen pipe 8 is inserted into the outer cylinder 5 and forms an annular space gap 11 with the inner wall of the outer cylinder 5;

[0054] Among them,

[0055] One end of the sieve tube 8 is hermetically connected to one end of the outer cylinder 5, and the other end of the sieve tube 8 is connected to the ball blocking plate 7;

[0056] A plurality of first flow holes 801 are provided on the tube wall of the sieve tube 8 and are circumferentially and uniformly distributed, and the plurality of first flow holes 801 communicate with the annular space 11;

[0057] The ball blocking plate 7 is provided with a flow hole group, and the flow hole group communicates with the space between the other ends of the sieve tube 8 and the outer cylinder 5 respectively, and between the annular space 11 and the other end of the outer cylinder 5.

[0058] The wellhead backflow material capturing device involved in the present application uses the sieve tube 8 as a captured material storage chamber. The backflow material can be captured and accommodated in the sieve tube 8, that is, in the captured material storage chamber. The backflow liquid can directly flow out from the sieve tube 8 through the flow hole group, or enter the annular space 11 through the sieve tube 8 and then flow out through the flow hole group; by setting the sieve tube 8, the captured material storage chamber is separated from the backflow liquid channel to play an anti-blocking function; the wellhead backflow material capturing device involved in the present application can be connected between the outlet of the oil / gas production tree and the surface blowout pipeline. During blowout, the backflow liquid first passes through the capturing device, and particulate or solid backflow materials such as plugging balls and undissolved substances carried in the backflow liquid will be blocked in the inner cavity of the capturing device, that is, in the sieve tube 8, and cannot enter the surface blowout pipeline, thereby protecting the safety of each valve in the blowout pipeline, and further solving the problem that wellhead backflow materials such as soluble plugging balls or soluble materials are prone to block the ball catcher, resulting in the inability to perform blowout operations.

[0059] The wellhead backflow material capturing device involved in the present application has a simple structure, can be directly installed horizontally on the oil / gas production tree, and then connected to the blowout pipeline, can effectively capture the backflow material, and avoid damaging the valves of the blowout pipeline; it can not only be used to capture plugging balls, but also be used to capture undissolved substances such as various soluble tool residues, and has a wide range of applications.

[0060] Please refer to Figure 1 , in a preferred embodiment of the present application, the wellhead backflow material capturing device further includes a first joint 1 and a second joint 6. The outer cylinder 5 includes a first end and a second end. The first end of the outer cylinder 5 is upstream of the second end of the outer cylinder 5. The first joint 1 is connected to the first end, and the second joint 6 is connected to the second end.

[0061] In this application, the first joint 1 is used to communicate with the outlet of the oil / gas production tree, and the second joint 6 is used to communicate with the surface blowout prevention pipeline. The wellhead backflow material capture device is of a tubular structure. The inner cavity of the tubular structure, that is, the inner cavity of the screen pipe 8, serves as a capture material storage chamber for accommodating granular or solid backflow materials. The backflow liquid enters the blowout prevention pipeline through the flow holes group on the ball blocking plate 7 or successively through the first flow holes 801 of the screen pipe 8, the annular space 11, and the flow holes group on the ball blocking plate 7, so as to achieve the purpose of preventing blockage.

[0062] Please refer to Figure 1 , in a preferred embodiment of this application, the wellhead backflow material capture device further includes a transition joint 2 and a check device. Among them,

[0063] The transition joint 2 is connected between the first joint 1 and the first end of the outer cylinder 5, and the transition joint 2 is connected between the first end of the outer cylinder 5 and the screen pipe 8. The check device is arranged inside the transition joint 2. Through the check device, the captured materials can be effectively prevented from falling back into the wellhead again.

[0064] Specifically, the check device includes a plurality of check spring pieces 3. The plurality of check spring pieces 3 are circumferentially and evenly distributed inside the transition joint 2. One end of each check spring piece 3 is connected to the inner wall of the transition joint 2, and the other end extends axially towards the inside of the transition joint 2.

[0065] Among them, the check spring piece 3 includes a rectangular section and a triangular section that are connected to each other. A plurality of mounting grooves 202 that are circumferentially and evenly distributed are provided on the inner wall of the transition joint 2. The rectangular section of each check spring piece 3 is connected to one mounting groove 202, and the tips of the triangular sections of the plurality of check spring pieces 3 are arranged close to each other.

[0066] One ends of the plurality of check spring pieces 3 are connected to the inner wall of the transition joint 2, and the other ends are arranged close to each other. When the backflow liquid and the backflow materials flow from the first joint 1 into the transition joint 2, the granular or solid backflow materials will flush open the tips of the plurality of check spring pieces 3 that are close to each other and enter the inner cavity of the screen pipe 8. The plurality of check spring pieces 3 will re-close under the action of their own restoring force. Since the check spring pieces 3 incline and close to each other from the outside to the inside along the liquid flow direction, when the backflow materials are located downstream of the check spring pieces 3, due to the inclination of the check spring pieces 3 and their arrangement with the tips close to each other, the backflow materials cannot flush open the check spring pieces 3 from the inside to the outside and fall back, so that the captured materials or backflow materials captured by the device can be effectively prevented from falling back into the wellhead again.

[0067] Please refer to Figure 1, in a preferred embodiment of the present application, the transition joint 2 is used to connect the screen pipe 8 to the outer cylinder 5 and connect the first joint 1 and the outer cylinder 5; the transition joint 2 includes a third end and a fourth end; wherein, the third end is inserted into the first joint 1 and is hermetically connected to the inner wall of the first joint 1 through a seal 9; the fourth end is inserted into the outer cylinder 5 and sleeved outside the screen pipe 8, and the fourth end of the transition joint 2 is hermetically connected to the inner wall of the outer cylinder 5 through a seal 9; the second joint 6 is inserted into the second end of the outer cylinder 5 and is hermetically connected to the second end through a seal 9; between the third end of the transition joint 2 and the first joint 1, between the fourth end of the transition joint 2 and the outer cylinder 5, and between the outer cylinder 5 and the second joint 6 are respectively connected through threads and set screws 10, and between the fourth end of the transition joint 2 and the screen pipe 8 is connected through threads. The outer wall of the second joint 6 is provided with a seal groove for installing the seal 9.

[0068] Please refer to Figure 1 , on the outer walls of the two ends of the transition joint 2, that is, the third end and the fourth end, there are respectively provided seal grooves 203 for installing the seal 9. The seal 9 can be an O-ring. On the two ends of the transition joint 2, there are also respectively provided external threads between the seal groove 203 and the boss 201 at the third end and between the seal groove 203 and the boss 201 at the fourth end. The fourth end of the transition joint 2 is also provided with internal threads. The third end of the transition joint 2 is inserted into the first joint 1 and is connected to the inner wall of the first joint 1 through threads. The fourth end of the transition joint 2 is inserted between the first end of the outer cylinder 5 and the screen pipe 8 and is respectively connected to the inner wall of the first end of the outer cylinder 5 and the outer wall of the screen pipe 8 through threads; one end of the second joint 6 is inserted into the second end of the outer cylinder 5 and is connected to the second end of the outer cylinder 5 through threads. In the present application, at the threaded connections between each joint and between the joint and the outer cylinder 5, a plurality of set screws 10 evenly distributed in the circumferential direction are used for fastening to prevent the threads from loosening, which can effectively improve the connection strength. The first joint 1 and the outer cylinder 5 are respectively provided with threaded holes for fixing the set screws 10 to connect the set screws 10.

[0069] Please refer to Figure 1 , Figures 3a to 3c , in a preferred embodiment of the present application, one end of the first joint 1 connected to the oil / gas production tree outlet is provided with tapered pipe internal threads. The first joint 1 is tapered and transitioned from the end with tapered pipe internal threads to the other end, so that the outer diameter of the other end of the first joint 1, that is, the connection end of the first joint and the transition joint 2, is greater than the outer diameter of its end with tapered pipe internal threads. There is a retaining ring 101 on the inner circumference of the other end of the first joint 1. The third end of the transition joint 2 is close to the retaining ring 101, and the inner diameter of the transition joint 2 is not less than the inner diameter of the retaining ring 101.

[0070] Please refer to Figures 3a to 3c, the transition joint 2 can be machined from 42CrMo / 35CrMo alloy steel material. The part of the transition joint 2 between the third end and the fourth end bulges outward to form a boss 201. The first joint 1 and the outer cylinder 5 are respectively abutted against both sides of the boss 201, and the outer wall of the boss 201 is flush with the outer wall of the other end of the first joint 1 and the outer wall of the outer cylinder 5.

[0071] In this application, a plurality of installation grooves 202 are provided on the inner wall of the third end of the transition joint 2, and each installation groove 202 is used to install a non-return spring piece 3. A plurality of fixing part threaded holes are provided in the installation groove 202 for connecting the fixing part 4, and the fixing part 4 can be a bolt.

[0072] Please refer to Figures 3a to 4b , in a preferred embodiment of this application, the installation groove 202 is an inclined groove, the non-return spring piece 3 is a flat plate structure, and the rectangular section of the non-return spring piece 3 is connected to the installation groove 202 through the fixing part 4. Since the installation groove 202 is inclined, the tip of the triangular section of the non-return spring piece 3 extends obliquely toward the axis of the transition joint 2, and a plurality of non-return spring pieces 3 are all inclined toward the axis, thus forming a structure in which the tips of the non-return spring pieces 3 are close to each other, so as to effectively prevent the captured object from falling back into the wellhead.

[0073] In other embodiments of this application, the installation groove 202 can be a straight groove, arranged along the direction parallel to the axis of the transition joint 2. The rectangular section of the non-return spring piece 3 is connected to the installation groove 202, and the triangular section of the non-return spring piece 3 is bent relative to the rectangular section, so that the tips of the triangular sections of a plurality of non-return spring pieces 3 are close to each other.

[0074] Please refer to Figure 4a , Figure 4b , the non-return spring piece 3 can be machined from 65Mn or 60Si2Mn alloy steel material. One end of the triangular section of the non-return spring piece 3 is connected to the rectangular section, and the other end is a tip, so that a plurality of non-return spring pieces 3 can be close to each other. The angle of the tip of the triangular section can be determined according to the number of non-return spring pieces 3 and the pipe diameter of the transition joint 2; a plurality of through holes are provided on the rectangular section of the non-return spring piece 3, and each through hole corresponds to a fixing part threaded hole for connecting a fixing part 4.

[0075] Please refer to Figures 2a to 2c , in a preferred embodiment of this application, the screen pipe 8 can be machined from 42CrMo / 35CrMo alloy steel material. The first flow holes 801 on the screen pipe 8 are distributed in multiple columns along the circumferential direction of the screen pipe 8, and each column includes a plurality of first flow holes 801; the aperture of the first flow holes 801 is 3-8 mm, and / or the length of the screen pipe 8 is not less than 350 mm.

[0076] Specifically, one end of the screen pipe 8 is provided with an external thread, and the external thread can be a trapezoidal thread. Please refer to Figure 1 andFigure 3b The fourth end of the transition joint 2 is provided with an internal thread, and one end of the screen tube 8 is inserted into the fourth end of the transition joint 2 and is threadedly connected to the fourth end of the transition joint 2. The internal thread on the inner wall of the fourth end of the transition joint 2 is concavely arranged, so that after the screen tube 8 is connected to the transition joint 2, the inner wall of the screen tube 8 does not protrude from the inner wall of the transition joint 2, thereby avoiding blocking of the backflow material.

[0077] The first flow holes 801 are arranged in multiple rows along the circumference of the screen tube 8, wherein 20-30 rows can be arranged, and the number of first flow holes 801 in each row can be 8-12. The number of first flow holes 801 and the number of rows of distribution can be adjusted as needed. When there are many granular or solid return materials, more first flow holes 801 can be arranged to increase the circulation rate of the return liquid and avoid the blockage of some flow holes and affect the flow of the return liquid; the aperture of the first flow hole 801 can be adjusted according to the particle size of the granular or solid return materials to appropriately block the granular or solid return materials. The transition joint 2 and the screen tube 8 form a capture storage room or a ball blocking channel, so the length of the screen tube 8 can also be adjusted as needed. When there are many granular or solid return materials, the length of the screen tube 8 can be appropriately lengthened to increase the accommodation space.

[0078] In other embodiments of the present application, the first flow hole 801 may also be an annular structure along the circumference of the screen tube 8, and multiple annular structures may be arranged along the axial direction of the screen tube 8, and adjacent annular structures may be staggered or aligned with the front and rear holes.

[0079] The aperture of the first flow hole 801 is preferably 4-5 mm, and the length of the screen tube 8 is preferably 1000 mm. Under this aperture, a better capture effect can be achieved, and the screen tube 8 of this length can also well capture granular or solid return flow.

[0080] See also Figures 5a to 5c In a preferred embodiment of the present application, the ball baffle plate 7 can be made of 42CrMo / 35CrMo alloy steel material, and a limit platform is provided on the inner wall of the outer cylinder 5. The ball baffle plate 7 is inserted into the outer cylinder 5 from the end of the outer cylinder 5 away from the transition joint 2 and abuts against the limit platform, and is positioned by being blocked by the limit platform. An annular groove 704 is provided on the side of the ball baffle plate 7 facing the first joint 1. The depth of the groove 704 is 1-3mm, preferably 2mm. The other end of the screen tube 8 is inserted into the groove 704 to achieve positioning. The groove 704 is used to position the screen tube 8. After the second joint 6 is inserted into the outer cylinder 5, it abuts against the other side of the ball baffle plate 7, and forms a clamp for the ball baffle plate 7 with the limit platform on the inner wall of the outer cylinder 5, so that the ball baffle plate 7 is fixed.

[0081] The over - flow hole group includes a plurality of second over - flow holes 701, a plurality of third over - flow holes 702, and a plurality of fourth over - flow holes 703 that penetrate axially. Among them, the plurality of second over - flow holes 701 are circumferentially distributed on the outer side of the groove 704, and the second over - flow holes 701 are used to connect the annulus gap 11 and the second joint 6; the plurality of third over - flow holes 702 and the plurality of fourth over - flow holes 703 are circumferentially distributed inside the groove 704 and are used to connect the screen pipe 8 and the second joint 6.

[0082] The second over - flow holes 701 are used to connect the annulus gap 11 and the second joint 6, so that the back - flow liquid entering the annulus gap 11 through the first over - flow holes 801 of the screen pipe 8 can enter the second joint 6 and be discharged to the flow - through line. The third over - flow holes 702 and the fourth over - flow holes 703 are used to discharge the back - flow liquid in the inner cavity of the screen pipe 8. Among them, the plurality of second over - flow holes 701 are annularly distributed, the plurality of third over - flow holes 702 and the plurality of fourth over - flow holes 703 are also annularly distributed, and the annular diameter where the plurality of third over - flow holes 702 are located is larger than the annular diameter where the plurality of fourth over - flow holes 703 are located.

[0083] Among them, please refer to Figure 1 , the connection end of the second joint 6 and the outer cylinder 5 is the insertion end. The other end of the second joint 6 is provided with an external taper pipe thread for connecting to the flow - through line; the inner wall of the end of the insertion end of the second joint 6 is an inclined mouth. The insertion end of the second joint 6 abuts against the edge of the ball - blocking plate 7 and is located outside the second over - flow holes 701, so that the back - flow liquid passing through the annulus gap 11 can enter the second joint 6 along the inclined mouth after passing through the second over - flow holes 701 and then enter the flow - through line. The inclined - mouth structure can guide the back - flow liquid and facilitate the flow towards the middle of the second joint 6.

[0084] The aperture diameters of the second over - flow holes 701, the third over - flow holes 702, and the fourth over - flow holes 703 are all not less than 3 mm and not more than 8 mm, and the aperture diameters of the third over - flow holes 702 and the fourth over - flow holes 703 are different. By using over - flow holes with different aperture diameters, back - flow substances with different particle sizes can be targeted to avoid all over - flow holes being blocked and affecting the flow of back - flow liquid.

[0085] As a preferred embodiment, the aperture diameter of the second over - flow holes 701 is 3 mm, the aperture diameter of the third over - flow holes 702 is 8 mm, and the aperture diameter of the fourth over - flow holes 703 is 5 mm. At this aperture diameter, back - flow substances with different particle sizes can be captured, and the capture effect is better.

[0086] The assembly process of the wellhead back - flow substance capture device involved in this application is as follows:

[0087] Install 12 anti-rebound pieces 3 into the corresponding installation grooves 202 of the transition joint 2 respectively, and fix each anti-rebound piece 3 in the installation groove 202 through 2 fixing parts 4; install 4 seals 9 in pairs in the sealing grooves 203 at both ends of the transition joint 2 respectively, then insert the end of the transition joint 2 with the installation groove 202 into the first joint 1 and connect them through threads. Install 4 set screws 10 into the threaded holes on the first joint 1 and tighten the set screws 10 to prevent the threads from loosening.

[0088] Insert the screen pipe 8 into the inner part of the other end of the transition joint 2 and connect it to the transition joint 2 through threads. Sleeve one end of the outer cylinder 5 on the outside of the other end of the transition joint 2 and connect the outer cylinder 5 and the transition joint 2 through threads. Then install 4 set screws 10 into the corresponding threaded holes on the outer cylinder 5 and tighten the set screws 10 to prevent the threads from loosening; insert the ball blocking plate 7 into the inner part from the other end of the outer cylinder 5 and align the groove 704 of the ball blocking plate 7 with the screen pipe 8, then press close so that the screen pipe 8 is inserted into the groove 704 and the ball blocking plate 7 abuts against the limiting platform on the inner wall of the outer cylinder 5.

[0089] Install 2 seals 9 into the sealing grooves on the outer wall of the second joint 6, then insert the second joint 6 into the inner part of the other end of the outer cylinder 5 and connect them through threads. Install 4 set screws 10 into 4 threaded holes on the outer wall of the other end of the outer cylinder 5 to prevent loosening at the connection between the second joint 6 and the outer cylinder 5. The assembly of the entire wellhead backflow material capturing device is completed.

[0090] Please refer to Figure 7 , the assembled wellhead backflow material capturing device can be connected to the production oil / gas tree outlet through the first joint 1 and connected to the surface blowout pipeline through the second joint 6 to prevent the backflow material from blocking the blowout pipeline.

[0091] During the above assembly process, the fixing part 4 can be a bolt or a screw, and the seal 9 can be an O-ring. The quantity of each component involved in the assembly process, such as 12 anti-rebound pieces 3, is only an exemplary illustration in the embodiment. The technical solution of the present application is not limited to this and can be adjusted adaptively according to actual needs.

[0092] The wellhead backflow material capturing device involved in the present application has the following specific working process:

[0093] Please refer to Figure 6, the backflow liquid and backflow substances will enter the inner cavity from the first joint 1 along the arrow direction, and then the particulate or solid backflow substances will be blocked by the ball blocking plate 7, while the backflow liquid continues to enter the second joint 6 and the blowout prevention pipeline through the third flow-through hole 702 and / or the fourth flow-through hole 703 of the ball blocking plate 7; when the inner cavity is blocked by the backflow substances, the backflow liquid can enter the annular space 11 through the first flow-through hole 801 of the screen pipe 8, and then continue to enter the second joint 6 and the blowout prevention pipeline through the second flow-through hole 701 of the ball blocking plate 7, so as to achieve the function of preventing blockage.

[0094] The wellhead backflow substance capturing device involved in the present application forms a first liquid channel through the inner cavity of the first joint 1, the inner cavity of the transition joint 2, and the inner cavity of the screen pipe 8 connected in sequence. The backflow liquid enters the second joint 6 and flows out through the third flow-through hole 702 and the fourth flow-through hole 703 on the ball blocking plate through the first liquid channel; a second liquid channel is formed through the inner cavity of the first joint 1, the inner cavity of the transition joint 2, the first flow-through hole 801 on the screen pipe 8, and the annular space 11. When there are more backflow substances in the first liquid channel, the backflow liquid can enter the second joint 6 and flow out through the second flow-through hole 701 on the ball blocking plate through the second liquid channel, and the particulate or solid backflow substances are stored in the inner cavity of the screen pipe 8. The present application separates the capture storage chamber from the liquid channel through the screen pipe 8 to play a role in preventing the device from being blocked. The check valve device can effectively prevent the captured substances from falling back into the wellhead again. It has a wide range of applications, a simple structure and a short length, and can be directly installed horizontally on the oil / gas production tree and then connected to the blowout prevention pipeline.

[0095] It can be understood that the relevant features in the above device can be referred to each other. In addition, the "first", "second", etc. in the above embodiments are used to distinguish each embodiment, and do not represent the advantages and disadvantages of each embodiment.

[0096] In the specification provided here, a large number of specific details are described. However, it can be understood that the embodiments of the present invention can be practiced without these specific details. In some instances, the well-known structures and technologies are not shown in detail so as not to obscure the understanding of this specification.

[0097] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claimed rights.

Claims

1. A wellhead backflow material capturing device, characterized in that, Comprising: An outer cylinder; A ball blocking plate, which is arranged radially along the outer cylinder and connected to the inner wall of the outer cylinder; A screen pipe, which is inserted into the outer cylinder and forms an annular space gap with the inner wall of the outer cylinder; Wherein, One end of the screen pipe is hermetically connected to one end of the outer cylinder, and the other end of the screen pipe is connected to the ball blocking plate; A plurality of first flow holes evenly distributed in the circumferential direction are provided on the pipe wall of the screen pipe, and the plurality of first flow holes communicate with the annular space gap; The ball blocking plate is provided with a flow hole group, and the flow hole group communicates between the screen pipe and the other end of the outer cylinder, and between the annular space gap and the other end of the outer cylinder respectively; It further includes a first joint and a second joint. The outer cylinder includes a first end and a second end. The first end of the outer cylinder is located upstream of the second end. The first joint is connected to the first end, and the second joint is connected to the second end; Wherein, The first flow holes on the screen pipe are distributed in multiple columns along the circumferential direction of the screen pipe, and each column includes a plurality of the first flow holes; An annular groove is provided on one side of the ball blocking plate facing the first joint; The flow hole group includes a plurality of second flow holes, a plurality of third flow holes and a plurality of fourth flow holes penetrating along the direction parallel to the axial direction. Wherein, The plurality of second flow holes are evenly distributed in the circumferential direction outside the groove and are used to communicate the annular space gap and the second joint; The plurality of third flow holes and the plurality of fourth flow holes are evenly distributed in the circumferential direction inside the groove and are used to communicate the screen pipe and the second joint; The aperture diameters of the second flow holes, the third flow holes and the fourth flow holes are all not less than 3 mm and not more than 8 mm, and the aperture diameters of the third flow holes and the fourth flow holes are different.

2. The wellhead backflow material capturing device according to claim 1, wherein, It further includes a transition joint and a check device. Wherein, The transition joint is connected between the first joint and the first end of the outer cylinder, and the transition joint is connected between the first end of the outer cylinder and the screen pipe. The check device is arranged in the transition joint.

3. The wellhead backflow material capturing device according to claim 2, wherein The check device includes a plurality of check spring pieces evenly distributed in the circumferential direction. One end of each check spring piece is connected to the inner wall of the transition joint, and the other end extends axially towards the transition joint.

4. The wellhead backflow material capturing device according to claim 3, wherein The check spring piece includes a rectangular section and a triangular section connected to each other. A plurality of installation grooves evenly distributed in the circumferential direction are provided on the inner wall of the transition joint. The rectangular section of each check spring piece is connected to one of the installation grooves, and the tips of the triangular sections of the plurality of check spring pieces are arranged close to each other.

5. The wellhead backflow material capturing device according to claim 2, wherein, The transition joint includes a third end and a fourth end; The third end is inserted into the first joint and is hermetically connected to the first joint; The fourth end is inserted into the outer cylinder and sleeved outside the screen pipe. The fourth end is hermetically connected to the outer cylinder; The second joint is inserted into the second end of the outer cylinder and is hermetically connected to the second end; The third end of the transition joint is connected to the first joint, the fourth end of the transition joint is connected to the outer cylinder, and the outer cylinder is connected to the second joint through threads and set screws respectively. The fourth end of the transition joint is connected to the screen pipe through threads.

6. The wellhead backflow material capturing device according to claim 1, wherein the aperture of the first flow hole is 3-8 mm, and / or the length of the screen pipe is not less than 350 mm.

7. The wellhead backflow material capturing device according to claim 1, wherein The depth of the groove is 1-3 mm, and the other end of the screen pipe is inserted into the groove.

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