A device for experimentally simulating the transformation of hydrothermal geothermal reservoirs by carbon dioxide

Abstract

The invention discloses a device for experimentally simulating carbon dioxide reforming a hydrothermal geothermal reservoir, comprising a simulation cabin, a thermostatic box, a first pressure pump, a first pressure sensing rod, a second pressure pump, a second pressure sensing rod, a third pressure pump, a third pressure sensing rod, a CO2 gas cylinder, an N2 gas cylinder, a first conduit, a second conduit, a third conduit, a funnel, a first solution barrel, a fourth conduit, a fifth conduit, a sixth conduit, a second solution barrel, a seventh conduit, a solution bottle, an eighth conduit and a ninth conduit. The device can simulate carbon dioxide in a laboratory to perform fracturing or acidification on a hydrothermal sandstone thermal reservoir and a carbonate bedrock thermal reservoir.

Description

Technical Field

[0001] The invention belongs to the technical field of geothermal resource development and relates to a device for experimentally simulating carbon dioxide transformation of a hydrothermal geothermal reservoir. Background Art

[0002] As a highly competitive clean and renewable energy, geothermal resources play an important role in addressing global climate change, energy conservation and emission reduction, and haze control. Hydrothermal geothermal resources refer to geothermal resources with a temperature exceeding 25°C, mainly steam or liquid water, and are usually buried at a depth of more than 200 meters and less than 3,000 meters. They are currently the main source of geothermal resources for heating and power generation in my country. According to lithology, they can be divided into sandstone hydrothermal heat storage and bedrock (carbonate rock) hydrothermal heat storage. Sandstone hydrothermal geothermal resource heat storage is usually distributed in high-permeability sandstone formations, but due to the compaction of the formation, the rock particles are cemented and the connectivity is poor, which often leads to low water output and difficulty in recharging. Bedrock hydrothermal geothermal heat storage is usually limestone formation. The porosity and permeability of the formation are greatly affected by the development of fractures or caves. If the fractures are not developed, the water output of geothermal drilling will be greatly reduced, which will directly affect the development effect and economy of geothermal resources. In view of the characteristics of this type of heat storage, fracturing or acidification is needed to improve the permeability of the heat storage, increase the water output and reinjection volume, and greatly improve the economic efficiency.

[0003] Previous studies have shown that CO 2 As a fracturing fluid, it can effectively reduce the fracturing pressure during fracturing, produce a small-scale and large-scale complex fracture network, the fractures extend far, and the fracturing flowback effect is good. It is a better medium for hydrothermal geothermal reservoir fracturing. 2 It is easily soluble in water and will form acidic fluids. When the acidic fluids enter the geothermal formation, they can effectively dissolve the clay minerals in the sandstone formation. It can also play a good dissolution role on the carbonate rock thermal reservoir, effectively improve the physical properties and connectivity of the geothermal reservoir, and achieve a good reservoir improvement effect.

[0004] Currently, for CO 2 The research on the effect and mechanism of improving hydrothermal geothermal reservoirs is still in its initial stage. 2 The effects of acidification and fracturing on different types of thermal storage are unclear, and there is a lack of relevant simulation experimental equipment.

[0005] Therefore, it is necessary to develop a device and system for experimentally simulating the transformation of hydrothermal geothermal reservoirs by carbon dioxide. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a device for experimentally simulating the transformation of hydrothermal geothermal reservoirs by carbon dioxide. The device can simulate the fracturing or acidification of hydrothermal sandstone thermal reservoirs and carbonate bedrock thermal reservoirs by carbon dioxide in the laboratory.

[0007] To achieve the above-mentioned purpose, the device for experimentally simulating carbon dioxide reforming hydrothermal geothermal reservoirs of the present invention comprises a simulation cabin, a constant temperature box, a first booster pump, a first pressure sensing rod, a second booster pump, a second pressure sensing rod, a third booster pump, a third pressure sensing rod, a CO 2 Gas cylinder, N 2 A gas cylinder, a first conduit, a second conduit, a third conduit, a funnel, a first solution barrel, a fourth conduit, a fifth conduit, a sixth conduit, a second solution barrel, a seventh conduit, a solution bottle, an eighth conduit, and a ninth conduit;

[0008] The geothermal reservoir sample is located in a simulation cabin, which is located in a constant temperature box. A first pressure sensing plate is arranged on the top of the geothermal reservoir sample, and a first pressure pump is connected to the first pressure sensing plate via a first pressure sensing rod. A second pressure sensing plate is arranged on the right side of the geothermal reservoir sample, and a second pressure pump is connected to the second pressure sensing plate via a second pressure sensing rod. A third pressure sensing plate is arranged on the front side of the geothermal reservoir sample, and a third pressure pump is connected to the third pressure sensing plate via a third pressure sensing rod.

[0009] CO 2 Gas cylinder outlet and N 2 The outlet of the gas cylinder is connected with the inlet of the first conduit, and the outlet of the first conduit is connected with the inlet on the left side of the simulation cabin via the second conduit; the upper end of the third conduit is connected with the funnel, and the lower end of the third conduit is inserted into the first solution barrel, the fourth conduit is inserted into the first solution barrel, the other end of the fourth conduit is connected with the inlet on the top of the simulation cabin via the fifth conduit, and the outlet at the bottom of the simulation cabin is connected with the second solution barrel via the sixth conduit, one end of the seventh conduit is inserted into the solution bottle, and the other end of the seventh conduit is connected with the outlet on the right side of the simulation cabin via the eighth conduit, and the end of the ninth conduit is inserted into the solution bottle.

[0010] CO 2 The outlet of the gas cylinder is connected with the first conduit via the first valve, the tenth conduit, the first liquid pump and the eleventh conduit, and the eleventh conduit is provided with a first flow meter.

[0011] N 2 The outlet of the gas cylinder is connected with the first conduit through the twelfth conduit, and the twelfth conduit is provided with a second valve, a second liquid extraction and a second flow meter.

[0012] The first conduit is provided with a third flow meter and a third valve.

[0013] The third conduit is provided with a fourth valve.

[0014] The fourth conduit is provided with a third liquid pump, a fifth valve and a fourth flow meter.

[0015] The sixth conduit is provided with a sixth valve and a fourth liquid pump.

[0016] The eighth conduit is provided with a fifth flow meter and a seventh valve.

[0017] The ninth conduit is provided with an eighth valve.

[0018] A bracket for supporting the incubator is also included.

[0019] The present invention has the following beneficial effects:

[0020] The device for experimentally simulating carbon dioxide reforming hydrothermal geothermal reservoirs of the present invention uses a pumping pump, a thermostatic box and a pressure pump to simulate the geological temperature and pressure conditions required by different hydrothermal geothermal reservoir formations during specific operation. Different lithology combinations and different structural forms can be designed in the simulation cabin according to the actual formation characteristics. Based on the experimental design, CO 2 、N 2 By injecting fluids with different ion concentrations into the simulation chamber, the state of formation water in the hydrothermal geothermal reservoir can be truly simulated; by using CO 2 Fluid or CO 2 and N 2 The fluid mixed in proportion is injected into the simulation chamber at a certain rate to fracture the rock samples in the simulation chamber, or to inject and soak them. By observing and CT scanning the hydrothermal geothermal rock samples before and after fracturing or soaking, macroscopic and microscopic analysis can be performed to qualitatively and quantitatively evaluate the CO 2 Fracturing and soaking effects on geothermal reservoir rock samples. 2 Fluids such as these are used as fracturing fluids to fractur e geothermal reservoir rock samples, which can effectively reduce the fracture initiation pressure, increase the complexity of the fractures, and reduce damage to the geothermal reservoir formation. 2 The device can be used to measure the changes in physical properties of hydrothermal geothermal reservoirs before and after fracturing and immersion dissolution of fluids, and to qualitatively and quantitatively evaluate the transformation effects of hydrothermal geothermal reservoirs. It has a simple structure and is easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the present invention;

[0022] Figure 2 A schematic diagram of a structure of a geothermal reservoir;

[0023] Figure 3 Another structural schematic diagram of a geothermal reservoir;

[0024] Figure 4 Another structural schematic diagram of a geothermal reservoir.

[0025] Among them, 1 is CO 2 The gas cylinder, 2 is the first valve, 3 is the tenth conduit, 4 is the first liquid pump, 5 is the eleventh conduit, 6 is the first flow meter, 7 is N 2 gas cylinder, 8 is the second valve, 9 is the second liquid pump, 10 is the second flow meter, 11 is the twelfth conduit, 12 is the first conduit, 13 is the third valve, 14 is the third flow meter, 15 is the second conduit, 16 is the first solution barrel, 17 is the third conduit, 18 is the fourth valve, 19 is the funnel, 20 is the fourth conduit, 21 is the third liquid pump, 22 is the fifth valve, 23 is the fourth flow meter, 24 is the fifth conduit, 25 is the thermostat, 26 is the simulation cabin, 27 is the first pressure pump, 28 is the first pressure Sensing rod, 29 is the first pressure sensing plate, 30 is the second pressure pump, 31 is the second pressure sensing rod, 32 is the second pressure sensing plate, 33 is the third pressure pump, 34 is the third pressure sensing rod, 35 is the third pressure sensing plate, 36 is the sixth valve, 37 is the sixth conduit, 38 is the fourth liquid pump, 39 is the second solution barrel, 40 is the bracket, 41 is the eighth conduit, 42 is the fifth flow meter, 43 is the seventh valve, 44 is the seventh conduit, 45 is the ninth conduit, 46 is the eighth valve, and 47 is the solution bottle. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0027] refer to Figure 1 The device for experimentally simulating carbon dioxide reforming hydrothermal geothermal reservoirs of the present invention comprises a simulation cabin 26, a thermostatic box 25, a first booster pump 27, a first pressure sensing rod 28, a second booster pump 30, a second pressure sensing rod 31, a third booster pump 33, a third pressure sensing rod 34, a CO 2 Gas cylinder 1, N 2Gas cylinder 7, first conduit 12, second conduit 15, third conduit 17, funnel 19, first solution barrel 16, fourth conduit 20, fifth conduit 24, sixth conduit 37, second solution barrel 39, seventh conduit 44, solution bottle 47, eighth conduit 41 and ninth conduit 45; the geothermal reservoir sample is located in the simulation cabin 26, the simulation cabin 26 is located in the constant temperature box 25, a first pressure sensing plate 29 is arranged on the top of the geothermal reservoir sample, a first booster pump 27 is connected to the first pressure sensing plate 29 via a first pressure sensing rod 28, a second pressure sensing plate 32 is arranged on the right side of the geothermal reservoir sample, a second booster pump 30 is connected to the second pressure sensing plate 32 via a second pressure sensing rod 31, a third pressure sensing plate 35 is arranged on the front side of the geothermal reservoir sample, and a third booster pump 33 is connected to the third pressure sensing plate 35 via a third pressure sensing rod 34; CO 2 The outlet of gas cylinder 1 and N 2 The outlet of the gas cylinder 7 is connected to the inlet of the first conduit 12, and the outlet of the first conduit 12 is connected to the inlet on the left side of the simulation cabin 26 through the second conduit 15; the upper end of the third conduit 17 is connected to the funnel 19, and the lower end of the third conduit 17 is inserted into the first solution barrel 16, the fourth conduit 20 is inserted into the first solution barrel 16, the other end of the fourth conduit 20 is connected to the inlet at the top of the simulation cabin 26 through the fifth conduit 24, and the outlet at the bottom of the simulation cabin 26 is connected to the second solution barrel 39 through the sixth conduit 37, one end of the seventh conduit 44 is inserted into the solution bottle 47, and the other end of the seventh conduit 44 is connected to the outlet on the right side of the simulation cabin 26 through the eighth conduit 41, and the end of the ninth conduit 45 is inserted into the solution bottle 47.

[0028] Specifically, CO 2 The outlet of the gas cylinder 1 is connected to the first conduit 12 via the first valve 2, the tenth conduit 3, the first liquid pump 4 and the eleventh conduit 5, and the eleventh conduit 5 is provided with a first flow meter 6; N 2 The outlet of the gas cylinder 7 is connected with the first conduit 12 via the twelfth conduit 11, and the twelfth conduit 11 is provided with a second valve 8, a second liquid pump 9 and a second flowmeter 10; the first conduit 12 is provided with a third flowmeter 14 and a third valve 13; the third conduit 17 is provided with a fourth valve 18; the fourth conduit 20 is provided with a third liquid pump 21, a fifth valve 22 and a fourth flowmeter 23; the sixth conduit 37 is provided with a sixth valve 36 and a fourth liquid pump 38; the eighth conduit 41 is provided with a fifth flowmeter 42 and a seventh valve 43; the ninth conduit 45 is provided with an eighth valve 46.

[0029] The present invention further includes a bracket 40 for supporting the thermostatic box 25 .

[0030] The size of each pressure sensor plate is consistent with the size of the square simulation cabin 26, and the size of the simulation cabin 26 is 80cm×80cm×80cm; the water volume in the first solution barrel 16 exceeds 2 / 3 of its volume; the solution bottle 47 contains 2 / 3 of the volume of lime water; the simulation cabin 26 is located in the thermostatic box 25, the temperature range of the thermostatic box 25 is 20℃-200℃, and the size of the thermostatic box 25 is 100cm×100cm×100cm; the range of each flow meter is 1000ml / min, the accuracy is 0.1ml / min, and the pressure resistance is 50MPa; the range of each pressure sensor is 0-50MPa, and the measurement accuracy is 0.1MPa.

[0031] The specific working process of the present invention is:

[0032] 1) According to the experimental design, the hydrothermal geothermal reservoir is prepared. The lithology and structural morphology of the geothermal reservoir are based on the experimental setting requirements. Figure 2 , Figure 3 and Figure 4 As shown, the size of the prepared thermal reservoir rock samples is 80cm×80cm×80cm, in order to reduce the error caused by the small size of the sample; the surface of the rock samples is photographed and described and CT three-dimensionally scanned, the porosity and permeability of each group of rock samples are measured, and multiple groups are prepared according to the experimental requirements to ensure the consistency of the mechanical and rock and mineral properties of the rock samples;

[0033] 2) Place the rock sample in the simulation chamber 26, which is fixed in the thermostatic chamber 25, so that the pressure sensing plates are placed on surfaces perpendicular to the simulation chamber 26, and adjust the thermostatic chamber 25 and the first pressure pump 27, the second pressure pump 30 and the third pressure pump 33 to set the temperature and pressure of the experiment;

[0034] 3) According to the experimental conditions, the fourth valve 18 is opened, salt is added from the funnel 19, the ion type and concentration in the solution barrel are configured, the third valve 13 and the seventh valve 43 are closed, the fifth valve 22 and the sixth valve 36 are opened, the third pumping pump 21 and the fourth pumping pump 38 are operated, and specific formation water is injected into the simulation chamber 26;

[0035] 4) Close the fifth valve 22 and the sixth valve 36, open the first valve 2, the second valve 8, the third valve 13 and the seventh valve 43, and use the first pump 4 or the second pump 9 to pump CO at a certain ratio and rate. 2 and N 2 A single gas or a mixed gas is injected into the simulation chamber 26 to perform fracturing on the rock sample, and the fracturing effect is observed through the solution bottle 47. After the solution bottle 47 continues to be turbid for a period of time, the fracturing experiment is stopped;

[0036] 5) Re-place the rock sample, and after the fracturing is completed, close the third valve 13 and the seventh valve 43, unload the loading pressure of the simulation cabin 26, observe the cracks on the surface of the rock sample, measure the porosity and permeability of the rock sample, and perform CT three-dimensional scanning;

[0037] 6) Close the second valve 8 and the fifth valve 22, open the first valve 2, the third valve 13 and the seventh valve 43, and use the first liquid pump 4 to pump CO at a certain ratio and rate. 2 The rock sample is immersed and dissolved in the injection simulation chamber 26, and the injection effect is observed through the solution bottle 47. After the solution bottle 47 continues to be turbid for a period of time, the injection is stopped, and then the valves are closed to soak for no less than 24 hours;

[0038] 7) After the immersion experiment is completed, the loading pressure of the simulation chamber 26 is unloaded, the cracks on the surface of the rock sample are observed, the porosity and permeability of the rock sample are measured, and a CT three-dimensional scan is performed;

[0039] 8) After the experiment is completed, clean the pipeline, monitor and close the valves.

[0040] Carry out multiple comparative experiments according to the experimental plan, analyze the differences, and select CO 2 The best combination of fracturing and soaking for thermal storage transformation.

Claims

1. A device for experimentally simulating the transformation of hydrothermal geothermal reservoirs by carbon dioxide, characterized in that: The device comprises a simulation cabin (26), a thermostatic box (25), a first pressure pump (27), a first pressure sensing rod (28), a second pressure pump (30), a second pressure sensing rod (31), a third pressure pump (33), a third pressure sensing rod (34), a CO2 gas cylinder (1), a N2 gas cylinder (7), a first conduit (12), a second conduit (15), a third conduit (17), a funnel (19), a first solution barrel (16), a fourth conduit (20), a fifth conduit (24), a sixth conduit (37), a second solution barrel (39), a seventh conduit (44), a solution bottle (47), an eighth conduit (41) and a ninth conduit (45); The geothermal reservoir sample is located in a simulation cabin (26), which is located in a constant temperature box (25). A first pressure sensing plate (29) is arranged on the top of the geothermal reservoir sample. A first pressure pump (27) is connected to the first pressure sensing plate (29) via a first pressure sensing rod (28). A second pressure sensing plate (32) is arranged on the right side of the geothermal reservoir sample. A second pressure pump (30) is connected to the second pressure sensing plate (32) via a second pressure sensing rod (31). A third pressure sensing plate (35) is arranged on the front side of the geothermal reservoir sample. A third pressure pump (33) is connected to the third pressure sensing plate (35) via a third pressure sensing rod (34). The outlet of the CO2 gas cylinder (1) and the outlet of the N2 gas cylinder (7) are connected to the inlet of the first conduit (12), and the outlet of the first conduit (12) is connected to the inlet on the left side of the simulation cabin (26) through the second conduit (15); the upper end of the third conduit (17) is connected to the funnel (19), the lower end of the third conduit (17) is inserted into the first solution barrel (16), the fourth conduit (20) extends into the first solution barrel (16), the other end of the fourth conduit (20) is connected to the inlet at the top of the simulation cabin (26) through the fifth conduit (24), the outlet at the bottom of the simulation cabin (26) is connected to the second solution barrel (39) through the sixth conduit (37), one end of the seventh conduit (44) is inserted into the solution bottle (47), the other end of the seventh conduit (44) is connected to the outlet on the right side of the simulation cabin (26) through the eighth conduit (41), and the end of the ninth conduit (45) is inserted into the solution bottle (47); The outlet of the CO2 gas cylinder (1) is connected to the first conduit (12) via the first valve (2), the tenth conduit (3), the first liquid pump (4) and the eleventh conduit (5), and the eleventh conduit (5) is provided with a first flow meter (6); The outlet of the N2 gas cylinder (7) is connected to the first conduit (12) via a twelfth conduit (11), and the twelfth conduit (11) is provided with a second valve (8), a second liquid pump (9) and a second flow meter (10); Also included is a bracket (40) for supporting the thermostatic box (25).

2. The device for experimentally simulating carbon dioxide reforming hydrothermal geothermal reservoir according to claim 1, characterized in that: A third flow meter (14) and a third valve (13) are arranged on the first conduit (12).

3. The device for experimentally simulating carbon dioxide reforming hydrothermal geothermal reservoir according to claim 2, characterized in that: The third conduit (17) is provided with a fourth valve (18).

4. The device for experimentally simulating carbon dioxide reforming hydrothermal geothermal reservoir according to claim 3, characterized in that: The fourth conduit (20) is provided with a third liquid pump (21), a fifth valve (22) and a fourth flow meter (23).

5. The device for experimentally simulating carbon dioxide reforming hydrothermal geothermal reservoir according to claim 4, characterized in that: The sixth conduit (37) is provided with a sixth valve (36) and a fourth liquid pump (38).

6. The device for experimentally simulating carbon dioxide reforming hydrothermal geothermal reservoir according to claim 5, characterized in that: The eighth conduit (41) is provided with a fifth flow meter (42) and a seventh valve (43).

7. The device for experimentally simulating carbon dioxide reforming hydrothermal geothermal reservoir according to claim 6, characterized in that: An eighth valve (46) is provided on the ninth conduit (45).

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