Heat preservation structure of geothermal heat recovery well

Abstract

The utility model relates to a heat preservation structure of a geothermal heat recovery well, which solves the problems that the depth of the geothermal heat energy heat recovery well of a dry and hot rock stratum is large, heat preservation is insufficient in the collection process, and particularly heat exchange exists between cold water and hot water of a single well structure, and pressure is unbalanced. A casing pipe used for reinforcing is arranged on the well wall of the upper middle portion of a heat recovery well, a circumferential heat preservation layer is arranged on the periphery of the casing pipe, a partition plate is arranged in the middle of the casing pipe, the partition plate is filled with a partition heat preservation layer, and two independent semicircular pipelines are formed on the two sides of the partition plate respectively. The two semicircular pipelines serve as a cold water descending channel and a hot water ascending channel respectively, the bottom end of the heat recovery well is drilled to a dry hot rock stratum, and cracks are formed in the position, corresponding to the dry hot rock stratum, of the lower end of the heat recovery well. The heat energy loss caused by heat exchange in the hot water large-stroke conveying process in the large-depth geothermal exploration process is reduced, the partition structure is reinforced, and the partition structure is prevented from being deformed due to pressure difference.

Description

Technical Field

[0001] This utility model belongs to the field of geothermal energy engineering, and relates to a deep geothermal well structure, particularly a thermal insulation structure for a geothermal well. Background Technology

[0002] Geothermal energy is a type of energy originating from within the Earth. Humans have utilized it for a long time, for example, through hot spring bathing, medical purposes, heating, building greenhouses, aquaculture, and drying grains. The most traditional method of using geothermal energy is to explore shallow geothermal layers and extract the groundwater heated by these layers. Low-temperature geothermal energy is widely distributed and is a clean, renewable energy source. Traditional geothermal energy exploration and extraction typically targets high-temperature groundwater, while the utilization of geothermal energy from deep, dry, hot rock layers is limited and lacks effective methods. Furthermore, traditional geothermal energy exploration and extraction often employs multi-well structures, resulting in high costs.

[0003] In practice, it has been found that for geothermal energy extraction wells, due to the generally large exploration depths, the water inside the well easily exchanges heat with the soil and low-temperature rock layers outside the well wall. This results in continuous heat loss during the large-scale hot water output process, leading to low extraction efficiency. Especially in single-well exploration and extraction methods, there is also a large-scale heat exchange between the downward-flowing cold water and the upward-flowing hot water, affecting the efficiency of thermal energy exploration and extraction. Moreover, due to the difference in specific gravity between cold and hot water, the pipeline is subjected to pressure and is prone to deformation. Utility Model Content

[0004] The purpose of this invention is to solve the problems of existing geothermal energy extraction wells in dry hot rock strata being too deep, having insufficient insulation during the extraction process, and especially the heat exchange and pressure imbalance between hot and cold water in single-well structures. This invention provides an insulation structure for geothermal extraction wells that effectively insulate the wells, reduce heat loss during transportation, and reinforce the pipelines to reduce deformation.

[0005] The technical solution adopted by this utility model to solve its technical problem is: a heat preservation structure for a geothermal well, including a heat preservation well opened vertically downward, a casing for reinforcement is provided on the upper part of the well wall, a circumferential heat preservation layer is provided around the casing, a partition plate is provided in the middle of the casing, the partition plate is filled with a partition heat preservation layer, two independent semi-circular pipes are formed on both sides of the partition plate, the two semi-circular pipes serve as a cold water downward channel and a hot water upward channel respectively, the bottom end of the heat preservation well is drilled to a dry hot rock layer, and there are cracks in the dry hot rock layer corresponding to the bottom end of the heat preservation well.

[0006] This device is a single-well geothermal energy extraction well, where cold water flows downwards and hot water flows upwards within the same well. The device utilizes a circumferential insulation layer to create thermal insulation between the casing sidewall and the soil and geothermal rock layers, and a partition insulation layer to create thermal insulation between the cold and hot water channels, reducing heat loss during large-scale water delivery and improving extraction efficiency.

[0007] Preferably, both the cold water downstream channel and the hot water upstream channel are centrally equipped with reinforcing ribs, which connect the midpoint of the partition plate and the midpoint of the inner wall of the sleeve. Due to the difference in specific gravity between cold water and hot water, there is a pressure difference on both sides of the partition plate at the same height. Therefore, reinforcing ribs are used to strengthen the pipe and reduce internal deformation.

[0008] Preferably, the reinforcing rib is provided with uniformly spaced connecting holes. This creates a connection between the two sides of the reinforcing rib, preventing a water level difference between the two sides and thus avoiding lateral pressure on the reinforcing rib.

[0009] Preferably, the connecting holes on the reinforcing rib are staggered vertically. This ensures the lateral structural strength of the reinforcing rib and reduces the possibility of bending.

[0010] Preferably, the casing depth is 50-90% of the depth of the heating well.

[0011] Preferably, the insulation layer is an aerogel insulation layer.

[0012] Preferably, the crack in the hot dry rock layer is located below the bottom end of the casing.

[0013] Preferably, the depth of the heating well is 3000-10000 meters.

[0014] Preferably, the cracks in the dry, hot rock layer are artificially formed using a splitting method.

[0015] Preferably, the cracks in the dry hot rock layer are formed using controlled blasting or hydraulic fracturing techniques.

[0016] This utility model adopts a heat insulation design to reduce the heat loss caused by heat exchange during the long-distance transportation of hot water in deep geothermal exploration and mining. At the same time, it fully considers the specific gravity difference between hot and cold water and strengthens the partition structure to prevent the partition structure from deforming due to pressure difference. Attached Figure Description

[0017] The present invention will be further described below with reference to the accompanying drawings.

[0018] Figure 1 This is a schematic diagram of a heat extraction well structure according to this utility model.

[0019] Figure 2 This is a schematic diagram of the cross-section of the thermal insulation structure of this utility model.

[0020] In the diagram: 1. Heating well, 2. Casing, 3. Circumferential insulation layer, 4. Partition insulation layer, 5. Reinforcing rib, 6. Connecting hole, 7. Dry hot rock layer, 8. Crack, 9. Cold water downward channel, 10. Hot water upward channel. Detailed Implementation

[0021] The present invention will be further described below with reference to specific embodiments and accompanying drawings.

[0022] Example: An insulation structure for a geothermal well, such as Figure 1 As shown. This device includes a vertically downward-facing heating well with a depth of 3000-10000 meters. A casing 2 for reinforcement is installed on the upper part of the heating well 1, with a depth of 75% of the heating well 1's depth. A circumferential insulation layer 3 is provided around the casing, and a partition plate is installed in the middle of the casing 3. The partition plate is filled with a partition insulation layer 4, both of which are aerogel insulation layers. The outer and inner walls of the casing, as well as the two side walls of the partition plate, are made of stainless steel to ensure strength and reduce water flow resistance. Two independent semi-circular pipes are formed on each side of the partition plate, serving as a cold water downward channel 9 and a hot water upward channel 10, respectively. The bottom of the heating well 1 is drilled to a dry hot rock layer 7, and a crack 8 is present at the corresponding dry hot rock layer at the bottom of the heating well. The crack 8 in the dry hot rock layer 7 is located below the bottom of the casing. Cracks in hot, dry rock layers are artificially created using a splitting method, specifically through controlled blasting or hydraulic fracturing techniques.

[0023] like Figure 1 , 2 As shown, both the cold water downstream channel 9 and the hot water upstream channel 10 are centrally located with reinforcing ribs 5, which connect the midpoint of the partition plate and the midpoint of the inner wall of the sleeve. The reinforcing ribs 5 have evenly spaced connecting holes 6. These connecting holes 6 are staggered vertically.

[0024] This device utilizes a circumferential insulation layer to create thermal insulation between the casing sidewall and the soil and geothermal rock layers, and a partition insulation layer to create thermal insulation between the cold and hot water channels, reducing heat loss during large-scale water delivery and improving heat extraction efficiency. Reinforcing ribs are used for reinforcement to reduce internal pipe deformation.

Claims

1. A thermal insulation structure for a geothermal well, comprising a vertically downward-facing well, characterized in that: The upper part of the heating well is equipped with a casing for reinforcement. The casing is surrounded by a circumferential insulation layer. A partition plate is installed in the middle of the casing. The partition plate is filled with a partition insulation layer. Two independent semi-circular pipes are formed on both sides of the partition plate. The two semi-circular pipes serve as a cold water downward channel and a hot water upward channel, respectively. The bottom end of the heating well is drilled to a dry hot rock layer. Cracks are present in the dry hot rock layer corresponding to the bottom end of the heating well.

2. The insulation structure of a geothermal well according to claim 1, characterized in that: Both the cold water downward channel and the hot water upward channel are centrally equipped with reinforcing ribs, which connect the midpoint of the partition plate and the midpoint of the inner wall of the sleeve.

3. The insulation structure of a geothermal well according to claim 2, characterized in that: The reinforcing rib plate has evenly spaced connecting holes.

4. The insulation structure of a geothermal well according to claim 3, characterized in that: The connecting holes on the reinforcing rib are staggered vertically.

5. The insulation structure of a geothermal well according to claim 3, characterized in that: The casing depth is 50-90% of the depth of the heating well.

6. The insulation structure of a geothermal well according to claim 1, characterized in that: The insulation layer is an aerogel insulation layer.

7. The insulation structure of a geothermal well according to claim 1, characterized in that: The crack in the hot, dry rock layer is located below the bottom of the casing.

8. The insulation structure of a geothermal well according to claim 1, characterized in that: The depth of the heating well is 3,000-10,000 meters.

9. The insulation structure of a geothermal well according to claim 1, characterized in that: The cracks in the dry, hot rock layer were artificially created using a splitting method.

10. The insulation structure of a geothermal well according to claim 9, characterized in that: The cracks in the dry, hot rock layer were formed using controlled blasting or hydraulic fracturing techniques.

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