Wellhead hanging sealing device for oilfield temperature and pressure measuring cable under pressure

Abstract

This utility model discloses a wellhead suspension and sealing device for running temperature and pressure measuring cables under pressure in oilfields, belonging to the field of oil well parameter detection technology. The device includes a suspension body, a large sealing ring, a large pressure ring, a pressure ring bushing, a large sealing nut, a small sealing ring, and a small sealing nut. The suspension body has a first central hole and a first sealing cavity, with the large sealing ring and large pressure ring located within the first sealing cavity. The large sealing nut has a second central hole and a second sealing cavity, with the small sealing ring located within the second sealing cavity. The large sealing nut is threadedly connected to the pressure ring bushing, and the small sealing nut is threadedly connected to the large sealing nut. The first and second central holes together form a central channel. This device can seal and clamp the temperature and pressure measuring cables through a two-stage axial compression sealing structure. It has a compact structure and is suitable for running temperature and pressure measuring cables under pressure in oil wells.

Description

Technical Field

[0001] This utility model belongs to the field of oil well parameter detection technology, specifically relating to a wellhead suspension sealing device for oilfield temperature and pressure measuring cables being run under pressure. Background Technology

[0002] Steam-assisted gravity drainage (SAGD) technology has been widely used in heavy oil thermal recovery in recent years. During this process, if the temperature and pressure parameters of key locations within the well can be obtained in real time, the steam injection parameters and production equipment parameters can be adjusted accordingly, increasing well production and reducing costs. To obtain downhole parameters, a common method involves inserting temperature and pressure measuring cables, ranging from hundreds to thousands of meters in length, into the well. These cables utilize thermocouples, capillaries, optical fibers, and pressure sensors to measure temperature and pressure at different locations within the well in real time, transmitting the signals to receiving equipment on the surface.

[0003] Because the temperature in SAGD oil wells can typically reach around 200℃ and the pressure can reach 2-3 MPa, it is a high-temperature and high-pressure environment. Therefore, a crucial issue to address during the insertion of temperature and pressure measuring cables into the well is ensuring effective sealing of the wellhead during the continuous cable insertion process, thereby guaranteeing operational safety. Currently, the most common method is to stop steam injection before cable injection, then inject a certain amount of cold water or kill fluid into the well. This lowers the well's temperature and pressure through cooling and the pressure of the coolant column, allowing the cable injection operation to begin—that is, completing the cable injection under cooled and depressurized conditions. After the operation is completed, steam injection is resumed, and once the pumping unit starts pumping, the low-temperature medium is gradually extracted, allowing the temperature and pressure of the oil produced in the well to gradually return to normal. However, this well-killing process disrupts the original state of the SAGD downhole conditions. After each well-killing, the pumping unit needs to pump fluid continuously for several days to resume oil production. This not only seriously affects the production of the oil well, but sometimes even completely destroys the downhole temperature and pressure environment that was established after several months of steam injection, which cannot be restored for a long time.

[0004] Therefore, using pressurized downhole methods to inject temperature and pressure measuring cables with minimal or no well pressure is highly economical. In recent years, related pressurized downhole devices and cable installation processes have received widespread attention in oilfields. Therefore, developing a wellhead sealing device capable of safely injecting temperature and pressure measuring cables under pressurized conditions with minimal or no well pressure has become an urgent technical challenge to be solved in oilfields. Utility Model Content

[0005] To address the aforementioned problems in the existing technology, this utility model provides a wellhead suspension and sealing device for oilfield temperature and pressure measuring cables under pressure. This device uses a two-stage independent locking and sealing structure, as well as the friction between the sealing element and the cable, as a suspension means to solve the problems of difficulty in sealing the wellhead, high well control operation costs, and impact on production when cables are under pressure in the existing technology.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A wellhead suspension sealing device for running oilfield temperature and pressure measuring cables under pressure includes a suspension body, a large sealing ring, a large pressure ring, a pressure ring bushing, a large well-sealing nut, a small sealing ring, and a small well-sealing nut. The suspension body has a first central hole extending axially, and the upper part of the suspension body forms a first sealing cavity communicating with the first central hole. The large sealing ring and the large pressure ring are axially disposed within the first sealing cavity. The lower part of the pressure ring bushing is fitted onto the outside of the suspension body and threadedly connected. The large well-sealing nut is threadedly connected to the pressure ring bushing and abuts against the large pressure ring. The large well-sealing nut has a second central hole communicating with the first central hole, and the upper part of the large well-sealing nut forms a second sealing cavity communicating with the second central hole. The small sealing ring is disposed within the second sealing cavity, and the small well-sealing nut is threadedly connected to the large well-sealing nut. The first central hole and the second central hole together form a central channel through which the temperature and pressure measuring cables pass.

[0007] Furthermore, the large sealing ring and the large pressure ring are arranged sequentially from bottom to top in the first sealing cavity, with the lower end face of the large sealing nut facing the upper end face of the large pressure ring, together forming the first-stage axial clamping structure.

[0008] Furthermore, a small sealing ring is disposed in the second sealing cavity, and the lower end face of the small sealing nut is disposed opposite to the upper end face of the small sealing ring, together forming the second-stage axial clamping structure.

[0009] Furthermore, both the large and small sealing rings are annular seals, and the inner holes of both the large and small sealing rings are coaxially arranged with the central channel. The axial end face of the large sealing ring is opposite to the large pressure ring, and the axial end face of the small sealing ring is opposite to the small well-sealing nut. Under axial compression, an annular sealing surface can be formed that fits against the outer wall of the temperature and pressure measuring cable or the outer wall of the sealing plug rod.

[0010] Furthermore, both the upper outer circumferential surface of the large well-sealing nut and the upper outer circumferential surface of the small well-sealing nut are provided with hexagonal clamping parts; the lower outer circumferential surface of the large well-sealing nut is provided with threads that mate with the upper inner circumferential surface of the pressure ring bushing, and the lower outer circumferential surface of the small well-sealing nut is provided with threads that mate with the inner circumferential surface of the large well-sealing nut.

[0011] Furthermore, the lower end of the suspension body is provided with a tapered thread connection part for connecting with the wellhead cover plate of the oil well. The tapered thread connection part is coaxially arranged with the first central hole of the suspension body.

[0012] Furthermore, the large sealing ring and the small sealing ring each have an annular inner wall surrounding the central channel, and the annular inner wall forms a clamping contact surface for the outer wall of the temperature and pressure measuring cable.

[0013] Furthermore, the device also includes a detachable sealing rod; the sealing rod includes a rod body and a limiting head located at the upper end of the rod body. The rod body is a columnar component that is clearance-fitted with the central channel. Its outer diameter is adapted to the outer diameter of the temperature and pressure measuring cable, and the axial length of the rod body covers the axial sealing area where the large sealing ring and the small sealing ring are located.

[0014] Furthermore, the large sealing ring includes multiple large annular sealing pieces stacked along the axial direction, and the small sealing ring includes multiple small annular sealing pieces stacked along the axial direction; the large sealing ring and the small sealing ring can be made of materials that are resistant to high temperature and oil and gas corrosion, and the materials are selected from one or more of polytetrafluoroethylene plastic, high temperature resistant rubber, graphite materials or fiber reinforced graphite materials.

[0015] Compared with existing technologies, this utility model forms a two-stage axial compression sealing structure with the suspension body, pressure ring bushing and two-stage threaded clamping parts arranged coaxially. It can seal and clamp the outer wall of the temperature and pressure measuring cable when it passes through the central channel, which helps to achieve safe injection of temperature and pressure measuring cables under high temperature and high pressure conditions, reduces the time and amount of cooling medium used in traditional well killing operations, reduces operating costs, avoids damage to the downhole temperature and pressure environment caused by long-term well killing, and shortens the oil well recovery production cycle. At the same time, the device has a compact structure, few parts, simple operation, and can be reused. It is suitable for various wellhead installation angles and has strong field adaptability. Attached Figure Description

[0016] Figure 1 An axial sectional view of the wellhead suspension sealing device of this utility model when installing temperature and pressure measuring cables; Figure 2 This is an axial sectional view of the wellhead suspension sealing device of this utility model when it is installed at the wellhead of an oil well and connected to the well casing.

[0017] Explanation of reference numerals in the attached figures: 1: Oil wellhead; 2: Suspension body; 3: Large sealing ring; 4: Large pressure ring; 5: Pressure ring bushing; 6: Large well sealing nut; 7: Small sealing ring; 8: Small well sealing nut; 9: Temperature and pressure measuring cable; 10: Sealing plug rod; 11: Oil well casing. Detailed Implementation

[0018] These embodiments are provided to make the present invention thorough and complete, and to fully express the scope of the present invention to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, material composition, numerical expressions, and values ​​set forth in these embodiments should be interpreted as merely exemplary and not as limiting.

[0019] This utility model includes a suspension body 2, a large sealing ring 3, a large pressure ring 4, a pressure ring bushing 5, a large well-sealing nut 6, a small sealing ring 7, and a small well-sealing nut 8. A sealing plug rod 10 can also be provided as a spare part if necessary. The suspension body 2 is made of carbon steel or stainless steel, with tapered threads machined at the lower end for direct screwing and fixing to the wellhead cover plate. High-temperature resistant metal sealant can be applied to the threads during installation to enhance sealing reliability. The upper part of the suspension body 2 forms a stepped hollow structure and has a first sealing cavity. The large sealing ring 3 and the large pressure ring 4 are arranged in the first sealing cavity from bottom to top. The lower part of the pressure ring bushing 5 is fitted onto the outside of the suspension body 2. The large well-sealing nut 6 is threadedly connected to the pressure ring bushing 5, and the lower end face of the large well-sealing nut 6 is opposite to the upper end face of the large pressure ring 4, thus forming a first-stage axial compression structure. The upper part of the large sealing nut 6 forms a second sealing cavity, and the small sealing ring 7 is set in the second sealing cavity. The small sealing nut 8 is threaded to the inner side of the large sealing nut 6 and is set opposite to the small sealing ring 7, thus forming a second-stage axial compression structure. The first center hole and the second center hole together form a central channel for the temperature and pressure measuring cable 9 to pass through. The outer circumference of both the large sealing nut 6 and the small sealing nut 8 are provided with hexagonal clamping parts, which facilitates quick tightening or loosening with a wrench on site. The large sealing ring 3 and the small sealing ring 7 are the core sealing elements of this device, and are made of high-temperature resistant and oil and gas corrosion resistant materials such as polytetrafluoroethylene plastic, high-temperature resistant rubber, graphite or fiber-reinforced graphite. The sealing plug rod 10 includes a rod body and a limiting head located at the upper end of the rod body. The outer diameter of the rod body is adapted to the outer diameter of the temperature and pressure measuring cable 9. When the temperature and pressure measuring cable 9 is not installed, the large sealing ring 3 and the small sealing ring 7 can form a sealing contact with the outer circumference of its rod body.

[0020] The embodiments of this utility model will be further described in detail below with reference to the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to illustrate the principles of this utility model by way of example, but should not be used to limit the scope of this utility model. This utility model can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0021] Example 1: Reference Figure 1 and Figure 2As shown, a SAGD production well in an oilfield has a vertical section length of 420m, a horizontal section length of 210m, and a wellbore diameter of 214mm. The wellhead operating pressure is typically between 2MPa and 3MPa, with a daily fluid production of approximately 130 cubic meters. Before operation, a measuring auxiliary pipe for introducing temperature and pressure measuring cables 9 is pre-installed inside the wellbore 11. The measuring auxiliary pipe can be made of 20# steel pipe with an outer diameter of 50mm. The temperature and pressure measuring cables 9 have a total length of approximately 620m, with an outer 316L stainless steel armored pipe with an outer diameter of 18mm, and multiple sets of thermocouple temperature measuring points and pressure transmission units installed inside.

[0022] In this embodiment, the suspension body 2 is made of stainless steel and is a stepped hollow component. Its lower end has a tapered threaded connection that connects to the upper cover plate of the oil wellhead 1. The first central hole of the suspension body 2 is axially continuous. A first sealing cavity is formed in the upper part of the suspension body 2, and a large sealing ring 3 and a large pressure ring 4 are arranged in the first sealing cavity from bottom to top. The large sealing ring 3 is formed by stacking five large annular sealing pieces. Each large annular sealing piece has an outer diameter of approximately 60 mm, an inner diameter of approximately 18.4 mm, and a thickness of approximately 6 mm. The large pressure ring 4 is located above the large sealing ring 3, with its lower end face opposite to the upper end face of the large sealing ring 3.

[0023] A pressure ring bushing 5 is located on the upper part of the suspension body 2, with its lower end fitted onto the outer side of the suspension body 2 and threadedly connected. A large sealing nut 6 is fitted inside the pressure ring bushing 5 and threadedly connected to the inner circumferential surface of the pressure ring bushing 5. The upper outer circumferential surface of the large sealing nut 6 has a hexagonal clamping part for easy wrench clamping. A second sealing cavity is formed on the upper part of the large sealing nut 6, and a small sealing ring 7 is located in the second sealing cavity. The small sealing ring 7 is formed by stacking four small annular sealing pieces, each with an outer diameter of approximately 40 mm, an inner diameter of approximately 18.4 mm, and a thickness of approximately 6 mm. A small sealing nut 8 is threadedly connected to the large sealing nut 6, with its lower end face facing the upper end face of the small sealing ring 7.

[0024] In this embodiment, the first central hole and the second central hole are coaxially connected and together form a central channel. When the temperature and pressure measuring cable 9 passes through the central channel, the annular inner walls of the large sealing ring 3 and the small sealing ring 7 are respectively arranged around the outer wall of the temperature and pressure measuring cable 9. When the large sealing nut 6 is screwed down, axial clamping force is transmitted to the large sealing ring 3 through the pressure ring bushing 5 and the large pressure ring 4; when the small sealing nut 8 is screwed down, axial clamping force is applied to the small sealing ring 7. After being compressed, the large sealing ring 3 and the small sealing ring 7 can respectively form annular sealing surfaces that fit against the outer wall of the temperature and pressure measuring cable 9, so that the device has a sealing and clamping function in both the moving and stopped states of the temperature and pressure measuring cable 9.

[0025] The exemplary usage is as follows: Before well completion and steam injection, the suspension body 2 is permanently fixed to the upper cover plate of the wellhead 1 via the tapered thread connection and high-temperature resistant sealant. The sealing plug rod 10 is inserted into the central channel, putting the wellhead in a standby sealing state. When it is necessary to install the temperature and pressure measuring cable 9, first use a small amount of cold water (about 5 m³) to briefly reduce the wellhead temperature to about 30°C and the wellhead pressure to the allowable operating pressure range, but it is not necessary to completely reduce the wellhead to atmospheric pressure. Then loosen the two-stage nuts, pull out the sealing plug rod 10, and introduce the temperature and pressure measuring cable 9 downward from the central channel into the measuring auxiliary pipe inside the wellbore 11. Confirm that it has entered the measuring auxiliary pipe for more than 1.5 m. Then adjust the large sealing nut 6 and the small sealing nut 8 respectively, and start the cable injection machine to inject at a speed of 5-10 m / min. If a slight leak occurs during the injection process, it can be paused at any time and the large sealing nut 6 and the small sealing nut 8 can be tightened again to make both sealing rings form circumferential contact with the outer wall of the temperature and pressure measuring cable 9. After all temperature and pressure measuring cables 9 are inserted, the large sealing nut 6 and the small sealing nut 8 are finally tightened, the surface control box is connected, and the pumping unit is started. Approximately 3 hours later, the wellhead temperature and pressure return to normal, and stable oil production begins. After all temperature and pressure measuring cables 9 are inserted, the large sealing ring 3 and the small sealing ring 7 are positioned within the circumferential limiting wall of their corresponding sealing cavities. Under axial compression, their axial compression deformation is restricted and converted into radial compression deformation towards the central channel, thus forming a circumferentially continuous sealing clamping surface on the outer wall of the temperature and pressure measuring cables 9. The two sealing clamping surfaces are spaced apart axially, forming a double-support clamping suspension structure, thereby reducing the risk of axial slippage of the temperature and pressure measuring cables due to their own weight or wellhead vibration. The annular inner walls of the two-stage sealing rings continue to form clamping contact surfaces with the outer wall of the temperature and pressure measuring cables 9, thus serving both sealing and suspension functions.

[0026] In this embodiment, the device has a maximum outer diameter of approximately 100mm and a total height of approximately 250mm, allowing it to be installed in the area of ​​a conventional SAGD wellhead cover without significantly interfering with the layout of wellhead valves and external pipelines. After continuous field use, the temperature and pressure measuring cable 9 did not show significant slippage during operation, no visible leakage occurred at the wellhead, and the temperature data was stably transmitted to the surface acquisition equipment. This indicates that the device can meet the requirements for pressurized installation and long-term suspended sealing of temperature and pressure measuring cables in heavy oil thermal recovery wells.

[0027] Example 2: This example provides a wellhead suspension sealing device suitable for temperature and pressure measuring composite cables with small outer diameters. Its basic structure is the same as that of Example 1, except that the size of the central channel, the inner hole of the sealing ring, and the number of sealing plates are adapted to the outer diameter of the temperature and pressure measuring cable 9. In this example, the temperature and pressure measuring cable 9 is a composite temperature and pressure measuring cable with an outer diameter of approximately 12 mm. The cable is equipped with an optical fiber temperature measuring unit and a capillary pressure measuring unit inside, and is protected by a metal armor layer on the outside.

[0028] To accommodate the outer diameter of the temperature and pressure measuring cable 9, the large sealing ring 3 is formed by stacking four large annular sealing plates, each with an inner diameter of approximately 12.3 mm; the small sealing ring 7 is formed by stacking three small annular sealing plates, each with an inner diameter of approximately 12.3 mm. The large sealing ring 3 and small sealing ring 7 can be made of high-temperature resistant rubber and graphite composite sealing plates, or a combination structure of alternating stacked polytetrafluoroethylene (PTFE) and graphite sealing plates. Through this arrangement, the large sealing ring 3 provides the primary wellhead sealing area, while the small sealing ring 7 forms a second auxiliary seal and clamping support above it.

[0029] In this embodiment, the second central hole of the large sealing nut 6 is coaxial with the first central hole of the suspension body 2. The lower end face of the large sealing nut 6, the large pressure ring 4, and the large sealing ring 3 sequentially form the first-stage axial clamping path; the lower end face of the small sealing nut 8 and the small sealing ring 7 form the second-stage axial clamping path. Since the two-stage axial clamping paths are arranged along the same central channel, the circumferential clamping force on the temperature and pressure measuring cable 9 is more uniform, which can reduce the risk of localized damage, uneven wear, or uneven sealing of the cable.

[0030] This embodiment is suitable for wellhead inspection scenarios with small cable outer diameters and high cable flexibility. In use, the small sealing ring 7 is initially tightened using the small sealing nut 8 to keep the temperature and pressure measuring cable 9 centered during installation. Then, the large sealing ring 3 is tightened using the large sealing nut 6, allowing the first-stage sealing structure to assume the primary sealing function. After installation, both stages of the sealing structure maintain clamping contact with the temperature and pressure measuring cable 9, thereby reducing the possibility of the cable 9 sliding down the well due to its own weight without the need for an additional independent hanger.

[0031] Example 3: This example provides a standby sealing structure for when the temperature and pressure measuring cable 9 is not installed or after it has been removed. Its basic structure is the same as in Example 1, except that the temperature and pressure measuring cable 9 is not installed in the central channel; instead, a sealing rod 10 is installed. The sealing rod 10 includes a columnar rod body and a limiting head located at the upper end of the rod body. The outer diameter of the columnar rod body is adapted to the outer diameter of the temperature and pressure measuring cable 9 to be installed, and the axial length of the columnar rod body is greater than the axial distance between the large sealing ring 3 and the small sealing ring 7, allowing it to pass through the axial sealing areas where both the large sealing ring 3 and the small sealing ring 7 are located simultaneously.

[0032] Specifically, when the outer diameter of the temperature and pressure measuring cable 9 is 18mm, the outer diameter of the sealing plug rod 10 can be set to approximately 18mm to 18.3mm; when the outer diameter of the temperature and pressure measuring cable 9 is 12mm, the outer diameter of the sealing plug rod 10 can be set to approximately 12mm to 12.3mm. The outer diameter of the limiting head at the upper end of the sealing plug rod 10 is larger than the diameter of the center hole of the small well sealing nut 8, so that the sealing plug rod 10 can be restricted above the device by the limiting head, preventing it from sliding down into the well under the action of wellhead pressure changes or vibration.

[0033] In the standby sealing state, the rod of the sealing plug 10 passes sequentially through the small sealing nut 8, the small sealing ring 7, the large sealing nut 6, the large pressure ring 4, and the large sealing ring 3, extending into the first central hole of the suspension body 2. The large sealing nut 6 is threadedly connected to the pressure ring bushing 5, and the small sealing nut 8 is threadedly connected to the large sealing nut 6. The two sets of nuts respectively cause the large sealing ring 3 and the small sealing ring 7 to form an annular sealing contact surface around the rod of the sealing plug 10. Thus, even without the temperature and pressure measuring cable 9 installed, the device can maintain the closed state of the wellhead central channel.

[0034] This embodiment is also applicable to temporary sealing scenarios after the temperature and pressure measuring cable 9 has been regularly inspected or replaced. Since the outer diameter of the sealing plug rod 10 is compatible with the outer diameter of the temperature and pressure measuring cable 9, it is not necessary to replace the suspension body 2, pressure ring bushing 5, large well sealing nut 6 and small well sealing nut 8 before and after replacing the temperature and pressure measuring cable 9. Only the sealing plug rod 10 and sealing ring assembly of the appropriate size need to be selected according to the actual cable outer diameter to restore the wellhead sealing state.

[0035] In the above embodiments, after the temperature and pressure measuring cable 9 is injected, the device remains reliably sealed and suspended. It has been running continuously for 120 days without any leakage, and the temperature measurement data is stably transmitted to the oilfield data center, which fully verifies the safety and reliability of the device.

[0036] The various embodiments of this utility model have now been described in detail. To avoid obscuring the concept of this utility model, some details known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0037] It should be noted that, in the description of this utility model, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicating orientation or positional relationships, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0038] Furthermore, the terms "first," "second," and similar words used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. "Vertical" is not strictly vertical, but within the allowable error range. "Parallel" is not strictly parallel, but within the allowable error range. Words such as "including" or "comprising" mean that the element preceding the word encompasses the element listed after it, and do not exclude the possibility of encompassing other elements as well.

[0039] It should also be noted that, in the description of this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this utility model depending on the specific circumstances. When a specific device is described as being located between a first device and a second device, an intermediary device may or may not be present between the specific device and the first or second device.

[0040] All terms used in this invention have the same meaning as understood by one of ordinary skill in the art to which this invention pertains, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant art, and not as idealized or highly formalized, unless expressly defined herein.

[0041] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0042] Although specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Those skilled in the art should understand that modifications can be made to the above embodiments or equivalent substitutions can be made to some technical features without departing from the scope and spirit of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any manner.

Claims

1. A wellhead suspension sealing device for running pressurized oilfield temperature and pressure measuring cables into wells, characterized in that: The system includes a suspension body (2), a large sealing ring (3), a large pressure ring (4), a pressure ring bushing (5), a large well-sealing nut (6), a small sealing ring (7), and a small well-sealing nut (8). The suspension body (2) has a first central hole that extends axially, and the upper part of the suspension body (2) forms a first sealing cavity that communicates with the first central hole. The large sealing ring (3) and the large pressure ring (4) are arranged axially in the first sealing cavity. The lower part of the pressure ring bushing (5) is sleeved on the outside of the suspension body (2) and threadedly connected. The large well-sealing nut (6) is threadedly connected to the pressure ring bushing (5) and abuts against the large pressure ring (4). The large sealing nut (6) is provided with a second central hole that communicates with the first central hole, and the upper part of the large sealing nut (6) forms a second sealing cavity that communicates with the second central hole; the small sealing ring (7) is disposed in the second sealing cavity, and the small sealing nut (8) is threadedly connected to the large sealing nut (6); the first central hole and the second central hole together form a central channel through which the temperature and pressure measuring cable (9) passes.

2. The wellhead suspension sealing device for running oilfield temperature and pressure measuring cables under pressure in wells according to claim 1, characterized in that: The large sealing ring (3) and the large pressure ring (4) are arranged sequentially from bottom to top in the first sealing cavity. The lower end face of the large sealing nut (6) is arranged opposite to the upper end face of the large pressure ring (4), and together with the large sealing ring (3), they form the first-stage axial compression structure.

3. The wellhead suspension sealing device for running oilfield temperature and pressure measuring cables under pressure in wells according to claim 1, characterized in that: The small sealing ring (7) is disposed in the second sealing cavity, and the lower end face of the small sealing nut (8) is disposed opposite to the upper end face of the small sealing ring (7), together forming the second-stage axial pressing structure.

4. The wellhead suspension sealing device for running oilfield temperature and pressure measuring cables under pressure in wells according to claim 1, characterized in that: Both the large sealing ring (3) and the small sealing ring (7) are annular seals. The inner holes of the large sealing ring (3) and the small sealing ring (7) are coaxially arranged with the central channel. The axial end face of the large sealing ring (3) is arranged opposite to the large pressure ring (4), and the axial end face of the small sealing ring (7) is arranged opposite to the small well sealing nut (8).

5. The wellhead suspension sealing device for running oilfield temperature and pressure measuring cables under pressure in wells according to claim 1, characterized in that: The upper outer circumferential surface of the large well sealing nut (6) and the upper outer circumferential surface of the small well sealing nut (8) are both provided with hexagonal clamping parts; the lower outer circumferential surface of the large well sealing nut (6) is provided with threads that mate with the upper inner circumferential surface of the pressure ring bushing (5), and the lower outer circumferential surface of the small well sealing nut (8) is provided with threads that mate with the inner circumferential surface of the large well sealing nut (6).

6. The wellhead suspension sealing device for running oilfield temperature and pressure measuring cables under pressure in wells according to claim 1, characterized in that: The lower end of the suspension body (2) is provided with a tapered thread connection part for connecting with the upper cover plate of the oil wellhead (1), and the tapered thread connection part is coaxially arranged with the first central hole.

7. The wellhead suspension sealing device for running oilfield temperature and pressure measuring cables under pressure in wells according to claim 1, characterized in that: The large sealing ring (3) and the small sealing ring (7) each have an annular inner wall surrounding the central channel, and the annular inner wall forms a clamping contact surface for the outer wall of the temperature and pressure measuring cable (9).

8. The wellhead suspension sealing device for running oilfield temperature and pressure measuring cables under pressure in wells according to claim 1, characterized in that: The wellhead suspension sealing device also includes a detachable sealing plug rod (10). The sealing plug rod (10) includes a rod body and a limiting head located at the upper end of the rod body. The rod body is a columnar member that is clearance-fitted with the central channel. The outer diameter of the rod body is adapted to the outer diameter of the temperature and pressure measuring cable (9), and the axial length of the rod body covers the axial sealing area where the large sealing ring (3) and the small sealing ring (7) are located.

9. The wellhead suspension sealing device for running oilfield temperature and pressure measuring cables under pressure in wells according to claim 1, characterized in that: The large sealing ring (3) includes multiple large annular sealing pieces stacked along the axial direction, and the small sealing ring (7) includes multiple small annular sealing pieces stacked along the axial direction. The multiple annular sealing pieces together form a multi-level annular sealing clamping surface under axial compression.

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