A multi-seat wellhead device

Abstract

The present invention provides a multi-seat wellhead device, which relates to the technical field of wellhead devices and includes a base, a casing head, a casing hanger, a sealing device, a tubing head, a tubing hanger, and a tubing head reducer. The base is arranged at the wellhead, and the casing head and the tubing head are stacked on the base in order from bottom to top. The casing head and the tubing head are fixedly connected. A bearing step is provided on the inner wall of the casing head, and the casing hanger is placed on the bearing step. The casing hanger is placed on the sealing device, and the tubing head is placed on the sealing device. The outer wall of the sealing device is provided with at least two annular sealing grooves, and sealing rings are provided in both sealing grooves. The lower sealing ring is used to seal the annular gap between the casing head and the casing hanger, and the upper sealing ring is used to seal the annular gap between the tubing head and the tubing hanger. The solution provided by the present invention uses a bearing step to support the tubing hanger and the casing hanger, making the wellhead device assembly simple to process and assemble.

Description

Technical Field

[0001] The present invention relates to the technical field of wellhead devices, in particular to a multi-seat wellhead device. Background Art

[0002] A wellhead assembly generally refers to a device installed at the wellhead during oil and gas drilling, which seals the annular space between the oil pipe, casing, and each layer of casing.

[0003] Existing wellhead devices are divided into integral wellheads and split wellheads. However, no matter which wellhead device is used, the tubing hanger and casing hanger are placed on different bearing steps, which not only makes the processing complicated, but also makes the assembly difficult. Therefore, a new type of wellhead device is urgently needed to solve the above problems. Summary of the Invention

[0004] The purpose of the present invention is to provide a multi-seat wellhead assembly to solve the problems existing in the above-mentioned prior art. A bearing step is used to carry the oil pipe hanger and the casing hanger, so that the wellhead assembly components are simple to process and assemble.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] The present invention provides a multi-seat wellhead device, comprising a base, a casing head, a casing hanger, a sealing device, a tubing head, a tubing hanger and a tubing head reducer; the base is arranged at the wellhead, the casing head and the tubing head are stacked on the base in sequence from bottom to top, the casing head and the tubing head are fixedly connected, a bearing step is provided on the inner wall of the casing head, a casing hanger is placed on the bearing step, a sealing device is placed on the casing hanger, a tubing head is placed on the sealing device, at least two annular sealing grooves are provided on the outer wall of the sealing device, sealing rings are provided in both sealing grooves, the lower sealing ring is used to seal the annular gap between the casing head and the casing hanger, and the upper sealing ring is used to seal the annular gap between the tubing head and the tubing hanger.

[0007] Preferably, the sealing device may be a common sealing device or an emergency sealing device; the casing hanger may be a mandrel-type casing hanger or an emergency slip hanger;

[0008] When the casing is lowered normally, a common sealing device and a mandrel-type casing hanger are used;

[0009] When the casing is obstructed from being lowered, an emergency sealing device and an emergency slip hanger are used.

[0010] Preferably, the tubing hanger has no extended diameter, is provided with a first through hole coaxial with the tubing, a second through hole is provided on one side of the first through hole, a cable passer is passed through the second through hole, and a sealing sleeve is coaxially provided on the first through hole to seal the gap between the tubing hanger and the tubing head reducer.

[0011] Preferably, the tubing head reducer includes a joint body and an annular flange, an annular flange is provided on the circumferential side of the joint body, the flange is provided on the circumferential side of the joint body and can be pressed against the annular flange, a plurality of bolt through holes are provided around the circumference of the flange, a sub-flange matching the flange is provided on the top of the tubing head, the flange and the sub-flange are fixedly connected by a plurality of bolts, a third through hole corresponding to the cable passer is provided on the joint body, and the cable passer passes through the third through hole.

[0012] Preferably, an annular gasket groove is provided on the flange surfaces facing each other of the casing head and the tubing head, and a gasket is placed in the gasket groove.

[0013] Preferably, the sealing device is locked by means of a top screw.

[0014] Compared with the prior art, the present invention has achieved the following technical effects:

[0015] 1. The multi-seat wellhead device provided by the present invention adopts one bearing step to bear the tubing hanger and the casing hanger, so that the wellhead device components are easy to process and assemble.

[0016] 2. The tubing head reducer features a split-body connector body and flange. During installation, simply align the third through-hole on the connector body with the second through-hole. The flange is then adjusted to align the threaded holes, completing installation. This eliminates the need for machining guide grooves on the wellhead and hanger to position the transducer, reducing costs and facilitating operation.

[0017] 3. A matching emergency slip hanger is designed. When the casing encounters resistance during lowering, the top of the casing is located above the casing head, making it easy to cut to a predetermined height outside the wellhead by flame cutting or other methods. The top of the integral wellhead casing is much lower than the wellhead top, and a special inner casing cutter must be used for cold cutting. Therefore, the solution provided by the present invention does not require a special casing cutting tool for cutting the casing.

[0018] 4. The SR-type gasket groove design is adopted between the flange surfaces of the casing head and the tubing head to achieve face-to-face fitting between the 6B flanges, ensuring the concentricity of the upper and lower flanges and avoiding the uneven tightening force of the connecting flange bolts, which may cause the upper and lower flanges to be out of center, thereby affecting the installation of the sealing device and the anti-wear sleeve.

[0019] 5. The sealing device adopts the top screw locking method, which is easy to operate and saves costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 A schematic diagram of the structure of a multi-seat wellhead device provided by the present invention;

[0022] In the figure: 1. Base; 2. Casing head; 3. Ball valve; 4. Mandrel-type casing hanger; 5. Conventional sealing device; 6. Emergency slip hanger; 7. Emergency sealing device; 8. Tubing head; 9. Tubing hanger; 10. Sealing sleeve; 11. Tubing head reducer; 12. 13-3 / 8" casing; 13. 9-5 / 8" casing; 14. 4-1 / 2 tubing. DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0024] The purpose of the present invention is to provide a multi-seat wellhead assembly to solve the problems existing in the above-mentioned prior art. A bearing step is used to carry the oil pipe hanger and the casing hanger, so that the wellhead assembly components are simple to process and assemble.

[0025] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] The present invention provides a multi-seat wellhead device, such as Figure 1As shown, it includes a base 1, a casing head 2, a casing hanger, a sealing device, a tubing head 8, a tubing hanger 9 and a tubing head reducer 11; the base 1 is arranged at the wellhead, the casing head 2 and the tubing head 8 are stacked on the base 1 from bottom to top, the casing head 2 and the tubing head 8 are fixedly connected, a bearing step is provided on the inner wall of the casing head 2, the bearing step is provided with a casing hanger, the casing hanger is provided with a sealing device, the tubing head 8 is provided with a sealing device, and the outer wall of the sealing device is provided with at least two annular sealing grooves, and sealing rings are provided in both sealing grooves, the lower sealing ring is used to seal the annular gap between the casing head 2 and the casing hanger, and the upper sealing ring is used to seal the annular gap between the tubing head 8 and the tubing hanger 9.

[0027] The multi-seat wellhead device provided by the present invention adopts one bearing step to bear the oil pipe hanger and the casing hanger, so that the wellhead device components are simple to process and assemble.

[0028] In some embodiments, the sealing device may be a common sealing device 5 or an emergency sealing device 7; the casing hanger may be a mandrel casing hanger 4 or an emergency slip hanger 6;

[0029] When the casing is lowered normally, a common sealing device 5 and a mandrel-type casing hanger 4 are used;

[0030] When the casing is obstructed from being lowered, the emergency sealing device 7 and the emergency slip hanger 6 are used.

[0031] The multi-seat wellhead device provided in this embodiment is designed with a matching emergency slip hanger 6. When the casing is lowered and encounters resistance, the top of the casing is located above the casing head 2, so that it is easy to cut to a predetermined height outside the wellhead by flame cutting or other methods. The top of the integral wellhead casing is much lower than the wellhead top, and a special inner casing cutter must be used for cold cutting. Therefore, in the solution provided by the present invention, no special casing cutting tool is required to cut the casing.

[0032] In some embodiments, the tubing hanger 9 has no extended diameter, and is provided with a first through hole coaxial with the tubing, a second through hole is provided on one side of the first through hole, a cable pass-through is passed through the second through hole, and a sealing sleeve 10 is coaxially provided on the first through hole to seal the gap between the tubing hanger 9 and the tubing head reducer 11.

[0033] The tubing hanger 9 in the multi-seat wellhead device provided in this embodiment adopts a design without an extended diameter. The sealing sleeve 10 is added to seal the tubing hanger and the tubing head reducer 11 without affecting the passage of the cable passer. The design without an extended diameter allows for more space to be arranged in the cable passage hole.

[0034] In some embodiments, the tubing head reducer 11 includes a joint body and an annular flange, an annular flange is provided on the circumferential side of the joint body, the flange is provided on the circumferential side of the joint body and can be pressed against the annular flange, a plurality of bolt through holes are provided around the circumference of the flange, a sub-flange matching the flange is provided on the top of the tubing head 8, the flange and the sub-flange are fixedly connected by a plurality of bolts, a third through hole corresponding to the cable passer is provided on the joint body, and the cable passer passes through the third through hole.

[0035] The tubing head reducer 11 employed in this embodiment features a split-body structure with a flange. During installation, simply align the third through-hole on the reducer body with the second through-hole. The flange is then adjusted to align the threaded holes, completing installation. This replaces the conventional method of machining guide grooves in the wellhead and hanger to position the traverser, reducing costs and facilitating operation.

[0036] In some embodiments, annular gasket grooves are provided on the opposing flange surfaces of the casing head 2 and the tubing head 8 , and gaskets are placed in the gasket grooves.

[0037] In the multi-seat wellhead device provided in this embodiment, an SR-type gasket groove design is adopted between the opposing flange surfaces of the casing head 2 and the tubing head 8, thereby achieving face-to-face fitting between the 6B flanges, ensuring the concentricity of the upper and lower flanges, and avoiding the uneven tightening force of the connecting flange bolts causing the upper and lower flanges to be out of center, thereby affecting the lowering of the sealing device and the anti-wear sleeve.

[0038] In some embodiments, the sealing device is locked by means of a jackscrew.

[0039] The sealing device in the multi-seat wellhead device provided in this embodiment adopts a top screw locking method, which is easy to operate and saves costs.

[0040] The base 1 bears the weight of the entire multi-seat wellhead assembly and the suspended pipe hangers.

[0041] The bottom of the casing head 2 is connected to a 13-3 / 8" casing 12, and the side is equipped with a ball valve 3 and other accessories, such as a pipe plug, a stop valve and a pressure gauge.

[0042] Under normal conditions: the 45° load-bearing step inside the casing head 2 carries the mandrel-type casing hanger 4. The bottom of the mandrel-type casing hanger 4 is connected to the 9-5 / 8" casing 13. The flange surfaces of the tubing head 8 and the casing head 2 are machined with SR gasket grooves to achieve face-to-face fit of the 6B flanges to avoid misalignment between the tubing head 8 and the casing head 2. The ordinary sealing device 5 is installed above the mandrel-type casing hanger 4 and is locked with a jackscrew to achieve sealing between the annuli.

[0043] When the casing is lowered and encounters resistance, the emergency slip hanger 6 and the emergency sealing device 7 are used. Since the casing is higher than the flange surface of the casing head 2, unlike the integral wellhead, a special casing cutting tool is not required.

[0044] The tubing head 8 has no internal bearing step. A 4.5-inch tubing 14 is connected to the tubing hanger 9, which is placed on the 45-degree slope of the standard seal 5 or emergency seal 7. Once the tubing hanger 9 is installed, the sealing sleeve 10 is installed, followed by the ESP tubing head reducer 11. After aligning the cable pass-through, the swivel flange is adjusted and the bolts are tightened.

[0045] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A multi-seat wellhead assembly, characterized in that: The tubing head is provided with a support, and the tubing head is provided with a support. A first through hole coaxial with the oil pipe, a second through hole is provided on one side of the first through hole, a cable passer is passed through the second through hole, and a sealing sleeve is coaxially provided on the first through hole to seal the gap between the oil pipe hanger and the oil pipe head reducer; the oil pipe head reducer includes a joint body and an annular flange, the circumferential side of the joint body is provided with an annular flange, the flange is provided on the circumferential side of the joint body and can be pressed on the annular flange, a plurality of bolt through holes are provided around the circumference of the flange, a sub-flange matching the flange is provided on the top of the oil pipe head, the flange and the sub-flange are fixedly connected by a plurality of bolts, a third through hole corresponding to the cable passer is provided on the joint body, and the cable passer passes through the third through hole.

2. The multi-seat wellhead assembly according to claim 1, characterized in that: The sealing device may be a common sealing device or an emergency sealing device; the casing hanger may be a mandrel-type casing hanger or an emergency slip hanger; When the casing is lowered normally, a common sealing device and a mandrel-type casing hanger are used; When the casing is obstructed from lowering, emergency sealing device and emergency slip hanger are used.

3. The multi-seat wellhead assembly according to claim 1, characterized in that: Annular gasket grooves are provided on the flange surfaces opposite to the casing head and the oil pipe head, and gaskets are placed in the gasket grooves.

4. The multi-seat wellhead assembly according to claim 1, characterized in that: The sealing device is locked by means of a jackscrew.

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