Underground integrated low-temperature geothermal ORC power generation system suitable for abandoned oil well

Abstract

The invention discloses a technical scheme of an underground integrated low-temperature terrestrial heat ORC power generation system suitable for a waste oil well, belongs to the field of power generation and energy utilization, and is characterized in that an underground sealed pressure-bearing power generation main body, a totally-closed organic working medium circulating system, a deep geological exploration module and a ground control unit are modularly integrated underground; and direct heat transfer of a heat source, thermal power-electric power closed loop and zero formation water contact are realized. The evaporator is directly attached to the underground outer wall to achieve heat exchange, a working medium is heated and evaporated and drives the power generator to output electric power through the expansion machine, vortex tubes are connected in series for condensation, condensation and liquid return are achieved through inert media, underground geological data can be stored off line and transmitted to the ground in real time, and the righting and positioning mechanism is adaptive to the inner diameter of a shaft of 3-7 inches. The armored cable realizes two-way transmission and remote control between underground and ground, has the advantages of low environmental risk, modularization, low cost investment and the like, and is suitable for improving geothermal potential and regional exploration of waste oil wells.

Description

Technical Field

[0001] This invention relates to the field of power generation, and in particular to an integrated downhole ORC power generation system and its integrated operation scheme for directly converting low-temperature geothermal resources into electricity in abandoned oil wells. Specifically, for medium- and low-temperature geothermal sources and complex wellbore environments, it provides a compact coupling structure of a fully enclosed working fluid circulation and an integrated downhole power generation unit. Heat exchange is achieved through an evaporator directly attached to the downhole outer wall, and energy-saving self-sufficient condensation at the surface is achieved using vortex tube series condensation. A deep geological exploration module and a surface control unit are integrated at the bottom of the well, and bidirectional data and power transmission and remote control between the downhole and surface are achieved via armored cables. This invention aims for modularity, standardization, and low-cost investment, and is suitable for modern development schemes for the efficient reuse of abandoned oil well resources and the assessment of regional geothermal potential. Background Technology

[0002] Current geothermal power generation technologies mostly focus on surface or wellbore perimeter heat extraction and power conversion. However, in abandoned oil wells and under low-to-medium temperature geothermal conditions, several bottlenecks remain, leading to low resource utilization efficiency, high environmental risks, and high system costs. Based on publicly available technology analysis, existing technologies can be broadly categorized into the following types and their shortcomings: 1) Wellhead-Surface Power Generation System Based on Surface Heat Exchange and Water-Geothermal Coupling Working principle and key points: By coupling the geothermal heat source with the ground heat exchanger, heat is extracted at the wellhead or underground and then transferred to the evaporation / expansion device through the ground heat network, and then the power generation and condensation circuit is completed on the ground.

[0003] Disadvantages: It requires large-scale groundwater recharge and surface condensation systems, which may lead to the risk of coupling between surface and groundwater resources; there are multiple potential leaks and pollution hazards between the heat source and the surface environment; it has poor tolerance for differences in well structure and inner diameter, making it difficult to achieve modular and standardized equipment integration within the well.

[0004] 2) Downhole open-circulation geothermal power generation system Working principle and key points: An open working fluid circulation is formed downhole, and the working fluid directly contacts the geothermal water / formation fluid to complete the stages of evaporation-expansion-power generation-condensation, and the condensate is recovered and recycled.

[0005] Disadvantages: Open circulation can easily cause formation water pollution, permeability damage and heat-water resource coupling risks; there are risks of corrosion and leakage during long-term operation, and environmental supervision costs are high; it is difficult to achieve compatibility and self-adaptation with the wellbore inner diameter.

[0006] 3) Multi-module integrated solutions for downhole closed-loop systems (but these often only work at a single wellhead or within a specific well diameter). Working principle and key points: A closed system that realizes working fluid circulation downhole, with modules such as evaporator, expander, generator, and condenser integrated through compact coupling.

[0007] Shortcomings: Existing solutions often lack the ability to adapt to differences in wellbore inner diameter, making it difficult to achieve self-adaptive fixing of 3-7 inch wellbores; the complex downhole environment, vibration, temperature, dust and other factors place high demands on equipment lifespan and reliability, and the low degree of standardization leads to high on-site installation costs and long construction cycles.

[0008] 4) Integrated application of downhole geological data acquisition and remote control Working principle and key points: Geological sensing and data acquisition modules are deployed at the bottom of the well. The data is transmitted to the ground control system through a communication link to realize on-site diagnosis and regional resource analysis.

[0009] Shortcomings: Existing systems are mostly based on standalone data acquisition, lacking tight coupling with the thermo-electric closed-loop system, and cannot achieve data-driven real-time process optimization; the hybrid mode of offline storage and online transmission has not yet formed a unified and scalable solution.

[0010] The aforementioned existing technology has the following problems: Safety and environmental risks: If leakage, corrosion or seal failure occurs during long-term circulation of the working fluid underground, it may cause regional environmental pollution and safety hazards. Furthermore, there is a lack of sustainable solutions that ensure fully enclosed working fluid circulation and zero discharge.

[0011] Insufficient equipment adaptability and modularity: The inner diameter of the well shaft varies greatly and the structure is diverse. The existing solution is not sufficiently designed for adaptive fixing and compatibility of 3-7 inch well shafts, resulting in high on-site customization costs and long installation time.

[0012] Energy efficiency and operating costs: Surface condensation systems still require additional equipment investment and energy consumption, reducing overall economic efficiency; bottom-hole thermo-electric coupling efficiency is limited, making it difficult to achieve efficient and stable output under low-temperature geothermal conditions.

[0013] Reliability of data transmission and ground control: The downhole environment is complex, and the stability of data transmission and remote diagnostic capabilities are insufficient, making it difficult to achieve real-time monitoring of the operating status and rapid response to faults. At the same time, the data support capability for regional geothermal potential analysis also needs to be improved.

[0014] Therefore, there is a need for a modular, standardized downhole ORC system that can directly convert heat sources into electricity downhole, avoid contact with formation water through a fully enclosed circulation system, and be self-adaptive to wellbore inner diameters of 3-7 inches. Furthermore, it should reduce surface energy consumption through vortex tube condensation, achieve deep geological data acquisition and offline storage at the wellbore bottom, and enable highly reliable data and power transmission between downhole and the surface via armored cables. This is precisely the core technical problem and objective that this invention aims to solve. Summary of the Invention

[0015] To address the problems existing in the prior art, this invention provides an integrated downhole cryogenic geothermal ORC power generation system and its integrated operation scheme. Its core lies in the modular and standardized integration of a fully enclosed organic working fluid circulation unit, a downhole integrated power generation unit, a deep geological exploration module, and a surface control unit into the downhole working environment. This enables direct heat exchange with the geothermal heat source, closed-loop heat-to-electricity conversion, and bidirectional data transmission and power output control between the downhole and surface via armored cables. The system's compact coupling structure achieves direct heat source transfer, closed-loop working fluid circulation, and zero contact with formation water, thereby reducing environmental risks and operating costs. Key points are as follows: 1) The integrated downhole power generation unit is a sealed pressure-bearing cavity structure, which can be directly lowered to the target geothermal layer through the oil well tubing without modifying the existing casing. The outer diameter design is compatible with common sizes of abandoned wellbores, and it has an adjustable inner diameter centering and positioning mechanism to adapt to different wellbore inner diameters and prevent collisions with the casing; 2) A fully enclosed organic working fluid circulation system is embedded inside the integrated downhole power generation unit, forming a closed-loop path of evaporator—expander—generator—condenser—circulation pump. The working fluid circulates within the pipeline and does not come into open contact with formation water or discharge externally; 3) The evaporator is directly attached to the outer wall of the downhole power generation unit, transferring geothermal heat to the working fluid through direct heat exchange, causing it to heat up and evaporate. The evaporation inlet temperature is set at 100-150℃ and the evaporation pressure is 2-4 MPa to ensure that the working fluid enters a high-energy state; 4) The expander performs work on the gaseous working fluid and drives a coaxial generator to generate electricity. The output DC or AC power is monitored and managed by the ground control unit. The expansion ratio is set between 1.5 and 4 to match different geothermal temperature conditions. 5) The condenser uses vortex tube series condensation, with inert gas as the medium for heat exchange condensation. The circulating pump sends the liquid working fluid back to the evaporator inlet to maintain a stable closed loop. 6) The deep geological exploration module is integrated at the bottom of the well, including temperature sensors, pressure sensors, and lithology detection components. It can transmit data to the ground control unit in real time and store it offline on-site when necessary for regional exploration and geological research. 7) The ground control unit is located at the wellhead and realizes bidirectional transmission of data and power output and remote control commands of the downhole system through armored cables. It has on-site offline data storage and local diagnostic self-testing functions. 8) In terms of working fluid selection, environmentally friendly working fluids suitable for medium and low temperature heat sources, such as R245fa and R134a, are selected. The circulation temperature range is controlled between 100-150℃, and the relative pressure is between 2-4. Within the MPa range, the system ensures stable and safe power output under different wellbore conditions by dynamically controlling key parameters such as evaporation inlet temperature, expansion ratio, and pumping pressure. Compared with existing technologies, this system achieves direct conversion of heat source into electricity downhole, avoids contact with formation water through a fully closed loop, reduces surface system impact through vortex tube condensation, and enables deep geological data acquisition and offline storage at the well bottom. This forms a new technical route characterized by downhole heat-electricity closed loop, low environmental risk, modular standardization, and low-cost investment.The system operates on a closed-loop model encompassing heat source, working fluid circulation, power output, and surface control. Data is transmitted bidirectionally between the well and the surface via armored cables, ensuring high reliability for remote monitoring and fault diagnosis. A self-adaptive positioning mechanism enables the fixing of 3-7 inch wellbores, significantly improving the utilization efficiency of abandoned oil wells and the availability of regional geothermal exploration data. Deep geological exploration data can be stored offline, facilitating regional resource assessment and geothermal potential analysis. Through the aforementioned structural design, this invention provides an integrated downhole cryogenic geothermal ORC power generation system and its integrated operation scheme that can be directly applied to existing oil and gas fields, without contact with formation water or external discharge. It offers excellent economic efficiency, environmental friendliness, and scalability.

[0016] 1) Overview of Technical Solution Downhole integrated power generation unit: As the core, sealed pressure-bearing cavity structure, it can be directly lowered to the target section of the wellbore through the oil well tubing, and achieve direct heat exchange with the wellbore evaporator assembly. The working fluid forms a closed loop downhole, ensuring that the heat source is isolated from the formation water and there is no external discharge. It has the ability to self-adapt to the wellbore inner diameter for clamping and positioning, preventing collision with the casing.

[0017] Fully enclosed organic working fluid circulation system: A complete closed loop is formed downhole from the inlet and outlet of the evaporator assembly to the expander, generator, condenser, and circulation pump. The working fluid circulates in the downhole pipeline and is always isolated from the formation water to avoid any discharge.

[0018] Evaporator assembly and heat exchange: The evaporator assembly is directly attached to the outer wall of the downhole power generation unit. Through efficient thermal contact, geothermal heat is directly transferred to the working fluid, allowing the working fluid to enter the evaporation process in the inlet zone of 100-150℃. The evaporation pressure is controlled between 2-4 MPa to ensure that the working fluid enters a high-energy state.

[0019] Expander and generator coupling: The expander does work on the gaseous working fluid, drives the coaxial generator to generate electricity, and outputs power. The expansion ratio is dynamically adjustable to adapt to the geothermal temperature range, ensuring stable power output and safe operation.

[0020] Condenser and vortex tube in series: The vortex tube series heat exchange structure is adopted, and inert gas is used as the medium for heat exchange to achieve condensation. This eliminates the need for a surface condensation system, reduces surface energy consumption and equipment investment, and the circulating pump returns the liquid working fluid to the evaporator inlet to maintain a closed loop.

[0021] Deep geological exploration module: A geological data acquisition unit integrated at the bottom of the well, equipped with temperature sensors, pressure sensors and lithology detection components. Data is transmitted downhole in real time or stored offline for use in regional exploration and geological research.

[0022] Ground control unit and armored cable transmission: The ground control unit is located at the wellhead and realizes bidirectional transmission of downhole data and power output, as well as remote control command issuance, through armored cables. It has offline storage and local diagnostic self-test functions.

[0023] Working fluid selection and operating range: Environmentally friendly working fluids suitable for medium and low temperature heat sources, such as R245fa and R134a, are selected. The circulation temperature range is controlled at 100-150℃ and the relative pressure is 2-4 MPa. The system achieves stable and safe power generation output by dynamically adjusting key parameters such as evaporation inlet temperature, expansion ratio, and pumping pressure.

[0024] 2) Innovations compared to existing technologies For the first time, direct heat exchange coupling of a fully enclosed organic working fluid circulation has been achieved downhole. The evaporator is directly attached to the downhole outer wall to achieve heat exchange, forming a downhole thermal-electric closed loop. This avoids contact with and discharge of formation water, improves thermal energy utilization efficiency, and reduces environmental risks.

[0025] By using vortex tubes in series for condensation and inert medium for heat exchange, the need for a surface condensation system is eliminated, significantly reducing surface energy consumption and equipment investment. At the same time, it achieves fully enclosed operation, improving the maintainability and safety of the system.

[0026] By integrating a deep geological exploration module at the bottom of the well, real-time / offline information on formation temperature, pressure, and lithology can be obtained, forming a complete data chain for regional geothermal potential assessment and providing reliable support for regional resource development and decision-making.

[0027] The centering and positioning mechanism enables self-adaptive fixing of wellbore inner diameters from 3 to 7 inches, improving the flexibility and standardization of on-site installation and reducing the difficulty and cost of single-well construction. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings are briefly described below: Figure 1 A structural block diagram of an integrated downhole cryogenic geothermal ORC power generation system provided in an embodiment of the present invention; Figure 2 A flowchart illustrating the operation method provided in an embodiment of the present invention; Figure 3 This is a flowchart illustrating the data interaction and processing between key modules in an embodiment of the present invention. Figure 4 This is a system topology diagram showing multiple wellbores operating in parallel. Detailed Implementation

[0029]

Example 1

Complete Implementation of the Core Solution for the Method Class

[0030] 1) System prerequisites and initial setup The downhole power generation unit is directly lowered into the target hot zone in the form of a sealed pressure chamber, with the outer wall of the chamber forming a direct heat exchange interface with the wellbore evaporator assembly. The centering and positioning mechanism achieves self-adaptive fixation to the 3-7 inch wellbore inner diameter through flexible clamping and an adjustable inner diameter structure, ensuring that the equipment is stably positioned in the wellbore and avoiding collision with the casing.

[0031] The fully enclosed organic working fluid circulation system is placed inside a sealed cavity downhole. It forms a complete loop according to the path of evaporator assembly – expander – generator – condenser – circulation pump. The working fluid circulates continuously in the pipeline and is completely isolated from the formation water to prevent any discharge.

[0032] 2) Heat exchange and working fluid evaporation of the evaporator assembly The evaporator assembly is directly attached to the outer wall of the downhole power generation unit, achieving heat transfer from geothermal energy to the working fluid through a direct contact interface with low thermal resistance. The evaporator inlet temperature is set at 100-150℃, and the evaporation pressure is in the range of 2-4 MPa. The downhole sensing system monitors the evaporator outer wall temperature, working fluid inlet temperature, pressure, and sealing status in real time, and the data is transmitted back to the surface control unit to form a closed-loop control system.

[0033] During the evaporation process, the working fluid enters a high-energy state, forming a high-pressure gas phase, which prepares for the subsequent work of the expander.

[0034] 3) Coupling and output control of expander and generator High-pressure gaseous working fluid enters the expander and performs work at a set expansion ratio (between 1.5 and 4), driving a coaxial generator to output electricity. The expansion ratio is dynamically adjusted within the geothermal temperature range to achieve smooth output power and stable system operation.

[0035] The ground control unit comprehensively evaluates the expansion ratio, generator efficiency, and output load, and outputs control commands to achieve smooth regulation of power output. Real-time data includes the high-pressure gaseous working fluid status, expander output power trend, generator efficiency assessment, and load curve.

[0036] 4) Self-contained condensation and loop management of the condenser The condenser employs a vortex tube series heat exchange structure, using an inert gas as the medium for heat exchange to achieve working fluid condensation. After condensation, the liquid working fluid is returned to the evaporator inlet via a circulating pump, maintaining a closed loop. This design avoids surface cooling systems, reduces surface energy consumption and equipment investment, and achieves zero external emissions.

[0037] The temperature, inert medium temperature, flow rate, and pipeline resistance during the condensation process are monitored by downhole sensors, and the data is periodically transmitted back to the surface control unit to form a real-time assessment of the entire closed-loop thermodynamic balance.

[0038] 5) Data acquisition and transmission of the deep geological exploration module The deep geological exploration module is integrated at the bottom of the well and is equipped with temperature sensors, pressure sensors, and lithology detection components to collect formation temperature, formation pressure, and lithology information in real time. The data is transmitted to the surface control unit via armored cables and can be stored offline on-site when necessary for regional exploration and geological research.

[0039] Data transmission employs redundant paths and error detection mechanisms to ensure the integrity and timeliness of data received from the ground.

[0040] 6) Armored cable transmission and ground control unit The surface control unit is located at the wellhead and enables bidirectional transmission of data and power output from the downhole system, as well as the issuance of remote control commands, via armored cables. The surface control unit features offline data storage and on-site self-diagnosis and self-testing capabilities, allowing for fault tolerance and fault playback in the event of transmission failures.

[0041] 7) Working fluid selection and system adaptive control The system uses environmentally friendly working fluids suitable for medium- and low-temperature heat sources, such as R245fa and R134a, with a circulation temperature of 100-150℃ and a relative pressure of 2-4 MPa. Through adaptive control of key parameters such as evaporation inlet temperature, expansion ratio, and pumping pressure, the system ensures stable and safe power output under various wellbore conditions. The system also features sealing condition monitoring and self-diagnostic functions to trigger alarms and emergency measures in case of abnormal sealing conditions.

[0042] 8) Online / offline collaboration of data and information Deep geological exploration data can be transmitted online to the surface control unit, and stored offline when necessary for regional resource assessment and analysis; the surface control unit monitors, diagnoses and logs the execution of commands by the downhole system, and has data playback capabilities for event tracking and fault diagnosis.

[0043] Summary of key implementation points: This embodiment realizes the coordinated operation of direct heat exchange from the downhole heat source to the working fluid, closed-loop control, replacement of surface condensation, real-time / offline acquisition of well bottom geological data, and remote command and diagnostic capabilities of the surface control unit, which is in line with the core idea of ​​this invention and the key points of claims 1-9.

[0044]

Example 2

Device / System Solution

[0045] 1) Structural design of the integrated downhole power generation unit Sealed pressure-bearing cavity: High-strength materials and multi-point sealing structure are used to maintain the sealing of the working fluid system under high temperature and high pressure conditions downhole, ensuring that formation water cannot enter the closed loop.

[0046] Adaptive straightening and positioning mechanism: An adjustable inner diameter clamping mechanism is provided on the outside of the cavity. It achieves self-adaptive fixing of the 3-7 inch wellbore inner diameter through a flexible interface. It has the ability to resist impact, vibration and buffer, and prevent displacement or collision caused by sudden changes in the well wall.

[0047] Evaporator assembly interface: The evaporator assembly is directly embedded in the outer wall of the downhole power generation unit and is designed with a high-efficiency heat transfer surface and thermal resistance control device to ensure that heat is transferred to the working fluid to the maximum extent.

[0048] 2) Internal structure of a fully enclosed organic working fluid circulation system The closed-loop path of evaporator-expander-generator-condenser-circulating pump is arranged in a compact ring layout to ensure that the working fluid circulates within a limited area downhole, reducing pipeline length and heat transfer loss.

[0049] The expander and generator are coupled in a single shaft, and the expansion ratio can be adjusted with feedback within the range of 1.5-4, providing a rapid response capability to follow fluctuations in geothermal temperature.

[0050] The vortex tube series structure and inert medium circuit design of the condenser enable the condensation process to be completed self-sufficiently downhole, reducing dependence on surface equipment.

[0051] 3) Implementation of the deep geological exploration module The deep geological exploration module is installed at the bottom of the well and integrates temperature sensors, pressure sensors and lithology detection components. Data can be transmitted in real time or offline via armored cables.

[0052] The module has offline caching capabilities, which can ensure data integrity even when the communication network is unstable, providing the data foundation required for regional geothermal potential analysis.

[0053] 4) Ground control unit and data transmission The ground control unit is installed at the wellhead and enables remote control and data transmission of the downhole system via armored cables. It has the capabilities of fault diagnosis, online monitoring and offline data storage.

[0054] Data transmission employs redundant channels, error detection, and retransmission mechanisms to ensure stable data transmission even in high-temperature, high-humidity, and dusty wellhead environments.

[0055] 5) Working medium and operating range The selection of working fluid follows the application principle of medium and low temperature heat source working fluid, and environmentally friendly working fluids such as R245fa and R134a are preferred; the circulation temperature is within the range of 100-150℃, the evaporation pressure is within the range of 2-4 MPa, and the expansion ratio is between 1.5 and 4 to ensure stable power output and system safety.

[0056] 6) Modularization, standardization, and field adaptability The self-adaptive design of the centering and positioning mechanism enables the same downhole integrated power generation unit to be freely adapted within a 3-7 inch wellbore without requiring modification of the existing casing, thus improving the speed and economy of on-site installation.

[0057] 7) Operation and Maintenance The entire system possesses self-diagnostic and self-testing capabilities, periodically diagnosing the sealing status, working fluid status, and sensor status, and triggering alarms or remote fault diagnosis when necessary. Offline data storage ensures that critical geological data is not lost due to communication interruptions.

[0058] Summary of key implementation points: Example 2 focuses on the specific structural design and modular implementation at the device level, emphasizing the design of wellbore self-adaptation, compact loop circuit, downhole self-sufficient condensation, and the reliability of the surface control unit, all of which conform to the core technical solution and corresponding points of the independent claims of this invention.

[0059]

Example 3

Variant Scheme or Special Application Scenarios

[0060] 1) System expansion for parallel operation of multiple wellbores Multiple wells are deployed within the same geothermal area, and the integrated downhole power generation units of these wells operate in parallel via a ground control unit. A distributed control algorithm coordinates the evaporation inlet temperature, expansion ratio, and pumping flow rate of each well to form a globally optimal thermo-electric closed loop.

[0061] Each wellbore has an independent deep geological exploration module that provides geological datasets for the region, and the surface control unit performs a comprehensive assessment of regional resources.

[0062] 2) Offline storage and regional geothermal potential analysis The deep geological exploration module's data can be cached offline and features data compression, indexing, and batch uploading capabilities. The regional geothermal potential assessment subroutine can quickly analyze regional resources based on offline data, outputting regional assessment reports to provide a basis for regional development decisions.

[0063] When the local network is unavailable, the underground data can still be stored offline and uploaded after communication is restored to ensure data integrity.

[0064] 3) Adaptive optimization under extreme wellbore conditions For extreme changes in the wellbore inner diameter (such as long straight pipe sections or corner sections) or temperature fluctuations in the geothermal layer, the system dynamically adjusts the evaporation inlet temperature, heat transfer area, and working fluid flow rate through an adaptive heat exchange control strategy to maintain the stability of the working fluid entering a high-energy state.

[0065] By introducing a redundant heat source management strategy, temporary power supply can be provided by switching to a backup well when some wells are not working properly, thus ensuring the continuity of regional power supply.

[0066] 4) Safety and emergency response strategies The system has a continuous monitoring and alarm mechanism for the sealing status. If potential signs of leakage, seal failure, or abnormal vibration are detected, emergency strategies will be triggered, such as reducing the expansion ratio, reducing output power, or switching to a backup wellbore, to ensure the safety and controllability of the overall operation.

[0067] Under extreme high temperature and high pressure conditions, maintain thermal stress management of the evaporator and pipelines, and adopt temperature buffering and structural reinforcement design to avoid structural damage caused by thermal shock.

[0068] Overall, Example 3 demonstrates the flexibility and scalability of this technical solution in different application scenarios by expanding on aspects such as regionalization, parallel operation of multiple wellbores, offline data analysis, adaptation to extreme wellbore conditions, and improved emergency and safety strategies.

Claims

1. An operation method for an integrated downhole low-temperature geothermal ORC power generation system, characterized in that, Includes the following steps: S1. Downhole, geothermal heat is transferred to the working fluid through direct heat exchange between the evaporator assembly and the well wall, causing the working fluid to heat up and evaporate within the evaporator assembly to form a high-pressure gaseous working fluid. During this process, data on the downhole heat source temperature, evaporator outer wall temperature, initial working fluid state, and sealing status are collected. Closed-loop monitoring of the heat exchange efficiency, pressure-temperature state, and sealing status during the evaporation process is implemented. An adaptive heat exchange control strategy is adopted to ensure the working fluid enters a high-energy state without leakage, outputting the high-pressure gaseous working fluid to the expander. S2. The high-pressure gaseous working fluid is fed into the expander, driving the expander to perform work and powering the generator. The output power is dispatched by the ground control unit. During this process, data on the high-pressure gaseous working fluid state, expansion ratio setpoint, and current generator load are collected. Dynamic adjustment is implemented within the adjustable expansion ratio range to match geothermal temperature conditions and ensure safe operation, outputting the expanded working fluid to the condensation circuit. S3. [Further details about the process are missing from the original text.] A condenser with a series vortex tube structure is used to achieve working fluid condensation through heat exchange with an inert gas medium. The liquid working fluid is then returned to the evaporator inlet via a circulation pump, maintaining a closed-loop circulation of the working fluid. During the process, data on condenser temperature, inert medium state, and circulation pump flow rate are collected to control condensation efficiency, heat exchange intensity, and circulation pump operating status in real time. Liquid working fluid is output to the evaporator inlet, and stable power is also output. S4: Formation temperature, formation pressure, and lithology information are collected downhole using a deep geological exploration module and temporarily cached. The collected data is then filtered and processed offline / online. Online transmission management transmits formation data to the surface control unit; S5, the surface control unit achieves bidirectional data and power output transmission of the downhole system via armored cables, issues remote control commands, and completes closed-loop control and status feedback of the downhole system; S6, the system collects wellbore inner diameter information and current status data of the positioning mechanism through the centering and positioning mechanism to achieve adaptive fixing and anti-collision positioning for wellbore inner diameters of 3 to 7 inches, and completes the stable fixing of the downhole power generation unit; S7, the system collects sealing status and leakage detection signals in real time, continuously evaluates the sealing integrity of the fully enclosed organic working fluid circulation system, triggers alarms and outputs emergency handling commands when abnormalities occur; S8, the system organizes, compresses and stores offline operation logs and regional resource data offline, uploads them to the surface control unit as needed, generates offline data archives and supports data playback; S9. The system takes the heat source-working fluid cycle-power output-ground control closed loop as the main axis, and combines the heat source status, working fluid cycle status and ground control commands. Through closed-loop monitoring and adaptive control, the system can achieve efficient and safe operation and continuously output power and heat-electric coupling data.

2. The operating method according to claim 1, characterized in that, In step S1, the working fluid state data at the evaporation inlet is also collected simultaneously. By dynamically evaluating the changes in expansion ratio, working fluid temperature gradient, and thermal resistance, the heat exchange intensity during the evaporation stage is optimized. Combined with the sliding window detection mechanism, the working fluid in the evaporator assembly is ensured to stably enter a controllable high-energy state.

3. The operating method according to claim 1, characterized in that, In step S2, the expander output power trend, generator efficiency assessment, and working fluid state curve data are also collected simultaneously. The expansion ratio is dynamically adjusted through a closed-loop control algorithm to match different geothermal temperature conditions and achieve smooth power output.

4. The operating method according to claim 1, characterized in that, In steps S4 and S5, the ground control unit performs intelligent scheduling based on the collected geological data and system operating status, translates ground control commands into specific actions of downhole equipment, and monitors the execution process; at the same time, according to the transmission network status, it manages the formation data using a hybrid mode of offline caching and online transmission, and completes data filtering and timing alignment processing; it performs error detection and redundant transmission on the issued remote control commands to ensure that the commands arrive safely and are executed reliably.

5. A downhole integrated low-temperature geothermal ORC power generation device, characterized in that, It includes an integrated downhole power generation unit, a fully enclosed organic working fluid circulation system, a deep geological exploration module, a surface control unit, and a centering and positioning mechanism. The fully enclosed organic working fluid circulation system is located within the sealed pressure-bearing cavity of the integrated downhole power generation unit. The closed-loop path sequentially includes an evaporator assembly, an expander, a generator, a condenser, a circulation pump, and connecting pipelines, used to complete the working fluid circulation and geothermal... Power conversion; the evaporator assembly adopts a heat exchange structure that directly adheres to the outer wall of the downhole power generation unit, used to achieve working fluid evaporation through direct heat exchange with the well wall; the expander and generator adopt a single-axis coupling structure with an adjustable expansion ratio, used to drive the generator to output electricity through the expansion of the working fluid; the condenser adopts a vortex tube series heat exchange structure with inert gas as the heat exchange medium, used to achieve working fluid condensation; the deep geological exploration module integrates temperature sensors, pressure sensors and lithology detection components, used to collect formation data and support real-time transmission or offline storage; the surface control unit is connected to each downhole module through armored cables, used to achieve bidirectional transmission of data and power output, and has remote control and local diagnostic functions; the centering and positioning mechanism is located on the outside of the downhole integrated power generation unit, with flexible clamping and buffering mechanisms, used to achieve adaptive fixing of the wellbore inner diameter and avoid collision with the well wall / casing.

6. The power generation device according to claim 5, characterized in that, The evaporator assembly achieves efficient heat transfer through contact thermal resistance control. It can adjust the thermal contact area and working fluid flow rate based on the downhole outer wall temperature, working fluid inlet temperature, and thermal conductivity data to achieve stable evaporation of the working fluid.

7. The power generation device according to claim 5, characterized in that, The expander and generator set can adjust the expansion ratio through closed-loop control based on the expander output power, generator load, and working fluid status data to achieve smooth power output and stable power output.

8. The power generation device according to claim 5, characterized in that, The condenser can adaptively adjust its condensation efficiency based on inert medium temperature, flow rate, and pipeline resistance data, reducing reliance on surface condensation systems and ensuring stable return of liquid working fluid to the evaporator inlet.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the operation method of the integrated low-temperature geothermal ORC power generation system according to any one of claims 1-4. The computer program includes: subroutines for evaporator and expander parameter control, heat exchange optimization, and working fluid flow regulation; subroutines for offline storage of deep geological exploration data and regional resource assessment and analysis; subroutines for data transmission and remote diagnosis of the surface control unit; subroutines for continuous system self-checking and safety strategy execution; subroutines for historical data analysis of working fluid status and parameter prediction; timing control subroutines for equipment collaborative operation; geological information fusion subroutines for regional geothermal potential analysis; and subroutines for multi-scenario operation simulation.

10. The computer-readable storage medium according to claim 9, characterized in that, The subroutine for multi-scenario operation simulation can run simulations and optimize system parameters based on input geothermal conditions, well conditions, and resource constraint data, and output the optimal operation scheme adapted to the corresponding scenario.

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