Double-pipe thermal recovery wellhead device

Abstract

The utility model provides a double-pipe thermal recovery wellhead device, which relates to the technical field of oil exploitation engineering and comprises an upper shaft and a lower shaft, the lower shaft is positioned at the bottom end of the upper shaft, an upper sealing mechanism body is mounted in the upper shaft, and a lower sealing mechanism body is mounted in the lower shaft. An inner heat insulation oil pipe is arranged in the upper shaft, an outer heat insulation oil pipe is arranged in the lower shaft, two sets of metal seals are arranged on the upper portion of the upper sealing mechanism body and the upper portion of the lower sealing mechanism body respectively, and four sets of sealing pieces are arranged in the two sets of metal seals respectively. The metal seal has high strength and hardness and can keep stable performance in various complex environments, due to the stability, the metal seal can still keep a good sealing effect under the severe conditions of high pressure, high temperature and the like, and the metal seal has good corrosion resistance and long service life.

Description

Technical Field

[0001] The utility model relates to the technical field of oil extraction engineering, in particular to a double-tube thermal recovery wellhead device. Background Technique

[0002] Oil extraction refers to the act of excavating and extracting oil in places where oil is stored. During the process of oil extraction, the driving mode of oil and gas flowing from the reservoir into the bottom of the well and then rising from the bottom of the well to the wellhead;

[0003] Chinese Patent Publication No. CN207315289U discloses a double-tube thermal recovery wellhead device, which includes a double-tube housing and a seal assembly. The double-tube housing includes: a first longitudinal channel, which is matched with a polished rod seal; a second longitudinal channel, which is separated from the first longitudinal channel; a first transverse channel, which is communicated with the first longitudinal channel, and a first gate valve is arranged on the first transverse channel; wherein, the seal assembly is arranged at the opening of the second longitudinal channel, and the seal assembly includes a seal body and a flow-through channel arranged on the seal body and communicated with the second longitudinal channel; the double-tube housing further includes a valve port communicated with the second longitudinal channel, and a second gate valve for controlling the on-off of the second longitudinal channel is arranged at the valve port;

[0004] In the existing design, the conventional oil pipe seal mechanism of the thermal recovery wellhead adopts graphite seal. This material has good high-temperature resistance and chemical stability, and the sealing performance is good, but its impact resistance is relatively weak. During the process of heavy oil extraction, heat needs to be injected repeatedly for multiple cycles. During this process, the graphite seal may be damaged by impacts such as steam and cause failure, and the graphite seal needs to be compressed to play a sealing role, which is inconvenient for installation;

[0005] Therefore, a double-tube thermal recovery wellhead device is designed to solve the above problems. Content of the Utility Model

[0006] The purpose of the utility model is to solve the technical problems put forward in the above background technique.

[0007] The utility model adopts the following technical scheme: a double-tube thermal recovery wellhead device, which includes an upper wellbore and a lower wellbore. The lower wellbore is located at the bottom end of the upper wellbore. An upper seal mechanism body is installed inside the upper wellbore, a lower seal mechanism body is installed inside the lower wellbore, an inner heat-insulated oil pipe is arranged inside the upper wellbore, and an outer heat-insulated oil pipe is arranged inside the lower wellbore.

[0008] Preferably, as a double-tube thermal recovery wellhead device of the utility model, an upper injection port is arranged at the top end of the upper wellbore, a side injection port is arranged on one side of the upper wellbore, and a production outlet is arranged on the other side of the upper wellbore.

[0009] Preferably, as a dual-tube thermal recovery wellhead device of the present utility model, the inner heat-insulating tubing is disposed inside the upper wellbore and the lower wellbore, the outer heat-insulating tubing is sleeved on the surface of the inner heat-insulating tubing, and an annular space is formed between the outer heat-insulating tubing and the inner heat-insulating tubing.

[0010] Preferably, as a dual-tube thermal recovery wellhead device of the present utility model, metal seals are provided on the upper parts of the upper sealing mechanism body and the lower sealing mechanism body.

[0011] Preferably, as a dual-tube thermal recovery wellhead device of the present utility model, there are two sets of the metal seals, and the two sets of metal seals are symmetrically distributed on the upper parts of the upper sealing mechanism body and the lower sealing mechanism body respectively.

[0012] Preferably, as a dual-tube thermal recovery wellhead device of the present utility model, four sets of sealing members are provided inside each of the two sets of metal seals.

[0013] Preferably, as a dual-tube thermal recovery wellhead device of the present utility model, the sealing surfaces of two of the sets of sealing members face the tops of the upper sealing mechanism body and the lower sealing mechanism body, and the sealing surfaces of the other two sets of sealing members face the bottoms of the upper sealing mechanism body and the lower sealing mechanism body.

[0014] Compared with the prior art, the advantages and positive effects of the present utility model are as follows.

[0015] 1. In the present utility model, during use, when the medium reaches the metal seal, it surges into the internal annular space to cause the metal seal to expand, realizing the seal between the sealing mechanism and the wellbore. At the same time, the metal seal has high strength and hardness, and can maintain stable performance in various complex environments. This stability enables it to maintain a good sealing effect under harsh conditions such as high pressure and high temperature, has good corrosion resistance, and a long service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic diagram of a dual-tube thermal recovery wellhead device proposed by the present utility model;

[0017] Figure 2 is a cross-sectional view of a dual-tube thermal recovery wellhead device proposed by the present utility model;

[0018] Figure 3 is a cross-sectional view of the structure of the upper sealing mechanism body of a dual-tube thermal recovery wellhead device proposed by the present utility model;

[0019] Figure 4 is a cross-sectional view of the structure of the lower sealing mechanism body of a dual-tube thermal recovery wellhead device proposed by the present utility model;

[0020] Figure 5This utility model provides a cross-sectional view of the seal structure of a dual-tube thermal recovery wellhead device.

[0021] Legend Explanation:

[0022] 1. Outer heat-insulated tubing; 2. Lower wellbore; 3. Lower seal mechanism body; 4. Inner heat-insulated tubing; 5. Upper wellbore; 6. Upper seal mechanism body; 7. Upper injection port; 8. Side injection port; 9. Production outlet; 10. Metal seal; 11. Seal. Specific Embodiment

[0023] In order to more clearly understand the above-mentioned objects, features, and advantages of this utility model, the following further describes this utility model with reference to the drawings and embodiments. It should be noted that, without conflict, the embodiments of this application and the features in the embodiments can be combined with each other.

[0024] In the following description, many specific details are set forth to facilitate a full understanding of this utility model. However, this utility model can also be implemented in other ways different from those described herein. Therefore, this utility model is not limited by the specific embodiments disclosed in the following specification.

[0025] Embodiment

[0026] Please refer to Figures 1-5 , this utility model provides a technical solution: a dual-tube thermal recovery wellhead device, including an upper wellbore 5 and a lower wellbore 2. The lower wellbore 2 is located at the bottom end of the upper wellbore 5. An upper injection port 7 is provided at the top end of the upper wellbore 5. A side injection port 8 is provided on one side of the upper wellbore 5. A production outlet 9 is provided on the other side of the upper wellbore 5. An upper seal mechanism body 6 is installed inside the upper wellbore 5. Metal seals 10 are provided on the upper parts of both the upper seal mechanism body 6 and the lower seal mechanism body 3. The number of metal seals 10 is two groups. The two groups of metal seals 10 are symmetrically distributed on the upper parts of the upper seal mechanism body 6 and the lower seal mechanism body 3 respectively. Four groups of seals 11 are provided inside the two groups of metal seals 10. The sealing surfaces of two of the seals 11 face the top ends of the upper seal mechanism body 6 and the lower seal mechanism body 3, and can seal the medium from the upper channel. The sealing surfaces of the other two seals 11 face the bottom ends of the upper seal mechanism body 6 and the lower seal mechanism body 3, and can seal the medium from the lower channel. A lower seal mechanism body 3 is installed inside the lower wellbore 2. An inner heat-insulated tubing 4 is provided inside the upper wellbore 5. The inner heat-insulated tubing 4 is arranged inside the upper wellbore 5 and the lower wellbore 2. An outer heat-insulated tubing 1 is provided inside the lower wellbore 2. The outer heat-insulated tubing 1 is sleeved on the surface of the inner heat-insulated tubing 4, and an annular space is formed between the outer heat-insulated tubing 1 and the inner heat-insulated tubing 4.

[0027] Working principle: During the gas injection operation, high-temperature steam is injected into the oil reservoir through the upper injection port 7 and the side injection port 8. After the steam diffusion operation is completed, power fluid is injected into the well from the upper injection port 7 to drive the oil and gas to return from the annular space between the inner heat-insulating tubing 4 and the outer heat-insulating tubing 1, and then the oil and gas are produced from the production outlet 9. Since the lower sealing mechanism body 3 is installed inside the lower wellbore 2 and the upper sealing mechanism body 6 is installed inside the upper wellbore 5, a metal seal 10 is installed in the lower sealing mechanism body 3 and the upper sealing mechanism body 6. The metal seal 10 is composed of seal members 11. When the medium reaches the metal seal 10, it surges into the internal annular space to cause the seal members 11 to expand, realizing the seal between the sealing mechanism and the wellbore.

[0028] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention in other forms. Any person skilled in the art may use the disclosed technical content to make changes or modifications into equivalent embodiments with equivalent changes and apply them to other fields. However, as long as it does not depart from the technical solution content of the present invention, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A dual-tube thermal recovery wellhead device, comprising an upper wellbore (5) and a lower wellbore (2), characterized in that: The lower wellbore (2) is located at the bottom end of the upper wellbore (5). An upper sealing mechanism body (6) is installed inside the upper wellbore (5), and a lower sealing mechanism body (3) is installed inside the lower wellbore (2). An inner heat-insulating oil pipe (4) is arranged inside the upper wellbore (5), and an outer heat-insulating oil pipe (1) is arranged inside the lower wellbore (2); Metal seals (10) are arranged on the upper parts of both the upper sealing mechanism body (6) and the lower sealing mechanism body (3); There are two groups of the metal seals (10), and the two groups of the metal seals (10) are symmetrically distributed on the upper parts of the upper sealing mechanism body (6) and the lower sealing mechanism body (3) respectively; Four sealing elements (11) are arranged inside each of the two groups of the metal seals (10).

2. The dual-tube thermal recovery wellhead device according to claim 1, characterized in that: An upper injection port (7) is arranged at the top end of the upper wellbore (5), a side injection port (8) is arranged on one side of the upper wellbore (5), and a production outlet (9) is arranged on the other side of the upper wellbore (5).

3. The double-tube thermal recovery wellhead device according to claim 1, characterized in that: The inner heat-insulating oil pipe (4) is arranged inside the upper wellbore (5) and the lower wellbore (2), and the outer heat-insulating oil pipe (1) is sleeved on the surface of the inner heat-insulating oil pipe (4), and an annular space is formed between the outer heat-insulating oil pipe (1) and the inner heat-insulating oil pipe (4).

4. The dual-tube thermal recovery wellhead device according to claim 1, wherein: The sealing surfaces of two of the sealing elements (11) face the top ends of the upper sealing mechanism body (6) and the lower sealing mechanism body (3), and the sealing surfaces of the other two sealing elements (11) face the bottom ends of the upper sealing mechanism body (6) and the lower sealing mechanism body (3).

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