A deep underground aquifer heat storage simulation experiment system and experiment method
The deep underground aquifer thermal storage simulation experimental system utilizes distributed fiber optic sensors and high-temperature and high-pressure simulation technology to solve the problem of difficulty in monitoring temperature and pressure changes during deep underground aquifer thermal storage, which is difficult in existing technologies. This enables accurate simulation and analysis of the deep aquifer thermal storage process.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- PETROCHINA SHENZHEN NEW ENERGY RESEARCH INSTITUTE CO LTD
- Filing Date
- 2024-11-28
- Publication Date
- 2026-05-29
AI Technical Summary
Existing technologies lack specialized physical experimental simulation systems and methods to study temperature and pressure changes during the thermal storage process of deep underground aquifers. It is difficult to accurately monitor temperature and pressure changes in three-dimensional space. Furthermore, existing devices have poor sealing performance under high temperature and high pressure conditions, making it difficult to simulate the thermal storage conditions of deep aquifers at 100-150℃.
A deep underground aquifer thermal storage simulation experimental system was adopted, including a deep aquifer simulation device, a thermal fluid injection device, a fiber optic monitoring system, and a thermal fluid extraction device. Distributed fiber optic temperature and pressure sensors were used to monitor temperature and pressure changes at multiple locations on the experimental rock samples in real time. Silicon oil was used to simulate a high-temperature and high-pressure environment, and a confining pressure loading device was used to simulate real formation conditions.
It enables accurate analysis of the laws governing temperature conduction, fluid diffusion, pressure transmission, and permeability decay during deep aquifer thermal storage, providing more accurate experimental data support. It is suitable for large-scale natural rock sample simulation and has a wide range of applications.
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Figure CN122109187A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of underground aquifer thermal storage simulation experiment technology, and in particular to a deep underground aquifer thermal storage simulation experiment system and experimental method. Background Technology
[0002] Currently, countries worldwide are vigorously developing new energy technologies such as solar and wind power to replace traditional fossil fuels. However, solar and wind power technologies are inherently limited by time and geographical constraints, resulting in insufficient flexibility, utilization rate, and stability in their energy supply. Furthermore, large amounts of high-temperature waste heat are generated during industrial production processes such as petrochemicals, thermal power generation, and distillation drying. Currently, this waste heat is not effectively recovered and utilized, leading to significant energy waste. Aquifer thermal energy storage technology refers to storing waste heat from daily production, industrial processes, and curtailed wind and solar energy in underground aquifers, which can then be extracted for use when needed. Aquifer thermal energy storage technology features large-scale energy storage, low cost, and wide applicability. It can effectively utilize wind, solar, and waste heat resources, achieving multi-energy complementarity and cross-seasonal thermal energy utilization.
[0003] Research and practice on aquifer thermal storage in my country mainly focuses on shallow aquifers, with virtually no research or engineering practice on deep aquifer thermal storage technology. Numerical simulation is currently the primary method for studying deep aquifer thermal storage technology, but its results typically require verification through physical experiments. Currently, there is no dedicated physical simulation system or process method for deep aquifer thermal storage technology within the industry. Some scholars use chamber-type sand-filled experimental devices or conventional high-temperature rock sample flow heat exchange devices to conduct experimental research on deep aquifer thermal storage.
[0004] While chamber-type sand-filled experimental devices can effectively accommodate temperature sensors for monitoring formation temperature during thermal storage, they can only simulate formation rock using sand and cannot test natural experimental rock samples. Furthermore, the chamber structure is difficult to maintain under high temperature and pressure, limiting its use to shallow to medium-depth thermal storage experiments with temperatures below 100℃, and making it unsuitable for studying deep aquifer thermal storage conditions at 100-150℃. Conventional high-temperature rock sample flow heat exchange devices can test natural experimental rock samples, but the samples are generally small. Because conventional temperature and pressure sensors are relatively large, the number of sensors that can be placed on the sample is very limited, allowing monitoring only of localized temperature and pressure values, and making it difficult to accurately monitor temperature and pressure changes across the entire three-dimensional space of the experimental rock sample. Summary of the Invention
[0005] The main objective of this invention is to propose a deep underground aquifer thermal storage simulation experimental system and method, which aims to achieve real-time monitoring of temperature and pressure changes at multiple points in the three-dimensional space of the thermal storage rock, so as to effectively analyze the laws of temperature conduction, fluid diffusion, pressure transmission and permeability decay during the deep aquifer thermal storage process.
[0006] To achieve the above objectives, the deep underground aquifer thermal storage simulation experimental system proposed in this invention includes a deep aquifer simulation device, a hot fluid injection device, a fiber optic monitoring system, and a hot fluid extraction device. The deep aquifer simulation device includes an experimental chamber and an experimental rock sample, with the rock sample housed in the experimental chamber. The hot fluid injection device extends through the experimental chamber into the rock sample and is equipped with an inlet temperature sensor and an inlet pressure sensor. The fiber optic monitoring system includes multiple fiber optic temperature monitoring devices and multiple fiber optic pressure monitoring devices, which are spaced apart within the rock sample. The hot fluid extraction device extends through the experimental chamber into the rock sample and is equipped with an outlet temperature sensor and an outlet pressure sensor.
[0007] In one embodiment, the fiber optic temperature monitoring device is a distributed fiber optic temperature sensor, the fiber optic pressure monitoring device is a distributed fiber optic strain sensor, and the fiber optic monitoring system further includes a distributed fiber optic analysis host. Both the distributed fiber optic temperature sensor and the distributed fiber optic strain sensor are connected to the distributed fiber optic analysis host.
[0008] In one embodiment, the interior of the experimental chamber contains silicone oil, the experimental rock sample is located in the silicone oil, and the deep water-bearing rock formation simulation device further includes a confining pressure loading device, which is connected to the interior of the experimental chamber.
[0009] In one embodiment, the outer wall of the experimental rock sample is provided with a high-temperature sealant, which is used to isolate the experimental rock sample from the silicone oil.
[0010] In one embodiment, the deep aquifer simulation device further includes a cabin heating and insulation sleeve, which is fitted onto the outer wall of the experimental cabin.
[0011] In one embodiment, the experimental rock sample comprises at least two types of natural rocks joined together in sequence.
[0012] In one embodiment, the hot fluid injection device includes an injection pipeline, an injection pump, a heating device, and an injection conduit. The injection pipeline is equipped with an inlet end temperature sensor and an inlet end pressure sensor. The injection pump and the heating device are located outside the experimental chamber, and the injection conduit is located inside the experimental chamber and extends into the experimental rock sample. The injection pipeline passes through the experimental chamber and is sequentially connected to the injection pump, the heating device, and the injection conduit.
[0013] In one embodiment, the thermal fluid extraction device includes a fluid extraction pipeline, a fluid extraction pump, a metering device, and a fluid extraction conduit. The fluid extraction pipeline is equipped with an outlet temperature sensor and an outlet pressure sensor. The fluid extraction pump and the metering device are located outside the experimental chamber. The fluid extraction conduit is located inside the experimental chamber and extends into the experimental rock sample. The fluid extraction pipeline passes through the experimental chamber and is sequentially connected to the fluid extraction conduit, the fluid extraction pump, and the metering device.
[0014] The present invention also proposes an experimental method, which is implemented using the deep underground aquifer thermal storage simulation experimental system described in any one of the above embodiments, and includes the following steps:
[0015] Natural rocks from the same stratum as the target stratum were taken to prepare experimental rock samples. The experimental rock samples were saturated with formation water by boiling. Multiple fiber optic temperature detection devices and multiple fiber optic pressure detection devices were installed in the experimental rock samples.
[0016] The experimental rock sample was placed in the experimental chamber, and the hot fluid injection device, the experimental chamber, and the hot fluid extraction device were connected in sequence and the experimental chamber was sealed.
[0017] Turn off the thermal fluid extraction device and turn on the thermal fluid injection device to inject thermal fluid into the experimental rock sample until the pressure sensor at the outlet end of the fluid extraction pipeline reaches the set value. Then turn off the thermal fluid injection device and record the injection temperature, injection pressure and injection flow rate.
[0018] The sample was left to stand for a certain period of time to allow the hot fluid to continue to exchange heat with the experimental rock sample until the internal pressure and temperature of the experimental rock sample monitored by the fiber optic temperature detection device and the fiber optic pressure detection device tended to stabilize.
[0019] Turn on the thermal fluid extraction device, extract the thermal fluid from the experimental rock sample, and record the fluid temperature, fluid pressure, and fluid flow rate.
[0020] Based on the experimental rock sample's geometric dimensions, temperature, confining pressure, injection temperature, injection pressure, injection flow rate, sampling temperature, sampling pressure, sampling flow rate, and data on temperature and pressure at various points inside the experimental rock sample monitored by fiber optic temperature and pressure detection devices, the changes in flow rate, temperature, and pressure during injection, heat storage, and heat extraction are analyzed.
[0021] In one embodiment, the fiber optic pressure detection device is a distributed fiber optic strain sensor. The distributed fiber optic strain sensor monitors the strain data of the experimental rock sample through optical fiber, and then combines the effective stress principle of porous media to indirectly measure the internal liquid pressure of the experimental rock sample.
[0022] The technical solution of the deep underground aquifer thermal storage simulation experimental system of the present invention simulates the environment of a real deep underground aquifer by using a deep aquifer simulation device, and uses a hot fluid injection device and a hot fluid extraction device to simulate the real thermal storage process. Multiple fiber optic temperature monitoring devices and multiple fiber optic pressure monitoring devices are set at intervals within the experimental rock sample to monitor the temperature and pressure at multiple locations of the experimental rock sample before, during, and after thermal storage. This enables real-time monitoring of temperature and pressure changes at multiple locations in the three-dimensional space of the thermal storage rock, which can be used to effectively analyze important laws such as temperature conduction, fluid diffusion, pressure transmission, and permeability decay during the deep aquifer thermal storage process. Attached Figure Description
[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.
[0024] Figure 1 A front view of the structure of an embodiment of the deep aquifer simulation device provided by the present invention;
[0025] Figure 2 for Figure 1 A partial top view of the structure of a mid-deep aquifer simulation device;
[0026] Figure 3 for Figure 1 A partial structural side view of a mid-deep aquifer simulation device;
[0027] Figure 4 This is a flowchart illustrating an embodiment of the experimental method provided by the present invention.
[0028] Explanation of icon numbers:
[0029] 1000. Deep underground aquifer thermal storage simulation experimental system;
[0030] 1. Deep aquifer simulation device; 11. Experimental chamber; 111. Silicone oil; 12. Experimental rock sample; 121. High-temperature sealant; 13. Confining pressure loading device; 14. Chamber heating and insulation jacket;
[0031] 2. Hot fluid injection device; 21. Inlet temperature sensor; 22. Inlet pressure sensor; 23. Injection pipeline; 24. Injection pump; 25. Heating device; 26. Injection conduit;
[0032] 3. Fiber optic monitoring system; 31. Fiber optic temperature monitoring device; 32. Fiber optic pressure monitoring device; 33. Fiber optic parsing host;
[0033] 4. Hot fluid extraction device; 41. Outlet temperature sensor; 42. Outlet pressure sensor; 43. Liquid collection pipeline; 44. Liquid collection pump; 45. Metering device; 46. Liquid collection conduit.
[0034] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation
[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0036] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.
[0037] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.
[0038] This invention proposes a deep underground aquifer thermal storage simulation experimental system 1000.
[0039] Please see Figures 1 to 3 In one embodiment of the present invention, the deep underground aquifer thermal storage simulation experimental system 1000 includes a deep aquifer simulation device 1, a hot fluid injection device 2, an optical fiber monitoring system 3, and a hot fluid extraction device 4. The deep aquifer simulation device 1 includes an experimental chamber 11 and an experimental rock sample 12, the experimental rock sample 12 being housed in the experimental chamber 11. The hot fluid injection device 2 extends through the experimental chamber 11 into the experimental rock sample 12. The hot fluid injection device 2 is equipped with an inlet temperature sensor 21 and an inlet pressure sensor 22. The optical fiber monitoring system 3 includes multiple optical fiber temperature monitoring devices 31 and multiple optical fiber pressure monitoring devices 32, which are spaced apart within the experimental rock sample 12. The hot fluid extraction device 4 extends through the experimental chamber 11 into the experimental rock sample 12. The hot fluid extraction device 4 is equipped with an outlet temperature sensor 41 and an outlet pressure sensor 42.
[0040] In this embodiment, the deep aquifer simulation device 1 functions to simulate deep, high-temperature, and high-pressure aquifers. The high-temperature fluid injected by the injection pump 24 flows within the natural rock sample 12 and exchanges heat with it, thus storing thermal energy within the aquifer. The experimental chamber 11 can be made of a high-temperature and high-pressure resistant material, such as a chamber forged from a nickel-based alloy. After being heated and pressurized, the experimental chamber 11 is used to simulate the real deep underground aquifer environment. The experimental chamber 11 has an inlet flange and an outlet flange at both ends, respectively. Sealing plugs are provided on the inlet and outlet flanges for threading the signal lines of the fiber optic monitoring system 3, ensuring a seal between the threaded signal lines and the flanges.
[0041] The function of the hot fluid injection device 2 is to heat cold water to the design temperature and inject it into the experimental rock sample 12 under a certain pump pressure, thereby simulating the process of generating and injecting high-temperature hot fluid into the formation. The injection pump 24 is used to inject the hot fluid into the experimental rock sample 12, and the inlet temperature and pressure sensors are used to detect the temperature and pressure of the fluid before it is injected into the experimental rock sample 12.
[0042] The function of the fiber optic monitoring system 3 is to continuously monitor the temperature and pressure at different locations on the natural experimental rock sample 12 during the experiment by embedding multiple fiber optic temperature monitoring devices 31 and multiple fiber optic pressure monitoring devices 32 at different locations on the sample. The fiber optic temperature monitoring devices 31 can be point-type fiber optic temperature sensors or distributed fiber optic temperature sensors, etc., and the fiber optic pressure monitoring devices 32 can be fiber Bragg grating pressure sensors, fiber grating array pressure sensors, or distributed fiber optic strain sensors, etc. Taking distributed fiber optic temperature sensors and distributed fiber optic pressure sensors as examples, the distributed fiber optic temperature sensors can measure temperature distributedly along the entire fiber length, and the distributed fiber optic pressure sensors can measure strain distributedly along the entire fiber length. The signals within the fiber are not subject to electromagnetic interference. The distributed fiber optic temperature sensor (0.9 mm in diameter) is placed inside a thin metal tube (1 mm in outer diameter) and is used to monitor temperature changes at different locations inside the experimental rock sample 12. The distributed fiber optic strain sensor is used to monitor the strain data of the experimental rock sample 12. Combined with the surrounding rock, pore pressure, and stress-strain relationship, the local pore pressure value of the experimental rock sample 12 is calculated, thereby achieving monitoring of the pressure at different locations on the experimental rock sample 12. According to experimental requirements, one distributed fiber optic temperature sensor and one distributed fiber optic strain sensor can be arranged side by side as a group and pre-embedded in different positions of the experimental rock sample 12.
[0043] The function of the thermal fluid extraction device 4 is to simulate the thermal fluid extraction process in the aquifer and to measure the temperature and mass of the extracted fluid. The outlet temperature sensor 41 and pressure sensor are used to detect the temperature and pressure of the fluid extracted from the experimental rock sample 12.
[0044] In this embodiment, experimental rock sample 12 can be a large-sized natural rock sample, for example, a rock sample with dimensions of 2m in length, 20cm in width, and 20cm in height. The rock sample can be a single type of rock sample or a combination of multiple types of rocks, which can effectively evaluate the comprehensive thermal storage effect of interbedded strata such as sandstone, carbonate rock, and mudstone, and provide a more accurate simulation of real deep water-bearing strata. The rock sample is pre-embedded with injection fluid metal conduits, produced fluid metal conduits, and distributed fiber optic sensors, and is completely sealed with high-temperature adhesive.
[0045] The deep underground aquifer thermal storage simulation experimental system 1000 of this embodiment uses a deep aquifer simulation device 1 to simulate the environment of a real deep underground aquifer, and uses a hot fluid injection device 2 and a hot fluid extraction device 4 to simulate the real thermal storage process. Multiple fiber optic temperature monitoring devices 31 and multiple fiber optic pressure monitoring devices 32 are spaced apart in the experimental rock sample 12 to monitor the temperature and pressure at multiple locations of the experimental rock sample 12 before, during, and after thermal storage. This enables real-time monitoring of temperature and pressure changes at multiple locations in the three-dimensional space of the thermal storage rock, which can be used to effectively analyze important laws such as temperature conduction, fluid diffusion, pressure transmission, and permeability decay during the deep aquifer thermal storage process.
[0046] Further, please refer to Figures 1 to 3 In one embodiment of the present invention, the fiber optic temperature monitoring device 31 is a distributed fiber optic temperature sensor, the fiber optic pressure monitoring device 32 is a distributed fiber optic strain sensor, and the fiber optic monitoring system 3 further includes a distributed fiber optic analysis host 33, to which both the distributed fiber optic temperature sensor and the distributed fiber optic strain sensor are connected. Specifically, in this embodiment, the distributed fiber optic analysis host 33 is used to transmit optical signals, receive returned optical signals, perform data analysis, and display results. The connection method between the distributed fiber optic analysis host 33 and the distributed fiber optic strain sensor and the distributed fiber optic temperature sensor can be: connected to the distributed fiber optic temperature sensor and the distributed fiber optic strain sensor respectively via fiber optic patch cords.
[0047] Further, please refer to Figures 1 to 3 In one embodiment of the present invention, the interior of the experimental chamber 11 contains silicone oil 111, the experimental rock sample 12 is located in the silicone oil 111, and the deep water-bearing rock strata simulation device 1 further includes a confining pressure loading device 13, which is connected to the interior of the experimental chamber 11.
[0048] In this embodiment, the experimental chamber 11 is integrally forged from a nickel-based alloy and is filled with silicone oil 111 during the experiment to provide the experimental rock sample 12 with a simulated high-temperature and high-pressure environment of the formation. The confining pressure loading device 13 is a confining pressure pump, which is connected to the experimental chamber 11 by a confining pressure pipeline. The confining pressure pipeline is equipped with a control valve. By adjusting the pumping pressure of the confining pressure pump, the pressure inside the experimental chamber 11 is changed so that the surrounding rock of the experimental rock sample 12 reaches the design pressure.
[0049] Please see Figures 1 to 3To prevent silicone oil 111 from seeping into the experimental rock sample 12 and affecting the temperature and pressure monitoring within the sample, in one embodiment of the present invention, a high-temperature sealant 121 is provided on the outer wall of the experimental rock sample 12. The high-temperature sealant 121 is used to isolate the experimental rock sample 12 from the silicone oil 111. Thus, the silicone oil 111 is only used to simulate the pressure environment of a deep underground aquifer and indirectly heat the experimental rock sample 12 to simulate the temperature environment of a deep underground aquifer, preventing the silicone oil 111 from seeping into the experimental rock sample 12 and affecting the temperature and pressure monitoring within the sample, as well as preventing the silicone oil 111 from damaging the simulated environment of the deep underground aquifer.
[0050] Further, please refer to Figures 1 to 3 In one embodiment of the present invention, the deep water-bearing rock strata simulation device 1 further includes a cabin heating and insulation sleeve 14, which is fitted onto the outer wall of the experimental cabin 11.
[0051] In this embodiment, a heating jacket is wrapped around the outer wall of the experimental chamber 11. Multiple sets of built-in electric heating rods directly heat the experimental chamber 11, transferring the temperature to the silicone oil 111 inside. The high-temperature silicone oil 111 indirectly heats the experimental rock sample 12 to the design temperature, which is based on the actual formation temperature, thus better simulating the formation temperature environment. This system can completely simulate the deep aquifer injection, storage, and extraction processes under 200℃ conditions. It can address key factors affecting the thermal storage effect of deep aquifers, such as formation lithology, temperature, geostress, porosity and permeability, and injection / production parameters. It has a wide range of applications and significant practical guidance value.
[0052] Further, please refer to Figures 1 to 3 In one embodiment of the present invention, the experimental rock sample 12 comprises at least two types of natural rocks sequentially joined together. In this embodiment, the deep underground aquifer thermal storage simulation experimental system 1000 can conduct experiments on large-sized natural rock samples (e.g., rock sample dimensions of 2m in length, 20cm in width, and 20cm in height). A pad is provided under the experimental rock sample 12 to support it, ensuring that the silicone oil 111 is in full contact with the bottom of the experimental rock sample 12. The rock sample can be a single type of rock sample or a combination of multiple types of rocks. It can use rocks joined in layers vertically or horizontally, effectively evaluating the comprehensive thermal storage effect of interbedded strata such as sandstone, carbonate rock, and mudstone, and providing a more accurate simulation of real deep aquifer strata.
[0053] Further, please refer to Figures 1 to 3In one embodiment of the present invention, the hot fluid injection device 2 includes an injection pipe 23, an injection pump 24, a heating device 25, and an injection conduit 26. The injection pipe 23 is provided with an inlet end temperature sensor 21 and an inlet end pressure sensor 22. The injection pump 24 and the heating device 25 are located outside the experimental chamber 11, and the injection conduit 26 is located inside the experimental chamber 11 and extends into the experimental rock sample 12. The injection pipe 23 passes through the experimental chamber 11 and is sequentially connected to the injection pump 24, the heating device 25, and the injection conduit 26.
[0054] In this embodiment, the heating device 25 is a high-pressure heating vessel, and the injection conduit 26 is used to guide the hot fluid into the interior of the experimental rock sample 12, simulating the actual injection process into the formation. The injection pipeline 23 is also equipped with a first control valve and a second control valve. The first control valve is located between the injection pump 24 and the heating device 25, and the second control valve is located between the heating device 25 and the experimental chamber 11. The first and second control valves are used to better control the flow rate and velocity of the hot fluid in the injection pipeline 23, preventing the pipeline system from overloading and posing a danger.
[0055] Please see Figures 1 to 3 In one embodiment of the present invention, the thermal fluid extraction device 4 includes a fluid extraction pipe 43, a fluid extraction pump 44, a metering device 45, and a fluid extraction conduit 46. The fluid extraction pipe 43 is equipped with an outlet end temperature sensor 41 and an outlet end pressure sensor 42. The fluid extraction pump 44 and the metering device 45 are located outside the experimental chamber 11, and the fluid extraction conduit 46 is located inside the experimental chamber 11 and extends into the experimental rock sample 12. The fluid extraction pipe 43 passes through the experimental chamber 11 and is sequentially connected to the fluid extraction conduit 46, the fluid extraction pump 44, and the metering device 45.
[0056] In this embodiment, the sampling pump 44 is used to draw out the hot fluid from the experimental rock sample 12, and the metering device 45 is a metering balance used to measure the hot fluid extraction rate. The sampling conduit 46 is used to guide the hot fluid from the center of the experimental rock sample 12 to the outside of the experimental rock sample 12, simulating the actual hot fluid extraction process. The sampling pipeline 43 is also equipped with a third control valve and a fourth control valve. The third control valve is located between the sampling pump 44 and the experimental chamber 11, and the fourth control valve is located between the metering device 45 and the sampling pump 44. The third and fourth control valves are used to better control the flow rate and velocity of the hot fluid in the sampling pipeline 43, prevent the pipeline system from overloading and causing danger, and cooperate with the metering balance to prevent exceeding the power of the metering balance.
[0057] Please see Figure 4 The present invention also proposes an experimental method, which is implemented using any one of the deep underground aquifer thermal storage simulation experimental systems described in the above embodiments, and includes the following steps:
[0058] Natural rocks from the same stratum as the target stratum were taken to prepare experimental rock samples. The experimental rock samples were saturated with formation water by boiling. Multiple fiber optic temperature detection devices and multiple fiber optic pressure detection devices were installed in the experimental rock samples.
[0059] The experimental rock sample was placed in the experimental chamber, and the hot fluid injection device, the experimental chamber, and the hot fluid extraction device were connected in sequence and the experimental chamber was sealed.
[0060] Turn off the thermal fluid extraction device and turn on the thermal fluid injection device to inject thermal fluid into the experimental rock sample until the pressure sensor at the outlet end of the fluid extraction pipeline reaches the set value. Then turn off the thermal fluid injection device and record the injection temperature, injection pressure and injection flow rate.
[0061] The sample was left to stand for a certain period of time to allow the hot fluid to continue to exchange heat with the experimental rock sample until the internal pressure and temperature of the experimental rock sample monitored by the fiber optic temperature detection device and the fiber optic pressure detection device tended to stabilize.
[0062] Turn on the thermal fluid extraction device, extract the thermal fluid from the experimental rock sample, and record the fluid temperature, fluid pressure, and fluid flow rate.
[0063] Based on the experimental rock sample's geometric dimensions, temperature, confining pressure, injection temperature, injection pressure, injection flow rate, sampling temperature, sampling pressure, sampling flow rate, and data on temperature and pressure at various points inside the experimental rock sample monitored by fiber optic temperature and pressure detection devices, the changes in flow rate, temperature, and pressure during injection, heat storage, and heat extraction are analyzed.
[0064] Since this experimental method adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be repeated here.
[0065] In this embodiment, taking two kinds of natural rocks as experimental objects as an example, natural rocks from the same stratum as the target stratum are prepared into experimental rock samples, and the experimental rock samples are saturated with formation water by boiling. The steps of installing multiple fiber optic temperature detection devices and multiple fiber optic pressure detection devices into the experimental rock samples specifically include the following steps:
[0066] ① Prepare experimental rock samples: Take one piece of each of two natural outcrops from the same stratigraphic position as the target stratum. Cut each rock into a rectangular sample with dimensions (length × width × height) of 1m × 0.2m × 0.2m. Drill a 2cm diameter, 15cm deep hole (approximately 5cm from the left edge of the sample) centered on the end of the sample near the injection conduit. Insert a thin metal tube to the bottom of the hole as the injection conduit. Seal the gap between the inner wall of the hole and the outer wall of the injection conduit with high-temperature adhesive. Drill a 2cm diameter, 15cm deep hole (approximately 5cm from the right edge of the sample) centered on the end of the sample near the sampling conduit. Insert a thin metal tube to the bottom of the hole as the sampling conduit. Seal the gap between the inner wall of the hole and the outer wall of the sampling conduit with high-temperature adhesive. A 1.8m long, 10cm deep, and 3-5mm wide groove was cut vertically downwards from the center of the upper surface of two experimental rock samples using an abrasive wheel cutter. Another 1.8m long, 5cm deep, and 3-5mm wide groove was cut vertically downwards 5cm above the first groove. The rock samples were then saturated with formation water by boiling.
[0067] ② Deploying distributed fiber optic sensors within the experimental rock sample: A distributed fiber optic temperature sensor is wrapped in a thin metal tube to shield the fiber optic monitoring data generated by rock sample strain. One thin metal tube already wrapped with a distributed fiber optic temperature sensor and one distributed fiber optic pressure sensor are placed side-by-side to form one set of distributed fiber optic sensors. A set of distributed fiber optic sensors is placed close to the rock wall at a depth of 10 cm in the fissure, and high-temperature sealant is poured in to a depth of 5 cm. After the high-temperature sealant in the fissure has completely solidified, another set of distributed fiber optic sensors is placed close to the rock wall at a depth of 5 cm in the fissure, and high-temperature sealant is poured in again to the upper surface of the rock sample. After the high-temperature sealant in the fissure has completely solidified, a set of distributed fiber optic sensors is placed close to the rock along the intersection line of the rock sample and the fissure, and then fixed with high-temperature sealant. Using the same method, a set of distributed fiber optic sensors is placed at a depth of 5 cm and on the upper surface of fissure 31; finally, a set of distributed fiber optic sensors is placed at the edge of the upper surface of the experimental rock sample (approximately 5 cm from fissure 31) and fixed with high-temperature sealant. A total of 6 sets of distributed fiber optic sensors were deployed on the entire experimental rock sample.
[0068] ③ Seal the rock samples entirely with high-temperature sealant: The two experimental rock samples, with their pre-embedded injection and sampling conduits and distributed fiber optic sensors, are completely encased and sealed using high-temperature sealant. The sealant thickness is approximately 2 cm. At this point, the preparation of the experimental rock samples is complete.
[0069] In this embodiment, the steps of placing the experimental rock sample into the experimental chamber, sequentially connecting the thermal fluid injection device, the experimental chamber, and the thermal fluid extraction device, and then sealing the experimental chamber specifically include the following steps:
[0070] Place the two prepared experimental rock samples onto the rock sample pad inside the experimental chamber; connect the data transmission line of the distributed optical fiber sensor, exposed outside the sealant, through the sealing plug on the flange at the outlet end of the experimental chamber to the distributed optical fiber analysis host; the injection pipeline enters the experimental chamber through the sealing plug on the flange at the inlet end of the experimental chamber and connects to the pre-embedded injection conduit; the sampling pipeline enters the experimental chamber through the sealing plug on the flange at the outlet end of the experimental chamber and connects to the pre-embedded sampling conduit; seal the experimental chamber, connect other pipelines outside the experimental chamber, and turn on the distributed optical fiber analysis host.
[0071] In this embodiment, the steps of shutting down the thermal fluid extraction device and turning on the thermal fluid injection device to inject thermal fluid into the experimental rock sample, until the pressure sensor at the outlet end of the fluid extraction pipeline reaches the set value, then shutting down the thermal fluid injection device, and recording the injection temperature, injection pressure, and injection flow rate specifically include the following steps:
[0072] Inject silicone oil into the experimental chamber by opening the control valves on the confining pressure pump and confining pressure pipeline, bringing the pressure inside the chamber to the design value P0, thus completing the confining pressure loading of the experimental rock sample. Then, close the control valves on the confining pressure pump and confining pressure pipeline. Turn on the heating function of the chamber's heating and insulation jacket. Once the average temperature displayed on the distributed fiber optic temperature sensor embedded 10cm into the slot reaches the design temperature T0, the entire experimental rock sample is considered to have reached the design temperature. Turn off the heating function of the chamber's heating and insulation jacket, completing the temperature loading of the experimental rock sample. Open the control valve on the confining pressure pipeline to release pressure appropriately, ensuring that the experimental rock sample maintains the design temperature T0 while the pressure inside the experimental chamber remains at the design pressure value P0. Throughout this process, the fiber optic analysis host monitors the temperature and pressure values at different locations on the experimental rock sample in real time.
[0073] In this embodiment, the step of allowing the sample to stand for a certain period of time to allow the hot fluid to continuously exchange heat with the experimental rock sample until the internal pressure and temperature of the experimental rock sample monitored by the fiber optic temperature detection device and the fiber optic pressure detection device tend to stabilize includes the following steps:
[0074] High-temperature fluid is continuously injected into the experimental rock sample. The high-temperature fluid gradually migrates from the rock sample to the sample and exchanges heat with it, causing the temperature and pore pressure inside the rock sample to increase. When the pressure sensor at the outlet of the sampling pipeline reaches the set value, the control valve on the injection pipeline is closed. After a certain period of settling, the high-temperature fluid continues to exchange heat with the rock sample. When the internal pressure and temperature of the rock sample, monitored by the distributed fiber optic sensor, stabilize, the thermal storage simulation of the rock sample is complete. During this process, the distributed fiber optic analyzer monitors the temperature and pressure values at different locations on the rock sample in real time, while simultaneously recording the total injection volume of the injection pump and the outflow volume collected by the metering balance.
[0075] In this embodiment, the steps of activating the thermal fluid extraction device, extracting the thermal fluid from the experimental rock sample, and recording the fluid temperature, fluid pressure, and fluid flow rate specifically include the following steps:
[0076] Opening the control valve on the sampling pipeline allows the high-temperature fluid within the experimental rock sample to automatically flow into the measuring balance under the pressure of the rock pores, recording the flow rate changes. Based on the extracted water flow rate and the pressure gradient changes in the experimental rock sample detected by the distributed fiber optic sensor, the hot water diffusion permeability at different locations in the rock sample can be calculated. Opening the control valve on the sampling pipeline allows the sampling pump to draw out the high-temperature fluid from the experimental rock sample at a certain negative pressure, recording the amount of high-temperature hot water drawn under different negative pressures. During this process, the fiber optic analysis host monitors the temperature and pressure values at different locations in the experimental rock sample in real time. The sum of the amount of high-temperature hot water flowing out of the experimental rock sample and the amount of high-temperature hot water drawn out by the sampling pump is the total amount of hot water that can be extracted from the experimental rock sample under a certain extraction pressure.
[0077] In this embodiment, because the longitudinal section of the experimental rock sample perpendicular to the horizontal axis is small (20cm in both width and height), the differences in rock properties are small, and the temperature and pressure at each point on the longitudinal section are considered symmetrical. By using the spatial distance between six sets of distributed fiber optic sensors on the longitudinal section and the measured temperature and pressure values, the temperature value T at each point on the longitudinal section can be calculated. yz and pressure value P yz .
[0078] However, the experimental rock sample has a relatively large length along its horizontal axis, and during heat storage and extraction, temperature and pressure differences occur significantly at different locations along this axis due to temperature conduction and fluid diffusion. The temperature values T on longitudinal sections every 1 cm along the horizontal axis of the experimental rock sample are shown below. yz and pressure value P yz There will be differences. Along the horizontal axis of the experimental rock sample, the temperature values T on all longitudinal sections (spaced 1 cm apart) will be recorded. yz and pressure value P yz By combining these parameters, the temperature values T at each point in the three-dimensional space of the test rock sample (spatial resolution of 1 cm) can be obtained. xyz and pressure value P xyz Based on the temperature values T at various points in the three-dimensional space of the experimental rock sample. xyz and pressure value P xyz It can effectively analyze important laws such as temperature conduction, fluid diffusion, pressure transmission and permeability decay in the deep aquifer thermal storage process.
[0079] In one embodiment of the present invention, a detection response point is set up every 1 cm along the optical signal transmission path for the distributed optical fiber temperature sensor and the distributed optical fiber pressure sensor. The optical fiber pressure detection device is a distributed optical fiber strain sensor. The distributed optical fiber strain sensor monitors the strain data of the experimental rock sample through optical fiber, and then combines the effective stress principle of porous media to realize the indirect measurement of the liquid pressure inside the experimental rock sample.
[0080] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.
Claims
1. A deep underground aquifer thermal storage simulation experimental system, characterized in that, The deep underground aquifer thermal storage simulation experimental system includes: A deep aquifer simulation device (1) is provided, comprising an experimental chamber (11) and an experimental rock sample (12), wherein the experimental rock sample (12) is contained in the experimental chamber (11); A hot fluid injection device (2) extends through the experimental chamber (11) into the experimental rock sample (12). The hot fluid injection device (2) is equipped with an inlet temperature sensor (21) and an inlet pressure sensor (22). The fiber optic monitoring system (3) includes multiple fiber optic temperature monitoring devices (31) and multiple fiber optic pressure monitoring devices (32), which are spaced apart within the experimental rock sample (12). A hot fluid extraction device (4) extends through the experimental chamber (11) into the experimental rock sample (12). The hot fluid extraction device (4) is equipped with an outlet temperature sensor (41) and an outlet pressure sensor (42).
2. The deep underground aquifer thermal storage simulation experimental system as described in claim 1, characterized in that, The fiber optic temperature monitoring device (31) is a distributed fiber optic temperature sensor, and the fiber optic pressure monitoring device (32) is a distributed fiber optic strain sensor. The fiber optic monitoring system (3) also includes a distributed fiber optic analysis host (33), and both the distributed fiber optic temperature sensor and the distributed fiber optic strain sensor are connected to the distributed fiber optic analysis host (33).
3. The deep underground aquifer thermal storage simulation experimental system as described in claim 1, characterized in that, The interior of the experimental chamber (11) contains silicone oil (111), and the experimental rock sample (12) is located in the silicone oil (111); The deep aquifer simulation device (1) also includes a confining pressure loading device (13), which is connected to the interior of the experimental chamber (11).
4. The deep underground aquifer thermal storage simulation experimental system as described in claim 3, characterized in that, The outer wall of the experimental rock sample (12) is provided with high-temperature sealant (121), which is used to isolate the experimental rock sample (12) from the silicone oil (111).
5. The deep underground aquifer thermal storage simulation experimental system as described in any one of claims 1 to 4, characterized in that, The deep water-bearing rock formation simulation device (1) also includes a cabin heating and insulation sleeve (14), which is fitted onto the outer wall of the experimental cabin (11).
6. The deep underground aquifer thermal storage simulation experimental system as described in any one of claims 1 to 4, characterized in that, The experimental rock sample (12) includes at least two types of natural rocks joined together in sequence.
7. The deep underground aquifer thermal storage simulation experimental system as described in any one of claims 1 to 4, characterized in that, The hot fluid injection device (2) includes an injection pipe (23), an injection pump (24), a heating device (25), and an injection conduit (26); The injection pipe (23) is equipped with the inlet end temperature sensor (21) and the inlet end pressure sensor (22); The injection pump (24) and the heating device (25) are located outside the experimental chamber (11), and the injection conduit (26) is located inside the experimental chamber (11) and extends into the experimental rock sample (12); The injection pipe (23) passes through the experimental chamber (11) and is connected in sequence to the injection pump (24), the heating device (25), and the injection conduit (26).
8. The deep underground aquifer thermal storage simulation experimental system as described in any one of claims 1 to 4, characterized in that, The hot fluid extraction device (4) includes a fluid extraction pipeline (43), a fluid extraction pump (44), a metering device (45), and a fluid extraction conduit (46); The liquid collection pipeline (43) is equipped with the outlet end temperature sensor (41) and the outlet end pressure sensor (42); The liquid sampling pump (44) and the metering device (45) are located outside the experimental chamber (11), and the liquid sampling conduit (46) is located inside the experimental chamber (11) and extends into the experimental rock sample (12); The liquid collection pipeline (43) passes through the experimental chamber (11) and is connected in sequence to the liquid collection conduit (46), the liquid collection pump (44), and the metering device (45).
9. An experimental method, implemented using the deep underground aquifer thermal storage simulation experimental system as described in any one of claims 1 to 8, characterized in that, Includes the following steps: Natural rocks from the same stratum as the target stratum were taken to prepare experimental rock samples. The experimental rock samples were saturated with formation water by boiling. Multiple fiber optic temperature detection devices and multiple fiber optic pressure detection devices were installed in the experimental rock samples. The experimental rock sample was placed in the experimental chamber, and the hot fluid injection device, the experimental chamber, and the hot fluid extraction device were connected in sequence and the experimental chamber was sealed. Turn off the thermal fluid extraction device and turn on the thermal fluid injection device to inject thermal fluid into the experimental rock sample until the pressure sensor at the outlet end of the fluid extraction pipeline reaches the set value. Then turn off the thermal fluid injection device and record the injection temperature, injection pressure and injection flow rate. The sample was left to stand for a certain period of time to allow the hot fluid to continue to exchange heat with the experimental rock sample until the internal pressure and temperature of the experimental rock sample monitored by the fiber optic temperature detection device and the fiber optic pressure detection device tended to stabilize. Turn on the thermal fluid extraction device, extract the thermal fluid from the experimental rock sample, and record the fluid temperature, fluid pressure, and fluid flow rate. Based on the experimental rock sample's geometric dimensions, temperature, confining pressure, injection temperature, injection pressure, injection flow rate, sampling temperature, sampling pressure, sampling flow rate, and data on temperature and pressure at various points inside the experimental rock sample monitored by fiber optic temperature and pressure detection devices, the changes in flow rate, temperature, and pressure during injection, heat storage, and heat extraction are analyzed.
10. The experimental method as described in claim 9, characterized in that, The fiber optic pressure detection device is a distributed fiber optic strain sensor. The distributed fiber optic strain sensor monitors the strain data of the experimental rock sample through optical fiber, and then combines the effective stress principle of porous media to indirectly measure the internal liquid pressure of the experimental rock sample.