Casing head for 140MPa

Abstract

The utility model discloses a 140MPa casing head, which belongs to the technical field of oil and gas exploitation wellhead equipment and comprises a main body, the upper portion of the main body is provided with a top connecting end, the lower portion of the main body is provided with a bottom connecting end, the top connecting end is connected with an adapter flange, and the adapter flange is detachably connected with the top connecting end. The main body is provided with a through hole penetrating in the axial direction, and first connecting holes distributed in the circumferential direction of the through hole are formed in the top connecting end; a jackscrew hole does not need to be machined at the top connecting end of the casing head body, and potential safety hazards such as leakage at the jackscrew position after well completion are completely eradicated. The main body is detachably connected with the adapter flange, the first flange is adopted in the well drilling stage, the second flange is adopted in the well completion stage, replacement can be carried out according to use requirements, different working requirements are met through different adapter flanges, and therefore the adapter flange can be suitable for different working environments.

Description

Technical Field

[0001] This utility model belongs to the technical field of oil and gas wellhead equipment, specifically relating to a casing head for 140MPa. Background Technology

[0002] The casing head is a fundamental component of the wellhead assembly, comprising the casing head body, hanger, packing system, set screw, gate valve, and pressure gauge. The casing head seals the annular space between the casing and tubing, effectively preventing formation fluid cross-contamination and providing a safe and reliable environment for downhole operations. Furthermore, the casing head provides a transitional connection for installing critical equipment such as blowout preventers, tubing heads, and Christmas trees, allowing these devices to be seamlessly integrated into the wellhead assembly. A casing head with excellent sealing performance effectively prevents oil and gas leakage, ensures the safety of wellhead operations, protects the surrounding environment, and guarantees the smooth operation of oil and gas production.

[0003] The existing casing head structure features radially arranged set screw holes at the flange connecting to the top equipment. The installation of these set screws further enhances the strength and stability of the connection. Under normal operating conditions, this design meets the needs of most wellhead operations. However, during actual application, special circumstances arose during the testing of some high-pressure gas wells in the Kuqa piedmont block. The shut-in oil pressure exceeded the casing head's rated operating pressure of 105 MPa, even reaching a maximum of 115 MPa. Under such high pressure, if a leak occurs in the tubing, the previously used casing head with a rated operating pressure of 105 MPa will not be able to guarantee a good seal. Because the pressure exceeds its design tolerance, the casing head's sealing structure may be damaged, leading to oil and gas leakage, thus failing to meet the shut-in requirements under full-well gas conditions. This not only poses a serious threat to the safety of wellhead operations but may also cause a series of problems such as environmental pollution.

[0004] Therefore, there is an urgent need for a sleeve head that can meet the requirements of higher pressure environments. Utility Model Content

[0005] The purpose of this utility model is to provide a bushing head for 140MPa, which, through the structure of a detachable adapter flange, enables the bushing head to achieve a screwless structure after installation, further improving the sealing performance of the bushing head when connected to other equipment. This overcomes the shortcomings of existing technologies that cannot withstand higher pressure working environments, which can damage the sealing structure of the bushing head and lead to oil and gas leakage.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] A bushing head for 140MPa includes a body, a top connecting end at the upper part of the body, a bottom connecting end at the lower part of the body, and an adapter flange connected to the top connecting end, the adapter flange being detachably connected to the top connecting end; the body has a through hole extending axially, and the top connecting end has a first connecting hole distributed circumferentially along the through hole.

[0008] Furthermore, the adapter flange is a first flange, which is annular. The inner diameter of the first flange is the same as the through hole diameter of the main body. The first flange includes multiple second connecting holes that extend axially. Each second connecting hole corresponds to a first connecting hole. The top connecting end and the first flange are fixed by connecting parts that pass through the second connecting holes and the first connecting holes in sequence. The first flange is a top screw flange, which is used to connect to the top connecting end of the main body during the drilling stage.

[0009] Furthermore, the transition flange is a second flange, which is annular. The inner diameter of the second flange is the same as the through hole diameter of the main body. The second flange includes multiple third connecting holes that extend axially. Each third connecting hole corresponds to a first connecting hole. The top connecting end and the second flange are fixed by connecting parts that pass through the third connecting holes and the first connecting holes in sequence. The second flange is a sealing transition flange used to connect to the top connecting end of the main body during the well completion stage.

[0010] Furthermore, a first sealing groove is provided on the surface where the first flange connects to the top connection end, and a first sealing element is embedded in the first sealing groove.

[0011] Furthermore, the cross-section of the first sealing groove is an inverted trapezoid, V-shape, U-shape, rectangle, or semi-circle.

[0012] Furthermore, the first flange has a plurality of set screw holes that are radially through it, the set screw holes being distributed circumferentially and each being connected to a set screw.

[0013] Furthermore, the surface where the second flange connects to the top connection end is provided with a second sealing groove, and a second sealing element is embedded in the second sealing groove; the inner wall of the second flange is provided with a plurality of third sealing grooves, and each third sealing groove is embedded with a third sealing element.

[0014] Furthermore, the cross-section of the second sealing groove is an inverted trapezoid, V-shape, U-shape, rectangle, or semi-circle.

[0015] Furthermore, the second flange is provided with multiple pressure relief holes, which are connected to the third sealing groove, and plugs are provided inside the pressure relief holes.

[0016] Furthermore, both the top connecting end 2 and the bottom connecting end 3 are provided with cylindrical flange structures for connecting and fixing with other equipment, such as drilling equipment, hangers, etc., to ensure the performance requirements of connection strength.

[0017] Compared with the prior art, the present invention has the following beneficial technical effects:

[0018] This utility model provides a casing head for 140MPa, with a detachable connection between the main body and the transition flange. During the drilling phase, a first flange, which is a top-screw flange, is used to fix the anti-wear sleeve. After drilling at this layer is completed, the top-screw flange can be removed along with the drilling jack for the next operation. Fixing the anti-wear sleeve and other equipment via the top-screw flange ensures smooth drilling operations. Furthermore, after removing the top-screw flange, the top connection end of the casing head body has no top-screw hole, thus improving the sealing performance of the casing head body. During the well completion phase, a second flange, a sealing transition flange, is used to compress and activate the seal on the upper part of the mandrel-type hanger, thereby improving wellhead integrity for the long-term production phase and meeting the requirements of higher pressure working environments.

[0019] This invention eliminates the need to machine a set screw hole at the top connection end of the casing head body, thus preventing safety hazards such as leakage at the set screw after well completion. The main body and the transition flange are detachably connected. A first flange is used during the drilling stage, and a second flange is used during the well completion stage. This allows for replacement according to usage requirements. Different transition flanges can meet different working needs, making it suitable for various working environments. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of a 140MPa bushing head according to an embodiment of the present invention.

[0021] Figure 2 This is a schematic diagram of the structure of a first flange for a 140MPa bushing head in an embodiment of the present invention.

[0022] Figure 3 This is a schematic diagram of the structure of a second flange for a 140MPa bushing head in an embodiment of the present invention.

[0023] In the diagram, 1. Main body; 2. Top connecting end; 3. Bottom connecting end; 4. First flange; 5. Second flange; 6. First sealing groove; 7. Top screw hole; 8. Top screw; 9. Second connecting hole; 10. Third connecting hole; 11. Second sealing groove; 12. Third sealing groove; 13. Pressure relief hole; 14. Plug; 15. Connecting piece. Detailed Implementation

[0024] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0025] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the utility model described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0026] Example 1

[0027] See Figure 1 A bushing head for 140MPa includes a body 1, a top connecting end 2 at the upper part of the body 1, a bottom connecting end 3 at the lower part of the body 1, and an adapter flange connected to the top connecting end 2, the adapter flange being detachably connected to the top connecting end 2; the body 1 has a through hole extending axially, and the top connecting end 2 has first connecting holes distributed circumferentially along the through hole.

[0028] The sleeve head provided in this embodiment has a detachable adapter flange on the top connecting end 2 that can be replaced according to usage requirements. Different adapter flanges can meet different working requirements, thus making it suitable for different working environments.

[0029] Example 2

[0030] See Figures 1 to 2 Based on Embodiment 1, the adapter flange is a first flange 4, which is annular and includes multiple second connecting holes 9 that extend axially. Each second connecting hole 9 corresponds to a first connecting hole. The top connecting end 2 and the first flange 4 are fixed by the connector 15 passing through the second connecting hole 9 and the first connecting hole in sequence.

[0031] The first flange 4 is a top-screw flange, which can be used in the drilling stage. The surface of the first flange 4 that connects to the top connecting end 2 is provided with a first sealing groove 6. The first sealing groove 6 is embedded with a first sealing element. The cross-section of the first sealing groove 6 is an inverted trapezoid, V-shaped, U-shaped, rectangular, or semi-circular. The first sealing groove 6 is an annular structure surrounding the through hole. The first sealing element can be made of high-performance sealing material, such as a sealing ring with good pressure resistance. Part of the first sealing element is embedded in the first sealing groove 6. When the first flange 4 is fixed to the body 1 by the connector 15, the first sealing element is deformed under pressure, thereby maintaining a seal between the first flange 4 and the body 1. Furthermore, the first flange 4 can achieve a sealed connection with other supporting equipment connected to its top through the first sealing groove 6 and the first sealing element.

[0032] The first flange 4 has a plurality of radially penetrating set screw holes 7, which are circumferentially distributed and each connected to a set screw 8. The first flange 4 is also connected to a fixing member for securing the set screws. One end of the fixing member is inserted into the set screw hole 7, and the other end is located outside the first flange 4. One end of the set screw 8 passes through the fixing member and the set screw hole 7, extending into the interior of the first flange 4 and threadedly connected to the fixing member. The other end of the set screw 8 protrudes outside the fixing member for easy operation. There are multiple set screws 8; the specific number can be determined according to actual needs, for example, four. The insertion length of the set screw 8 can be adjusted to regulate the force exerted on the equipment passing through the set screw flange. The portion of the fixing member located inside the set screw hole 7 can be connected to a sealing element, such as a rubber sleeve, fitted onto the set screw 8 to maintain a seal at the set screw hole 7.

[0033] The casing head provided in this embodiment of the present invention uses a detachable adapter flange. During the drilling stage, a first flange 4, namely a top-screw flange, is used to fix the anti-wear sleeve. After the drilling operation of this layer is completed, the top-screw flange is removed together with the drilling cross-connector for the next operation. Fixing the anti-wear sleeve and other equipment with the top-screw flange can ensure the smooth progress of the drilling operation. At the same time, the top connecting end 2 of the body 1 after removing the top-screw flange does not have a top-screw hole 7, thereby improving the sealing performance of the casing head body.

[0034] The casing head provided in the embodiment of this utility model is connected to the supporting equipment through a detachable adapter flange, and the main body 1 does not need to be additionally processed with the top screw hole 7. In addition to eliminating safety hazards such as leakage at the top screw after well completion, it can also simplify the manufacturing process and reduce production costs.

[0035] The casing head provided in the embodiment of this utility model has a cylindrical flange structure on both the top connecting end 2 and the bottom connecting end 3 for connecting and fixing with other equipment, such as drilling equipment, hangers, etc., to ensure the performance requirements of connection strength.

[0036] Example 3

[0037] See Figure 1 , Figure 3 Based on Embodiment 1, the transition flange is a second flange 5, which is annular and includes multiple axially penetrating third connecting holes 10. Each third connecting hole 10 corresponds to a first connecting hole. The top connecting end 2 and the second flange 5 are fixed by connecting members 15 passing through the third connecting holes 10 and the first connecting holes in sequence. The second flange 5 is a sealing transition flange, which can be a P-type sealing transition flange.

[0038] The surface of the second flange 5 connected to the top connecting end 2 is provided with a second sealing groove 11, and a second sealing element is embedded in the second sealing groove 11. The cross-section of the second sealing groove 11 is an inverted trapezoid, V-shaped, U-shaped, rectangular, or semi-circular. The second sealing groove 11 is an annular structure surrounding the through hole. The second sealing element can be made of high-performance sealing material, such as a sealing ring with good pressure resistance. Part of the second sealing element is embedded in the second sealing groove 11. When the second flange 5 and the body 1 are fixed by the connector 15, the second sealing element is deformed under pressure, thereby maintaining a seal between the second flange 5 and the body 1. Furthermore, the second flange 5 can achieve a sealed connection with other supporting equipment connected to its top through the second sealing groove 11 and the second sealing element.

[0039] The inner wall of the second flange 5 is provided with a plurality of third sealing grooves 12, each of which is embedded with a third sealing element; a portion of each third sealing element is embedded in a third sealing groove 12. The third sealing groove 12 is an annular structure embedded circumferentially in the inner wall of the through hole. The third sealing element can be made of high-performance sealing material, such as a sealing ring with good pressure resistance. The portion of the third sealing element is embedded in the third sealing groove 12 to seal the supporting equipment passing through the second flange 5, such as a spindle-type hanger. For example, the upper part of the spindle-type hanger is pressed against the inner wall of the second flange 5, causing the third sealing element to be deformed under pressure, thereby forming a seal between the second flange 5 and the supporting equipment.

[0040] The second flange 5 is provided with a plurality of pressure relief holes 13, which are connected to the third sealing groove 12. A plug 14 is provided in the pressure relief hole 13. One end of the plug 14 is connected from the outside of the second flange 5 to the pressure relief hole 13 for unsealing during disassembly.

[0041] In this embodiment of the invention, the connector 15 can be a bolt, and a nut for connecting to the connector 15 is provided on the side of the top connecting end 2 facing away from the first flange 4 or the second flange 5. The nut can be fixed integrally with the top fixing end 2, or it can be independent of the top fixing end 2. Fixing the first flange 4 or the second flange 5 to the top connecting end 2 of the main body 1 with bolts can ensure connection strength and also facilitate disassembly, making it convenient to remove the first flange 4 or the second flange 5 later.

[0042] An embodiment of this utility model also provides a wellhead device, including the aforementioned casing head; the wellhead device provided by this utility model has good sealing performance and can meet the working requirements of 140MPa.

[0043] The casing head provided in this embodiment of the utility model can meet the application requirements of different scenarios through a detachable adapter flange. During the drilling stage, a top screw flange can be used in conjunction with the installation of supporting equipment. During the well completion stage, a sealing conversion flange can be used in conjunction with the installation and sealing of supporting equipment. The main body 1 of the casing head does not require additional machining of the top screw hole 7, thereby meeting the requirements of high sealing performance. Therefore, it can be used in higher pressure working environments, and the pressure rating can meet the working requirements of 140MPa.

[0044] In the description of this specification, references to terms such as "some embodiments," "optionally," "furthermore," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

Claims

1. A casing head for 140MPa, characterized in that, The system includes a main body (1), a top connecting end (2) on the upper part of the main body (1), a bottom connecting end (3) on the lower part of the main body (1), and a transition flange connected to the top connecting end (2), which is detachably connected to the top connecting end (2); the main body (1) has a through hole that extends along the axial direction, and the top connecting end (2) has a first connecting hole distributed circumferentially along the through hole; The transition flange is a first flange (4), which is annular. The first flange (4) includes multiple second connecting holes (9) that pass through along the axial direction. Each second connecting hole (9) corresponds to a first connecting hole. The top connecting end (2) and the first flange (4) are fixed by the connector (15) passing through the second connecting hole (9) and the first connecting hole in sequence. The transition flange is a second flange (5), which is annular. The second flange (5) includes multiple third connecting holes (10) that pass through along the axial direction. Each third connecting hole (10) corresponds to a first connecting hole. The top connecting end (2) and the second flange (5) are fixed by the connector (15) passing through the third connecting hole (10) and the first connecting hole in sequence. The second flange (5) is provided with a second sealing groove (11) on the surface where it connects to the top connection end (2), and a second sealing element is embedded in the second sealing groove (11); a plurality of third sealing grooves (12) are provided on the inner wall of the second flange (5), and a third sealing element is embedded in each third sealing groove (12).

2. The bushing head for 140MPa according to claim 1, characterized in that, The surface of the first flange (4) connected to the top connection end (2) is provided with a first sealing groove (6), and a first sealing element is embedded in the first sealing groove (6).

3. A casing head for 140MPa according to claim 2, characterized in that, The first flange (4) has a plurality of set screw holes (7) arranged radially through it. The set screw holes (7) are distributed circumferentially and are all connected to set screws (8).

4. A casing head for 140MPa according to claim 2, characterized in that, The second flange (5) is provided with multiple pressure relief holes (13), which are connected to the third sealing groove (12), and a plug (14) is provided in the pressure relief hole (13).

5. A casing head for 140MPa according to claim 1, characterized in that, Both the top connecting end (2) and the bottom connecting end (3) are provided with cylindrical flange structures.

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