Integrated wellhead device

Abstract

The present application relates to the technical field of wellhead devices. Provided is an integrated wellhead device, comprising a casing head body, an elevation flange and a well completion flange, which are sequentially connected from bottom to top, wherein the casing head body has a first inner cavity; a first hanger assembly and a second hanger assembly are respectively connected to upper and lower ends of the first inner cavity in a sealed manner; the elevation flange has a second inner cavity; the well completion flange is provided with a medium output hole; a heat exchange medium injection end is connected to a lower portion of the casing head body, and an exhaust end is connected to an upper end of the casing head body; and the heat exchange medium injection end and the exhaust end are in communication with an annular space. An outflow sealed flow channel for an injected fluid is formed by means of the annular space, an inner pipe, the second inner cavity and the medium output hole, thereby achieving the function of performing both liquid injection and mining in a single well. A heat exchange medium is directly injected, and then directly flows through the outflow sealed flow channel, thereby realizing the outflow of the heat exchange medium. The integrated wellhead device can be specifically and quickly adapted for cyclic heat exchange in abandoned wells or idle geothermal wells, the overall technical solution is convenient to implement, and the transformation and assembly can be rapidly completed.

Description

Integrated wellhead equipment

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 202310815519.4, filed on July 5, 2023, entitled “Integrated Wellhead Device,” which is incorporated herein by reference in its entirety. Technical Field

[0003] The present application relates to the technical field of wellhead devices, and in particular to an integrated wellhead device that is universally applicable to new and old wells. Background Art

[0004] Wellheads are typically installed at the wellhead of oil, natural gas, or geothermal wells to control the pressure and direction of gas and liquid flows, such as conventional Christmas trees or Christmas trees.

[0005] Abandoned oil and gas wells and idle geothermal wells often contain a large amount of geothermal energy. In order to utilize the large amount of geothermal energy in the wells, deep well circulation heat exchange technology is usually used. This technical solution is green and low-carbon, has strong applicability and good stability.

[0006] Existing deep well circulation heat exchange technology is usually for newly drilled wells and is not applicable to old or abandoned wells. New drilling costs are high and a large number of existing abandoned old wells cannot be used, resulting in low well utilization.

[0007] Summary of the Invention

[0008] The present application provides an integrated wellhead device to solve the defect of the prior art in that it is difficult to utilize geothermal energy in abandoned oil and gas wells.

[0009] The present application provides an integrated wellhead device, comprising: a casing head body, a riser flange, and a completion flange connected sequentially from bottom to top;

[0010] The casing head body defines a first inner cavity, the upper end of the first inner cavity is sealedly connected to the first hanger assembly, and the lower end of the first inner cavity is sealedly connected to the second hanger assembly;

[0011] The raised flange defines a second internal cavity, the second internal cavity being in communication with the first hanger assembly;

[0012] The completion flange is provided with a medium output hole, and the medium output hole is communicated with the second inner cavity;

[0013] Among them, the first hanger assembly can be sealed and connected to the inner pipe in the well so that the inner pipe passes through the first inner cavity and forms an annulus around the inner pipe. The casing head body is connected to a heat exchange medium injection end and an exhaust end. The heat exchange medium injection end and the exhaust end are respectively connected to the annulus, and the exhaust end is located above the heat exchange medium injection end.

[0014] The integrated wellhead device provided in the present application further includes a base assembly connected to the lower end of the casing head body, and the base assembly is configured to provide support for the casing head body.

[0015] According to the integrated wellhead device provided in the present application, the completion flange is provided with a cable passage hole, an optical fiber passage hole and a sampling hole, the cable passage hole and the optical fiber passage hole are respectively provided with sealing assemblies, and the sampling hole is connected with a sealing plug.

[0016] According to the integrated wellhead device provided in the present application, the first hanger is further constructed with a plurality of passages for sealed passage of the wire harness, so that the wire harness can enter the annular area through the passages.

[0017] According to the integrated wellhead device provided in the present application, a plurality of intermediate sealing rings are arranged in the casing head body near one end of the second hanger assembly, and a grease injection check valve is provided between the intermediate sealing rings to inject sealing material through the grease injection check valve to achieve sealing between the casing head body and the surface casing.

[0018] According to the integrated wellhead device provided in the present application, the base assembly includes a base bracket and a base plate, the base plate is connected to the base bracket, and the base bracket has a cavity capable of accommodating a surface casing.

[0019] According to the integrated wellhead device provided in the present application, the upper portion of the casing head body has a plurality of top screws suitable for fixing the first hanger assembly.

[0020] According to the integrated wellhead device provided by the present application, the first hanger assembly is a mandrel-type hanger, and the second hanger assembly is a slip-type hanger.

[0021] According to the integrated wellhead device provided in the present application, the second hanger assembly includes slips and a support body suitable for supporting the slips, and the slips are configured to be fixed to the lower end of the casing head body through the support body.

[0022] According to the integrated wellhead device provided in the present application, the inner wall of the support body has an inverted stepped conical surface, and the outer wall of the corresponding slip is constructed with a matching stepped conical surface so that the support body and the slip conical surface are matched and limited.

[0023] Through any of the above embodiments, the present application has at least the following beneficial effects:

[0024] The present application provides an integrated wellhead device, which is assembled at the wellhead position through the wellhead device of the present application, and forms an outflow closed flow channel for the injected fluid through the annulus, inner tube, second inner cavity and medium output hole, thereby realizing the circulation heat exchange function of single well simultaneous injection and production. This makes it possible to directly inject heat exchange medium when geothermal energy is needed, and the heat exchange medium directly flows out through the outflow closed flow channel, without the need for separate drilling work and independent production and injection channels, so that it can be applied to the circulation heat exchange of new and old wells. Especially when abandoned oil and gas wells are utilized, underground geothermal energy can be utilized by direct socket assembly. The overall technical solution is easy to implement, has low production cost, and can quickly complete the transformation and assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the present application or the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0026] FIG1 is a schematic diagram of the structure of a pipe fitting at the wellhead of an existing oil and gas well;

[0027] FIG2 is a schematic structural diagram of the wellhead device provided in this application;

[0028] FIG3 is a schematic structural diagram of the end face of the completion flange provided in the present application;

[0029] FIG4 is a schematic structural diagram of a sleeve assembly provided in the present application;

[0030] FIG5 is a schematic structural diagram of the first hanger assembly provided by the present application;

[0031] FIG6 is a schematic structural diagram of the second hanger assembly provided by the present application;

[0032] FIG7 is a schematic diagram of the wellhead device provided in the present application connected to the wellhead for circulating heat exchange.

[0033] Figure markings: 1: sealing plug; 2: optical fiber through hole; 3: cable through hole; 4: medium output hole; 5: completion flange; 6: lifting flange; 6-1: second inner cavity; 7: first hanger assembly; 8: casing head body; 8-1: annulus; 9: grease injection check valve; 10: intermediate sealing ring; 11: exhaust end; 11-1: exhaust valve; 12: second hanger assembly; 13: base assembly; 14: top screw; 15: heat exchange medium injection end; 15-1: valve; 16: annular groove; 17: through channel; 18: step surface; 19: thread; 20: slip; 21: support body; 22: threaded through hole. DETAILED DESCRIPTION

[0034] To make the objectives, technical solutions, and advantages of this application more clear, the technical solutions of this application will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.

[0035] In the description of the embodiments of the present application, it should be noted that the terms "upper," "lower," "bottom," "axial," "circumferential," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended only to facilitate the description of the embodiments of the present application and to simplify the description. They do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be construed as limiting the embodiments of the present application. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0036] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "connection" and "configuration" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances. In addition, the term "multiple" in the present application refers to two or more.

[0037] In the description of this specification, the descriptions with reference to the terms "specific embodiment", "some embodiments", "specific examples", etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiments of the present application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

[0038] FIG1 is a schematic diagram of the structure of the pipe fittings at the wellhead of an existing oil and gas well. In some existing embodiments, a casing procedure is required at the wellhead of an oil and gas well to form the wellhead of the oil and gas well. The casing procedure of the oil and gas well comprises an outermost surface casing B and an inner pipe A (or oil pipe) that can extend to the bottom of the well inside the surface casing B. In common existing embodiments, a Christmas tree or other wellhead device is installed at the wellhead position at the top of the inner pipe to collect oil and gas. However, it is difficult to utilize the geothermal energy of a large number of existing idle wells. Based on this, the present application can provide an integrated wellhead device suitable for utilizing geothermal energy.

[0039] The integrated wellhead device of the present application is described below with reference to FIG. 2 to FIG. 4 , and is particularly configured as a wellhead device suitable for abandoned oil and gas wells, and capable of achieving cyclic heat exchange through the wellhead device. It includes a casing head body 8, a rising flange 6 and a completion flange 5 connected in sequence from bottom to top, the casing head body 8 defines a first inner cavity, the upper end of the first inner cavity is sealedly connected to the first hanger assembly 7, and the lower end of the first inner cavity is sealed to the second hanger assembly 12; the rising flange 6 defines a second inner cavity 6-1, and the second inner cavity 6-1 is connected to the first hanger assembly 7; the completion flange 5 has a medium output hole 4, and the medium output hole 4 is connected to the second inner cavity 6-1; wherein, the first hanger assembly 7 can be sealed and connected to the inner pipe A in the well, so that the inner pipe A passes through the first inner cavity and cooperates to form an annulus 8-1 around the first inner cavity, and the casing head body 8 is connected to a heat exchange medium injection end 15 and an exhaust end 11, the heat exchange medium injection end 15 and the exhaust end 11 are respectively connected to the annulus 8-1, and the exhaust end 11 is located above the heat exchange medium injection end 15.

[0040] As shown in Figure 2, the casing head body 8, the riser flange 6 and the completion flange 5 connected in sequence are sealed to each other. The sealed connection is achieved by providing a sealing ring on the connecting surface. For example, the completion flange 5 and the riser flange 6 are connected by bolts, and a rubber sealing ring is provided between the connecting surfaces of the completion flange 5 and the riser flange 6, and the sealing between the connecting surfaces is achieved by the sealing ring. Similarly, the connecting surfaces of the casing head body 8 and the riser flange 6 also have the same sealing structure. The completion flange 5, the riser flange 6 and the casing head body 8 connected in sequence from top to bottom are coaxially arranged. In a specific example, the first hanger and the casing head body 8 are coaxially arranged, and the second hanger and the casing head body 8 are also coaxially arranged, which makes the entire wellhead device a coaxial wellhead device.

[0041] The raised flange 6 has flange end faces at both ends, which are connected by a middle pipe body structure, and the pipe body structure defines a second inner cavity 6-1; the casing head body 8 is a tubular structure as a whole, so a first inner cavity is defined inside, and the first hanger assembly 7 is connected to the upper end of the first inner cavity and is sealed with the inner wall of the first inner cavity, so that the first hanger assembly 7 separates the first inner cavity and the second inner cavity 6-1; when in working condition, the wellhead device is connected to the wellhead position of the drilling well, and when connected, the inner pipe A in the well is sealed with the first hanger assembly 7, which forms an annulus 8-1 in the area other than the inner pipe A in the first inner cavity, and the entire wellhead device is also sealed with the casing part protruding from the ground when connected to the wellhead of the oil and gas well, which makes the annulus 8-1 area a closed space.

[0042] In the above embodiment, a plurality of intermediate sealing rings 10 are disposed within the casing head body 8 near one end of the second hanger assembly 12. A grease injection check valve 9 is disposed between the intermediate sealing rings 10 and the surface casing. A sealing material is injected through the grease injection check valve 9 to achieve a seal between the intermediate sealing rings 10, thereby achieving a seal between the annulus 8-1 and the flow channel space within the surface casing, allowing the injected heat exchange medium to enter the flow channel space within the surface casing from the annulus 8-1 region. In a specific example, at least two intermediate sealing rings 10 are provided, and a grease injection hole is machined in the casing head body 8 between the two intermediate sealing rings 10. A grease injection check valve 9 is disposed within the grease injection hole to allow a grease-based sealing material to be injected through the check valve to achieve a seal between the annulus 8-1.

[0043] During wellhead assembly, the existing inner tube A at the wellhead is threadedly connected to the first hanger assembly 7 via threads 19, achieving a sealed connection between the inner tube and the first hanger assembly 7. The surface casing B at the wellhead is sealed between the outer wall of the surface casing B and the lower end of the casing head body 8 via an intermediate sealing ring 10 and a grease injection check valve 9. This seals the annulus 8-1 within the casing head body 8, connecting it only to the flow channel space within the surface casing.

[0044] It is understood that, as shown in Figures 4 and 7, where the arrows in Figure 7 indicate the flow direction of the heat exchange medium, the annulus 8-1 is connected to the heat exchange medium injection port 15 and the exhaust port 11, respectively. The exhaust port 11 is used to discharge gas mixed in the annulus 8-1. This allows the heat exchange medium to be continuously injected into the annulus 8-1, and the heat exchange medium can be injected downhole along the outer wall of the inner tube A. After exchanging heat with geothermal energy, the injected heat exchange medium enters the first inner cavity through the flow channel within the inner tube A. The completion flange 5 is provided with a medium output hole 4 to realize the output of the heat exchange medium through the medium output hole 4, forming a circulating heat exchange flow channel, thereby realizing simultaneous production and injection in a single well.

[0045] Furthermore, as shown in Figure 1, the heat exchange medium injection port 15 has two injection ports. Each heat exchange medium injection port 15 is provided with a valve 15-1 for opening and closing and controlling the injection rate of the heat exchange medium. The heat exchange medium can be any fluid capable of exchanging heat. Preferably, water is used as the heat exchange medium in this embodiment. A corresponding exhaust valve 11-1 is also provided on the exhaust port 11. In a specific example, the heat exchange medium injection port 15 is located at the bottom of the casing head body 8, and the exhaust port 11 is located at the top of the casing head body 8.

[0046] As shown in FIG5 , in a specific example, a step surface 18 is constructed on the outer wall of the first hanger, and a corresponding limiting step that can cooperate with the step surface 18 is processed on the inner wall of the upper end of the casing head body 8, so that the first hanger can be connected to the first inner cavity defined by the casing head body 8. Furthermore, there is no limitation on the sealing connection between the first hanger and the casing head body 8, for example, it can be a sealing threaded connection or other sealing connection structure. Preferably, a plurality of annular grooves 16 for connecting sealing rings are processed on the outer wall of the first hanger. By installing a sealing ring in each annular groove 16, the connection between the first hanger and the inner wall of the casing head body 8 is a sealed connection. The sealing ring is easy to disassemble and can utilize the thermal expansion effect during the heat exchange process to achieve a better sealing effect.

[0047] Furthermore, as can be seen from the above embodiment, the bottom end of the first hanger is installed in the first inner cavity via a limiting step, while the top of the first hanger is fixed by a top screw 14. There is no limit on the number of top screws 14. Multiple top screws 14 are arranged on the upper portion of the casing head body 8. By rotating the top screws 14 so that they abut against the first hanger, the top end of the first hanger is fixed in the casing head body 8. In a specific example, four radial threaded holes are evenly distributed circumferentially on the upper portion of the casing head body 8. A top screw 14 is respectively arranged in each of the four threaded holes. The four top screws 14 are respectively located in four symmetrical directions of the first hanger to fix the first hanger.

[0048] In some embodiments, the integrated wellhead assembly further includes a base assembly 13 connected to the lower end of the casing head body 8. The base assembly 13 is configured to provide support for the casing head body 8 and the entire wellhead assembly. The base assembly 13 supports all upper components, allowing the wellhead assembly to be placed on the ground at the wellhead location, facilitating quick assembly at the wellhead of an idle well.

[0049] When in working state, the base assembly 13 can accommodate the surface casing B, so that the surface casing B is located in the cavity of the base, and when the wellhead device of the present application is assembled, it can be directly locked and connected with the surface casing B of the wellhead through the second hanger assembly 12, and sealed through the intermediate sealing ring 10 and the grease injection check valve 9, so that heat exchange can be quickly circulated in abandoned old wells. It should be understood that even if the existing deep well circulation heat exchange technology can be used to transform the existing drilling wells, the transformation also requires a comprehensive transformation of the existing wellhead device, which will undoubtedly increase the difficulty of the work and make the transformation cost too high. However, through the wellhead device of the present application, it can be quickly combined with the surface casing at the existing wellhead, the overall difficulty is relatively low, the assembly is convenient, and the cost is low.

[0050] The base assembly 13 comprises a base bracket and a base plate. The base bracket has a cavity capable of accommodating the surface casing B, and the base plate is connected to the base bracket. Specifically, the base bracket is provided with threaded holes around its perimeter, and the base plate is also provided with corresponding threaded holes around its perimeter. The base plate and base bracket are connected by a set of long bolts. The cavity is slightly larger than the size of the surface casing B. During wellhead assembly, the surface casing B can pass through the cavity, centered within the base bracket, and locked into place via the second hanger assembly 12.

[0051] As shown in FIG3 , some specific examples include a cable through hole 3 , an optical fiber through hole 2 and a sampling hole provided on the completion flange 5 . Sealing components are respectively provided in the cable through hole 3 and the optical fiber through hole 2 , and a sealing plug 1 is connected to the sampling hole.

[0052] A sealing assembly is installed in the cable passageway 3, allowing the cable to pass through the completion flange 5 and maintain a sealed connection between the cable and the flange. This sealing assembly can be an existing cable pass-through or a sealing assembly composed of sealing materials and other structures; the specific selection depends on actual needs. The cable passageway 3 allows the cable to be input from the outside into the second inner cavity 6-1 defined by the raised flange 6. Similarly, a sealing assembly is installed in the optical fiber passageway 2, allowing the optical fiber to pass through the completion flange 5 and maintain a sealed connection between the optical fiber and the flange 5.

[0053] The sealing plug 1 is connected to the completion flange 5 by means of threads or other detachable sealing connection methods, so that sampling and observation can be achieved through the sampling hole by removing the sealing plug 1.

[0054] The body of the first hanger assembly 7 is machined with multiple passageways 17 for sealed wiring harness passage. This allows wiring harnesses fed through the completion flange 5 to enter the wellbore through these passageways 17 for power or signal transmission. Cables and optical fibers are used to provide power and input / output control signals to equipment such as downhole submersible pumps. Specifically, the first hanger assembly 7 is provided with fiber passageways 17 corresponding to the fiber passageways 2 in the completion flange 5. Optical fibers pass through these passageways 17 into the annulus 8-1 and, through the inner tube A, reach the wellbore bottom. Following the inner tube A into the wellbore, data acquisition is completed within the annulus 8-1. The cable passageway 3, connected to the downhole submersible pump assembly, is lowered from the inner tube A to the designed position.

[0055] In a specific example, the first hanger assembly 7 is a mandrel hanger, and the second hanger assembly 12 is a slip hanger. Of course, the type selection for the first hanger assembly 7 and the second hanger assembly 12 can be replaced or adjusted according to actual needs.

[0056] Among them, when the slip hanger is connected to the lower end of the casing head body 8, it is installed in an inverted form, so that when the slip hanger is connected to the casing head body 8, an inverted slip hanger structure is formed, and the surface casing is locked by the slip hanger, so that the surface casing is fixed in the casing head body 8.

[0057] As shown in FIG6 , the slip hanger includes slips 20 and a support body 21 adapted to support the slips. The slips 20 and the support body 21 are separate structures, and the slips 20 are configured to be fixed to the lower end of the casing head body 8 via the support body 21. The support body 21 is fixedly connected to the lower end of the casing head body 8, and the slips 20 are confined in the lower end of the casing head body 8 by the fixed connection with the support body 21.

[0058] Specifically, the inner wall of the support body 21 has an inverted stepped conical surface, and the outer wall of the corresponding slips 20 is configured with a matching stepped conical surface, so that the conical surfaces of the support body 21 and the slips 20 match.

[0059] The support body 21 is bolted to the lower end of the casing head body 8 and has a recessed platform at the lower end. As the support body 21 moves upward during tightening, the inverted stepped conical surface of the support body 21 contacts and mates with the mating stepped conical surface on the outer wall of the slip 20, axially restraining the slip 20. This contact and fit of the conical surfaces gradually develop into an interference fit, circumferentially restraining the slip 20. This split structure better accommodates thermal expansion during heat exchange.

[0060] Furthermore, the interior of the slips 20 is a hollow structure, and the inner wall of the slip hanger is surrounded by closed slip teeth 20, preferably with sharp tips. The slip teeth 20 are gradually retracted during the upward movement of the bracket 21 to secure and lock the surface casing B. The upward movement of the bracket 21 is also the process of bolting the bracket 21 to the lower end of the casing head body 8. As shown in Figure 6, in a specific example, the bracket 21 is provided with threaded through-holes 22 on its periphery. Bolts pass through the threaded through-holes 22 and connect to the lower end surface of the casing head body 8, thereby securing the slip hanger to the lower end of the casing head body 8 via the bolts.

[0061] Through the description of the above embodiments, those skilled in the art can clearly understand that in the embodiments of the present application, the assembly of the wellhead device forms an annulus 8-1 in the first inner cavity outside the inner tube A, and forms an outflow closed flow channel for the injected fluid through the annulus 8-1, the inner tube A, the second inner cavity 6-1 and the medium output hole 4, thereby realizing the simultaneous injection and production of a single well; an exhaust port 11 is connected to the annulus 8-1, and the gas mixed in the annulus 8-1 can be discharged through the exhaust port 11, so that the heat exchange medium injection port 15 can be continuously injected to realize the circulating heat exchange function; further, through the second hanger The locking and fixation with the pipe body of the surface casing B and the sealing of the intermediate sealing ring 10 enable it to be directly assembled on the pipe assembly of the wellhead, which makes the present application convenient and suitable for abandoned wellheads and idle wellheads; further, the end face of the completion flange 5 of the present application is provided with an optical fiber through hole 2, a cable through hole 3, a water outlet hole, and a sampling hole. The external optical fiber can enter the main barrel from the center hole of the completion flange 5, pass through the core shaft hanger assembly along the outer wall of the inner tube A, and enter the well together with the inner tube A to complete the temperature data monitoring and collection in the entire wellbore; the upper end of the completion flange 5 is connected to the observation hole plug, which can be used for sampling and observation, etc.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An integrated wellhead device, comprising: The casing head body, the riser flange and the completion flange are connected sequentially from bottom to top; The casing head body defines a first inner cavity, the upper end of the first inner cavity is sealedly connected to a first hanger assembly, and the lower end of the first inner cavity is sealedly connected to a second hanger assembly; The raised flange defines a second inner cavity, the second inner cavity being in communication with the first hanger assembly; The completion flange is provided with a medium output hole, and the medium output hole is communicated with the second inner cavity; Among them, the first hanger assembly can be sealed and connected with the inner pipe in the well so that the inner pipe passes through the first inner cavity and forms an annulus around the inner pipe, and the casing head body is connected with a heat exchange medium injection end and an exhaust end, the heat exchange medium injection end and the exhaust end are respectively connected to the annulus, and the exhaust end is located above the heat exchange medium injection end.

2. The integrated wellhead device according to claim 1, wherein: The invention also comprises a base assembly connected to the lower end of the casing head body, wherein the base assembly is configured to provide support for the casing head body.

3. The integrated wellhead device according to claim 1 or 2, wherein: The completion flange is provided with a cable passing hole, an optical fiber passing hole and a sampling hole. The cable passing hole and the optical fiber passing hole are respectively provided with sealing components, and the sampling hole is connected with a sealing plug.

4. The integrated wellhead device according to claim 3, wherein: The first hanger is also configured with a plurality of passages for the wire harness to pass through in a sealed manner, so that the wire harness can enter the annular space through the passages.

5. The integrated wellhead device according to claim 3, wherein: A plurality of intermediate sealing rings are arranged in the casing head body near one end of the second hanger assembly, and a grease injection check valve is arranged between the intermediate sealing rings so as to inject sealing material through the grease injection check valve to achieve sealing between the casing head body and the surface casing.

6. The integrated wellhead device according to claim 2, wherein: The base assembly comprises a base bracket and a bottom plate, wherein the bottom plate is connected to the base bracket, and the base bracket has a cavity capable of accommodating a surface sleeve.

7. The integrated wellhead device according to claim 3, wherein: The upper portion of the casing head body is provided with a plurality of top screws suitable for fixing the first hanger assembly.

8. The integrated wellhead device according to claim 3, wherein: The first hanger assembly is a mandrel hanger, and the second hanger assembly is a slip hanger.

9. The integrated wellhead device according to claim 8, wherein: The second hanger assembly includes slips and a support body suitable for supporting the slips, and the slips are configured to be fixed to the lower end of the casing head body through the support body.

10. The integrated wellhead device according to claim 9, wherein: The inner wall of the support body is provided with an inverted stepped conical surface, and the corresponding outer wall of the slip is configured with a matching stepped conical surface, so that the conical surfaces of the support body and the slip are matched and limited.

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