A composite wellhead fixing structure

Abstract

The present application discloses a composite wellhead structure, including a tubing head, a casing head, a tubing hanger, a rod sealer and a rotating flange; wherein the tubing head is arranged above the casing head, and the tubing hanger is arranged in the casing head; the tubing head includes an upper end portion of the tubing head and a lower end portion of the tubing head, the casing head includes an upper end portion of the casing head, and the tubing hanger includes an upper end portion of the tubing hanger and a lower end portion of the tubing hanger; the upper end portion of the tubing hanger is connected to the rod sealer through a rotating flange; the lower end portion of the tubing hanger is connected to the upper end portion of the tubing head through a locking mechanism; and the lower end portion of the tubing head is connected to the upper end portion of the casing head through a ball buckle. The composite wellhead structure simplifies the wellhead structure through an optimized design, saves materials, is more convenient to assemble, and realizes quick connection, thereby improving production efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of wellhead related equipment, in particular to a composite wellhead fixing structure. Background Art

[0002] When extracting oil or coalbed methane at the wellhead, it is necessary to connect the oil pipe made of steel pipe to the inside of the wellhead, pump the water inside the wellhead up through external devices, and control the size of the water flow through the pressure gate and water valve.

[0003] Today's composite fixed wellheads are assembled by connecting various components through bolts and flanges. When components of different sizes are assembled, flanges of different sizes are selected to connect the components to complete the assembly of the composite fixed wellhead.

[0004] Although there are many types and quantities of composite fixed wellheads on the market, most of them have the following disadvantages: when assembling and connecting, the composite fixed wellheads are connected by flanges, and the sealing rings are easy to fall off when the device is assembled. Moreover, the flange connection occupies more space, and the device may have the problem that the core shaft production casing suspension cannot be lowered to the designed depth. Therefore, the current composite fixed wellheads need to be improved.

[0005] Therefore, there is an urgent need in the art to develop a new composite wellhead fixing structure to solve the above-mentioned drawbacks of the existing wellheads. Summary of the invention

[0006] The object of the present invention is to provide a composite locking wellhead structure to solve the problem raised in the above background technology that the composite locking wellheads currently on the market are all connected by flanges during assembly and connection, and the sealing ring is easy to fall off when the device is assembled, and the flange is used to connect, which occupies more space, and the device will have a core shaft production casing suspension that cannot be lowered to the designed depth.

[0007] The present invention provides a composite wellhead fixing structure, comprising a tubing head, a casing head, a tubing hanger, a polished rod sealer and a rotary flange; wherein the tubing head is arranged above the casing head, and the tubing hanger is arranged in the casing head;

[0008] The tubing head comprises an upper end portion and a lower end portion of the tubing head, the casing head comprises an upper end portion of the casing head, and the tubing hanger comprises an upper end portion and a lower end portion of the tubing hanger;

[0009] The upper end portion of the tubing hanger is connected to the polished rod sealer via a rotating flange;

[0010] The lower end portion of the tubing hanger is connected to the upper end portion of the tubing head through a locking mechanism;

[0011] The locking mechanism comprises a first step arranged at the lower end portion of the tubing hanger, the first step is symmetrically milled off at a first angle, a first annular groove matching the first step is arranged on the inner circumference of the upper end portion of the tubing head, the lower end surface of the first annular groove is symmetrically milled off at a second angle, when the lower end portion of the tubing hanger is connected to the upper end portion of the tubing head, the remaining first step portion of the lower end portion of the tubing hanger corresponds to the lower end surface of the milled off first annular groove, so that when the tubing hanger is rotated 90 degrees, the tubing hanger is locked in the tubing head;

[0012] In addition, the lower end portion of the tubing head is connected to the upper end portion of the casing head by means of a ball buckle.

[0013] In another preferred embodiment, a first angle of symmetrical milling of the first step is 95°, and a second angle of symmetrical milling of the lower end surface of the first annular groove is 95°.

[0014] In another preferred example, the composite locking wellhead further comprises an anti-loosening cover, which is connected to the upper end portion of the tubing head and the tubing hanger via a nut to prevent the tubing hanger from rotating.

[0015] In another preferred example, the lower end portion of the tubing head is inserted into the upper end portion of the casing head, the outer cylindrical surface of the upper end portion of the casing head is connected to the inner cylindrical surface of the lower end portion of the tubing head by sealing, and the outer cylindrical surface of the upper end portion of the casing head is provided with a second step, the lower end portion of the tubing head comprises a lower end body, a recessed screw, a connecting piece, a plurality of balls and a locking screw, the connecting piece is connected to the lower end of the lower end body of the tubing head, the inner cylindrical surface of the lower end body and the connecting piece in cooperation with each other is provided with an annular groove 1, an annular groove 2 is provided at a position corresponding to the annular groove 1 on the outer cylindrical surface of the connecting piece, a threaded hole is provided at a position corresponding to the annular groove 1 on the outer cylindrical surface of the lower end body, the plurality of balls are poured into the circular groove formed by the annular groove 1 and the annular groove 2 through the threaded hole, the recessed screw is used to block the threaded hole, the lower end body of the tubing head and the connecting piece rotate around the axis through the balls, and the lower part of the connecting piece is connected to the second step of the upper end portion of the casing head as a whole through the locking screw.

[0016] In another preferred example, a positioning countersunk hole is disposed on the outer circumferential surface of the second step of the upper end portion of the casing head, and the positioning countersunk hole is cooperatively connected with a locking screw.

[0017] In another preferred example, a second annular groove corresponding to the second step is provided on the inner periphery of the connecting member.

[0018] In another preferred embodiment, the second annular groove is provided with a countersunk threaded hole, and when the lower end portion of the tubing head and the upper end portion of the casing head are axially installed, the locking screw is inserted into the countersunk threaded hole and the positioning countersunk hole on the second step.

[0019] In another preferred embodiment, a limit block is provided in the second annular groove, and the limit block is used to stop the rotation of the connecting piece when the locking screw is aligned with the positioning countersunk hole on the second step of the upper end part of the casing head.

[0020] In another preferred embodiment, the second step, the positioning countersunk hole, the countersunk threaded hole, and the locking screw are all provided with two, and the two positioning countersunk holes are symmetrically arranged.

[0021] In another preferred example, a sealing ring groove is provided on the outer circumferential surface of the upper end portion of the casing head, a sealing ring is provided in the sealing ring groove, the outer circumferential surface of the upper end portion of the casing head is sealed and connected to the inner circumferential surface of the lower end portion of the tubing head through the sealing ring, and the second step is provided above the sealing ring groove.

[0022] In another preferred example, the composite locking structure also includes an emergency slip hanger and an emergency sealing bushing.

[0023] In another preferred example, the upper interface of the oil pipe head is connected to the oil production tool by means of a ball buckle. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is the general assembly drawing of the composite fixed wellhead structure of the present application;

[0025] Figure 2 It is a partial enlarged view of the lower end of the tubing head and the upper end of the casing head of the present application;

[0026] Figure 3 It is a schematic cross-sectional structure diagram of the connection between the lower end of the tubing head and the upper end of the casing head of the present application;

[0027] Figure 4 It is a structural schematic diagram of the lower end of the tubing head of the present application;

[0028] Figure 5 yes Figure 4 A-direction view;

[0029] Figure 6 This is a schematic diagram of the upper end structure of the casing head of the present application;

[0030] Figure 7 yes Figure 6 A top view of

[0031] Figure 8 It is a partial enlarged view of the locking mechanism at the upper end of the tubing head of the present application.

[0032] In each of the accompanying drawings, the symbols are as follows:

[0033] 1-Tubing head

[0034] 11-Upper part of the tubing head

[0035] 12-Lower end of tubing head

[0036] 121-lower end of tubing head

[0037] 122-socket head screw

[0038] 123-Connectors

[0039] 124-Ball

[0040] 125-Locking screw

[0041] 126-Limiting block

[0042] 2-Casing head

[0043] 21-Upper end of casing head

[0044] 211-Second Step

[0045] 212-Seal ring groove

[0046] 213-Seal ring

[0047] 3-Tubing hanger

[0048] 321-First Step

[0049] 322-first annular groove

[0050] 4- Bare Rod Sealer

[0051] 5-Swivel flange

[0052] 6- Anti-loosening cover

[0053] 7-Slip Hanger

[0054] 8-Emergency sealing core DETAILED DESCRIPTION

[0055] Through extensive and in-depth research, the inventors have developed for the first time a composite fixed wellhead structure, in which the tubing hanger is locked in the tubing head by a locking mechanism, the tubing head and the casing head are connected by a "ball buckle method", the upper interface of the tubing head and the oil production tool are also connected by a "ball buckle method", and the tubing hanger is connected to the upper end structure by a flange, which not only improves the installation efficiency but also simplifies the wellhead structure.

[0056] In the following description, many technical details are provided to help readers better understand the present application. However, those skilled in the art can understand that the technical solution claimed in the present application can be implemented even without these technical details and various changes and modifications based on the following embodiments.

[0057] The terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not expressly listed, or also includes elements inherent to such process, method, article, or apparatus.

[0058] As used herein, "tubing head" and "tubing head body" are used interchangeably.

[0059] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0060] Reference Figure 1 As shown, the composite wellhead fixing structure includes a tubing head 1, a casing head 2, a tubing hanger 3, a polished rod sealer 4, a rotating flange 5, an anti-loosening cover 6, an emergency slip hanger 7 and an emergency bushing 8.

[0061] The polished rod sealer 4 is arranged above the tubing head 1, the tubing head 1 is arranged above the casing head 2, and the tubing hanger 3 is arranged inside the tubing head 1. The tubing head 1 includes an upper tubing head portion 11 and a lower tubing head portion 12, and the tubing hanger 3 includes an upper tubing hanger portion 31 and a lower tubing hanger portion 32.

[0062] (a) The upper end portion 31 of the tubing hanger 3 is connected to the rod sealer 4 through the rotating flange 5, which plays the role of the flange on the tubing head, simplifying the wellhead structure; different from the flange connection on the traditional tubing head (the flange on the traditional tubing head is connected to the tubing head body, and its function is to seal the pressure on the upper end of the tubing head body, seal the tubing hanger, and then connect the rod sealer), in this embodiment, the rotating flange 5 on the tubing hanger plays the role of the flange on the traditional tubing head, saving materials. Compared with the traditional tubing head structure: there are fewer parts such as the flange, bolts, nuts, and sealing steel rings on the tubing head, and it saves materials compared to the traditional structure, and is easy to install / disassemble / maintain, and labor-saving.

[0063] (b) The upper end portion 11 of the tubing head is connected to the lower end portion 32 of the tubing hanger by a locking mechanism

[0064] refer to Figure 7 The locking mechanism includes a first step 321 arranged on the outer circumferential surface of the lower end portion 32 of the tubing hanger, wherein the first step 321 is symmetrically milled off by 95°, and a first annular groove 322 which is matched and connected with the first step 321 is provided on the inner circumference of the upper end portion 11 of the tubing head, and the lower end surface of the first annular groove 322 is symmetrically milled off by 95°. When the tubing hanger 3 is connected to the upper end portion 11 of the tubing head, the first step 321 of the tubing hanger 3 is inserted into the first annular groove 322 of the upper end portion of the tubing head. Specifically, the remaining part of the first step 321 of the tubing hanger 3 corresponds to the milled-off part of the lower end surface of the first annular groove 322 of the upper end portion 11 of the tubing head. After axial installation in place, the tubing hanger 3 is then rotated 90° to lock the tubing hanger and the tubing head together. Accordingly, this locking mechanism connection only needs to be rotated 90° to remove the tubing hanger 3, which replaces the traditional use of a top screw to lock the tubing hanger, and is easy to operate.

[0065] In other words, the locking mechanism works like Figures 3 to 6 The design principle is similar to that of the tubing head body, which has an annular groove designed in it and a part of it is machined off. A raised ring is designed on the outer circle of the tubing hanger, and a part of it is machined off. During installation, the remaining raised ring part on the tubing hanger corresponds to the machined part of the annular groove designed in the tubing head body. The tubing hanger is installed into the tubing head body, and the tubing hanger is rotated 90 degrees, and the tubing hanger and the tubing head are locked together without the need for screws / bolts and other fixation. Reduce fluid leakage. (In actual situations, the tubing hanger or the tubing head body is rotated)

[0066] In this embodiment, the anti-loosening cover 6 is connected to the upper end part 11 of the tubing head through a nut and is stuck on the outer cylindrical surface of the upper end part 11 of the tubing head. At the same time, the anti-loosening cover 6 is also connected to the tubing hanger 3 through a nut. The function of the anti-loosening cover 6 is to prevent the tubing hanger from rotating and disengaging from the meshing part of the tubing head body due to the impact and vibration of the fluid in the well (it will disengage if rotated 90°), that is, it is a locking mechanism anti-rotation device, and it also protects against the entry of foreign matter such as dust.

[0067] (c) The lower end portion 12 of the tubing head 1 is connected to the upper end portion 21 of the casing head by means of a ball buckle

[0068] As shown in Figure 2 to Figure 6 As shown, the tubing head lower end portion (12) is connected to the casing head upper end portion (21) by means of a ball buckle, the tubing head lower end portion 12 is inserted into the casing head upper end portion 21, and the outer circumferential surface of the casing head upper end portion 21 is sealedly connected to the inner circumferential surface of the tubing head lower end portion 12;

[0069] The outer circumferential surface of the upper end portion 21 of the casing head is provided with a second step 211, the lower end portion 12 of the tubing head includes a lower end body 121, a socket head screw 122, a connecting piece 123, a plurality of balls 124 and a locking screw 125, the lower end portion 12 of the tubing head 1 and the upper end portion 21 of the casing head are connected by the connecting piece 123, the connecting piece 123 is connected to the lower end of the lower end body 121 of the tubing head, the inner circumferential surface of the lower end body 121 of the tubing head and the connecting piece 123 is provided with an annular groove 1 with a hemispherical cross section, and the outer circumferential surface of the connecting piece 123 corresponds to the annular groove 1. A second annular groove with a hemispherical cross section is provided at the location where the lower end body 121 of the tubing head is located, and a threaded hole is provided at a position corresponding to the first annular groove on the outer circumferential surface of the lower end body 121 of the tubing head. After the lower end body 121 of the tubing head 1 and the connecting piece 123 are axially assembled in place, a number of balls 124 are poured into the circular groove formed by the first annular groove and the second annular groove through the threaded hole. After the balls are filled, a recessed screw 122 is sealed at the threaded hole, thereby realizing the connection between the lower end body 121 of the tubing head and the connecting piece 123, and the connection can be rotated smoothly around the axis at will; in this embodiment, there are two recessed screws and several balls. The lower part of the connecting piece 123 is installed as a whole with the second step 211 of the upper end part 21 of the casing head through a locking screw 125. Preferably, there are two locking screws 125.

[0070] The second step 211 of the upper end portion 21 of the casing head is symmetrically milled off by 95°, and two symmetrical positioning countersunk holes are provided on the remaining outer cylindrical surface of the second step, and the positioning countersunk holes are connected with the locking screw 125: the inner circumference of the connecting piece 123 is provided with a second annular groove connected with the second step 211, and the lower end surface of the second annular groove is symmetrically milled off by 95°, and two countersunk threaded holes are designed to be symmetrically arranged in the center of the second annular groove, and the locking screw 125 is also installed in the countersunk threaded hole. The connecting piece 123 and the second step 211 are installed as a whole through the countersunk threaded hole and the locking screw 125; preferably, the second step 211, the positioning countersunk hole, and the countersunk threaded hole are each provided with two, and the two positioning countersunk holes are symmetrically arranged. A limiting block 126 is provided in the second annular groove of the lower end portion 12 of the tubing head, and the limiting block 126 is used to stop the lower end portion 12 of the tubing head 1 from rotating when the locking screw 125 is aligned with the positioning countersunk hole on the upper end portion 21 of the casing head.

[0071] The outer circumferential surface of the upper end portion 21 of the casing head is provided with a sealing ring groove 212, which is arranged above the second step 211. A sealing ring 213 is installed in the sealing ring groove 212. The outer circumferential surface of the upper end portion 21 of the casing head is sealed and connected to the inner circumferential surface of the lower end portion 12 of the tubing head 1 through the sealing ring 213.

[0072] When connecting the lower end portion 12 of the tubing head 1 with the upper end portion 21 of the casing head, install a sealing ring in the sealing groove of the upper end portion 21 of the casing head, and the direction of the locking screw installed on the lower end portion 12 of the tubing head 1 corresponds to the part of the second step 211 milled off from the upper end portion 21 of the casing head. Insert the lower end portion 12 of the tubing head 1 into the upper end portion 21 of the casing head. After the lower end portion 12 of the tubing head 1 and the upper end portion 21 of the casing head are axially installed in place, grasp the two locking screws with both hands to rotate the connecting piece 90°. When the locking screw is adjusted to correspond to the positioning countersunk hole of the upper end portion 21 of the casing head, tighten the locking screw so that the upper end portion 21 of the casing head and the lower end portion 12 of the tubing head 1 cannot rotate relative to each other. After the lower end portion 12 of the tubing head 1 rotates 90°, the limit block 126 can stop the lower end portion 12 of the tubing head 1 from rotating, and also facilitates the alignment of the locking screw with the positioning countersunk hole on the upper end portion 21 of the casing head, which is convenient for installation.

[0073] In this embodiment, when the upper end portion 11 of the tubing head 1 is connected to the oil production tool (not shown), the ball buckle method of the lower end portion of the tubing head and the upper end portion of the casing head can also be used. The oil production tool is connected to the upper end portion of the tubing head only when oil is produced, so it is not shown in the drawings of this application.

[0074] In this embodiment, the emergency slip hanger 7 and the emergency bushing 8 are arranged in the casing head 2 to solve the emergency situation that the mandrel-type production casing hanger cannot be lowered to the designed depth.

[0075] The main advantages of the present invention are:

[0076] (a) The upper end of the tubing hanger is connected to its upper end structure through a rotating flange, which simplifies the wellhead structure and saves materials;

[0077] (b) The tubing hanger is connected to the tubing head through a locking mechanism. The tubing hanger can be removed by simply rotating it 90°, replacing the traditional top screw locking mechanism, which is easy to operate.

[0078] (c) The lower end of the tubing head and the lower end of the casing head are connected by ball buckles, replacing the traditional flange connection, achieving quick connection and sealing of the tubing head and casing head, and improving installation efficiency;

[0079] (d) When the upper end of the tubing head is connected to the oil extraction tool (not shown), a ball buckle is also used to facilitate the rapid disassembly of the oil extraction tool;

[0080] (e) The composite wellhead structure of the present application also includes an emergency slip hanger and an emergency core plug to solve the emergency situation where the mandrel-type production casing hanger cannot be lowered to the designed depth.

[0081] All documents mentioned in this application are considered to be included in the disclosure of this application as a whole, so that they can be used as the basis for modification when necessary. In addition, it should be understood that after reading the above disclosure of this application, those skilled in the art can make various changes or modifications to this application, and these equivalent forms also fall within the scope of protection claimed in this application.

Claims

1. A composite wellhead fixing structure, characterized in that: It comprises a tubing head (1), a casing head (2), a tubing hanger (3), a polished rod sealer (4) and a rotating flange (5); wherein the tubing head (1) is arranged above the casing head (2), and the tubing hanger (3) is arranged in the casing head (2); The tubing head (1) comprises an upper tubing head portion (11) and a lower tubing head portion (12), the casing head (2) comprises an upper tubing head portion (21), and the tubing hanger (3) comprises an upper tubing hanger portion and a lower tubing hanger portion; The upper end portion of the tubing hanger is connected to the polished rod sealer (4) via a rotating flange (5); The lower end portion of the tubing hanger is connected to the upper end portion (11) of the tubing head via a locking mechanism; The locking mechanism comprises a first step (321) arranged at the lower end portion of the tubing hanger, the first step is symmetrically milled off at a first angle, a first annular groove (322) matching the first step (321) is arranged on the inner periphery of the upper end portion of the tubing head, the lower end surface of the first annular groove (322) is symmetrically milled off at a second angle, when the lower end portion of the tubing hanger is connected to the upper end portion of the tubing head, the remaining first step (321) portion of the lower end portion of the tubing hanger corresponds to the milled off lower end surface of the first annular groove (322), so that when the tubing hanger is rotated 90 degrees, the tubing hanger is locked in the tubing head; In addition, the lower end portion of the tubing head is connected to the upper end portion of the casing head by means of a ball buckle.

2. The composite wellhead fixing structure according to claim 1 is characterized in that: The first angle at which the first step (321) is symmetrically milled is 95°, and the second angle at which the lower end surface of the first annular groove (322) is symmetrically milled is 95°.

3. The composite wellhead fixing structure according to claim 1 is characterized in that: The composite locking wellhead also includes an anti-loosening cover (6), which is connected to the upper end portion of the tubing head (1) and the tubing hanger (3) through a nut and is used to prevent the tubing hanger (3) from rotating.

4. The composite wellhead fixing structure according to claim 1, characterized in that: The lower end portion of the tubing head is inserted into the upper end portion of the casing head. The outer circumferential surface of the upper end portion of the casing head is connected to the inner circumferential surface of the lower end portion of the tubing head through a seal. The outer circumferential surface of the upper end portion of the casing head is provided with a second step (211). The lower end portion (12) of the tubing head comprises a lower end body (121), a recessed head screw (122), a connecting piece (123), a plurality of balls (124) and a locking screw (125). The connecting piece (123) is connected to the lower end of the lower end body (121) of the tubing head. The inner circumferential surface of the lower end body (121) and the connecting piece (123) are provided with an annular groove. A second annular groove is provided at a position corresponding to the first annular groove on the outer circumferential surface of the connecting piece (123); a threaded hole is provided at a position corresponding to the first annular groove on the outer circumferential surface of the lower end body (121); the plurality of balls (124) are poured into the circular groove formed by the first annular groove and the second annular groove through the threaded hole; the recessed head screw (122) is used to block the threaded hole; the lower end body (121) of the tubing head and the connecting piece (123) rotate around the axis through the balls; the lower part of the connecting piece (123) is connected to the second step (211) of the upper end part (21) of the casing head through a locking screw (125) to form a whole.

5. The composite wellhead fixing structure according to claim 4 is characterized in that: The outer circumferential surface of the second step (211) of the upper end portion (21) of the casing head is provided with a positioning countersunk hole, and the positioning countersunk hole is matched and connected with a locking screw (125).

6. The composite wellhead fixing structure according to claim 5 is characterized in that: The inner periphery of the connecting member (123) is provided with a second annular groove corresponding to the second step (211).

7. The composite wellhead fixing structure according to claim 6 is characterized in that: A limit block (126) is provided in the second annular groove, and the limit block (126) is used to stop the connection member (123) from rotating when the locking screw (125) is aligned with the positioning counterbore on the second step (211) of the upper end portion (21) of the casing head.

8. The composite wellhead fixing structure according to claim 7 is characterized in that: The outer circumferential surface of the upper end portion (21) of the casing head is provided with a sealing ring groove (212), a sealing ring (213) is arranged in the sealing ring groove (212), the outer circumferential surface of the upper end portion (21) of the casing head is sealedly connected to the inner circumferential surface of the lower end portion (12) of the tubing head through the sealing ring (213), and the second step (211) is arranged above the sealing ring groove (212).

9. The composite wellhead fixing structure according to claim 1, characterized in that: The composite wellhead locking structure also includes an emergency slip hanger (7) and an emergency sealing core (8).

10. The composite wellhead structure according to claim 1, characterized in that: The interface of the upper end portion (11) of the oil pipe head is connected to the oil production tool by means of a ball buckle.

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