Carbon dioxide flooding injection wellhead device

Abstract

The utility model relates to the technical field of well head devices, in particular to a carbon dioxide flooding injection well head device which comprises a tubing head four-way joint, a coiled tubing anti-falling device, a middle sealing anti-jacking assembly, an upper flange and a Christmas tree assembly. The middle sealing anti-jacking assembly comprises a middle flange and an inner sealing assembly, the inner sealing assembly is fixedly installed in the middle flange, the Christmas tree assembly, the upper flange and the middle flange are sequentially and fixedly installed together from top to bottom, and the lower end of the middle flange and an upper port of the tubing head four-way joint are fixedly installed together. The coiled tubing can be hung and sealed in the wellhead device, the coiled tubing anti-falling device for preventing the coiled tubing from falling and the middle sealing anti-jacking assembly with the function of preventing the coiled tubing from jacking upwards are designed, the coiled tubing can serve as a hanging pipe column of the wellhead device of an injection well, and the injection requirement of gas such as carbon dioxide is met.

Description

Technical Field

[0001] This utility model relates to the field of wellhead device technology, and is a carbon dioxide injection wellhead device. Background Technology

[0002] Carbon capture, utilization, and storage (CCUS) technology, as a key means of reducing CO2 emissions, has applications in industries such as power and chemicals. Domestic oilfield companies have successively conducted pilot tests of CO2 enhanced oil recovery. In existing CO2 enhanced oil recovery technologies, the tubing used for CO2 injection into the wellbore is tubing, gas-tight tubing, etc. CO2, under high-pressure supercritical conditions, is highly corrosive and permeable, easily leading to leaks at tubing thread joints, welds, or weak points, causing CO2 escape. This not only reduces oil recovery efficiency but may also cause safety and environmental problems. Using coiled tubing injection can effectively avoid these problems, but the suspension and sealing of the coiled tubing at the wellhead remains a pressing issue.

[0003] Patent document CN204457557U discloses a dual-tube thermal recovery wellhead device. In this document, a sealing ring is installed inside the inspection hole, and a clamping device is positioned above the sealing ring to press it down. The clamping device is installed inside the inspection hole, and its lower surface is in contact with the upper surface of the sealing ring. This clamping device can compress the sealing ring, reducing the gap between the sealing ring and the guide wire, thereby enhancing the sealing effect. Although this clamping device has a T-shaped structure, it cannot prevent the coiled tubing from pushing up in a high-pressure carbon dioxide environment.

[0004] Patent document CN207905776U discloses a SAGD oil production wellhead device. Under high temperature and high pressure conditions, during continuous service, both the main pipe neck high-pressure resistant seal and the auxiliary pipe neck high-pressure resistant seal of the device can adapt to the conditions. Under these conditions, whether it is the pre-tightening force or the oil and gas reaction force, both the main pipe neck high-pressure resistant seal and the auxiliary pipe neck high-pressure resistant seal can achieve self-pressure sealing function, which can enhance the sealing effect of the installation position of the seal. Although the tubing can be suspended by the tubing hanger, the suspended tubing is not a split structure, which is inconvenient for tubing installation.

[0005] Although the aforementioned literature mentions sealing structures, they are not applicable to the suspension and sealing of coiled tubing in CO2-driven injection wellhead devices. Summary of the Invention

[0006] This invention provides a carbon dioxide injection wellhead device that can effectively solve the problems of suspension and sealing of coiled tubing in carbon dioxide injection wellhead devices.

[0007] The technical solution of this utility model is achieved through the following measures: a carbon dioxide flooding injection wellhead device, including a tubing head four-way connector, a coiled tubing anti-fall device, a central sealing anti-overhead assembly, an upper flange, and a Christmas tree assembly. The coiled tubing anti-fall device is fixedly installed inside the upper port of the tubing head four-way connector. The central sealing anti-overhead assembly includes a central flange and an inner sealing assembly. The inner sealing assembly is fixedly installed inside the central flange. The Christmas tree assembly, the upper flange, and the central flange are fixedly installed together in sequence from top to bottom. The lower end of the central flange is fixedly installed together with the upper port of the tubing head four-way connector. A stepped sealing ring groove is provided inside the central flange. The inner sealing assembly includes a first sealing assembly, a T-shaped sealing assembly locking ring, an inverted T-shaped anti-overhead ring, and an upper locking ring. The inverted T-shaped anti-overhead ring, the T-shaped sealing assembly locking ring, and the first sealing assembly are fixedly installed in the sealing ring groove in sequence from top to bottom. The upper locking ring is fixedly installed between the upper outer side of the inverted T-shaped anti-overhead ring and the sealing ring groove.

[0008] The following are further optimizations and / or improvements to the above-mentioned utility model technical solution:

[0009] Furthermore, the first sealing component includes at least one sealing ring; the lower outer side of the locking ring of the T-shaped sealing component is provided with threads, and the inner side of the sealing ring groove corresponding to the lower outer side of the locking ring of the T-shaped sealing component is provided with threads; the lower outer side of the locking ring of the T-shaped sealing component is fixedly installed in the sealing ring groove by threads; a second sealing component is provided in the sealing ring groove above the threaded section of the lower outer side of the locking ring of the T-shaped sealing component, and the second sealing component includes at least one sealing ring.

[0010] Furthermore, the outer side of the aforementioned upper locking ring is provided with threads, and the inner side of the sealing ring groove corresponding to the outer side of the upper locking ring is provided with threads. The upper locking ring is fixedly installed in the sealing ring groove by the threads, and the inner side of the inverted T-shaped upper locking ring is provided with threads for connecting to the continuous tubing.

[0011] Furthermore, the aforementioned coiled tubing anti-fall device is a split structure, comprising a fixed body and inner slips. The inner slips are placed inside the fixed body. The fixed body includes a left body and a right body, with the right side of the left body and the left side of the right body abutting each other. The left and right bodies are fixed together by fastening bolts. The inner slips include a left slip and a right slip, both with slip teeth on their inner sides. The right side of the left slip and the left side of the right slip abutting each other. The lower parts of both the left and right bodies have rail holes, and each rail hole has a rail screw passing through it. The rail screw is fixedly installed to the lower part of the corresponding inner slip. The left and right bodies are radially fixed with positioning screws that radially pass through the corresponding inner slips. The tops of both the left and right bodies are fixed with clamping bolts, with the bottom of the clamping bolts abutting against the top of the corresponding inner slips.

[0012] Furthermore, a suspension ring platform is provided inside the upper port of the aforementioned oil pipe head four-way, and the fixed body is seated at the suspension ring platform. The top of the fixed body is conical, and at least two set screw sealing mechanisms are fixedly installed at intervals along the circumference at the upper port of the oil pipe head four-way, with the set screw sealing mechanisms abutting against the outer side of the top of the fixed body.

[0013] Furthermore, at least one metal sealing ring is provided between the bottom of the upper flange and the top of the middle flange, and at least one metal sealing ring is provided between the bottom of the middle flange and the upper port of the oil pipe head four-way.

[0014] Furthermore, the aforementioned central flange is provided with at least one radial grease injection groove with an outward opening along the circumference, and a plug is fixedly installed in the radial grease injection groove.

[0015] Furthermore, the aforementioned tree assembly includes an upper four-way valve, with at least one gate valve fixedly installed between the lower port of the upper four-way valve and the upper flange, and at least one gate valve fixedly installed at the upper port, left port, and right port of the upper four-way valve respectively; and at least one gate valve fixedly installed at the left port and right port of the tubing head four-way valve respectively.

[0016] This invention enables the suspension and sealing of coiled tubing in wellhead equipment. It designs a coiled tubing anti-fall device to prevent coiled tubing from falling and a central sealing anti-overhead component to prevent coiled tubing from overshooting, so that coiled tubing can be used as a suspension string for injection wellhead equipment to meet the requirements for gas injection such as carbon dioxide. Attached Figure Description

[0017] Appendix Figure 1 This is a partial sectional view of the main structure of this utility model;

[0018] Appendix Figure 2 for Figure 1 A magnified structural diagram at point A;

[0019] Appendix Figure 3 This is a magnified front half-section view of the coiled tubing anti-fall device.

[0020] Appendix Figure 4 A magnified front sectional view of the locking ring of the T-type sealing assembly;

[0021] Appendix Figure 5 This is a magnified front view sectional diagram of the inverted T-shaped top ring.

[0022] Appendix Figure 6 This is a magnified schematic diagram of the main sectional view of the upper locking ring.

[0023] The codes in the attached diagram are as follows: 1 is the tubing head four-way valve, 2 is the upper flange, 3 is the middle flange, 4 is the sealing ring groove, 5 is the first sealing assembly, 6 is the T-type sealing assembly locking ring, 7 is the inverted T-type anti-top ring, 8 is the top locking ring, 9 is the second sealing assembly, 10 is the grease injection opening groove, 11 is the plug, 12 is the left body, 13 is the right body, 14 is the fastening bolt, 15 is the continuous tubing, 16 is the right slip, 17 is the slip thread, 18 is the track hole, 19 is the track screw, 20 is the positioning screw, 21 is the clamping bolt, 22 is the suspension ring platform, 23 is the set screw sealing mechanism, 24 is the metal sealing ring, 25 is the upper four-way valve, and 26 is the gate valve. Detailed Implementation

[0024] This utility model is not limited to the following embodiments, and the specific implementation method can be determined according to the technical solution of this utility model and the actual situation.

[0025] In this utility model, for ease of description, the description of the relative positions of the components is based on the appendix to the specification. Figure 1 The layout is described using a diagrammatic method, such as the positional relationships of front, back, top, bottom, left, and right, which are based on the instructions attached. Figure 1 The orientation of the layout is determined by the direction of the map.

[0026] In this utility model, it should be noted that the terms "first", "second", etc., are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the components referred to must have a specific order and operation. They are mainly used for distinction and should not be construed as limitations on this utility model.

[0027] The present invention will be further described below with reference to the embodiments and accompanying drawings:

[0028] Example 1: As shown in the attached document Figure 1 , 2 As shown, the carbon dioxide flooding injection wellhead device includes a tubing head tee 1, a coiled tubing anti-fall device, a central sealing anti-overhead assembly, an upper flange 2, and a Christmas tree assembly. The coiled tubing anti-fall device is fixedly installed inside the upper port of the tubing head tee 1. The central sealing anti-overhead assembly includes a central flange 3 and an inner sealing assembly. The inner sealing assembly is fixedly installed inside the central flange 3. The Christmas tree assembly, upper flange 2, and central flange 3 are sequentially fixed together from top to bottom. The lower end of the central flange 3 is fixedly installed together with the upper port of the tubing head tee 1. (See attached diagram) Figure 2 , 4As shown in Figure 5, a stepped sealing ring groove 4 is provided inside the middle flange 3. The inner sealing assembly includes a first sealing assembly 5, a T-shaped sealing assembly locking ring 6, an inverted T-shaped anti-top ring 7, and an upper locking ring 8. The inverted T-shaped anti-top ring 7, the T-shaped sealing assembly locking ring 6, and the first sealing assembly 5 are sequentially fixed in the sealing ring groove 4 from top to bottom. The upper locking ring 8 is fixedly installed between the upper outer side of the inverted T-shaped anti-top ring 7 and the sealing ring groove 4.

[0029] The central sealing anti-top component not only prevents the continuous tubing 15 from rising, but also provides a sealing function.

[0030] The first sealing component 5 can improve the sealing performance between the sealing ring groove 4 and the continuous oil pipe 15. The locking ring 6 of the T-type sealing component presses the first sealing component 5, so that the first sealing component 5 can better perform its sealing function.

[0031] The above-mentioned carbon dioxide flooding injection wellhead device can be further optimized and / or improved according to actual needs:

[0032] Example 2: As an optimization of the above examples, as shown in the appendix Figure 2 , 4 As shown, the first sealing component 5 includes at least one sealing ring; the lower outer side of the T-shaped sealing component locking ring 6 is threaded, and the inner side of the sealing ring groove 4 corresponding to the lower outer side of the T-shaped sealing component locking ring 6 is threaded. The lower outer side of the T-shaped sealing component locking ring 6 is fixedly installed in the sealing ring groove 4 by the threads. A second sealing component 9 is provided in the sealing ring groove 4 above the threaded section of the lower outer side of the T-shaped sealing component locking ring 6. The second sealing component 9 includes at least one sealing ring. The second sealing component 9 serves as an auxiliary seal.

[0033] Example 3: As an optimization of the above embodiments, as shown in the appendix Figure 2 , 6 As shown, the outer side of the upper locking ring 8 is provided with threads, and the inner side of the sealing ring groove 4, which corresponds to the outer side of the upper locking ring 8, is provided with threads. The upper locking ring 8 is fixedly installed in the sealing ring groove 4 by threads. The inner side of the inverted T-shaped upper locking ring 7 is provided with threads for connecting to the continuous tubing 15.

[0034] Because the CO2-driven injection well is under high pressure, the coiled tubing 15 tends to move upwards within the well. This device addresses this by firstly fixing the outer edge of the top of the coiled tubing 15 to the inner edge of the inverted T-shaped anti-overhead ring 7 via threads, thereby enhancing the locking effect on the coiled tubing 15 and preventing it from overshooting; secondly, by further enhancing the locking effect on the coiled tubing 15 through the overshoot locking ring 8, achieving a double locking effect.

[0035] Example 4: As an optimization of the above embodiments, as shown in the appendix. Figure 2As shown, the central flange 3 has at least one radial grease injection groove 10 with an outward opening along its circumference. A plug 11 is fixedly installed in the radial grease injection groove 10. Sealing grease can be injected through the radial grease injection groove 10 to further improve the sealing performance within the sealing ring groove 4.

[0036] Example 5: As an optimization of the above embodiments, as shown in the appendix Figure 2 , 3 As shown, the coiled tubing anti-fall device is a split structure, comprising a fixed body and inner slips. The inner slips are located inside the fixed body. The fixed body includes a left body 12 and a right body 13. The right side of the left body 12 and the left side of the right body 13 are abutted together, and the left body 12 and the right body 13 are fixed together by fastening bolts 14. The inner slips include a left slip and a right slip 16. Both the left slip and the right slip 16 have slip teeth 17 on their inner sides. The right side of the left slip and the right slip 16 are abutted together. The left side of 6 is connected, and the lower part of the left body 12 and the right body 13 are provided with track holes 18. Each track hole 18 is provided with a track screw 19. The track screw 19 is fixedly installed with the lower part of the corresponding inner clasp. The left body 12 and the right body 13 are both radially fixedly installed with positioning screws 20. The positioning screws 20 radially pass through the corresponding inner clasp. The top of the left body 12 and the right body 13 are both fixedly installed with clamping bolts 21. The bottom of the clamping bolts 21 abuts against the top of the corresponding inner clasp.

[0037] The split-type coiled tubing anti-fall device allows for installation before coiled tubing 15 cutting operations. This is achieved by connecting the left body 12, right body 13, and left and right slips 16 to clamp and hold the coiled tubing 15. Tightening the clamping bolts 21 causes the inner slips to retract and secure the coiled tubing 15, thus preventing it from falling.

[0038] First, the coiled tubing 15 is clamped using the left and right slips 16, so that the inner slips provide suspension support for the coiled tubing 15, preventing it from falling and preparing for subsequent cutting of the coiled tubing 15 at the wellhead. After the coiled tubing 15 is cut at the wellhead, the middle flange 3 is fixedly installed on the upper end of the tubing head four-way 1. The first sealing component 5 is first fixedly installed in the sealing ring groove 4 of the middle flange 3. The first sealing component 5 is then pressed tightly using the T-shaped sealing component locking ring 6. After the first sealing component 5 is installed, a threading process is performed on the top end of the coiled tubing 15. After the threading is completed, the top end of the coiled tubing 15 is fixedly installed together with the inverted T-shaped anti-overhead ring 7 by threads. The lower end of the tubing head four-way 1 is fixedly installed at the wellhead device of the injection well. The upper flange 2 and the Christmas tree assembly are then fixedly installed sequentially above the middle flange 3, completing the entire installation of the carbon dioxide injection wellhead device.

[0039] Example 6: As an optimization of the above embodiments, as shown in the appendix Figure 2 As shown, a suspension ring platform 22 is provided inside the upper port of the oil pipe head four-way 1, and the fixed body is seated at the suspension ring platform 22. The top of the fixed body is conical. At least two set screw sealing mechanisms 23 are fixedly installed at the upper port of the oil pipe head four-way 1 along the circumference. The set screw sealing mechanism 23 abuts against the outer side of the top of the fixed body.

[0040] The top screw sealing mechanism 23 has a limiting effect on the fixed body, preventing it from moving upward and making it firmly seated at the suspension ring platform 22, thereby further improving the suspension support effect on the coiled tubing 15.

[0041] The top screw sealing mechanism 23 can be a top screw locking sealing mechanism in the prior art, such as the left or right top screw sealing mechanism described in the patent application document CN204851201U (Patent title: Wellhead connection device and steam injection device and production device).

[0042] Example 7: As an optimization of the above embodiments, as shown in the appendix Figure 2 As shown, at least one metal sealing ring 24 is provided between the bottom of the upper flange 2 and the top of the middle flange 3, and at least one metal sealing ring 24 is provided between the bottom of the middle flange 3 and the upper port of the oil pipe head four-way 1.

[0043] Example 8: As an optimization of the above embodiments, as shown in the appendix Figure 1 As shown, the wellhead assembly includes an upper four-way valve 25. At least one gate valve 26 is fixedly installed between the lower port of the upper four-way valve 25 and the upper flange 2. At least one gate valve 26 is fixedly installed at the upper port, left port, and right port of the upper four-way valve 25, respectively. At least one gate valve 26 is fixedly installed at the left port and right port of the tubing head four-way valve 1, respectively.

[0044] The above technical features constitute various embodiments of this utility model, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

Claims

1. A carbon dioxide flood injection wellhead apparatus, characterized by, The oil pipe head four-way pipe, the continuous oil pipe anti-falling device, the middle part sealing anti-jacking assembly, the upper flange and the oil tree assembly are sequentially fixed and installed together from top to bottom, and the lower end of the middle part flange is fixed and installed together with the upper port of the oil pipe head four-way pipe; the middle part flange is provided with a stepped sealing ring groove, the inner sealing assembly includes a first sealing assembly, a T-shaped sealing assembly locking ring, an inverted T-shaped anti-jacking ring and a jacking locking ring, the inverted T-shaped anti-jacking ring, the T-shaped sealing assembly locking ring and the first sealing assembly are sequentially fixed and installed in the sealing ring groove from top to bottom, and the jacking locking ring is fixed and installed between the outer side of the upper part of the inverted T-shaped anti-jacking ring and the sealing ring groove.

2. The carbon dioxide flood injection wellhead apparatus of claim 1, wherein, The first sealing assembly includes at least one sealing ring; the outer side of the lower part of the T-shaped sealing assembly locking ring is provided with a thread, the inner side of the sealing ring groove corresponding to the inner and outer of the lower part of the T-shaped sealing assembly locking ring is provided with a thread, the outer side of the lower part of the T-shaped sealing assembly locking ring is fixed and installed in the sealing ring groove through the thread, and the second sealing assembly is arranged in the sealing ring groove above the threaded section of the outer side of the lower part of the T-shaped sealing assembly locking ring; the second sealing assembly includes at least one sealing ring; Or / and, the outer side of the jacking locking ring is provided with a thread, the inner side of the sealing ring groove corresponding to the inner and outer of the outer side of the jacking locking ring is provided with a thread, and the jacking locking ring is fixed and installed in the sealing ring groove through the thread; the inner side of the inverted T-shaped anti-jacking ring is provided with a thread for connecting with the continuous oil pipe.

3. The carbon dioxide flood injection wellhead apparatus of claim 1 or 2, wherein, The continuous oil pipe anti-falling device is of a split structure, and includes a fixed body and an inner slip. The inner slip is arranged on the inner side of the fixed body. The fixed body includes a left body and a right body. The right side surface of the left body and the left side surface of the right body are butted, and the left body and the right body are fixed and installed together through fastening bolts. The inner slip includes a left slip and a right slip. The inner sides of the left slip and the right slip are provided with slip teeth. The right side surface of the left slip and the left side surface of the right slip are butted. The lower parts of the left body and the right body are each provided with a track hole. Each track hole is provided with a track screw. The track screw is fixed and installed together with the lower part of the corresponding inner slip. The left body and the right body are each fixed and installed with a positioning screw in the radial direction. The positioning screw passes through the corresponding inner slip in the radial direction. The top parts of the left body and the right body are each fixed and installed with a pressing bolt. The bottom part of the pressing bolt abuts against the top part of the corresponding inner slip.

4. The carbon dioxide flood injection wellhead apparatus of claim 3, wherein, The upper port of the oil pipe head four-way pipe is provided with a hanging ring table. The fixed body is arranged at the hanging ring table. The top part of the fixed body is conical. At least two jacking thread sealing mechanisms are fixed and installed at the upper port of the oil pipe head four-way pipe along the circumference at intervals. The jacking thread sealing mechanisms abut against the outer side of the top part of the fixed body.

5. The carbon dioxide flood injection wellhead apparatus of claims 1 or 2 or 4, wherein, At least one metal sealing ring is arranged between the bottom part of the upper flange and the top part of the middle part flange. At least one metal sealing ring is arranged between the bottom part of the middle part flange and the upper port of the oil pipe head four-way pipe.

6. The carbon dioxide flood injection wellhead apparatus of claim 3, wherein, At least one metal sealing ring is arranged between the bottom part of the upper flange and the top part of the middle part flange. At least one metal sealing ring is arranged between the bottom part of the middle part flange and the upper port of the oil pipe head four-way pipe.

7. The carbon dioxide flood injection wellhead apparatus of claims 1 or 2 or 4 or 6, wherein, The middle flange is radially provided with at least one radially outwardly opening grease injection slot, and a plug is fixedly installed in the radially outwardly opening grease injection slot; Or / and, the Christmas tree assembly comprises an upper cross, at least one gate valve is fixedly installed between the lower port of the upper cross and the upper flange, and at least one gate valve is fixedly installed on the upper port, the left port and the right port of the upper cross respectively; at least one gate valve is fixedly installed on the left port and the right port of the tubing head cross respectively.

8. The carbon dioxide flood injection wellhead apparatus of claim 3, wherein, The middle flange is radially provided with at least one radially outwardly opening grease injection slot, and a plug is fixedly installed in the radially outwardly opening grease injection slot; Or / and, the Christmas tree assembly comprises an upper cross, at least one gate valve is fixedly installed between the lower port of the upper cross and the upper flange, and at least one gate valve is fixedly installed on the upper port, the left port and the right port of the upper cross respectively; at least one gate valve is fixedly installed on the left port and the right port of the tubing head cross respectively.

9. The carbon dioxide flood injection wellhead apparatus of claim 5, wherein, The middle flange is radially provided with at least one radially outwardly opening grease injection slot, and a plug is fixedly installed in the radially outwardly opening grease injection slot; Or / and, the Christmas tree assembly comprises an upper cross, at least one gate valve is fixedly installed between the lower port of the upper cross and the upper flange, and at least one gate valve is fixedly installed on the upper port, the left port and the right port of the upper cross respectively; at least one gate valve is fixedly installed on the left port and the right port of the tubing head cross respectively.

Images