A large-size single-drum double-well wellhead device

Abstract

The present invention is applicable to the technical field of oil production equipment, and provides a large-sized single-tube double-well wellhead device, which includes: a base having a first installation cavity opening downward, a first sealing ring provided in a first annular groove, a first injection hole provided on the peripheral wall of the first annular groove, and a glue guide groove provided on the side of the first sealing ring close to the first injection hole; a plurality of connection components are arranged at circumferential intervals, a second annular groove provided on the peripheral wall of the first installation cavity, a first threaded hole extending to the outside of the base provided on the peripheral wall of the second annular groove, a locking member is threadedly connected to the first threaded hole, a cava head is located in the second annular groove and at the end of the locking member, the locking member has a first through-hole, and a limit bolt passes through the first through-hole and is connected to the cava head. Filler is injected into the glue guide groove through the first injection hole, and the sealing ring is squeezed to make it close to the watertight conduit to achieve a tight seal. In addition, a plurality of cava heads clamp the watertight conduit to achieve a reliable connection between the watertight conduit and the base.

Description

Technical Field

[0001] The invention belongs to the technical field of oil production equipment, and in particular relates to a large-size single-barrel double-well wellhead device. Background Art

[0002] The wellhead assembly, also known as the completion wellhead, is installed at the wellhead to suspend pipes such as riser, casing, and tubing, and to seal the annular spaces between the tubing and casing, as well as between the layers of casing. It typically consists of a base, casing head, tubing head, and Christmas tree.

[0003] The largest single-tube, dual-well riser used on current offshore platforms is only 36 inches, while single-tube, dual-well wellhead systems larger than 36 inches are still unavailable. For small-sized risers, the outer diameter and roundness errors are relatively small, allowing traditional welding to effectively connect the riser to the base. Traditional sealing rings, with their interference fit, can also provide a good seal. However, for larger risers, the outer diameter and roundness errors are difficult to guarantee, making traditional welding connections and sealing methods difficult to apply. Summary of the Invention

[0004] The purpose of the embodiments of the present application is to provide a large-sized single-barrel dual-well wellhead device, aiming to solve the problem that the existing welding connection method and sealing method are difficult to apply to large-sized water-resistant pipes.

[0005] The embodiment of the present application is implemented as follows: a large-scale single-barrel dual-well wellhead device, the device comprising:

[0006] A base, the base being used to be installed at the wellhead of an oil well, the base having a first installation cavity opening downward, the first installation cavity being used to install a water-resistant pipe, and a first annular groove being provided on a peripheral wall of the first installation cavity;

[0007] a first sealing ring disposed in the first annular groove, a first injection hole being provided on a peripheral wall of the first annular groove, and a glue guide groove being provided on a side of the first sealing ring close to the first injection hole;

[0008] Multiple groups of connecting components, multiple groups of connecting components are arranged at intervals along the circumference of the first mounting cavity, the peripheral wall of the first mounting cavity is provided with a second annular groove, the peripheral wall of the second annular groove is provided with a first threaded hole extending to the outside of the base, the connecting components include a cava head, a limiting bolt and a locking piece, the locking piece is threadedly connected to the first threaded hole, the cava head is located in the second annular groove and at the end of the locking piece, the locking piece has a first through hole, the limiting bolt passes through the first through hole and is connected to the cava head.

[0009] As a preferred embodiment of the present application, the length of the shaft of the limiting bolt is less than the sum of the circumferential lengths of the second threaded hole and the locking member, but greater than the length of the locking member.

[0010] As a preferred embodiment of the present application, a support ring is further provided in the first annular groove, the support ring abuts against the side of the first sealing ring away from the first injection hole, two support rings are provided at intervals, and the first sealing ring can be deformed and extruded from between the two support rings.

[0011] As a preferred embodiment of the present application, two first annular grooves are arranged at intervals, the first sealing ring is arranged in each of the two first annular grooves, and a second injection hole is arranged on the peripheral wall of the first mounting cavity, and the second injection hole is located between the two first annular grooves.

[0012] As a preferred embodiment of the present application, the base is provided with two wellbores, which are connected to the first installation cavity. Both wellbores are covered with casing heads, and the casing heads are connected to the base through flanges. The sides of the two flanges close to each other have avoidance cutting edges.

[0013] As a preferred embodiment of the present application, a first casing hanger is inserted into the wellbore, the first casing hanger is used to hang the first casing, the first casing hanger is provided with a second sealing ring abutting the inner wall of the wellbore, the casing head has a second installation cavity connected to the wellbore, the first casing hanger extends into the second installation cavity, and the first casing hanger is also provided with a third sealing ring abutting the inner wall of the second installation cavity.

[0014] As a preferred embodiment of the present application, the end of the casing head away from the base is connected to a tubing head, and a tubing hanger for hanging the tubing is provided in the tubing head, and a convex ring portion is provided on the outer periphery of the tubing hanger, and a stepped hole for installing the tubing hanger is provided in the tubing head, and the convex ring portion abuts against the stepped surface of the stepped hole to achieve the installation of the tubing hanger, and a sealing assembly is provided on the outer periphery of the tubing hanger, and the sealing assembly is located at the end of the convex ring portion away from the stepped surface.

[0015] As a preferred embodiment of the present application, the sealing assembly includes a first trapezoidal sealing ring and a second trapezoidal sealing ring which are sleeved on the outside of the tubing hanger. The first trapezoidal sealing ring and the second trapezoidal sealing ring overlap along the radial portion of the tubing hanger. The first sealing ring is located on the outside of the second sealing ring. When the first trapezoidal sealing ring and the second trapezoidal sealing ring move toward each other in the axial direction, the first trapezoidal sealing ring expands radially and the second trapezoidal sealing ring contracts radially.

[0016] As a preferred embodiment of the present application, a driving ring is provided on the oil pipe hanger which can be raised and lowered, the end of the first trapezoidal sealing ring away from the second trapezoidal sealing ring abuts the convex ring portion, and the end of the second trapezoidal sealing ring away from the first trapezoidal sealing ring abuts the driving ring, and the oil pipe head has a driving screw arranged along its radial direction, the driving screw is threadedly connected to the oil pipe head, and the end of the driving screw close to the convex ring portion has a driving cone surface, and the driving cone surface is used to drive the driving ring to rise and fall.

[0017] As a preferred embodiment of the present application, both of the oil tubing heads are connected to a Christmas tree, and the two Christmas trees are arranged in a centrally symmetrical manner.

[0018] The embodiment of the present application provides a large-sized single-tube double-well wellhead device, which injects filler between the sealing ring and the peripheral wall of the first annular groove through the first injection hole on the peripheral wall of the first annular groove, squeezes the sealing ring to make it close to the watertight pipe, overcomes the outer diameter error and roundness error of the watertight pipe, and achieves a tight seal. In addition, by driving the locking member to rotate relative to the base, the locking member pushes the cava head to move radially to press the watertight pipe. Multiple groups of the connecting components are arranged at intervals along the circumference of the first mounting cavity, which can ensure that even if the watertight pipe has a relatively large roundness error, there are still enough cava heads to press the watertight pipe, thereby achieving a reliable connection between the watertight pipe and the base. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A three-dimensional structural diagram of a large-scale single-barrel dual-well wellhead device provided in an embodiment of the present application;

[0020] Figure 2 for Figure 1 a cross-sectional view of an embodiment;

[0021] Figure 3 for Figure 2 A partial view of the embodiment;

[0022] Figure 4 for Figure 1 A cross-sectional view of the base at another angle in the embodiment;

[0023] Figure 5 for Figure 1 A cross-sectional view of the base at another angle in the embodiment;

[0024] Figure 6 for Figure 2 A partial view of point B in the embodiment;

[0025] Figure 7 for Figure 1 A schematic structural diagram of the base and casing head in the embodiment;

[0026] Figure 8 for Figure 1 A schematic structural diagram of an embodiment from another perspective.

[0027] In the picture:

[0028] 100, base; 101, first mounting cavity; 110, first annular groove; 111, first injection hole; 120, second annular groove; 121, first threaded hole; 130, second injection hole; 140, first casing hanger; 141, second sealing ring; 142, third sealing ring;

[0029] 200, casing head; 210, second installation cavity; 220, second casing hanger; 230, flange;

[0030] 300, tubing head; 310, stepped hole; 320, tubing hanger; 321, convex ring;

[0031] 400, Christmas tree;

[0032] 510, slip head; 511, second threaded hole; 520, locking member; 521, first through hole; 530, limit bolt;

[0033] 610, first sealing ring; 611, rubber guide groove; 620, support ring;

[0034] 710, first trapezoidal sealing ring; 720, second trapezoidal sealing ring; 730, drive ring; 740, limit ring; 750, drive screw; 800, pressure test hole. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0036] The specific implementation of this application is described in detail below in conjunction with specific embodiments.

[0037] like Figure 1 and Figure 3 As shown, a large-sized single-barrel dual-well wellhead device provided in an embodiment of the present application includes: a base 100, a first sealing ring 610, and multiple groups of connection components.

[0038] The base 100 is used to be installed at the wellhead of an oil well. The base 100 has a first installation cavity 101 opening downward. The first installation cavity 101 is used to install a water-proof pipe. The peripheral wall of the first installation cavity 101 is provided with a first annular groove 110.

[0039] The first sealing ring 610 is disposed in the first annular groove 110 . A first injection hole 111 is disposed on a peripheral wall of the first annular groove 110 . A glue guiding groove 611 is formed on one side of the first sealing ring 610 close to the first injection hole 111 .

[0040] Multiple groups of connecting components, multiple groups of connecting components are arranged at circumferential intervals along the first installation cavity 101, the peripheral wall of the first installation cavity 101 is provided with a second annular groove 120, the peripheral wall of the second annular groove 120 is provided with a first threaded hole 121 extending to the outside of the base 100, the connecting components include a cava head 510, a limiting bolt 530 and a locking member 520, the locking member 520 is threadedly connected to the first threaded hole 121, the cava head 510 is located in the second annular groove 120 and at the end of the locking member 520, the locking member 520 has a first through hole 521, the limiting bolt 530 passes through the first through hole 521 and is connected to the cava head 510.

[0041] In this embodiment, filler is injected between the first sealing ring 610 and the circumferential wall of the first annular groove 110 through the first injection hole 111 on the circumferential wall of the first annular groove 110, squeezing the first sealing ring 610 to force it against the watertight pipe, overcoming the outer diameter error and roundness error of the watertight pipe and achieving a tight seal. Furthermore, by driving the locking member 520 to rotate relative to the base 100, the locking member 520 pushes the slip head 510 to move radially to press against the watertight pipe. Multiple groups of the connecting assemblies are arranged at intervals along the circumference of the first mounting cavity 101, ensuring that even if the watertight pipe has a large roundness error, there are still enough slip heads 510 to press against the watertight pipe, achieving a reliable connection between the watertight pipe and the base 100.

[0042] like Figure 5 As shown, in some embodiments of the present application, the slip head 510 is in the shape of an arc strip. The inner arc surface of the slip head 510 is provided with teeth that can engage the outer circumference of the watertight conductor to achieve a stable connection with the watertight conductor. The outer arc surface of the slip head 510 is provided with a second threaded hole 511. The tail end of the limit bolt 530 passes through the first through-hole 521 of the locking member 520 and is threadedly connected to the second threaded hole 511 of the slip head 510. The bolt head of the limit bolt 530 is larger than the diameter of the first through-hole 521. This prevents the slip head 510 from detaching from the locking member 520. When the locking member 520 is screwed into the first threaded hole 121 of the base 100, the slip head 510 is also restrained on the base 100 and will not detach from the base 100, preventing loss. It should be noted that the first through-hole 521 is not threaded, and the diameter of the first through-hole 521 is slightly larger than the diameter of the shaft of the limit bolt 530.

[0043] In one example of this application, a 42-inch riser is used. Twenty connection assemblies are provided, each of which uses a single iron ring for its slips 510. After machining, the iron ring is precision-cut into twenty identical slips 510 and hardened. In this embodiment, the provision of twenty slips 510 ensures that even if the riser is not round enough or has dimensional deviations, sufficient teeth are still present to contact and penetrate the riser, providing sufficient load-bearing capacity.

[0044] In some embodiments of the present application, the length of the limiting bolt 530 is less than or equal to the sum of the circumferential lengths of the second threaded hole 511 and the locking member 520, but greater than the length of the locking member 520. In this embodiment, when the shaft length of the limiting bolt 530 meets the above conditions, when the limiting bolt 530 is screwed into the second threaded hole 511 of the slip head 510, the two ends of the locking member 520 are respectively pressed by the slip head 510 and the bolt head of the limiting bolt 530, and the three are locked into one. The slip head 510 is restricted in the second annular groove 120 and cannot rotate, and the locking member 520 is also unable to rotate. In this way, the locking member 520 can be prevented from loosening from the first threaded hole 121. Specifically, during use, the stop bolt 530 is not fully screwed into the second threaded hole 511 at the beginning, and the stop bolt 530 does not clamp the locking member 520. The locking member 520 can rotate within the first threaded hole 121, pushing the slip head 510 to move, thereby causing the slip head 510 to press against the watertight pipe. The stop bolt 530 is then rotated to press the locking member 520 to prevent it from loosening. In this way, the stop bolt 530 can not only prevent the slip head 510 from separating from the base 100, but also prevent the locking member 520 from loosening, killing two birds with one stone.

[0045] In some embodiments of the present application, an elastic gasket is provided between the bolt head of the limiting bolt 530 and the locking member 520 , so that the pre-tightening force can be maintained to prevent the limiting bolt 530 from loosening.

[0046] like Figure 4 As shown, as another preferred embodiment of the present application, a support ring 620 is further disposed within the first annular groove 110. The support ring 620 abuts against the side of the first sealing ring 610 away from the first injection hole 111. Two support rings 620 are provided at intervals, and the first sealing ring 610 can be deformed and extruded between the two support rings 620. In this embodiment, the support ring 620 ensures that the first sealing ring 610 can be stably positioned within the first annular groove 110 and prevents the first sealing ring 610 from being completely extruded out of the first annular groove 110 by the filler.

[0047] like Figure 4As shown, as another preferred embodiment of the present application, two first annular grooves 110 are provided at intervals, and the first sealing ring 610 is provided in each of the two first annular grooves 110. The peripheral wall of the first installation cavity 101 is provided with a second injection hole 130, and the second injection hole 130 is located between the two first annular grooves 110. In this embodiment, the two first sealing rings 610 are tightly attached to the watertight pipe, so that a closed space is formed between the two first sealing rings 610. Sealant is injected into the closed space to obtain a wider sealing area, further improving the sealing effect. In addition, the sealant has fluidity before solidification, so even if the watertight pipe is not round enough or has size deviations, a good seal can still be achieved.

[0048] like Figure 3 and Figure 7 As shown in the figure, as a preferred embodiment of the present application, the base 100 is provided with two wellbores, the wellbores are connected to the first installation cavity 101, and the two wellbores are both covered with casing heads 200, and the casing heads 200 are connected to the base 100 through flanges 230. The sides of the two flanges 230 that are close to each other have an avoidance cutting edge. It can be understood that the general flange 230 is a complete circle. During installation, a certain distance needs to be spaced between the two sleeve heads to prevent interference between the two full-circular flanges 230. In this embodiment, a part of the side of the two flanges 230 that are close to each other is cut off to form an avoidance cutting edge, which reduces the installation distance required between the two sleeve heads and makes the structure more compact.

[0049] like Figure 2 and Figure 3 As shown, as a preferred embodiment of the present application, a first casing hanger 140 is inserted into the wellbore, the first casing hanger 140 is used to hang the first casing, the first casing hanger 140 is provided with a second sealing ring 141 abutting the inner wall of the wellbore, the casing head 200 has a second installation cavity 210 connected to the wellbore, the first casing hanger 140 extends into the second installation cavity 210, and the first casing hanger 140 is also provided with a third sealing ring 142 abutting the inner wall of the second installation cavity 210.

[0050] like Figure 2 As shown, in some embodiments of the present application, a second casing hanger 220 is further disposed in the second installation cavity 210 of the casing head 200 , and the second casing hanger is used to hang a second casing.

[0051] In this embodiment, the ends of the first casing hanger 140 extend into the wellbore and the second mounting cavity 210, respectively, and provide a seal for the base 100 and the casing head 200 via the second sealing ring 141 and the third sealing ring 142. Compared to conventional techniques, in which a sealing steel ring is installed between the two flanges 230 and is pressed against the inner pipe body by activation bolts radially arranged on the flanges 230, this embodiment does not require activation bolts, allowing the two casing heads 200 to be close to each other.

[0052] In some embodiments of the present application, reference is made to Figure 3 As shown, two second sealing rings 141 are provided, and a pressure test hole 800 is provided on the base 100. The pressure test hole 800 on the base 100 is located between the two second sealing rings 141. The sealing effect of the two second sealing rings 141 can be tested through the pressure test hole 800 on the base 100. Two third sealing rings 142 are provided, and a pressure test hole 800 is also provided on the casing head 200. The pressure test hole 800 on the casing head 200 is located between the two third sealing rings 142. The sealing effect of the two third sealing rings 142 can be tested through the pressure test hole 800 on the casing head 200.

[0053] like Figure 2 and Figure 6 As shown, as a preferred embodiment of the present application, the end of the casing head 200 away from the base 100 is connected to a tubing head 300. A tubing hanger 320 for suspending tubing is disposed within the tubing head 300. The tubing hanger 320 has a raised ring portion 321 on its outer circumference. A stepped hole 310 is formed within the tubing head 300 for mounting the tubing hanger 320. The raised ring portion 321 abuts against a stepped surface of the stepped hole 310 to facilitate mounting of the tubing hanger 320. A sealing assembly is disposed on the outer circumference of the tubing hanger 320, located at the end of the raised ring portion 321 away from the stepped surface. In this embodiment, the sealing assembly is located at the end of the raised ring portion 321 away from the stepped surface. When the tubing hanger 320 is placed within the tubing head 300, this reduces collisions and jamming between the sealing assembly and the inner wall of the stepped hole 310 of the tubing head 300, and facilitates replacement and maintenance.

[0054] like Figure 6As shown, as a preferred embodiment of the present application, the sealing assembly includes a first trapezoidal sealing ring 710 and a second trapezoidal sealing ring 720, which are mounted on the outside of the tubing hanger 320. The first trapezoidal sealing ring 710 and the second trapezoidal sealing ring 720 overlap in the radial direction of the tubing hanger 320. The first sealing ring 610 is located outside the second sealing ring 141. When the first trapezoidal sealing ring 710 and the second trapezoidal sealing ring move toward each other in the axial direction, the first trapezoidal sealing ring 710 expands radially and the second trapezoidal sealing ring contracts radially. In this embodiment, the radial movement of the first trapezoidal sealing ring 710 and the second trapezoidal sealing ring 720 ensures that the first trapezoidal sealing ring 710 and the second trapezoidal sealing ring are respectively in close contact with the inner wall of the stepped hole 310 and the outer wall of the tubing hanger 320, thereby improving the sealing effect.

[0055] like Figure 6 As shown in a preferred embodiment of the present application, a drive ring 730 is provided on the tubing hanger 320 for elevation. The end of the first trapezoidal sealing ring 710 away from the second trapezoidal sealing ring 720 abuts the convex ring portion 321, and the end of the second trapezoidal sealing ring 720 away from the first trapezoidal sealing ring 710 abuts the drive ring 730. The tubing head 300 is provided with a drive screw 750 disposed radially therefrom. The drive screw 750 is threadedly connected to the tubing head 300. The end of the drive screw 750 near the convex ring portion 321 has a drive conical surface for driving the drive ring 730 upward and downward. In this embodiment, when the drive screw 750 is rotated, the drive conical surface of the drive screw 750 moves toward the drive ring 730, and the drive conical surface pushes the drive ring 730 to move, thereby driving the first trapezoidal sealing ring 710 and the second trapezoidal sealing ring 720 to move axially toward each other. This facilitates seal activation, and the expansion or contraction of the first and second trapezoidal seal rings 710 and 720 can be adjusted circumferentially by using multiple drive screws 750, ensuring that each portion of the two trapezoidal seal rings is in close contact with the inner wall of the stepped hole 310 or the outer wall of the tubing hanger 320, thereby enhancing the sealing effect. In some embodiments of the present application, a stop ring 740 is further provided at the end of the drive ring 730 away from the convex ring portion 321 to prevent the drive ring 730 from separating from the tubing hanger 320.

[0056] like Figure 8 As shown, as a preferred embodiment of the present application, the two tubing heads 300 are both connected to a Christmas tree 400 , and the two Christmas trees 400 are arranged in a centrally symmetrical manner, which can effectively avoid interference between the two Christmas trees 400 .

[0057] In some embodiments of the present application, a large-size single-barrel double-well wellhead device of the present application can be installed by lowering the water-resistant pipe into the well, cutting the excess water-resistant pipe after it is in place, cutting the end face of the water-resistant pipe to be horizontal, trimming the bevel, lifting the base 100, keeping it horizontal, adjusting the orientation of the base 100, straightening and centering it, and lowering it steadily so that the first installation cavity 101 of the base 100 is inserted into the water-resistant pipe, tightening a circle of locking parts 520 and limit bolts 530 on the outer periphery of the base 100, so that the cava head 510 tightly holds the water-resistant pipe.

[0058] The end of the first casing is fixedly connected to the first casing hanger 140 and lowered into a predetermined position through the wellbore. After both wellbores are lowered into place, cementing and setting are carried out.

[0059] Afterwards, the casing head 200 is installed above the wellbore, and the casing head 200 riser and blowout preventer group are installed, the drill bit is lowered, and the drill is drilled to the designed depth with the drill bit, and the second casing is lowered to the predetermined position, cemented and waited for setting, the riser and blowout preventer group are removed, the second casing hanger 220 is installed, the redundant second casing is cut and polished, the oil tubing head 300 is installed above the casing head 200, and the first injection hole 111 and the second injection hole 130 of the base 100 are sealed by injection of glue.

[0060] Install the tubing head 300 to raise the tubing and the blowout preventer group, lower the drill bit, drill to the designed depth with the drill bit, connect the tubing to the tubing hanger 320 through the thread and lower it into the well.

[0061] Install the integral Christmas tree 400.

[0062] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A large-size single-drum double-well wellhead device, characterized in that: The device comprises: A base, the base being used to be installed at the wellhead of an oil well, the base having a first installation cavity opening downwardly, the first installation cavity being used to install a water-resistant pipe, the peripheral wall of the first installation cavity being provided with a first annular groove, the base being provided with two wellbores, the wellbores being connected to the first installation cavity; a first sealing ring disposed in the first annular groove, a first injection hole being provided on a peripheral wall of the first annular groove, and a glue guide groove being provided on a side of the first sealing ring close to the first injection hole; Multiple groups of connecting components, multiple groups of connecting components are arranged at intervals along the circumference of the first mounting cavity, the peripheral wall of the first mounting cavity is provided with a second annular groove, the peripheral wall of the second annular groove is provided with a first threaded hole extending to the outside of the base, the connecting component includes a cava head, a limiting bolt and a locking piece, the locking piece is threadedly connected to the first threaded hole, the cava head is located in the second annular groove and at the end of the locking piece, the locking piece has a first through hole, the cava head is provided with a second threaded hole, the limiting bolt passes through the first through hole and is connected to the second threaded hole of the cava head.

2. A large-scale single-drum dual-well wellhead device according to claim 1, characterized in that: The length of the shaft of the limiting bolt is less than the sum of the circumferential lengths of the second threaded hole and the locking member, but greater than the length of the locking member.

3. A large-scale single-drum dual-well wellhead device according to claim 1, characterized in that: A support ring is further provided in the first annular groove, the support ring abuts against a side of the first sealing ring away from the first injection hole, two support rings are provided at intervals, and the first sealing ring can be deformed and extruded from between the two support rings.

4. A large-scale single-drum dual-well wellhead device according to claim 3, characterized in that: Two first annular grooves are provided at intervals, and the first sealing ring is provided in each of the two first annular grooves. A second injection hole is provided on the peripheral wall of the first installation cavity, and the second injection hole is located between the two first annular grooves.

5. The large-scale single-drum dual-well wellhead device according to claim 1, characterized in that: The two wellbores are both covered with casing heads, which are connected to the base through flanges, and the sides of the two flanges close to each other are provided with avoidance cutting edges.

6. A large-scale single-drum dual-well wellhead device according to claim 5, characterized in that: A first casing hanger is inserted into the wellbore, and the first casing hanger is used to hang the first casing. The first casing hanger is provided with a second sealing ring that abuts the inner wall of the wellbore. The casing head has a second installation cavity connected to the wellbore, and the first casing hanger extends into the second installation cavity. The first casing hanger is also provided with a third sealing ring that abuts the inner wall of the second installation cavity.

7. A large-scale single-drum dual-well wellhead device according to claim 6, characterized in that: The end of the casing head away from the base is connected to a tubing head, and a tubing hanger for hanging the tubing is provided in the tubing head. The outer circumference of the tubing hanger is provided with a convex ring portion, and the tubing head has a stepped hole for mounting the tubing hanger. The convex ring portion abuts against the stepped surface of the stepped hole to achieve the installation of the tubing hanger. The outer circumference of the tubing hanger is provided with a sealing assembly, and the sealing assembly is located at the end of the convex ring portion away from the stepped surface.

8. The large-scale single-drum dual-well wellhead device according to claim 7, characterized in that: The sealing assembly includes a first trapezoidal sealing ring and a second trapezoidal sealing ring which are sleeved on the outside of the tubing hanger. The first trapezoidal sealing ring and the second trapezoidal sealing ring overlap along the radial portion of the tubing hanger. The first sealing ring is located outside the second sealing ring. When the first trapezoidal sealing ring and the second trapezoidal sealing ring move toward each other in the axial direction, the first trapezoidal sealing ring expands radially and the second trapezoidal sealing ring contracts radially.

9. A large-scale single-drum dual-well wellhead device according to claim 8, characterized in that: A driving ring is provided on the tubing hanger so as to be able to be raised and lowered. An end of the first trapezoidal sealing ring away from the second trapezoidal sealing ring abuts against the convex ring portion, and an end of the second trapezoidal sealing ring away from the first trapezoidal sealing ring abuts against the driving ring. The tubing head is provided with a driving screw arranged along its radial direction, the driving screw is threadedly connected to the tubing head, and an end of the driving screw close to the convex ring portion has a driving conical surface, and the driving conical surface is used to drive the driving ring to rise and fall.

10. A large-scale single-drum dual-well wellhead device according to claim 9, characterized in that: The two oil pipe heads are both connected with a Christmas tree, and the two Christmas trees are arranged in a centrally symmetrical manner.

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