Vacuum bottle type oil casing for U-shaped geothermal well

Abstract

The invention relates to the technical field of petroleum pipes in the water and petroleum industry, in particular to a U-shaped thermos bottle type petroleum casing pipe for a geothermal well, which comprises an inner-layer casing pipe, an outer-layer casing pipe and a vacuum module. The inner-layer sleeve and the outer-layer sleeve are both of a hollow cylindrical structure, the outer-layer sleeve is connected with the inner-layer sleeve through two annular connecting pieces to form a vacuum interlayer, the outer wall of the outer-layer sleeve is provided with a through hole and an NPT bolt, the NPT bolt is used for vacuumizing the vacuum interlayer, the outer wall of the outer-layer sleeve is provided with a vacuum degree module, and the vacuum degree module is connected with the outer-layer sleeve. The vacuum degree module comprises a shell, an air bag, a sealing ring, a spring and a vacuum ruler and is used for monitoring the vacuum degree of the vacuum interlayer in real time. According to the thermos bottle type petroleum casing pipe for the U-shaped geothermal well, the design is similar to a thermos bottle, heat conduction can be effectively reduced, the heat preservation effect of the inner-layer casing pipe is improved, meanwhile, the monitoring module is arranged, the thermos bottle type petroleum casing pipe is suitable for the high-temperature geothermal environment, and the exploitation efficiency and safety of the geothermal well are improved.

Description

Technical Field

[0001] This invention relates to the field of oil pipe technology in the water and oil industry, and particularly to a U-shaped thermos bottle-type oil casing for geothermal wells. Background Technology

[0002] The abundance and wide distribution of geothermal resources in China provide important support for the optimization of the country's energy structure. The development of medium and low temperature geothermal resources can not only meet the energy needs of heating, greenhouse planting, aquaculture and other fields, but also effectively reduce dependence on traditional fossil energy, promote energy conservation, emission reduction and environmental protection.

[0003] The application of U-shaped geothermal well technology has made the utilization of geothermal energy more efficient and sustainable. This technology extracts heat energy without directly extracting groundwater by forming a closed-loop system in the strata, thus protecting groundwater resources. In addition, U-shaped geothermal wells have advantages such as small footprint and low operation and maintenance costs, making them one of the mainstream technologies for geothermal development today.

[0004] However, in practice, the conventional standard oil casing used in the drilling, completion, and oil production of geothermal wells is not well-suited to the specific requirements of geothermal extraction. Due to heat exchange between the formation fluids and the surrounding rock and soil during migration, significant heat loss occurs. This heat loss is particularly pronounced in areas with low-grade geothermal resources, ultimately leading to low wellhead temperatures in water intake wells. This not only affects the efficient utilization of geothermal energy but also increases the operating costs of geothermal development projects, reducing economic benefits. Summary of the Invention

[0005] (a) Technical problems to be solved This invention provides a U-shaped thermos bottle-type oil casing for geothermal wells to overcome the problem that existing standard oil casings have high heat exchange with the surrounding rock and soil media during the transport of formation fluids, resulting in heat loss of the formation fluids.

[0006] (II) Technical Solution To achieve the above objectives, the present invention provides a U-shaped geothermal well thermos bottle-type oil casing, comprising: an inner casing, an outer casing, and a vacuum module; The inner sleeve is a hollow cylindrical structure, the outer sleeve is a hollow cylindrical structure, the inner diameter of the outer sleeve is larger than the outer diameter of the inner sleeve, and the outer sleeve is located on the outer wall of the inner sleeve. The outer sleeve is connected to the inner sleeve by two annular connecting pieces, which are circular annular structures. A vacuum partition is provided between the inner sleeve and the outer sleeve. The vacuum partition is a sealed annular space composed of the outer sleeve, the inner sleeve and two annular connecting pieces. The outer sleeve has a through hole on its outer wall, and an NPT bolt is installed in the through hole; The outer wall of the outer sleeve is provided with a vacuum module, which includes: a shell, an air bladder, a sealing ring, a spring, and a vacuum gauge; The airbag is located inside the outer shell and is connected to the outer sleeve through a sealed pipe. The lower end of the airbag is provided with a sealing ring, a spring, and a vacuum gauge. The spring is connected to the lower end of the sealing ring, the sealing ring is connected to the upper end of the vacuum ruler, the lower end of the outer shell is provided with a through hole, and the upper end of the vacuum ruler is located in the through hole.

[0007] Preferably, the two annular connecting pieces are respectively disposed at the upper and lower ends of the outer sleeve, and the annular connecting pieces are connected to the outer sleeve and the inner sleeve by laser welding.

[0008] Preferably, the outer sleeve is made of stainless steel, which has tensile strength and ductility, and the length of the outer sleeve is less than the length of the inner sleeve.

[0009] Preferably, the NPT bolt is welded to the outer sleeve, and the NPT bolt is a vacuum interface. The vacuum spacer between the inner sleeve and the outer sleeve is evacuated through the NPT bolt.

[0010] Preferably, the vacuum module is used to detect the vacuum level of the vacuum compartment in the outer sleeve.

[0011] Preferably, the outer shell is a hollow cylindrical structure, and the outer shell is tightly attached to the outer wall of the outer sleeve.

[0012] Preferably, the outer diameter of the sealing ring matches the inner diameter of the outer casing, and the sealing ring can slide on the inner wall of the outer casing.

[0013] Preferably, the vacuum ruler has a cylindrical structure, and the sealing ring is integrated with the vacuum ruler.

[0014] Preferably, the spring is fitted onto the vacuum ruler, and a sealing ring is connected to the upper end of the spring, with the spring limiting the movement of the sealing ring and the vacuum ruler.

[0015] (III) Beneficial Effects This invention provides a U-shaped geothermal well casing in the form of a thermos bottle. By incorporating a vacuum layer between the inner and outer casings, heat conduction is significantly reduced, thereby improving the insulation effect of the inner casing. This design, similar to the principle of a thermos bottle, effectively maintains the temperature of the internal pipes in high-temperature geothermal environments. Two annular connecting pieces connect the inner and outer casings, ensuring the airtightness of the vacuum layer. An NPT bolt provides an interface for vacuuming. A vacuum module allows for real-time monitoring of the vacuum level within the vacuum layer. The vacuum gauge in the module retracts from its outer shell in case of sealing failure. During use, the position of the vacuum gauge can be monitored to determine the vacuum insulation effect within the casing, thus effectively improving the extraction efficiency and safety of geothermal wells. Attached Figure Description

[0016] Figure 1 This diagram illustrates a U-shaped geothermal well insulated bottle-type oil casing structure according to the present invention. Figure 2 Show Figure 1 A magnified view of part A in the diagram.

[0017] Wherein: 1: Inner sleeve; 2: Outer sleeve; 3: NPT bolt; 4: Airbag; 5: Sealing ring; 6: Spring; 7: Vacuum gauge; 8: Annular connecting piece; 9: Outer shell. Detailed Implementation

[0018] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. The technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] In the description of this invention, it is necessary to understand that the orientations or positional relationships indicated by terms such as "upper," "lower," "left," "right," "inner," "outer," "top," and "bottom" are based on the orientations or positional relationships shown in the accompanying drawings. They are intended only to facilitate the description of this invention and to simplify the description, and are not intended to indicate or imply that the components referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0020] like Figure 1-2 As shown, the present invention provides a U-shaped geothermal well thermos bottle-type oil casing, comprising: an inner casing 1, an outer casing 2, and a vacuum module; like Figure 1As shown, the U-shaped geothermal well uses a thermos-type oil casing consisting of an inner casing 1 and an outer casing 2. The inner casing 1 is a hollow cylindrical structure, and the outer casing 2 is a hollow cylindrical structure. The inner diameter of the outer casing 2 is larger than the outer diameter of the inner casing 1, so that the outer casing 2 can be fitted onto the outside of the inner casing 1. To ensure a secure connection between the inner sleeve 1 and the outer sleeve 2, the outer sleeve 2 is connected to the inner sleeve 1 via two annular connecting pieces 8. These two annular connecting pieces 8 are both circular in structure and are respectively located at the upper and lower ends of the outer sleeve 2. Through advanced laser welding technology, the annular connecting pieces 8 are firmly connected to the outer sleeve 2 and the inner sleeve 1, thereby forming a sealed annular space. This space is the vacuum layer. By evacuating the vacuum, heat conduction can be significantly reduced, and the insulation effect of the inner sleeve 1 can be improved. The outer sleeve 2 has a through hole on its outer wall, and an NPT bolt 3 is installed in the through hole. The NPT bolt 3 is fixed to the outer sleeve 2 by welding. The NPT bolt 3 is a vacuum interface. The vacuum spacer between the inner sleeve 1 and the outer sleeve 2 can be evacuated to a vacuum state through the NPT bolt 3, thereby achieving a high-efficiency heat preservation effect. The outer casing 2 is made of stainless steel, which not only has good tensile strength and ductility, but also excellent corrosion resistance, to ensure the long-term stable operation of the entire U-shaped geothermal well insulated bottle-type oil casing. It is worth noting that the length of the outer casing 2 is less than the length of the inner casing 1. This design can reduce the use of materials and lower production costs while ensuring structural strength.

[0021] like Figure 2 As shown, the outer wall of the outer sleeve 2 is provided with a vacuum module, which is used to monitor the vacuum level of the vacuum compartment in real time. The vacuum module includes: a shell 9, an airbag 4, a sealing ring 5, a spring 6, and a vacuum gauge 7. The outer shell 9 has a hollow cylindrical structure and contains an air bladder 4. The air bladder 4 is cylindrical and is attached to the upper end of the inner wall of the outer shell 9. The air bladder 4 is connected to the outer sleeve 2 through a sealed pipe, thereby communicating with the vacuum layer. The lower end of the air bladder 4 is provided with a sealing ring 5, a spring 6, and a vacuum ruler 7. One side of the outer shell 9 is sealed, while the other side has a through hole, which allows the vacuum ruler 7 to extend or retract from the through hole. The outer shell 9 is attached to the outer wall of the outer sleeve 2 to ensure its stability. The outer diameter of the sealing ring 5 matches the inner diameter of the outer shell 9. The sealing ring 5 can slide axially in the inner wall of the outer shell 9. The vacuum ruler 7 is a cylindrical structure and is integrated with the sealing ring 5. The outer diameter of the vacuum ruler 7 matches the inner diameter of the through hole provided on one side of the outer shell 9, so that the vacuum ruler 7 can move in the through hole. The spring 6 is sleeved on the vacuum ruler 7, and the upper end of the spring 6 is connected to the sealing ring 5. The spring 6 limits the sealing ring 5 to prevent it from moving excessively in the outer shell 9, and at the same time provides elastic force for the vacuum ruler 7 to return to its original position. The vacuum module is used to detect the vacuum level of the vacuum compartment in the outer sleeve 2. When the vacuum level in the vacuum compartment changes, this pressure change is transmitted to the airbag 4 through the sealed pipe. The pressure inside the airbag 4 will also change accordingly, causing the sealing ring 5 to move along the inner wall of the outer shell 9 under the push of the airbag 4. The vacuum module is not only simple and practical in design, but also capable of real-time monitoring of the vacuum level of the vacuum layer, ensuring the long-term stable operation of the system. By periodically checking and adjusting the vacuum level, the insulation effect of the inner casing 1 can be effectively maintained, further improving the extraction efficiency and safety of the geothermal well.

[0022] The following is a detailed description of the actual working scenario of a U-shaped geothermal well using a thermos-type oil casing.

[0023] In actual operation, when this type of geothermal well tubing is working normally, it is first necessary to perform a vacuuming operation using ground vacuum equipment to ensure that the vacuum barrier between the inner and outer casings reaches an ideal vacuum state. The specific operating steps are as follows: Step S1: Connect the ground vacuum equipment to the NPT bolt 3 located on the outer wall of the outer sleeve 2. The NPT bolt 3 serves as a connection point, allowing the vacuum equipment to communicate with the vacuum partition. Step S2: Start the vacuum equipment to begin extracting air from the vacuum compartment. As the vacuum process proceeds, the air pressure inside the vacuum compartment gradually decreases, forming a vacuum state. Step S3: When the air pressure inside the vacuum layer reaches the predetermined vacuum level, the vacuum pumping equipment stops working. At this time, the vacuum layer is in an ideal vacuum state. The vacuum environment formed between the outer casing 2 and the inner casing 1 helps to reduce heat loss and improve the energy utilization efficiency of the geothermal well.

[0024] During the vacuuming process, as the pressure inside the vacuum compartment decreases, the pressure in the outer sleeve 2 decreases, causing the airbag 4 to slowly expand. The airbag 4 pushes the sealing ring 5 to move downwards. During the movement of the sealing ring 5, the vacuum ruler 7 overcomes the elastic force of the spring 6 and extends downwards out of the outer shell 9. If the vacuum compartment leaks and loses its vacuum state, the pressure in the vacuum compartment will increase, and the airbag 4 will slowly retract. Under the elastic force of the spring 6, the sealing ring 5 will move upward. During the movement of the sealing ring 5, the vacuum ruler 7 will retract into the outer shell 9. By observing the extension state of the vacuum gauge 7, the vacuum status of the U-shaped geothermal well's thermos-type oil casing can be directly judged. If the vacuum gauge 7 is fully extended from the air bladder 4, it indicates that the vacuum compartment is in a good vacuum state. If the vacuum gauge 7 is partially retracted into the through hole, it indicates that there is an air leakage in the vacuum compartment, which requires timely inspection and maintenance.

[0025] It is understood that the various embodiments mentioned above in this invention can be combined with each other to form combined embodiments without violating the principle and logic. Due to space limitations, this invention will not elaborate further.

[0026] Those skilled in the art will understand that, in the above-described method of the specific implementation, the order in which each step is written does not imply a strict execution order and does not constitute any limitation on the implementation process. The specific execution order of each step should be determined by its function and possible internal logic.

[0027] This invention provides a U-shaped geothermal well tubing in the form of a thermos bottle. By setting a vacuum layer between the inner casing 1 and the outer casing 2, heat conduction is greatly reduced, thereby improving the insulation effect of the inner casing 1. This design is similar to the principle of a thermos bottle, which can effectively maintain the temperature of the internal pipes in a high-temperature geothermal environment. The inner casing 1 and the outer casing 2 are connected by two annular connecting pieces 8, ensuring the sealing of the vacuum layer. An NPT bolt 3 is provided to provide a vacuuming interface. By setting a vacuum module, the vacuum level in the vacuum layer can be monitored in real time. The vacuum gauge 7 in the vacuum module can retract from the outer shell 9 of the vacuum module when the vacuum layer fails to seal. During use, the position of the vacuum gauge 7 can be detected according to actual needs to determine the vacuum insulation effect in the tubing, thereby effectively improving the extraction efficiency and safety of geothermal wells.

[0028] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A thermos-type oil casing for U-shaped geothermal wells, characterized in that, include: Inner sleeve (1), outer sleeve (2), and vacuum module; The inner sleeve (1) is a hollow cylindrical structure, the outer sleeve (2) is a hollow cylindrical structure, the inner diameter of the outer sleeve (2) is larger than the outer diameter of the inner sleeve (1), and the outer sleeve (2) is located on the outer wall of the inner sleeve (1). The outer sleeve (2) is connected to the inner sleeve (1) through two annular connecting pieces (8), and the annular connecting pieces (8) are circular annular structures; A vacuum spacer is provided between the inner sleeve (1) and the outer sleeve (2). The vacuum spacer is a sealed annular space composed of the outer sleeve (2), the inner sleeve (1) and two annular connecting pieces (8). The outer sleeve (2) has a through hole on its outer wall, and an NPT bolt (3) is provided in the through hole; The outer wall of the outer sleeve (2) is provided with a vacuum module, which includes: a shell (9), an airbag (4), a sealing ring (5), a spring (6), and a vacuum gauge (7). The airbag (4) is located in the outer shell (9). The airbag (4) is connected to the outer sleeve (2) through a sealed pipe. The lower end of the airbag (4) is provided with a sealing ring (5), a spring (6) and a vacuum ruler (7). The spring (6) is connected to the lower end of the sealing ring (5), the sealing ring (5) is connected to the upper end of the vacuum ruler (7), the lower end of the outer shell (9) is provided with a through hole, and the lower end of the vacuum ruler (7) is located in the through hole.

2. The U-shaped geothermal well insulated bottle-type oil casing according to claim 1, characterized in that, The two annular connecting pieces (8) are respectively located at the upper and lower ends of the outer sleeve (2), and the annular connecting pieces (8) are connected to the outer sleeve (2) and the inner sleeve (1) by laser welding.

3. The U-shaped geothermal well insulated bottle-type oil casing according to claim 1, characterized in that, The outer sleeve (2) is made of stainless steel, which has tensile strength and ductility. The length of the outer sleeve (2) is less than the length of the inner sleeve (1).

4. The U-shaped geothermal well insulated bottle-type oil casing according to claim 1, characterized in that, The NPT bolt (3) is welded to the outer sleeve (2). The NPT bolt (3) is a vacuum interface. The vacuum partition between the inner sleeve (1) and the outer sleeve (2) is evacuated through the NPT bolt (3).

5. The U-shaped geothermal well insulated bottle-type oil casing according to claim 1, characterized in that, The vacuum module is used to detect the vacuum level of the vacuum compartment in the outer sleeve (2).

6. The U-shaped geothermal well insulated bottle-type oil casing according to claim 1, characterized in that, The outer shell (9) is a hollow cylindrical structure, and the outer shell (9) is tightly attached to the outer wall of the outer sleeve (2).

7. The U-shaped geothermal well insulated bottle-type oil casing according to claim 6, characterized in that, The outer diameter of the sealing ring (5) matches the inner diameter of the outer shell (9), and the sealing ring (5) can slide on the inner wall of the outer shell (9).

8. The U-shaped geothermal well insulated bottle-type oil casing according to claim 1, characterized in that, The vacuum ruler (7) is a cylindrical structure, and the sealing ring (5) is integrated with the vacuum ruler (7).

9. The U-shaped geothermal well insulated bottle-type oil casing according to claim 1, characterized in that, The spring (6) is fitted onto the vacuum ruler (7), and the upper end of the spring (6) is connected to the sealing ring (5). The spring (6) limits the sealing ring (5) and the vacuum ruler (7).

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