CN115615022B - Multi-branch geothermal well system and construction method - Google Patents
Multi-branch geothermal well system and construction method Download PDFInfo
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- CN115615022B CN115615022B CN202211296055.2A CN202211296055A CN115615022B CN 115615022 B CN115615022 B CN 115615022B CN 202211296055 A CN202211296055 A CN 202211296055A CN 115615022 B CN115615022 B CN 115615022B
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- 238000010276 construction Methods 0.000 title claims description 15
- 230000005484 gravity Effects 0.000 claims abstract description 18
- 238000012546 transfer Methods 0.000 claims abstract description 14
- 239000007788 liquid Substances 0.000 claims description 70
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 30
- 238000000926 separation method Methods 0.000 claims description 22
- 238000005482 strain hardening Methods 0.000 claims description 22
- 238000003860 storage Methods 0.000 claims description 17
- 238000005553 drilling Methods 0.000 claims description 12
- 239000000498 cooling water Substances 0.000 claims description 11
- 238000011010 flushing procedure Methods 0.000 claims description 3
- 238000000034 method Methods 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims description 2
- 238000011084 recovery Methods 0.000 abstract description 2
- 238000005516 engineering process Methods 0.000 description 4
- 238000000605 extraction Methods 0.000 description 4
- 238000004891 communication Methods 0.000 description 3
- 238000005086 pumping Methods 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- 239000011435 rock Substances 0.000 description 2
- 230000001133 acceleration Effects 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24T—GEOTHERMAL COLLECTORS; GEOTHERMAL SYSTEMS
- F24T10/00—Geothermal collectors
- F24T10/20—Geothermal collectors using underground water as working fluid; using working fluid injected directly into the ground, e.g. using injection wells and recovery wells
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24T—GEOTHERMAL COLLECTORS; GEOTHERMAL SYSTEMS
- F24T10/00—Geothermal collectors
- F24T2010/50—Component parts, details or accessories
- F24T2010/53—Methods for installation
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/10—Geothermal energy
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- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Sustainable Development (AREA)
- Sustainable Energy (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
Abstract
The utility model provides a multi-branch geothermal well system, including ground heat transfer unit and underground heat transfer unit, underground heat transfer unit is including geothermal well and heat exchange tube, the heat exchange tube is arranged in the heat exchange well and is communicated with ground heat transfer unit, geothermal well is including main shaft and a plurality of branch well, the main shaft is the vertical well, the inner wall of main shaft is provided with a well cementation sleeve pipe and fixed sleeve pipe extends along the length direction of main shaft at least, a plurality of slope branch wells that set up downwards have been seted up on the bore hole part of main shaft and/or the fixed sleeve pipe, be provided with the heat exchange tube in a plurality of branch wells and the main shaft, the heat exchange tube is equipped with the shutoff layer with the interface department of branch well and main shaft, the heat exchange tube is gravity heat pipe or coaxial sleeve pipe. The invention adopts a multi-branch structure in the deep layer with high geothermal temperature by sharing the main well, thereby increasing the heat exchange area and improving the heat recovery quantity of the single well.
Description
Technical Field
The invention relates to the technical field of geothermal energy development and utilization, in particular to a multi-branch geothermal well system and a construction method.
Background
The geothermal energy is used as a green low-carbon renewable clean energy source which can be recycled, is basically not influenced by geographic positions, climates and seasons, has the characteristics of large reserve, wide distribution, cleanness, environmental protection, stability, reliability and the like, and has the important effects of optimizing energy structure, saving energy, reducing emission and improving environment. For the technical mode of underground indirect heat exchange, the underground heat exchange surface is not large enough, the well depth is limited, so that the heat extraction amount of a single well is small, and the single well cannot be popularized and utilized in a large range. Therefore, there is a need to develop a geothermal dry rock heat extraction technology with higher heat extraction efficiency and lower cost for a single well to solve the above problems.
In order to improve the underground indirect heat exchange geothermal energy utilization efficiency and single well heat extraction, the existing geothermal energy utilization heat transfer enhancement mode comprises a fracturing technology for EGS, a convection acceleration tube technology for indirect heat exchange, an air flow blending heat exchange technology and the like. However, at present, the technologies have high investment cost and high technical difficulty, are in a research and development stage and are not put into commercial operation on a large scale.
Disclosure of Invention
In view of the above, the present invention aims to provide a multi-branch geothermal well system and a construction method thereof, which use a multi-branch structure in a deep layer with high geothermal temperature by sharing a main well, so as to increase heat exchange area and increase heat recovery of a single well.
In order to achieve the above purpose, the invention adopts the following technical scheme:
the utility model provides a multi-branch geothermal well system, includes ground heat transfer unit and underground heat transfer unit, underground heat transfer unit is including geothermal well and heat exchange tube, the heat exchange tube is arranged in the heat transfer well and with ground heat transfer unit intercommunication, geothermal well is including main shaft and a plurality of branch well, the main shaft is the vertical well, the inner wall of main shaft is provided with at least one well cementation sleeve pipe just fixed sleeve pipe is followed the length direction of main shaft extends, the bore hole part of main shaft and/or set up on the fixed sleeve pipe a plurality of slope sets up downwards the branch well, a plurality of the branch well with be provided with in the main shaft the heat exchange tube, the heat exchange tube with the branch well with the interface department of main shaft is equipped with the shutoff layer, the heat exchange tube is gravity heat pipe or coaxial sleeve pipe.
Preferably, the heat exchange pipe in the main well is communicated with the heat exchange pipe in the branch well, and a liquid separator is arranged at the communicating position and is provided with a liquid separation zone, the liquid separation zone is arranged in the heat exchange pipe in the main well, and the liquid separation zone is also communicated with the heat exchange pipe in the branch well.
Preferably, the liquid separator comprises a liquid separating plate and a liquid storing ring, wherein the liquid storing ring is arranged on the pipe wall of the heat exchange pipe in the main well and surrounds the pipe wall of the heat exchange pipe to form a liquid separating area, the liquid separating plate is arranged in the liquid separating area, one end of the liquid separating plate is fixed on the inner side wall of the liquid storing ring, and the other end of the liquid separating plate extends into the heat exchange pipe in the branch well.
Preferably, the heat exchange tube is a gravity assisted heat tube, and the liquid storage ring is arranged on the tube wall of the gravity assisted heat tube in the main well and surrounds the tube wall of the gravity assisted heat tube to form the liquid separation region.
Preferably, the heat exchange tube is a coaxial sleeve, the coaxial sleeve comprises an inner tube and an outer tube, a flow gap is formed between the inner tube and the outer tube, the liquid storage ring is arranged in the flow gap of the coaxial sleeve in the main well, one end of the liquid storage ring is attached to the outer side wall of the inner tube, and the other end of the liquid storage ring is fixed on the inner side wall of the outer tube and forms the liquid separation zone with the inner side wall of the outer tube.
Preferably, the above-ground heat exchange unit comprises a condenser, a hot working medium valve and a cold working medium valve, wherein a hot working medium port, a cold working medium port, a cooling water inlet and a cooling water outlet are formed in the condenser, the heat exchange tube in the main well is respectively communicated with the hot working medium port and the cold working medium port of the condenser through pipelines, and the hot working medium valve and the cold working medium valve are respectively arranged on the communicating pipelines.
Preferably, the heat exchange tube is a gravity heat tube, the condenser is further provided with a vacuumizing port and a condensate water outlet, the vacuumizing port is communicated with a vacuum pump through a pipeline, a vacuum valve is arranged on a connecting pipeline, and a condensate water valve is arranged on the pipeline communicated with the condensate water outlet.
Preferably, the bottom hole spacing of a plurality of branch wells is greater than 50 meters, the fixed casing is arranged in the branch wells, and the fixed casing is arranged along the inner walls of the branch wells and extends along the length direction of the branch wells.
Meanwhile, the invention also provides a construction method of the multi-branch geothermal well system, which is used for manufacturing the multi-branch geothermal well system, and comprises the following steps:
s1, determining the ground construction position of a main well of a geothermal well, the number of branch wells and the depths of the main well and each branch well;
s2, drilling a well at a main well construction position, and at least using one fixed sleeve to fix the well according to geological conditions;
s3, laterally drilling a plurality of branch wells on an open hole part of the main well and/or a fixed sleeve in an open hole mode and/or a well cementation mode;
s4, after drilling the branch well in an open hole mode, plugging the junction of the heat exchange tube under the branch well, and then drilling a next branch well; when the branch wells are completely drilled in a well cementation mode, one branch well can be directly drilled, and after all the other branch wells are completely drilled, the heat exchange tubes are also arranged and the joint is plugged;
s5, flushing the main well, then connecting the heat exchange tubes in the main well with the heat exchange tubes in the branch wells;
s6, communicating the heat exchange tube in the main well with the hot working medium port and the cold working medium port of the condenser through pipelines.
Preferably, when the gravity heat pipe is adopted as the heat exchange pipe, the main well and the branch well need to drain the heat exchange pipe after the pipe is arranged, the cold working medium valve is closed, the hot working medium valve is opened, the vacuum valve is opened, the condensed water valve is closed, the heat exchange pipe in the main well is communicated with the condenser, the vacuum pump is used for vacuumizing the condenser to the absolute pressure of 1-3 KPa and keeping the absolute pressure, 7 ℃ cooling water is introduced, the vapor in the heat exchange pipe is condensed into water, and the condensed water valve is opened to drain the water, so that the water in the heat exchange pipe is completely drained.
Compared with the prior art, the multi-branch geothermal well system provided by the invention adopts a multi-branch structure in a deep layer with high geothermal temperature through sharing the main well, so that the heat exchange area of deep geothermal heat of the heat taking well is greatly increased. By inserting the ultra-long gravity heat pipe or the coaxial sleeve into the multi-branch geothermal well, the single well heat collection amount of the heat collection well can be greatly improved, and the improvement of 3-5 times of heat collection amount can be realized on the premise of improving the engineering cost by 0.5-1 time.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic semi-sectional view of an internal structure of an underground heat exchange unit;
FIG. 2 is a schematic semi-sectional view of another internal structure of an underground heat exchange unit;
FIG. 3 is a schematic view of the structure of the above-ground heat exchange unit;
FIG. 4 is a schematic view of the structure of the dispenser;
FIG. 5 is a schematic view of the internal structure of the dispenser;
FIG. 6 is a top view of a reservoir ring placed within a gravity assisted heat pipe;
fig. 7 is a top view of the reservoir ring disposed within the coaxial sleeve.
Reference numerals and description of the components referred to in the drawings:
1. a main well; 2. a sleeve; 3. two sleeve pipes are opened; 4. a first branch well; 5. a second branch well; 6. a heat exchange tube main pipe; 7. a first heat exchange tube branch pipe; 8. a second heat exchange tube branch pipe; 9. a knockout; 10. a liquid separation area; 11. an inner tube; 12. an outer tube; 13. a flow gap; 14. a condenser; 15. a hot working fluid valve; 16. a cold working medium valve; 17. a hot working medium port; 18. a cold working medium port; 19. a cooling water inlet; 20. a cooling water outlet; 21. a vacuum pumping port; 22. a condensed water outlet; 23. a vacuum valve; 24. a condensate valve; 25. cementing casing of branch well;
901. a liquid separation plate; 902. and a liquid storage ring.
Detailed Description
The technical scheme of the present invention will be clearly and completely described in the following detailed description. It will be apparent that the described embodiments are only some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Referring to fig. 1, a multi-branch geothermal well system includes an above-ground heat exchange unit and an underground heat exchange unit. The underground heat exchange unit comprises a geothermal well and a heat exchange tube, and the heat exchange tube is arranged in the geothermal well and is communicated with the above-ground heat exchange unit.
The geothermal well comprises a main well 1 and a plurality of branch wells, wherein the main well 1 is a vertical well, at least one well cementation sleeve is arranged on the inner wall of the main well 1, and a fixed sleeve extends along the length direction of the main well 1, in the embodiment, one-open sleeve 2 and two-open sleeve 3 are used for well cementation, if the geological condition is better, only one-open well cementation can be used, and if the geological condition is worse, three-open well cementation or more needs to be carried out. The main well 1 is in a multi-branch structure in a deep layer with high geothermal temperature, namely, a plurality of branch wells which are obliquely downwards arranged are arranged on the open hole part and/or the fixed sleeve of the main well 1, the branch wells can be well-fixed by adopting well-fixed sleeves, the well-fixed sleeves 25 of the branch wells are arranged along the inner wall of the branch well and extend along the length direction of the branch well, and of course, the branch wells can also be directly drilled in an open hole mode, namely, the well-fixed sleeves are shown in the figure 2. According to the number of branch wells selected according to actual needs, 2 branch wells are adopted in the embodiment, one branch well is arranged at the naked eye part of the main well 1 and is a first branch well 4, and the other branch well is arranged on a fixed sleeve and is a second branch well 5. The well bottom interval of the branch wells is more than 50 meters, the interval requirement of the structure on the branch wells is not high, and the arrangement of the multi-branch well is facilitated.
Heat exchange tubes are arranged in the first branch well 4, the second branch well 5 and the main well 1, and the heat exchange tubes are gravity heat tubes or coaxial sleeves. And the interfaces of the heat exchange tube, the first branch well 4, the second branch well 5 and the main well 1 are provided with plugging layers. For convenience of description, the heat exchange pipe located in the main well 1 is defined as a heat exchange pipe main pipe 6, the heat exchange pipe located in the first branch well 4 is defined as a heat exchange pipe branch pipe one 7, and the heat exchange pipe located in the second branch well 5 is defined as a heat exchange pipe branch pipe two 8.
The heat exchange tube main tube 6, the heat exchange tube branch tube I7 and the heat exchange tube branch tube II 8 are communicated, and a liquid distributor 9 is arranged at the communicating position. In the operation process, cold working medium flows in along the wall surface of the top end of the main heat exchange tube 6, and flows into the first heat exchange tube branch tube 7, the second heat exchange tube branch tube 8 and the main heat exchange tube 6 after being split by the splitter 9. The liquid separator 9 has a plurality of liquid separation areas 10, and the liquid separation areas 10 are respectively arranged in the heat exchange tube main tube 6 at the communication position of the heat exchange tube main tube 6 and the first heat exchange tube branch tube 7 and at the communication position of the heat exchange tube main tube 6 and the second heat exchange tube branch tube 8. Referring to fig. 4 to 5 specifically, the liquid separator 9 includes a liquid separating plate 901 and a liquid storing ring 902, the liquid storing ring 902 is disposed on a pipe wall of the main heat exchange pipe 6 and forms a liquid separating area 10 surrounding the pipe wall of the main heat exchange pipe 6, the liquid separating plate 901 is disposed in the liquid separating area 10, one end of the liquid separating plate is fixed on an inner side wall of the liquid storing ring 902, and the other end of the liquid separating plate extends into the first heat exchange pipe branch pipe 7 or the second heat exchange pipe branch pipe 8. Referring to fig. 6, when the heat exchange tube is a gravity assisted heat pipe, a liquid storage ring 902 is disposed on the wall of the main heat exchange tube 6 and surrounds the wall of the main heat exchange tube 6 to form a liquid separation zone 10. Referring to fig. 7, when the heat exchange tube is a coaxial sleeve, the coaxial sleeve includes an inner tube 11 and an outer tube 12, a flow gap 13 is provided between the inner tube 11 and the outer tube 12, a liquid storage ring 902 is disposed in the flow gap 13, one end of the liquid storage ring 902 is attached to the outer side wall of the inner tube 11, and the other end is fixed on the inner side wall of the outer tube 12 and encloses with the inner side wall of the outer tube 12 to form a liquid separation zone 10.
According to the heat collection capacity of each branch well and the main well 1 of the geothermal well and the flow resistance of the heat exchange working medium, the liquid mass entering each heat exchange tube is distributed, so that the heat collection capacity of each heat exchange tube is exerted to the greatest extent. According to the ratio of the mass of the inflow liquid of the first heat exchange tube branch pipe 7, the second heat exchange tube branch pipe 8 and the main heat exchange tube pipe 6, a liquid storage ring 902 and a liquid separation plate 901 with proper sizes are calculated, so that the percentage of the wall of the main heat exchange tube pipe 6 surrounded by the liquid storage ring 902 to the wall of the whole main heat exchange tube pipe 6 is the same as the ratio of the mass of the inflow liquid.
Referring to fig. 3 again, the above-ground heat exchange unit includes a condenser 14, a hot working medium valve 15, and a cold working medium valve 16, wherein the condenser 14 is provided with a hot working medium port 17, a cold working medium port 18, a cooling water inlet 19, and a cooling water outlet 20, the main heat exchange tube 6 is respectively communicated with the hot working medium port 17 and the cold working medium port 18 of the condenser 14 through pipelines, and the communication pipelines are respectively provided with the hot working medium valve 15 and the cold working medium valve 16. Cold working medium enters from the main heat exchange tube 6 and sequentially enters the branch heat exchange tube 7, the branch heat exchange tube 8 and the main heat exchange tube 6 through the liquid separator 9 to indirectly exchange heat with the high-temperature rock stratum, and the heat working medium after heat exchange returns to the condenser 14 from the heat working medium port 17 through a pipeline to exchange heat. The inflow working medium can be water, ammonia and other low-boiling-point freon working medium, and the outflow working medium can be gas or liquid of the working medium.
In the heat exchange pipe laying construction process, water possibly exists in the heat exchange pipe, and if the gravity heat pipe is adopted by the heat exchange pipe, the water in the pipe needs to be discharged. Therefore, the condenser 14 is also provided with a vacuum-pumping port 21 and a condensed water outlet 22, the vacuum-pumping port 21 is communicated with a vacuum pump through a pipeline, a vacuum valve 23 is arranged on a connecting pipeline, and a condensed water valve 24 is arranged on the pipeline communicated with the condensed water outlet 22. Closing a cold working medium valve 16, opening a hot working medium valve 15, opening a vacuum valve 23, closing a condensed water valve 24, after the main heat exchange tube pipe 6 is communicated with the condenser 14, vacuumizing the condenser 14 to an absolute pressure of 1-3 KPa by a vacuum pump, keeping the absolute pressure, introducing 7 ℃ cooling water, converging water vapor in the first heat exchange tube branch pipe 7, the second heat exchange tube branch pipe 8 and the main heat exchange tube pipe 6, condensing the water into water in the condenser 14, and opening the condensed water valve 24 to drain water so as to drain all water in the heat exchange tubes.
The actual construction method of the multi-branch geothermal well system comprises the following steps:
s1, determining the ground construction position of a main well of the geothermal well, the number of branch wells and the depths of the main well and each branch well.
S2, drilling a well at a main well construction position, and at least using one fixed sleeve to fix the well according to geological conditions, wherein in the embodiment, one-casing-opening and two-casing-opening well cementation are adopted.
S3, sidetrack is conducted on the open hole part of the main well and the fixed casing, and the first branch well and the second branch well are drilled laterally.
S4, after the first branch well is drilled in an open hole mode, plugging the joint of the underground heat exchange tube branch pipe of the first branch well, and then drilling a second branch well in an open hole mode and performing a second heat exchange tube branch pipe;
when the first branch well is drilled in a well cementation mode, the second branch well can be drilled directly, and after the second branch well is drilled, the heat exchange tubes can be lowered together and the joint can be plugged.
In the geothermal well provided by this embodiment, the drilling mode of the branch well may be an open hole mode or a well cementation mode, and the basic drilling principle is that if the currently drilled branch well is drilled in an open hole mode, the heat exchange tube needs to be first drilled and then the next branch well is drilled, and if the currently drilled branch well is drilled in a well cementation mode, the branch well can be drilled together after the other branch wells are drilled.
S5, flushing the main well, then, main the main underground heat exchange pipe, and connecting the main heat exchange pipe with the first heat exchange pipe branch pipe and the second heat exchange pipe branch pipe.
S6, communicating the main pipe of the heat exchange pipe with the hot working medium port and the cold working medium port of the condenser through pipelines.
The invention adopts a multi-branch structure at the deep layer with high geothermal temperature by sharing the main well, greatly increases the heat exchange area of the deep geothermal of the heat taking well, greatly improves the single well heat taking quantity of the heat taking well, and realizes the improvement of the heat taking quantity by 3-5 times on the premise of improving the engineering cost by 0.5-1 time.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (8)
1. The utility model provides a multi-branch geothermal well system, includes ground heat transfer unit and underground heat transfer unit, underground heat transfer unit is including geothermal well and heat exchange tube, the heat exchange tube is arranged in the geothermal well and with ground heat transfer unit intercommunication, its characterized in that: the geothermal well comprises a main well and a plurality of branch wells, the main well is a vertical well, at least one well cementation sleeve is arranged on the inner wall of the main well and extends along the length direction of the main well, a plurality of branch wells which are obliquely downwards arranged are arranged on the open hole part of the main well and/or the well cementation sleeve, heat exchange tubes are arranged in the plurality of branch wells and the main well, and a plugging layer is arranged at the interface of the heat exchange tubes, the branch wells and the main well, and the heat exchange tubes are gravity heat tubes or coaxial sleeves; the heat exchange pipe located in the main well and the heat exchange pipe located in the branch well are communicated, a liquid separator is arranged at the communicating position of the heat exchange pipe located in the branch well and is provided with a liquid separation area, the liquid separation area is arranged in the heat exchange pipe located in the main well and is also communicated with the heat exchange pipe located in the branch well, the liquid separator comprises a liquid separation plate and a liquid storage ring, the liquid storage ring is arranged on the pipe wall of the heat exchange pipe located in the main well and surrounds the pipe wall of the heat exchange pipe to form the liquid separation area, the liquid separation plate is arranged in the liquid separation area, one end of the liquid separation plate is fixed on the inner side wall of the liquid storage ring, the other end of the liquid separation plate extends to the heat exchange pipe located in the branch well, and the pipe wall of the heat exchange pipe located in the main well is equal to the liquid mass ratio of the heat exchange pipe located in the branch well.
2. A multi-branch geothermal well system according to claim 1, wherein: the heat exchange tube is a gravity heat tube, and the liquid storage ring is arranged on the tube wall of the gravity heat tube in the main well and surrounds the tube wall of the gravity heat tube to form the liquid separation region.
3. A multi-branch geothermal well system according to claim 1, wherein: the heat exchange tube is a coaxial sleeve, the coaxial sleeve comprises an inner tube and an outer tube, a flowing gap is formed between the inner tube and the outer tube, the liquid storage ring is arranged in the flowing gap of the coaxial sleeve in the main well, one end of the liquid storage ring is attached to the outer side wall of the inner tube, and the other end of the liquid storage ring is fixed on the inner side wall of the outer tube and surrounds the inner side wall of the outer tube to form the liquid separation zone.
4. A multi-branch geothermal well system according to claim 1, wherein: the above-ground heat exchange unit comprises a condenser, a hot working medium valve and a cold working medium valve, wherein a hot working medium port, a cold working medium port, a cooling water inlet and a cooling water outlet are formed in the condenser, a heat exchange pipe in the main well is respectively communicated with the hot working medium port and the cold working medium port of the condenser through pipelines, and the hot working medium valve and the cold working medium valve are respectively arranged on a communicating pipeline.
5. A multi-branch geothermal well system according to claim 4, wherein: the heat exchange tube is a gravity heat tube, the condenser is also provided with a vacuumizing port and a condensate water outlet, the vacuumizing port is communicated with a vacuum pump through a pipeline, a vacuum valve is arranged on a connecting pipeline, and the condensate water outlet is communicated with the pipeline, and a condensate water valve is arranged on the pipeline.
6. A multi-branch geothermal well system according to claim 1, wherein: the well bottom distance of a plurality of branch wells is greater than 50 meters, well cementation sleeves are arranged in the branch wells, and the well cementation sleeves are arranged along the inner walls of the branch wells and extend along the length directions of the branch wells.
7. A construction method of a multi-branch geothermal well system is characterized by comprising the following steps: a method for manufacturing a multi-branch geothermal well system according to any one of claims 1 to 6, comprising the steps of:
s1, determining the ground construction position of a main well of a geothermal well, the number of branch wells and the depths of the main well and each branch well;
s2, drilling a well at a main well construction position, and at least using one well cementation sleeve to fix the well according to geological conditions;
s3, laterally drilling a plurality of branch wells on an open hole part of the main well and/or a well cementation sleeve in an open hole mode and/or a well cementation mode;
s4, after drilling the branch well in an open hole mode, plugging the junction of the heat exchange tube under the branch well, and then drilling a next branch well; when the branch wells are completely drilled in a well cementation mode, one branch well can be directly drilled, and after all the other branch wells are completely drilled, the heat exchange tubes are also arranged and the joint is plugged;
s5, flushing the main well, then connecting the heat exchange tubes in the main well with the heat exchange tubes in the branch wells;
s6, communicating the heat exchange tube in the main well with the hot working medium port and the cold working medium port of the condenser through pipelines.
8. The multi-branch geothermal well system construction method according to claim 7, wherein: when the gravity heat pipe is adopted in the heat exchange pipe, the main well and the branch well need to drain the heat exchange pipe after the pipe is arranged, the cold working medium valve is closed, the hot working medium valve is opened, the vacuum valve is opened, the condensed water valve is closed, the heat exchange pipe in the main well is communicated with the condenser, the vacuum pump is used for vacuumizing the condenser to absolute pressure of 1-3 KPa and keeping the absolute pressure, 7 ℃ of cooling water is introduced, the vapor in the heat exchange pipe is condensed into water, and the condensed water valve is opened to drain the water, so that the water in the heat exchange pipe is completely drained.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211296055.2A CN115615022B (en) | 2022-10-21 | 2022-10-21 | Multi-branch geothermal well system and construction method |
| PCT/CN2022/139329 WO2024082412A1 (en) | 2022-10-21 | 2022-12-15 | Multi-branch geothermal well system and construction method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211296055.2A CN115615022B (en) | 2022-10-21 | 2022-10-21 | Multi-branch geothermal well system and construction method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115615022A CN115615022A (en) | 2023-01-17 |
| CN115615022B true CN115615022B (en) | 2023-12-22 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211296055.2A Active CN115615022B (en) | 2022-10-21 | 2022-10-21 | Multi-branch geothermal well system and construction method |
Country Status (2)
| Country | Link |
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| CN (1) | CN115615022B (en) |
| WO (1) | WO2024082412A1 (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN208901664U (en) * | 2018-08-20 | 2019-05-24 | 中国石油化工集团公司 | Geothermal well system based on single-well injection-production exploitation of geothermal energy |
| CN109798091A (en) * | 2019-01-08 | 2019-05-24 | 中国石油大学(北京) | The development approach of closed cycle well and hot dry rock |
| CN110986401A (en) * | 2019-12-06 | 2020-04-10 | 中国石油大学(北京) | Geothermal resource development system adopting multi-branch radial horizontal well and method thereof |
| CN111043780A (en) * | 2018-10-11 | 2020-04-21 | 中国石油化工集团公司 | Hydrothermal multi-branch directional mining and grouting geothermal well and construction method |
| CN213208258U (en) * | 2020-05-14 | 2021-05-14 | 广东中科光年数智科技有限公司 | Geothermal well heat-taking structure |
| WO2021145776A1 (en) * | 2020-01-17 | 2021-07-22 | Eyvind Normann | Exploiting geothermal energy through heat recovery by circulating working fluid in purpose-built system of multilateral wells |
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| CN106285475B (en) * | 2016-08-30 | 2018-07-17 | 中国石油集团川庆钻探工程有限公司工程技术研究院 | A kind of geothermal well thermal circulation method |
| CN110748293A (en) * | 2018-07-24 | 2020-02-04 | 中国石油化工股份有限公司 | Multilateral well open hole completion method |
| CN114278270B (en) * | 2020-09-27 | 2023-09-26 | 中国石油大学(北京) | Methane in-situ control blasting fracturing method and device |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN208901664U (en) * | 2018-08-20 | 2019-05-24 | 中国石油化工集团公司 | Geothermal well system based on single-well injection-production exploitation of geothermal energy |
| CN111043780A (en) * | 2018-10-11 | 2020-04-21 | 中国石油化工集团公司 | Hydrothermal multi-branch directional mining and grouting geothermal well and construction method |
| CN109798091A (en) * | 2019-01-08 | 2019-05-24 | 中国石油大学(北京) | The development approach of closed cycle well and hot dry rock |
| CN110986401A (en) * | 2019-12-06 | 2020-04-10 | 中国石油大学(北京) | Geothermal resource development system adopting multi-branch radial horizontal well and method thereof |
| WO2021145776A1 (en) * | 2020-01-17 | 2021-07-22 | Eyvind Normann | Exploiting geothermal energy through heat recovery by circulating working fluid in purpose-built system of multilateral wells |
| CN213208258U (en) * | 2020-05-14 | 2021-05-14 | 广东中科光年数智科技有限公司 | Geothermal well heat-taking structure |
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| WO2024082412A1 (en) | 2024-04-25 |
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