On-site temporary heating system and method based on geothermal drilling construction period

Abstract

The invention relates to the technical field of geothermal energy utilization and constructional engineering, in particular to an on-site temporary heating system and method based on a geothermal drilling construction period, and solves the problems that high-temperature geothermal fluid, namely hot water, can be generated once a geothermal drilling well drills a heated reservoir during construction of the geothermal drilling construction period, and the construction cost is low in a traditional construction mode. In order to solve the problem of waste of valuable heat resources during construction due to the fact that the heat is often directly discharged or idle after the test is completed until a formal geothermal power station or heating station is built, the system comprises a geothermal well subsystem which comprises at least one geothermal exploitation well for producing hot fluid and at least one geothermal reinjection well for reinjection of fluid. According to the system, the functions of instant and efficient utilization and zero waste of geothermal resources in the drilling construction period can be achieved in a mining and using and closed-loop circulation mode, meanwhile, geothermal energy can be directly used for replacing traditional fuel, and the function of remarkably reducing the heating operation cost and energy consumption is achieved.

Description

Technical Field

[0001] This invention relates to the field of geothermal energy utilization and building engineering technology, specifically to a temporary on-site heating system and method based on geothermal drilling construction. Background Technology

[0002] When drilling in geothermal fields, the cycle usually lasts from several weeks to several months. Construction workers need to set up temporary offices, dormitories and other facilities on site. In cold seasons or high-latitude areas, there is an urgent need for on-site heating. Currently, traditional heating methods such as electric heaters and oil-fired boilers are mainly used, which have problems such as high energy consumption, high operating costs, fire hazards, carbon emissions or exhaust pollution.

[0003] During the construction of existing geothermal wells, once the well encounters a geothermal reservoir, it produces high-temperature geothermal fluid, i.e., hot water. In traditional construction methods, this heat is often directly discharged or left idle after testing until the formal geothermal power plant or heating station is built. This results in the waste of valuable heat resources during construction. Therefore, this does not meet the current needs. To address this, we propose a temporary on-site heating system and method based on the geothermal well construction period. Summary of the Invention

[0004] The purpose of this invention is to provide a temporary on-site heating system and method based on the geothermal drilling construction period, in order to solve the problem mentioned in the background art that when a geothermal well encounters a hot reservoir during construction, it will produce high-temperature geothermal fluid, i.e., hot water. In the traditional construction mode, this part of the heat is often directly discharged or left idle after the test is completed, until the formal geothermal power plant or heating station is built. This results in the waste of valuable heat resources during the construction period.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a temporary on-site heating system and method based on geothermal drilling construction, comprising: A geothermal well subsystem includes at least one geothermal production well that produces hot fluid and at least one geothermal reinjection well for fluid reinjection; A fluid extraction and pretreatment unit is connected to the wellhead of the geothermal extraction well and is used to extract geothermal fluid and remove solid impurities therein; The modular heat exchange and heating unit has its primary side connected to the outlet of the pretreatment unit to receive the purified geothermal fluid, and its secondary side forms an independent antifreeze circulation loop, which is connected to the heating terminal of the construction site through a temporary heating network. The tailwater reinjection unit includes a reinjection control valve connected between the outlet on the primary side of the heat exchange unit and the geothermal reinjection well, for reinjecting the geothermal tailwater after heat exchange into the ground. The intelligent monitoring and regulation unit is used to monitor system operating parameters and automatically adjust fluid flow and equipment operating status according to heating demand.

[0006] Preferably, the fluid extraction and pretreatment unit includes a water pump and a sand filter.

[0007] Preferably, the modular heat exchange and heating unit includes a plate heat exchanger and a secondary side circulation pump, and the antifreeze circulation loop is filled with an aqueous solution of ethylene glycol or propylene glycol as an antifreeze medium.

[0008] Preferably, the intelligent monitoring and adjustment unit integrates a PLC or an Internet of Things controller. The PLC is electrically connected to an indoor temperature sensor, and the PLC can automatically adjust the primary fluid flow rate and the frequency of the secondary circulation pump based on the data fed back by the indoor temperature sensor.

[0009] Preferably, the intelligent monitoring and regulation unit further includes an integrated control box for monitoring and backwashing control of the pressure difference of the sand removal filter in the fluid extraction and fluid extraction and pretreatment unit, and for monitoring and over-limit protection of the reinjection pipeline pressure and flow rate.

[0010] Preferably, all units of the on-site temporary heating system are integrated into a movable skid-mounted or containerized module.

[0011] A method for providing temporary on-site heating based on a geothermal drilling construction system includes the following steps: S1: After the geothermal extraction well and reinjection well are completed and the conditions are met, the fluid extraction and pretreatment unit, the modular heat exchange and heating unit, the temporary heating network and the tailwater reinjection unit are connected to form a physical loop. S2: Set parameters such as target heating temperature and upper limit of reinjection pressure in the intelligent monitoring and regulation unit; S3: Start the system. Hot water from the well is extracted, filtered and desanded, and then enters the primary side of the heat exchanger. It transfers heat to the antifreeze circulating medium on the secondary side. The heated antifreeze supplies heat to the temporary facilities through the heating network. S4: The temperature of the geothermal tailwater decreases after heat exchange and is injected into the reinjection well through the tailwater reinjection unit. The intelligent monitoring and regulation unit monitors the indoor and outdoor temperatures in real time and automatically adjusts the system operation status. S5: When the drilling construction period ends or before the formal heating system is put into operation, stop the operation of this system, disassemble each unit modularly, and transfer it to the next construction site for reuse.

[0012] Preferably, in step S4, the adjustment includes dynamically adjusting the geothermal fluid extraction rate and the antifreeze medium circulation flow rate according to the indoor and outdoor temperature difference.

[0013] Preferably, step S4 further includes differential pressure monitoring and automatic or manual backwashing of the sand filter in the fluid extraction and pretreatment unit.

[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention, through the combination of geothermal extraction wells and reinjection wells, can achieve the immediate and efficient utilization of geothermal resources with zero waste during the drilling construction period through the immediate use and closed-loop circulation. At the same time, this invention, through the combination of geothermal fluid extraction unit and plate heat exchanger, can directly use geothermal energy to replace traditional fuels, thereby significantly reducing heating operating costs and energy consumption. 2. This invention, through the combination of tailwater reinjection unit and indirect heat exchange design, can achieve the reinjection of all geothermal tailwater in the same layer without combustion emissions, thus achieving the functions of environmental protection, low carbon emissions and green construction. At the same time, this invention, through the combination of plate heat exchanger and independent antifreeze circulation loop, can prevent pipe scaling, corrosion and freezing by isolating geothermal water from heating terminals, thus achieving the function of safe and reliable system operation. 3. Through the combination of skid-mounted modular design and standardized interfaces, this invention enables the system to be reused and flexibly deployed at multiple drilling sites via rapid installation, disassembly, and transportation. Furthermore, through the combination of intelligent monitoring units and on-demand adjustment mechanisms, this invention enables stable heating, energy-saving optimization, and unmanned operation through real-time monitoring and automatic control. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall process flow of the system of the present invention.

[0016] 1. Geothermal extraction well; 2. Geothermal reinjection well; 3. Water pump; 4. Sand filter; 5. Plate heat exchanger; 6. Secondary side circulation pump; 7. Temporary heating network; 8. Reinjection control valve; 9. Integrated control box; 10. Indoor temperature sensor. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0018] Please see Figure 1 The first embodiment provided by the present invention: A temporary on-site heating system and method based on geothermal drilling construction, comprising: A geothermal well subsystem includes at least one geothermal production well 1 that produces hot fluid and at least one geothermal reinjection well 2 for fluid reinjection; The fluid extraction and pretreatment unit is connected to the wellhead of the geothermal extraction well 1 and is used to extract geothermal fluid and remove solid impurities therein. The modular heat exchange and heating unit has its primary side connected to the outlet of the pretreatment unit to receive the purified geothermal fluid, and its secondary side forms an independent antifreeze circulation loop, which is connected to the heating terminal of the construction site through the temporary heating network 7. The tailwater reinjection unit includes a reinjection control valve 8, which is connected between the outlet of the primary side of the heat exchange unit and the geothermal reinjection well 2, and is used to reinject the geothermal tailwater after heat exchange into the ground. The intelligent monitoring and regulation unit is used to monitor system operating parameters and automatically adjust fluid flow and equipment operating status according to heating demand.

[0019] The fluid extraction and pretreatment unit includes a water pump 3 and a sand filter 4.

[0020] The modular heat exchange and heating unit includes a plate heat exchanger 5 and a secondary circulation pump 6, and the antifreeze circulation loop is filled with an aqueous solution of ethylene glycol or propylene glycol as an antifreeze medium.

[0021] The intelligent monitoring and control unit integrates a PLC or IoT controller. The PLC is electrically connected to an indoor temperature sensor 10. The PLC can automatically adjust the primary fluid flow rate and the frequency of the secondary circulation pump 6 based on the data fed back by the indoor temperature sensor 10.

[0022] The intelligent monitoring and regulation unit also includes an integrated control box 9, which is used to monitor the differential pressure of the sand filter 4 of the fluid extraction and pretreatment unit and control backwashing, as well as to monitor and protect the pressure and flow of the reinjection pipeline from over-limits.

[0023] All units of the on-site temporary heating system are integrated into movable skid-mounted or containerized modules.

[0024] A method for providing temporary on-site heating based on a geothermal drilling construction system includes the following steps: S1: After the geothermal extraction well 1 and the reinjection well are completed and the conditions are met, the fluid extraction and pretreatment unit, the modular heat exchange and heating unit, the temporary heating network 7 and the tailwater reinjection unit are connected to form a physical loop. S2: Set parameters such as target heating temperature and upper limit of reinjection pressure in the intelligent monitoring and regulation unit; S3: Start the system. Hot water from the well is extracted, filtered and desanded, and then enters the primary side of the heat exchanger. It transfers heat to the antifreeze circulating medium on the secondary side. The heated antifreeze supplies heat to the temporary facilities through the heating network. S4: The temperature of the geothermal tailwater decreases after heat exchange and is injected into the reinjection well through the tailwater reinjection unit. The intelligent monitoring and regulation unit monitors the indoor and outdoor temperatures in real time and automatically adjusts the system operation status. S5: When the drilling construction period ends or before the formal heating system is put into operation, stop the operation of this system, disassemble each unit modularly, and transfer it to the next construction site for reuse.

[0025] In step S4, the adjustment includes dynamically adjusting the geothermal fluid extraction rate and the antifreeze medium circulation flow rate based on the indoor and outdoor temperature difference.

[0026] Step S4 also includes differential pressure monitoring and automatic or manual backwashing of the sand filter 4 in the fluid extraction and pretreatment unit.

[0027] Please see Figure 1 The second embodiment provided by the present invention: At the geothermal drilling site, two wells, namely geothermal extraction well 1 and geothermal reinjection well 2, have been drilled to a depth of 2,000 meters in the geothermal reservoir, with a water temperature of about 85°C. There are four temporary prefabricated steel houses on site that require heating, each about 300 square meters.

[0028] First, a cyclone sand separator with a processing capacity of 10 m³ / h is connected in series with a basket filter with a precision of 100 microns to serve as sand separator 4.

[0029] A brazed plate heat exchanger with a plate area of ​​5 square meters was selected as the core heat exchange equipment, plate heat exchanger 5.

[0030] A temporary heating network 7 was laid to connect the fan coil units in each prefabricated house, and the secondary side circuit was filled with ethylene glycol aqueous solution as an antifreeze medium.

[0031] The target temperature for the dormitory is set to 20℃ using the integrated control box 9.

[0032] After the system is started, geothermal water at 85℃ is extracted at a flow rate of 8m³ / h. After sand removal and filtration, it enters the heat exchanger at a temperature of about 82℃. After heat transfer, the tailwater temperature drops to about 50℃ and is then injected into geothermal reinjection well 2 through the reinjection pipeline. The secondary side antifreeze is heated to 55-60℃, and the circulating heating keeps the indoor temperature stable at 20±2℃.

[0033] The system can operate sustainably throughout the construction season, completely replacing the traditional planned diesel boiler, saving approximately 150,000 yuan in diesel costs, and producing no flue gas emissions. After construction, the system can be completely dismantled within two days.

[0034] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A temporary on-site heating system based on geothermal drilling construction, characterized in that, include: A geothermal well subsystem includes at least one geothermal production well (1) that produces hot fluid and at least one geothermal reinjection well (2) for fluid reinjection. A fluid extraction and pretreatment unit is connected to the wellhead of the geothermal extraction well (1) for extracting geothermal fluid and removing solid impurities therein; The modular heat exchange and heating unit has its primary side connected to the outlet of the pretreatment unit to receive the purified geothermal fluid, and its secondary side forms an independent antifreeze circulation loop, which is connected to the heating terminal of the construction site through a temporary heating network (7). The tailwater reinjection unit includes a reinjection control valve (8), which is connected between the outlet of the primary side of the heat exchange unit and the geothermal reinjection well (2) for reinjecting the geothermal tailwater after heat exchange into the ground. The intelligent monitoring and regulation unit is used to monitor system operating parameters and automatically adjust fluid flow and equipment operating status according to heating demand.

2. The on-site temporary heating system based on geothermal drilling construction as described in claim 1, characterized in that, The fluid extraction and pretreatment unit includes a water pump (3) and a sand filter (4).

3. A temporary on-site heating system based on geothermal drilling construction as described in claim 2, characterized in that, The modular heat exchange and heating unit includes a plate heat exchanger (5) and a secondary circulation pump (6), and the antifreeze circulation loop is filled with an aqueous solution of ethylene glycol or propylene glycol as an antifreeze medium.

4. The on-site temporary heating system based on geothermal drilling construction as described in claim 1, characterized in that, The intelligent monitoring and adjustment unit integrates a PLC or an Internet of Things controller. The PLC is electrically connected to an indoor temperature sensor (10). The PLC can automatically adjust the primary fluid flow rate and the frequency of the secondary circulation pump (6) based on the data fed back by the indoor temperature sensor (10).

5. A temporary on-site heating system based on geothermal drilling construction as described in claim 1, characterized in that, The intelligent monitoring and regulation unit also includes an integrated control box (9) for monitoring and backwashing control of the pressure difference of the sand filter (4) of the fluid extraction and fluid extraction and pretreatment unit, and for monitoring and over-limit protection of the reinjection pipeline pressure and flow.

6. A temporary on-site heating system based on geothermal drilling construction as described in claim 1, characterized in that, All units of the on-site temporary heating system are integrated into movable skid-mounted or containerized modules.

7. A method for on-site temporary heating based on a geothermal drilling construction period temporary heating system according to any one of claims 1-6, characterized in that, Includes the following steps: S1: After the geothermal extraction well (1) and the reinjection well are completed and the conditions are met, the fluid extraction and pretreatment unit, the modular heat exchange and heating unit, the temporary heating network (7) and the tailwater reinjection unit are connected to form a physical loop. S2: Set parameters such as target heating temperature and upper limit of reinjection pressure in the intelligent monitoring and regulation unit; S3: Start the system. Hot water from the well is extracted, filtered and desanded, and then enters the primary side of the heat exchanger. It transfers heat to the antifreeze circulating medium on the secondary side. The heated antifreeze supplies heat to the temporary facilities through the heating network. S4: The temperature of the geothermal tailwater decreases after heat exchange and is injected into the reinjection well through the tailwater reinjection unit. The intelligent monitoring and regulation unit monitors the indoor and outdoor temperatures in real time and automatically adjusts the system operation status. S5: When the drilling construction period ends or before the formal heating system is put into operation, stop the operation of this system, disassemble each unit modularly, and transfer it to the next construction site for reuse.

8. A temporary on-site heating method for a temporary on-site heating system based on geothermal drilling construction as described in claim 7, characterized in that, In step S4, the adjustment includes dynamically adjusting the geothermal fluid extraction rate and the antifreeze medium circulation flow rate according to the indoor and outdoor temperature difference.

9. A temporary on-site heating method for a temporary on-site heating system based on geothermal drilling construction as described in claim 7, characterized in that, Step S4 also includes differential pressure monitoring and automatic or manual backwashing of the sand filter (4) in the fluid extraction and pretreatment unit.

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