A water circulation system for a fidelity corer

Abstract

This invention provides a water circulation system for a high-fidelity coring device, belonging to the technical field of in-situ high-fidelity coring equipment. The invention includes a coring device, a first heating device, a pressurizing device, a second heating device, a filtering device, and a depressurization device. The second heating device includes a heating pipe and at least two medium-frequency heating coils mounted on the heating pipe. The first heating device is used for preliminary heating of the circulating fluid. The pressurizing device pressurizes the circulating fluid output from the first heating device and then delivers it to the heating pipe for secondary heating. The medium-frequency heating coils heat the circulating fluid to a preset temperature step by step through the heating pipe. The heating pipe is connected to the coring device to deliver circulating fluid at the required temperature to the coring device, thereby achieving the purpose of cleaning the coring device. This system adopts a combination of preheating and multi-stage medium-frequency gradient heating, replacing the traditional single electromagnetic heating method, which solves the problems of slow heating and uneven heating of large-flow, high-pressure fluids.

Description

Technical Field

[0001] This invention relates to the field of in-situ high-fidelity coring equipment technology, and more particularly to a water circulation system for a high-fidelity coring device. Background Technology

[0002] With the increasing depth of deep mineral resources and underground energy development, the geological environment of deep strata exhibits complex characteristics of high temperature, high pressure, and high stress. In-situ core sampling technology is a core technology for accurately analyzing the structure, composition, and physical and mechanical properties of deep strata. To ensure the operational performance of deep in-situ core sampling equipment and verify its adaptability to complex deep strata, a dedicated simulation test platform needs to be built to replicate the real high-temperature and high-pressure working conditions in-situ and conduct simulation calibration tests. During the simulated drilling test, the circulating fluid plays a crucial role in cooling the drill bit, removing cuttings from the borehole, and optimizing drilling conditions, directly determining the stability of the test, drilling efficiency, and drill bit lifespan.

[0003] In existing coring water circulation systems, the mainstream heating methods for heating the circulating fluid are divided into three categories: low-frequency electromagnetic heating, high-frequency electromagnetic heating, and resistance heating. Among them, low-frequency heating has low thermal efficiency and slow heating rate, and cannot achieve rapid heating of large flow fluids. Although high-frequency electromagnetic heating has excellent heating performance, it will generate strong thermal shock to high-pressure pipelines, which can easily cause pipeline damage, system instability, and other safety hazards.

[0004] Therefore, existing circulating fluid heating solutions have significant shortcomings, failing to balance heating efficiency, temperature control accuracy, and equipment operational safety. Summary of the Invention

[0005] To address the shortcomings of existing circulating fluid heating technologies, this invention provides a water circulation system for a high-fidelity coring instrument. This system utilizes a first heating device and a second heating device for gradient heating, resulting in good heating performance and minimal thermal shock to the equipment and pipelines.

[0006] This invention is achieved through the following technical solution:

[0007] A water circulation system for a high-fidelity core sampler, comprising the core sampler;

[0008] A first heating device is used to initially heat the circulating fluid;

[0009] A pressurizing device, wherein the receiving end of the pressurizing device is connected to the output end of the first heating device, and the pressurizing device pressurizes the circulating liquid output by the first heating device;

[0010] The second heating device includes a heating pipe and at least two medium-frequency heating coils disposed on the heating pipe. One end of the heating pipe is connected to the output end of the pressurizing device, and the other end of the heating pipe is connected to the receiving end of the core extractor. The medium-frequency heating coils heat the circulating liquid to a preset temperature step by step by heating the heating pipe.

[0011] A filtration device, wherein the receiving end of the filtration device is connected to the output end of the core sampler, and the filtration device is used to filter impurities in the circulating liquid;

[0012] The pressure reducing device has its receiving end connected to the output end of the filter device and its output end connected to the receiving end of the first heating device. The pressure reducing device is used to reduce the pressure of the circulating liquid and then deliver it to the first heating device to complete the circulation of the circulating liquid.

[0013] In one embodiment, the filtration device includes at least three filters connected in parallel, each filter having its two ends connected to the output end of the core extractor and the receiving end of the step-down device, respectively.

[0014] In one embodiment, a pressure-reducing device is also included, comprising a pressure-reducing tank and a stepped expansion coil disposed within the pressure-reducing tank, wherein the receiving end of the stepped expansion coil is connected to the output end of the filter.

[0015] In one embodiment, the first heating device includes a heating tank and a resistance heater disposed within the heating tank, the resistance heater being used to initially heat the circulating liquid.

[0016] In one embodiment, the heating tank is provided with an insulating sleeve to prevent heat loss from the heating tank.

[0017] In one embodiment, the pressurizing device includes an ultra-high pressure plunger pump, the two ends of which are respectively connected to the first heating device and the second heating device, and the ultra-high pressure plunger pump is also provided with an overflow port, which is connected to the first heating device.

[0018] In one embodiment, the heating pipe is an ultra-high pressure electromagnetic induction pipe.

[0019] In one embodiment, the second heating device further includes an electromagnetic induction controller and a temperature sensor connected to the electromagnetic induction controller, the temperature sensor being disposed on the heating pipe and located between two adjacent medium-frequency heating coils.

[0020] In one embodiment, a safety pool is further included, the receiving end of which is connected to the second heating device, the core extractor, the filter device, and the pressure reducing device, respectively.

[0021] In one embodiment, a one-way valve is provided between the second heating device and the pressurizing device to prevent the circulating fluid from flowing back from the second heating device to the pressurizing device.

[0022] The beneficial effects of this invention are as follows: By providing a water circulation system for a high-fidelity core extractor, including a core extractor, a first heating device, a pressurizing device, a second heating device, a filtering device, and a depressurizing device, the second heating device includes a heating pipe and at least two medium-frequency heating coils disposed on the heating pipe. One end of the heating pipe is connected to the pressurizing device. The first heating device is used to initially heat the circulating liquid. The pressurizing device is connected to the first heating device and pressurizes the circulating liquid output from the first heating device before sending it to the heating pipe for secondary heating. The medium-frequency heating coils heat the circulating liquid to a preset temperature step by step by heating the heating pipe. The heating pipe is connected to the core extractor to deliver circulating liquid at the required temperature to the core extractor, thereby achieving the purpose of cleaning the core extractor. The filtering device is connected to the core extractor and is used to filter impurities in the circulating liquid and send it to the depressurizing device. Finally, the depressurizing device pressurizes the circulating liquid and sends it to the first heating device to complete the circulation. This system adopts a combination of preheating and multi-stage medium-frequency gradient heating to replace the traditional single electromagnetic heating method. This not only solves the problems of slow heating and uneven heating of large-flow, high-pressure fluids, but also avoids the strong thermal shock caused by high-frequency heating, protects high-pressure pipelines, and improves the stability of system operation. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the circulation structure of the water circulation system used in the core extractor.

[0025] In the diagram, 10 - core extractor;

[0026] 100 - First heating device; 110 - Heating tank; 120 - Resistance heater;

[0027] 200 - Pressurization device;

[0028] 300 - Second heating device; 310 - Heating pipe; 320 - Medium frequency heating coil; 330 - Electromagnetic induction controller; 340 - Temperature sensor;

[0029] 400 - Filter device; 410 - Filter;

[0030] 500 - Pressure reducing device; 510 - Pressure reducing tank; 520 - Stage expansion coil;

[0031] 600-Safety Pool;

[0032] 700 - Check Valve;

[0033] 800 - Pressure sensor;

[0034] 900 - Control device;

[0035] 1000 - Control valve. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0037] Example 1

[0038] With the increasing development of deep mineral resources, geothermal resources, and underground engineering, in-situ rock coring in deep strata has become a core part of geological exploration. Deep strata generally present extreme conditions of high temperature and high pressure, and conventional surface coring equipment and its supporting circulation system cannot simulate the in-situ underground environment, making it difficult to complete the performance testing, functional calibration, and experimental verification of the coring equipment.

[0039] During deep in-situ core sampling operations and indoor simulation tests, it is necessary to continuously supply circulating fluid to cool, clean, and remove chips from the core sampler drill bit. This ensures continuous drilling operations, extends the lifespan of the drill bit, and improves drilling efficiency. It is also a key condition for achieving the "five guarantees" (fidelity, pressure, temperature, composition, and structure) calibration of the core sampler.

[0040] Existing conventional water circulation systems have several technical shortcomings: First, traditional heating methods are insufficient for rapid and uniform heating of large-flow, high-pressure fluids. Low-frequency electromagnetic heating alone is inefficient, while high-frequency electromagnetic heating is prone to severe thermal shock, damaging the high-pressure pipeline structure and resulting in poor system safety and stability. Second, conventional fluid transport equipment cannot achieve continuous and stable output of large-flow, ultra-high-pressure fluids, making it difficult to match the 140 MPa-level high-pressure conditions at depths. Third, the circulating fluid after coring operations contains a large amount of rock debris and impurities, and a single filtration structure is prone to clogging, causing drastic fluctuations in pipeline pressure and interrupting the test process. Fourth, directly depressurizing and cooling fluids containing high-temperature, high-pressure rock debris can easily lead to sudden pressure drops and temperature changes, posing safety hazards and preventing closed-loop fluid recycling, resulting in low resource utilization.

[0041] Currently, the high-temperature and high-pressure water circulation system for high-fidelity coring simulation testing in deep in-situ extreme environments of 150 ℃ and 140 MPa is still in the technological gap stage. Existing water circulation systems cannot simultaneously meet the comprehensive requirements of ultra-high pressure stable delivery, high-flow fluid precise temperature rise, efficient filtration of debris-containing fluid, safe gradient cooling and pressure relief, and closed-loop circulation operation, which seriously restricts the research, development, testing and engineering application of deep in-situ high-fidelity coring devices.

[0042] To address the shortcomings of existing technologies in deep in-situ high-fidelity coring simulation testing, such as the lack of a suitable high-temperature and high-pressure water circulation system, unstable fluid pressure, poor heating effect, easy pipe blockage, low safety of pressure relief and cooling, and inability to achieve closed-loop circulation, this invention provides a water circulation system for high-fidelity coring machines. This system can achieve stable pressure delivery of circulating fluid, gradient heating, multi-stage impurity filtration, and staged safe cooling and pressure relief under extreme deep working conditions of 150 ℃ and 140 MPa, completing closed-loop fluid circulation. This meets the cooling, chip flushing, and chip removal requirements of deep in-situ high-fidelity coring simulation testing, ensuring stable operation and performance calibration of the coring machine. The invention will be further described below with reference to the accompanying drawings.

[0043] in, Figure 1 This is a schematic diagram of the circulation structure of the water circulation system used in the core extractor.

[0044] like Figure 1 As shown, the present invention provides a water circulation system for a high-fidelity core extractor, applied to the core extractor 10, including a first heating device 100, which is used to preheat the circulating liquid;

[0045] The pressurizing device 200 has its receiving end connected to the output end of the first heating device 100, and the pressurizing device 200 pressurizes the circulating liquid output by the first heating device 100.

[0046] The second heating device 300 includes a heating pipe 310 and at least two intermediate frequency heating coils 320 disposed on the heating pipe 310. One end of the heating pipe 310 is connected to the output end of the pressurizing device 200, and the other end of the heating pipe 310 is connected to the receiving end of the core extractor 10. The intermediate frequency heating coils 320 heat the heating pipe 310 to heat the circulating liquid to a preset temperature step by step.

[0047] The filter device 400 is connected to the output end of the core extractor 10. The filter device 400 is used to filter impurities in the circulating liquid.

[0048] The pressure reducing device 500 has its receiving end connected to the output end of the filter device 400 and its output end connected to the receiving end of the first heating device 100. The pressure reducing device 500 is used to reduce the pressure of the circulating liquid and then deliver it to the first heating device 100 to complete the circulation of the circulating liquid.

[0049] The water circulation system for the core extractor disclosed in this embodiment consists of a first heating device 100, a pressurizing device 200, a second heating device 300, a core extractor 10, a filtration device 400, and a pressure reducing device 500 forming a closed-loop circulation structure.

[0050] The circulating fluid is first sent to the first heating device 100 for preliminary preheating to reduce the load of subsequent high-temperature heating. After preheating, the circulating fluid enters the pressurization device 200 for pressurization treatment, so that the fluid reaches the ultra-high pressure state required for deep working conditions. The high-pressure circulating fluid flows into the second heating device 300, where it is heated step by step by at least two sets of medium-frequency heating coils 320 on the heating pipe 310 to steadily raise the temperature of the circulating fluid to the preset high temperature of 150 ℃, avoiding the problem of instantaneous high temperature impact. The circulating fluid that has reached the temperature and pressure parameters is transported to the core drill 10 to cool, flush, and remove chips from the core drill bit, ensuring the continuous operation of the core drilling. The circulating fluid carrying rock chips and impurities is discharged from the core drill 10 and enters the filtration device 400 to intercept solid impurities such as rock chips in the fluid. The filtered clean fluid enters the depressurization device 500, and after gradient depressurization treatment, it flows back to the first heating device 100 to re-enter the circulation process, realizing the closed-loop recycling of the fluid.

[0051] Depending on the actual design requirements, 2-5 sets of 320 medium-frequency heating coils can be used.

[0052] This embodiment adopts a combination of preheating and multi-stage medium-frequency gradient heating to replace the traditional single electromagnetic heating method. This not only solves the problems of slow heating and uneven heating of large-flow, high-pressure fluids, but also avoids the strong thermal shock caused by high-frequency heating, protects the high-pressure pipeline, and improves the stability of system operation.

[0053] Furthermore, it integrates a full range of functional modules for pressurization, heating, filtration, cooling, and pressure relief, forming a complete closed-loop water circulation circuit. It can continuously provide circulating fluid to the core sampler 10 that meets the in-situ working conditions of 150 ℃ and 140 MPa at depth, perfectly matching the requirements of deep in-situ high-fidelity core sampling simulation testing.

[0054] The circulating fluid is reused, which greatly reduces the consumption of media and lowers the test cost. The whole system can simultaneously realize multiple functions such as drill bit cooling, cleaning and chip removal, effectively improving the core drilling efficiency, extending the service life of the core feeder 10 drill bits, and ensuring the normal conduct of the core feeder's "five guarantees" capability calibration test.

[0055] In one embodiment, the filtration device 400 includes at least three filters 410 connected in parallel, with each filter 410 having its two ends connected to the output end of the core extractor 10 and the receiving end of the step-down device 500, respectively.

[0056] The filtration device 400 is equipped with at least three filters 410 arranged in parallel. The input end of each filter 410 is connected to the output end of the core sampler 10, and the output ends are all connected to the input end of the pressure reducing device 500. The parallel connection of multiple filters 410 can distribute the fluid flow and impurity load.

[0057] For example, the filter device 400 may also be provided with two or more sets to improve filtration efficiency.

[0058] By increasing the overall flow cross-sectional area through the parallel filter 410 structure, the flow load of a single filter 410 is effectively reduced, the filter element clogging speed is slowed down, and the problem of sudden pressure rise and flow interruption in pipeline caused by clogging of a single filter 410 is avoided.

[0059] Furthermore, when a single filter 410 is under maintenance or its filter element is replaced, the other filters 410 can operate normally without the system needing to be shut down, ensuring the continuous and uninterrupted operation of the water circulation system and improving the continuity of the test.

[0060] Multi-channel diversion makes the distribution of rock debris-containing fluid more uniform, the filtration effect more stable, effectively suppresses pipeline pressure fluctuations, and ensures constant pressure in the high-pressure circulation system.

[0061] In one embodiment, the present invention further includes a pressure-reducing device 500, which includes a pressure-reducing tank 510 and a stepped expansion coil 520 disposed within the pressure-reducing tank 510. The receiving end of the stepped expansion coil 520 is connected to the output end of the filter 410. The diameter of the stepped expansion coil 520 gradually increases from thin to thick along the fluid flow direction. The pressure-reducing tank 510 is filled with circulating cooling water. When the high-temperature, high-pressure fluid flows through the coil, the fluid velocity gradually decreases and the pressure drops gently as the pipe diameter gradually increases. Simultaneously, the cooling water in the tank continuously exchanges heat and cools the coil and the internal fluid.

[0062] The use of a graded expansion structure to achieve gradual pressure relief replaces the traditional instantaneous pressure relief method, avoiding the water hammer effect and impact vibration caused by the sudden pressure relief of high-pressure fluids, and greatly improving the service life and operational safety of high-pressure pipelines, valves and other components.

[0063] The coil is immersed in cooling water. The fluid undergoes heat exchange and cooling simultaneously while slowly depressurizing. The temperature and pressure decrease steadily and synchronously. The integrated design of cooling and depressurization results in a compact structure and high heat exchange efficiency.

[0064] Multi-stage expansion coils extend the fluid flow path, ensuring that high-temperature and high-pressure fluids have sufficient time for heat exchange and pressure relief, resulting in thorough cooling and pressure relief. The parameters of the circulating fluid returning to the front end are stable, ensuring consistent operating conditions throughout the entire circulation system.

[0065] In one embodiment, the first heating device 100 includes a heating tank 110 and a resistance heater 120 disposed within the heating tank 110. The resistance heater 120 is used to preheat the circulating liquid. By relying on the resistance heater 120 to preheat the circulating liquid in the tank as a whole, the circulating liquid at room temperature can be stably preheated to 70°C.

[0066] The resistance heater 120, paired with a large heating tank 110, can uniformly preheat a large volume of circulating liquid. The preheating temperature is controllable and highly stable, providing a stable foundation for the subsequent medium-frequency precision heating. Pre-heating the low-temperature section significantly reduces the heating load on the secondary heating device 300, decreases the operating time and power loss of the medium-frequency heating coil 320, and extends the service life of the heating components. The tank-type liquid storage structure provides a buffering and pressure-stabilizing effect, balancing instantaneous flow fluctuations throughout the system and improving the overall fluid transport stability.

[0067] In one embodiment, a heat insulation sleeve is provided on the outside of the heating tank 110 to prevent heat loss from the heating tank 110. This effectively reduces heat loss of the preheated fluid inside the heating tank 110, reduces the continuous power consumption of the resistance heater 120, and saves energy; it maintains a constant internal temperature of the heating tank 110, avoids preheating temperature fluctuations due to heat loss, ensures a consistent temperature of the circulating liquid entering the pressurization device 200, and improves the overall temperature and pressure control accuracy at the downstream end; it also prevents the high temperature on the tank surface from causing burns or heat radiation to personnel and surrounding equipment, improving the safety of equipment use.

[0068] In one embodiment, the pressurizing device 200 includes an ultra-high pressure plunger pump, with its two ends connected to a first heating device 100 and a second heating device 300, respectively. The ultra-high pressure plunger pump also has an overflow port, which is connected to the first heating device 100. This embodiment preferably uses a horizontal three-cylinder flow plunger pump with a plunger diameter of 18 mm, used in conjunction with a frequency converter and a voltage regulator.

[0069] Among them, the ultra-high pressure plunger pump can stably output a large flow rate of high-pressure fluid with a maximum pressure of 140 MPa and a flow rate of 1200 L / h, fully meeting the requirements of deep extreme high-pressure working conditions. An overflow port is added to form an overflow pressure stabilization circuit. When the pipeline pressure exceeds the set threshold, part of the fluid flows back to the heating tank 110 through the overflow port, automatically adjusting the system pressure to achieve self-pressure stabilization and prevent system overpressure damage. Combined with a frequency converter and pressure stabilization structure, it further ensures the continuous stability of the pump's output flow rate and pressure, eliminating pressure pulsation and providing a constant pressure source for the downstream heating and coring processes.

[0070] In one embodiment, the heating pipe 310 is an ultra-high pressure electromagnetic induction pipe. This ultra-high pressure electromagnetic induction pipe has a high pressure resistance rating, capable of withstanding 140 MPa ultra-high pressure conditions for extended periods. It also features high structural strength, strong resistance to deformation, and is suitable for the high-pressure operating environment of the system. Furthermore, the electromagnetic induction pipe exhibits excellent thermal conductivity, allowing the heat generated by the medium-frequency heating coil 320 to be quickly and evenly transferred to the circulating fluid inside the pipe, resulting in high heating efficiency, uniform fluid heating, and prevention of localized overheating. The integrated pipe structure provides excellent sealing, eliminating the risk of leakage under high temperature and high pressure conditions, thus improving the system's airtightness and operational safety.

[0071] In one embodiment, the second heating device 300 further includes an electromagnetic induction controller 330 and a temperature sensor 340 connected to the electromagnetic induction controller 330. The temperature sensor 340 is disposed on the heating pipe 310 and located between two adjacent medium-frequency heating coils 320.

[0072] Among them, the temperature sensor 340 collects the real-time temperature of the circulating fluid in the heating pipe 310 in segments, realizing segmented temperature measurement and segmented temperature control, accurately controlling the temperature rise of each stage of medium frequency heating, and stabilizing the fluid temperature at the preset value of 150 ℃, greatly improving the temperature control accuracy; the electromagnetic induction controller 330 automatically adjusts the output power of the medium frequency heating coil 320 according to the temperature signal fed back by the sensor, realizing intelligent dynamic temperature adjustment, and coping with interference factors such as flow fluctuations and changes in ambient temperature; real-time temperature monitoring can promptly detect heating faults and abnormal temperature rise in the pipeline, and has fault early warning capabilities, further improving the reliability of system operation.

[0073] In one embodiment, a safety pool 600 is also included, the receiving end of which is connected to the second heating device 300, the core extractor 10, the filter device 400, and the pressure reducing device.

[0074] In case of emergency conditions such as pipeline leaks, component failures, or abnormal pressure / temperature, the high-temperature and high-pressure fluid in each module can be quickly released to the safety pool 600 to achieve emergency unloading and prevent the direct spraying of high-temperature and high-pressure fluid from causing safety accidents.

[0075] The safety pool 600 uniformly collects abnormally discharged circulating fluid, allowing for media recycling and reprocessing, thus avoiding media waste and on-site pollution; it also features multiple safety fallback structures for the entire high-temperature and high-pressure system, significantly enhancing the equipment's safety protection capabilities under extreme operating conditions and fault states.

[0076] In one embodiment, a one-way valve 700 is provided between the second heating device 300 and the pressurizing device 200 to prevent the circulating fluid from flowing back from the second heating device 300 to the pressurizing device 200. The one-way valve 700 effectively prevents the high-temperature, high-pressure fluid inside the second heating device 300 from flowing back to the pressurizing device 200, avoiding the impact and corrosion of the pump body's internal precision structure by the high-temperature medium, preventing high-temperature damage to the plunger pump, and protecting the core power components. It maintains a unidirectional flow of fluid within the pipeline, preventing backflow from causing pipeline pressure disturbances and flow fluctuations, ensuring orderly flow and stable operation of the entire water circulation system. The one-way valve 700 has a simple structure, responds quickly, does not affect normal fluid transport, and simultaneously enhances the isolation and protection capabilities between the high-temperature, high-pressure section and the pressurization section.

[0077] In one embodiment, the system further includes a control device 900, a pressure sensor 800, a one-way valve 700, and a control valve 1000, wherein the control device 900 is electrically connected to the pressure sensor 800, the temperature sensor 340, the one-way valve 700, and the control valve 1000, respectively.

[0078] The pressure sensors 800 are installed along the fluid flow direction at each of the following locations: the outlet pipe of the pressurizing device 200, the inlet and outlet pipes of the second heating device 300, the inlet and outlet pipes of the core sampler 10, the outlet pipe of the filter device 400, and the front end pipe of the staged expansion coil 520. All pressure sensors 800 are electrically connected to the control device 900 via signal lines. Real-time fluid pressure data at different nodes along the entire pipeline is collected, including pressure after pressurization, pressure in the heating section, pressure in the core sampling section, pressure after filtration, and pressure before depressurization. The analog signals are transmitted to the control device 900. The system can monitor in real time for abnormal operating conditions such as overpressure, underpressure, pressure fluctuations, and pipeline blockage.

[0079] The control valve 1000 is an electric / pneumatic high-pressure control valve 1000, which is respectively installed in the feed pipeline between the first heating device 100 and the pressurizing device 200, the main conveying pipeline between the pressurizing device 200 and the second heating device 300, the pipeline between the filter device 400 and the pressure reducing device 500, and the return pipeline from the pressure reducing device 500 to the first heating device 100; at the same time, the control valve 1000 is also installed in the overflow pipeline of the plunger pump and the emergency drainage pipeline of the safety pool 600; all control valves 1000 are uniformly driven and controlled by the control device 900. As an actuator for pipeline on / off and flow regulation: Under normal operating conditions, the main control valve 1000 remains fully open to ensure continuous closed-loop fluid circulation; when starting or stopping the system, the pipelines are opened / closed sequentially according to the instructions of the control device 900 to achieve orderly system start-up and shutdown; when the pressure sensor 800 detects abnormal pressure or equipment failure, the corresponding branch control valve 1000 quickly cuts off the flow path, isolates the fault area, and prevents the fault from spreading; the control valves 1000 of the overflow pipeline and emergency pipeline can cooperate to complete pressure relief and emergency liquid drainage actions.

[0080] One-way valve 700: Strictly installed on the pipeline between the outlet of the ultra-high pressure plunger pump and the inlet of the second heating device 300, located downstream of the control valve 1000 in this section. The fluid flow direction is allowed to be from the pressurizing device 200 to the second heating device 300, and is cut off in the reverse direction. It physically blocks the backflow of the high-temperature and high-pressure circulating fluid in the second heating device 300 to the pressurizing device 200, avoiding the erosion and damage of the plunger pump's internal precision structure by the 150℃ high-temperature medium, and protecting the core power components; at the same time, it stabilizes the fluid flow direction in the pipeline, prevents pressure turbulence and flow fluctuations caused by backflow, and ensures stable output conditions of the front-end pressurizing unit.

[0081] When paired with the control valve 1000 in this section, if it is necessary to inspect the check valve 700 or the second heating device 300, the control device 900 instructs the control valve 1000 to close, cutting off the pipeline medium. This, combined with the double isolation provided by the check valve 700, ensures the safety of the inspection operation.

[0082] Pressure sensor 800 is installed on both sides of the pipeline before and after check valve 700 to monitor the pressure difference between the upstream and downstream of check valve 700 in real time. Control valve 1000 and pressure sensor 800 in this section of pipeline are connected to control device 900. Control device 900 is independently arranged in the equipment control cabinet, serving as the central unit of the entire system. It is electrically connected to all pressure sensors 800, temperature sensors 340, medium frequency heating coils 320, pressurizing devices 200, and various control valves 1000, integrating data acquisition, logic operation, automatic control, and fault alarm functions. The system receives pressure and temperature parameters collected by pressure sensor 800 and temperature sensor 340, and compares and analyzes them with preset operating parameters (150 ℃, 140 MPa). It automatically adjusts the output power and frequency conversion parameters of pressurizing device 200 to stabilize system pressure; it links with the electromagnetic induction controller 330 of the second heating device 300 to achieve precise temperature control; and it automatically triggers the on / off of corresponding control valve 1000, equipment shutdown, and audible and visual alarms based on abnormal pressure and temperature signals. This achieves automated operation, closed-loop control of operating conditions, and active fault protection for the entire water circulation system.

[0083] The system features 800 multi-node pressure sensors for comprehensive pressure monitoring throughout the entire process, enabling early detection of issues such as pipeline blockage, overpressure, and leakage, significantly reducing the probability of equipment failure and safety accidents. 1000 multi-point control valves provide zoned management of pipeline flow channels, allowing for segmented isolation and independent maintenance without requiring system-wide shutdown, thus improving equipment maintenance convenience and testing continuity. The 900 control unit integrates all units including pressure, temperature, heating, pressurization, and valves, achieving automated, interconnected system control, eliminating the tedious manual point-by-point adjustments, and significantly improving operational accuracy and efficiency. It possesses fault self-diagnosis, automatic shutdown, and emergency isolation functions, constructing a multi-level safety protection system suitable for extreme operating conditions such as 140 MPa ultra-high pressure and 150 ℃ high temperature.

[0084] This invention is designed to enable high-fidelity coring simulation testing in a deep, high-temperature and high-pressure in-situ environment of 150 ℃ and 140 MPa. It constructs a closed-loop water circulation system consisting of preheating, pressurization, multi-stage medium-frequency gradient heating, cooling and chip removal, multi-stage filtration, and graded diameter expansion for cooling and pressure relief.

[0085] First, the ambient temperature circulating fluid enters the first heating device 100 and is preheated to 70°C by the resistance heater 120. The heat insulation sleeve on the outside of the heating tank 110 reduces heat loss and ensures stable preheating temperature. The preheated fluid flows into the ultra-high pressure plunger pump, which pressurizes the fluid to a maximum of 140 MPa. With the help of the overflow circuit and the frequency conversion voltage stabilization structure, constant pressure and flow are achieved.

[0086] High-pressure fluid flows into the ultra-high-pressure electromagnetic induction pipeline of the second heating device 300 through the one-way valve 700, and undergoes gradient heating by passing through at least two sets of medium-frequency heating coils 320. Temperature sensors 340 between adjacent coils collect the temperature in real time and feed it back to the electromagnetic induction controller 330 to dynamically adjust the heating power and accurately heat the fluid to 150 ℃. The multi-stage medium-frequency heating mode avoids the defects of low efficiency of single low-frequency heating and large thermal shock of high-frequency heating, ensuring pipeline safety and heating effect.

[0087] High-temperature, high-pressure circulating fluid reaching the target temperature and pressure is delivered to the core sampler 10 to continuously cool, flush, and remove cuttings from the core drill bit, ensuring the normal operation of the core sampling process and the performance calibration test of the core sampler 10. After the circulating fluid carrying a large amount of rock cuttings flows out of the core sampler 10, it enters multiple parallel filters 410. Each filter 410 uses a three-stage filtration structure to sequentially intercept large particles, medium and small particles, and fine rock cuttings. The parallel structure effectively prevents flow channel blockage and pressure fluctuations.

[0088] The filtered clean, high-temperature, and high-pressure fluid enters the stepped expansion coil 520 inside the pressure reducing tank 510. The fluid flows slowly along the coil with the diameter gradually increasing from thin to thick, the flow rate decreases step by step, and the pressure is released steadily. At the same time, the cooling water in the pressure reducing tank 510 exchanges heat with the coil to achieve synchronous cooling of the fluid. The circulating fluid that has completed cooling and depressurization flows back to the first heating device 100 to enter the next cycle.

[0089] The entire system works in concert with all modules to achieve stable delivery of high-flow-rate, ultra-high-pressure fluid, precise gradient heating, efficient filtration of rock cuttings, and safe and gradual cooling and depressurization, with closed-loop operation throughout the entire process. The supporting one-way valve 700, safety pool 600, and thermal insulation structure further enhance the system's safety and stability, fully meeting the requirements for deep in-situ core sampling simulation testing.

[0090] Based on the above technical solutions and embodiments, the present invention has the following overall technical advantages compared with the prior art:

[0091] 1. Strong adaptability to working conditions: It can stably simulate extreme high temperature and high pressure working conditions at 150 ℃ and 140 MPa in deep environments, filling the technical gap in a dedicated water circulation system for in-situ high-fidelity coring tests in deep environments, and providing core test support for the development and performance calibration of the deep coring device 10.

[0092] 2. High temperature and pressure control accuracy and good stability: The preheating + multi-stage medium frequency gradient heating combination heating scheme is adopted, coupled with a segmented temperature measurement and intelligent temperature control structure, so that the temperature rise is uniform and there is no strong thermal shock; the plunger pump, combined with overflow pressure stabilization and frequency conversion pressure regulation structure, ensures constant output pressure and flow rate; the 520 staged expansion coil realizes gradient pressure relief and cooling, and the temperature and pressure are controllable throughout the process.

[0093] 3. Excellent anti-clogging capability: It adopts a composite filtration structure of multiple 410 filters in parallel + single 410 filter in three stages, which greatly reduces the probability of rock debris clogging. The system can run continuously for a long time with low risk of test interruption.

[0094] 4. Comprehensive safety protection system: It integrates a 700-degree check valve to prevent backflow, a heat insulation jacket to prevent heat loss, an overflow circuit to prevent overpressure, and a 600-degree safety pool for emergency relief. Multiple safety structures ensure adequate isolation and protection in high-pressure and high-temperature areas, greatly improving the safety of equipment and personnel.

[0095] 5. Good operating economy: The closed-loop circulation design allows for repeated use of the circulating fluid, resulting in low media consumption; the load distribution of each heating and pressurizing component is reasonable, resulting in low energy consumption, minimal component wear, and long equipment service life.

[0096] 6. High degree of functional integration: A single system can simultaneously achieve multiple functions such as drill bit cooling, cleaning, chip removal, media circulation, and temperature and pressure simulation. It has a compact structure and is compatible with the integration and installation requirements of indoor simulation test platforms.

[0097] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A water circulation system for a high-fidelity core extractor, comprising a core extractor (10), characterized in that, Also includes: The first heating device (100) is used to initially heat the circulating liquid; A pressurizing device (200) is provided, wherein the receiving end of the pressurizing device (200) is connected to the output end of the first heating device (100), and the pressurizing device (200) pressurizes the circulating liquid output by the first heating device (100); The second heating device (300) includes a heating pipe (310) and at least two intermediate frequency heating coils (320) disposed on the heating pipe (310). One end of the heating pipe (310) is connected to the output end of the pressurizing device (200), and the other end of the heating pipe (310) is connected to the receiving end of the core extractor (10). The intermediate frequency heating coils (320) heat the circulating liquid to a preset temperature step by step by heating the heating pipe (310). A filter device (400) is provided, the receiving end of which is connected to the output end of the core extractor (10), and the filter device (400) is used to filter impurities in the circulating liquid. The pressure reducing device (500) is connected to the output end of the filter device (400) and the output end of the pressure reducing device (500) is connected to the receiving end of the first heating device (100). The pressure reducing device (500) is used to reduce the pressure of the circulating liquid and then deliver it to the first heating device (100) to complete the circulation of the circulating liquid.

2. The water circulation system for a core extractor according to claim 1, characterized in that, The filtration device (400) includes at least three filters (410) connected in parallel, with each filter (410) having its two ends connected to the output end of the core extractor (10) and the receiving end of the step-down device (500), respectively.

3. The water circulation system for a core extractor according to claim 2, characterized in that, It also includes a pressure reducing device (500), which includes a pressure reducing tank (510) and a graded expansion coil (520) disposed in the pressure reducing tank (510). The receiving end of the graded expansion coil (520) is connected to the output end of the filter (410).

4. The water circulation system for a core extractor according to claim 3, characterized in that, The first heating device (100) includes a heating tank (110) and a resistance heater (120) disposed in the heating tank (110), the resistance heater (120) being used to preheat the circulating liquid.

5. The water circulation system for a core extractor according to claim 3, characterized in that, The heating tank (110) is provided with an insulation sleeve to prevent heat loss from the heating tank (110).

6. The water circulation system for a core extractor according to any one of claims 1-5, characterized in that, The pressurizing device (200) includes an ultra-high pressure plunger pump, the two ends of which are connected to the first heating device (100) and the second heating device (300) respectively. The ultra-high pressure plunger pump is also provided with an overflow port, which is connected to the first heating device (100).

7. The water circulation system for a core extractor according to any one of claims 1-5, characterized in that, The heating pipe (310) is an ultra-high pressure electromagnetic induction pipe.

8. The water circulation system for a core extractor according to any one of claims 1-5, characterized in that, The second heating device (300) further includes an electromagnetic induction controller (330) and a temperature sensor (340) connected to the electromagnetic induction controller (330). The temperature sensor (340) is disposed on the heating pipe (310) and located between two adjacent medium-frequency heating coils (320).

9. The water circulation system for a core extractor according to any one of claims 1-5, characterized in that, It also includes a safety pool (600), the receiving end of which is connected to the second heating device (300), the core extractor (10), the filter device (400) and the pressure reducing device respectively.

10. The water circulation system for a core extractor according to any one of claims 1-5, characterized in that, A one-way valve (700) is provided between the second heating device (300) and the pressurizing device (200) to prevent the circulating liquid from flowing back from the second heating device (300) to the pressurizing device (200).

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