A method for determining the amount of gaseous-supercritical CO2 stored.

Abstract

The application discloses a method for determining the storage amount of gaseous-supercritical CO2, which comprises the following steps: saturating a CO2 storage model with simulated formation water by vacuum saturation, and determining the porosity of the model; then injecting the simulated formation water into the model at a constant speed in a displacement mode, monitoring and recording the pressure change at the injection and production ends of the model, and calculating the water permeability of the model; eliminating the influence of CO2 dissolution on the determination result of the storage amount of gaseous-supercritical CO2; eliminating the influence of mineral precipitation generated by the geochemical reaction of CO2 on the determination result of the storage amount of gaseous-supercritical CO2; calculating the storage amount of gaseous-supercritical CO2 for a water layer with a closed boundary or a constant pressure boundary; and constructing a chart of the storage amount of gaseous-supercritical CO2 changing with temperature and pressure conditions according to the calculated storage amount of gaseous-supercritical CO2.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas field development technology, specifically relating to a method for determining the amount of gaseous-supercritical CO2. Background Technology

[0002] With the continuous development of society and the economy, global carbon emissions are showing a year-on-year increasing trend, leading to an increasingly prominent greenhouse effect. Compared with CO2 oil and gas reservoir storage, coal seam storage, and salt cavern storage, CO2 aquifer storage has advantages such as a wide range of site selection, huge storage space, and fewer constraints, making it an important direction for current theoretical research and engineering applications of CO2 storage. However, the existing theories and technical systems for CO2 aquifer storage are not perfect, and the amount of CO2 stored under different occurrence conditions cannot be accurately measured. Summary of the Invention

[0003] Therefore, the present invention aims to provide a method for determining the amount of gaseous-supercritical CO2 stored, thereby solving the aforementioned problems.

[0004] To achieve the above objectives, the present invention provides a method for determining the amount of gaseous-supercritical CO2 stored, comprising the following steps: A vacuum saturation method was used to saturate the CO2-filled model to simulate formation water, and the model porosity was measured. Then, simulated formation water was injected into the model at a constant rate using a displacement method. Pressure changes at both injection and production ends of the model were monitored and recorded, and the model water permeability was calculated. Eliminate the influence of CO2 dissolution on the measurement results of gaseous-supercritical CO2 burial volume; Eliminate the influence of mineral precipitation caused by CO2 geochemical reactions on the measurement results of gaseous-supercritical CO2 burial volume; For aquatic layers with closed or constant-pressure boundaries, calculate the gaseous-supercritical CO2 burial quantity. Based on the calculated gaseous-supercritical CO2 stockpile, a graph showing the variation of gaseous-supercritical CO2 stockpile with temperature and pressure conditions was constructed. Based on the graph of gaseous-supercritical CO2 burial quantity as a function of temperature and pressure, with burial temperature T, burial pressure P, and overlying strata pressure P... R When the formation water salinity is M, the gaseous-supercritical CO2 burial quantity V is obtained from indoor experiments. C ; The CO2 storage model includes: A cylindrical model body, the model body having a cylindrical cavity inside, the cylindrical cavity having a first end and a second end located at both ends, the cylindrical cavity being used to fill model sand, and multiple monitoring ports penetrating the outer side of the model body; An axial pressure loading system is installed at the second end and divides the cylindrical cavity into a first cavity and a second cavity. The axial pressure loading system has a sampling outlet along the axial direction. The sampling outlet communicates with the first cavity and extends through the second cavity to the outside. The axial pressure loading system is used to apply overburden pressure to the model sand body in the cylindrical cavity. A monitoring device is installed at the plurality of monitoring ports to monitor the resistivity changes at the monitoring ports in order to monitor the changes in the fluid phase and content within the model sand body, or to monitor the pressure at the monitoring ports. A rotating device, installed on the model body, is used to rotate the model body to a preset angle; An upper plug structure, installed at the first end, is used to seal the first end. The upper plug structure has an upper injection port and a lower injection port extending axially, and the upper and lower injection ports are spaced apart in the vertical direction. The lower plug structure is installed at the second end to close the second end. The lower plug structure has a plurality of axial pressure injection ports and axial vent ports arranged in the vertical direction. The lower plug structure is located on the side opposite to the upper plug structure of the axial pressure loading system. The axial pressure injection ports and axial vent ports are respectively connected to the second cavity to inject fluid into or release fluid into the second cavity. The first cavity is filled with the model sand.

[0005] Preferably, in the method for determining the amount of gaseous-supercritical CO2 stored, the axial compression loading system includes: An axial compression loading structure, housed within the cylindrical cavity, divides the cylindrical cavity into a first cavity and a second cavity, the axial compression loading structure having an axially extending outlet; and... A screen pressure plate is installed at the end of the axial pressure loading structure near the first end, and the screen pressure plate covers the outer edge of the extraction outlet to prevent particles of the model sand in the first cavity from entering and blocking the extraction outlet during the extraction process.

[0006] Preferably, in the method for determining the amount of gaseous-supercritical CO2, the number of monitoring ports is eight, and the eight monitoring ports are evenly distributed on the outside of the model body.

[0007] Preferably, in the method for determining the amount of gaseous-supercritical CO2, the monitoring port is equipped with a monitoring probe that integrates an electrode probe and a pressure sensor.

[0008] Preferably, in the method for determining the gaseous-supercritical CO2 stockpile, the step of calculating the gaseous-supercritical CO2 stockpile for aquatic layers with closed or constant pressure boundaries includes: For aquatic layers with closed boundaries, a method of injection without extraction is adopted. CO2 is injected into the upper injection port of the CO2 storage model at a constant speed through a gas flow controller at an experimentally set injection rate q. During this process, the extraction port is closed and no water is drained. Real-time dynamic monitoring and recording of resistivity and pressure data at multiple monitoring ports; continuous injection of CO2 until the upper injection port and any one of the multiple monitoring ports reach the upper limit pressure P. U Stop the injection and record the injection time t. Let the model stand still until the fluid and pressure in the model stabilize, and then read the pressure data of the pressure points of the CO2 burial model. For a water layer with a closed boundary, the upper limit of the burial pressure is P. U At that time, the amount of gaseous-supercritical CO2 buried V C for: (1) V C This refers to the amount of gaseous-supercritical CO2 stored, sm 3 (Volume at 20℃ and 1 atm standard conditions, the same below); q represents the CO2 injection rate, sm 3 / min; t represents the CO2 injection time, in minutes; V PVL Let m be the pore volume of the sand body model. 3 ; For buried pressure CO2 solubility sm in simulated formation water 3 / m 3 ; S P The solubility sm of CO2 in simulated formation water when the outlet back pressure is P. 3 / m 3 .

[0009] Preferably, in the method for determining the gaseous-supercritical CO2 stockpile, the step of calculating the gaseous-supercritical CO2 stockpile for aquatic layers with closed or constant pressure boundaries includes: For a water layer with a constant pressure boundary, the pressure at the model outlet is set to P to simulate the constant pressure boundary condition, and the pressure of the axial compression loading system is set to P. R The pressure of the overlying strata was simulated. CO2 was injected from the upper injection port of the CO2 storage model by displacement, and the CO2 injection rate was controlled to be q and kept constant. Formation water was extracted from the production port of the CO2 storage model to simulate the reverse water intrusion process of formation water flowing to the water body during CO2 storage. The resistivity and pressure data at each measuring point are monitored and recorded in real time. The sweep pattern of injected CO2 is tracked by the changes in resistivity data from multiple monitoring ports. When the average resistivity monitored at the monitoring port closest to the production outlet drops to 0.5 times the resistivity of the initial saturated formation water, and the injected CO2 has not yet broken through the production outlet, CO2 injection is stopped and the production outlet valve is closed. At this time, the injected CO2 reaches or approaches the production outlet but has not yet broken through it. This process is used to simulate the process of CO2 injected into the actual water layer migrating to the interface between the water layer and the water body but not yet entering the water body. Metered cumulative water output V WL Record the CO2 injection time t. Let the model stand for 1 hour until the fluid and pressure in the model stabilize. Then, read the pressure data at each pressure point of the CO2 burial model (multiple monitoring ports, the upper injection port, and the extraction port; in this embodiment, the pressure points include 8 pressure monitoring ports, the upper injection port, and the extraction port). Take the average value as the CO2 burial pressure, denoted as t. The gaseous-supercritical CO2 burial quantity V of the water layer with constant pressure boundary is... C for: (2) V WL To accumulate the water production, m 3 ; V C This refers to the amount of gaseous-supercritical CO2 stored, sm 3 ; q represents the CO2 injection rate, sm 3 / min; t represents the CO2 injection time, in minutes; V PVL Let m be the pore volume of the sand body model. 3 ; For buried pressure CO2 solubility sm in simulated formation water 3 / m 3 ; S P The solubility sm of CO2 in simulated formation water when the outlet back pressure is P. 3 / m 3 .

[0010] Preferably, in the method for determining the amount of gaseous-supercritical CO2, the step of determining the amount of gaseous-supercritical CO2 based on a graph showing the variation of gaseous-supercritical CO2 with temperature and pressure conditions, wherein the burial temperature is T, the burial pressure is P, and the pressure of the overlying strata is P R When the formation water salinity is M, the gaseous-supercritical CO2 burial quantity V is obtained from indoor experiments. CSubsequently, the determination method further includes: The amount of gaseous-supercritical CO2 stored in an aquifer, taking into account the effects of temperature, pressure, and salinity, is denoted as V. C-(P,T,M) Based on indoor experimental measurements of gaseous-supercritical CO2 burial volume V C When the burial temperature is T, the burial pressure is P, and the formation water salinity is M, the actual amount of gaseous-supercritical CO2 burial in the mine is V. C-(P,T,M) The calculation method is as follows: (3) V C-(P,T,M) This represents the actual gaseous-supercritical CO2 storage capacity of the aquifer in the mine, sm 3 ; V C To determine the amount of gaseous-supercritical CO2 stored in the laboratory, sm 3 ; V PVL Let m be the pore volume of the sand body model. 3 ; V PVR The actual pore volume of the aquifer in the mine is given in m. 3 .

[0011] Preferably, in the method for determining the amount of gaseous-supercritical CO2 stored, the step of eliminating the influence of CO2 dissolution on the measurement results of the amount of gaseous-supercritical CO2 stored includes: The pressure of the overlying strata above the target buried aquifer is P. R Based on this, the CO2 burial model was maintained at the experimentally set temperature T, and the pressure of the axial compression loading system of the CO2 burial model was set to P. R ; Saturated CO2 formation water was injected from the lower injection port of the CO2 storage model using a displacement method. The back pressure at the model outlet was set to P, and CO2-free formation water was extracted from the production outlet. The saturated CO2 formation water replacement is completed when 10.0 PV of saturated CO2 formation water is cumulatively injected.

[0012] Preferably, in the method for determining the amount of gaseous-supercritical CO2, the step of eliminating the influence of mineral precipitation caused by CO2 geochemical reactions on the measurement results of gaseous-supercritical CO2 includes: After completing the saturated CO2 formation water replacement process, the CO2 burial model was pressurized and statically placed at the experimentally set temperature T to allow the model sand body and dissolved CO2 in the CO2 burial model to fully react. Saturated CO2 formation water was then re-injected from the lower injection port of the CO2 burial model using a displacement method, and the formation water after the CO2 geochemical reaction was extracted from the production port. During this process, the pressure of the axial pressure loading system and the pressure at the model outlet were set to P, respectively. R And P; a cumulative injection of 10.0 PV was completed to achieve secondary replacement of saturated CO2 formation water.

[0013] To achieve the above objectives, the present invention also provides a method for determining the total amount of CO2 in a water layer, including the method for determining the amount of gaseous-supercritical CO2 as described above.

[0014] The present invention has the following beneficial effects: The method provided by this invention employs saturated CO2 formation water replacement when determining the amount of gaseous-supercritical CO2, thereby eliminating the influence of CO2 dissolution. By pretreatment, the saturated CO2 formation water is allowed to fully contact and react with the model sand body, and the precipitates generated by the geochemical reaction are discharged from the model through secondary replacement with saturated CO2 formation water, which effectively reduces the intensity of geochemical reaction in the subsequent gaseous-supercritical CO2 sequestration experiment.

[0015] Furthermore, the quartz sand used to fill the CO2 storage model has a single composition, stable properties, and no cementing material. In addition, the experimental time is relatively short. Therefore, the amount of CO2 mineralization and storage during the gaseous-supercritical CO2 storage measurement experiment can be ignored.

[0016] Furthermore, the experimental apparatus for measuring the gaseous supercritical and dissolved CO2 stockpiles in aquatic layers provided by this invention can simulate stockpiles in aquatic layers with inclination angles, aquatic layers connected to open edge and bottom water, and high-injection-low-production gas-injection-drainage systems, etc., and the gaseous-supercritical CO2 stockpiles V. C - (P,T,M) The measurement and calculation methods are similar to those described above, and will not be repeated here. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 A cross-sectional view of the experimental apparatus for measuring the amount of gaseous supercritical and dissolved CO2 in an aquatic layer, which is provided for this invention.

[0019] Figure 2 for Figure 1 A partial schematic diagram of point A in the middle; Figure 3 for Figure 2 A schematic diagram of the central axial compression loading system being pushed to another state; Figure 4 A graph showing the variation of gaseous-supercritical CO2 stockpile with temperature and pressure conditions; Figure 5 A chart showing the variation of dissolved CO2 reserves with formation water resistivity and salinity; Figure 6 Schematic diagram of the high-temperature reactor for the CO2 geochemical reaction experiment in the water layer; Figure 7 This is a graph showing the relationship between the amount of mineralized solid CO2 buried and the burial time.

[0020] 1-Model body, 11-First end, 12-Second end, 13-Monitoring port, 14-Cylindrical cavity, 141-First cavity, 142-Second cavity, 2-Axial pressure loading system, 21-Screen pressure plate, 22-Axial pressure loading structure, 23-Outlet, 3-Rotating device, 4-Upper plug structure, 41-Upper injection port, 42-Lower injection port, 5-Lower plug structure, 51-Axial pressure injection port, 52-Axial pressure vent.

[0021] 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

[0022] In this embodiment of the invention, the term "and / or" describes the relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The character " / " generally indicates that the preceding and following associated objects have an "or" relationship.

[0023] It should be noted that the terms "first," "second," etc., in the specification, claims, and drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0024] In this embodiment of the invention, the term "multiple" refers to two or more, and other quantifiers are similar.

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details are presented in the embodiments of the present invention to facilitate a better understanding of the invention. However, the technical solutions claimed in the present invention can be implemented even without these technical details and various variations and modifications based on the following embodiments. The division of the following embodiments is for ease of description and should not constitute any limitation on the specific implementation of the present invention. The various embodiments can be combined with and referenced by each other without contradiction.

[0026] Example 1

[0027] This invention provides an experimental apparatus for determining the amount of gaseous supercritical and dissolved CO2 in an aquatic layer. Please refer to [link / reference]. Figures 1 to 3 The experimental apparatus for measuring the amount of gaseous supercritical and dissolved CO2 in the water layer includes a cylindrical model body 1, an axial compression loading system 2, a monitoring device, a rotating device 3, an upper plug structure 4, and a lower plug structure 5. The model body 1 has a cylindrical cavity 14 with a first end 11 and a second end 12 at both ends. The cylindrical cavity 14 is used to fill model sand. Multiple monitoring ports 13 are provided on the outer side of the model body 1. An axial pressure loading system 2 is installed at the second end 12 and divides the cylindrical cavity 14 into a first cavity 141 and a second cavity 142. The axial pressure loading system 2 has a sampling outlet 23 along the axial direction. The sampling outlet 23 communicates with the first cavity 141 and extends through the second cavity 142 to the outside. The axial pressure loading system 2 is used to apply overburden pressure to the model sand in the cylindrical cavity 14. A monitoring device is installed at the multiple monitoring ports 13 to monitor the resistivity change at the monitoring ports 13 to monitor the change in fluid phase and content in the model sand or to monitor the pressure at the monitoring ports 13. A rotating device 3 is installed on the model body 1 to drive the model body 1 to rotate to a preset angle; an upper plug structure 4 is installed on the first end 11 to close the first end 11. The upper plug structure 4 has an upper injection port 41 and a lower injection port 42 extending along the axial direction. The upper injection port 41 and the lower injection port 42 are arranged at intervals in the vertical direction; a lower plug structure 5 is installed on the second end 12 to close the second end 12. The lower plug structure 5 has a plurality of axial pressure injection ports 51 and axial vent ports arranged in the vertical direction. The lower plug structure 5 is located on the side opposite to the upper plug structure 4 of the axial pressure loading system 2. The axial pressure injection ports 51 and the axial vent ports are respectively connected to the second cavity 142 to inject fluid into or release fluid into the second cavity 142; wherein, the first cavity 141 is filled with the model sand.

[0028] It should be noted that the gaseous supercritical CO2 mentioned in this invention refers to the total continuous phase CO2 and residual dispersed phase CO2 sealed in the pore throat of the aquifer, existing in a gaseous, supercritical, or gas-supercritical mixed transitional state, and denoted by V. C .

[0029] In practice, a model sand body with an appropriate mesh size, such as quartz sand, can be selected and filled into the model body 1 using a dry method. That is, the model body 1 can also be understood as a CO2 burial model.

[0030] In this embodiment, the model body 1 can be made of a material resistant to corrosion from high-concentration CO2 and highly mineralized formation water, such as 316L stainless steel. In this embodiment, the cylindrical cavity 14 of the model body 1 has an inner diameter of 5.0 cm, a length of 50 cm, and a total internal volume of 0.982 L. Preferably, the model body 1 has a pressure resistance of at least 40 MPa and a high temperature resistance of at least 150°C. The inner cavity of the model body 1 is roughened to form a rough wall surface, reducing the influence of wall flow.

[0031] Preferably, in the experimental apparatus for determining the amount of gaseous supercritical and dissolved CO2 in the water layer, the axial pressure loading system 2 includes an axial pressure loading structure 22 and a screen plate 21. The axial pressure loading structure 22 is housed in the cylindrical cavity 14 to divide the cylindrical cavity 14 into a first cavity 141 and a second cavity 142. The axial pressure loading structure 22 has an axially extending outlet 23. The screen plate 21 is installed at the end of the axial pressure loading structure 22 near the first end 11, and the screen plate 21 covers the outer edge of the outlet 23 to prevent particles of the model sand in the first cavity 141 from entering and clogging the outlet 23 during extraction. Additionally, the screen plate 21 can also be laid across the entire end of the axial loading structure and extend to the inner wall of the cylindrical cavity 14, thus preventing sand particles of the model sand in the first cavity 141 from entering the gap between the axial pressure loading structure 22 and the cylindrical cavity 14 during the movement of the axial pressure loading structure 22.

[0032] By applying overburden pressure to the model sand body within the cylindrical cavity 14 through the axial pressure loading structure 22, the formation environment can be simulated more realistically. When pressure is injected through the axial pressure injection port 51, hydraulic pressure can push the axial pressure loading system 2 towards the first end 11, thereby achieving the effect of compacting the model sand body and applying overburden pressure. The axial pressure injection port 51 and the axial pressure vent port 52 respectively inject or discharge fluid into the second cavity 142 to increase or decrease the hydraulic pressure within the second cavity 142, and to synchronously change the axial pressure of the first cavity 141.

[0033] In this embodiment, there are eight monitoring ports 13, which are evenly arranged on the outer side of the model body 1. Alternatively, the eight monitoring ports 13 can be arranged in two rows on the outer side of the model body 1, or they can be arranged in multiple rows, depending on the actual needs. The monitoring device can be a device that monitors the resistivity changes at the monitoring port 13 locations. For example, it can be a monitoring probe that integrates an electrode probe and a pressure sensor, thus allowing it to be used in conjunction with the monitoring port 13. Installing the monitoring probe with the integrated electrode probe and pressure sensor on the monitoring port 13 allows for real-time dynamic monitoring and recording of resistivity changes at the measuring point, thereby reflecting changes in the fluid phase and content within the sand body. Simultaneously, it can measure and record the dynamic pressure changes at different locations within the model.

[0034] The rotating device 3 can be located in the middle of the model body 1 to drive its rotation, or it can be located in other positions; no specific restrictions are placed here. The rotation angle driven by the rotating device 3 can be any angle between 0 and 360°; no specific restrictions are placed here, and the required rotation angle can be determined according to the specific experiment. For example, to simulate a stratum with a certain dip angle, the rotating device 3 can be used to rotate the model body 1 to the same dip angle as the stratum to simulate the formation. For example, by continuously increasing the dip angle of the model body to close to or equal to 90°, the plume phenomenon of CO2 in the formation water caused by gravitational differentiation can be simulated. In addition, by injecting CO2 into the model through the upper injection port 41 and the lower injection port 42, the influence of gas-water gravitational differentiation on the sweep pattern and burial volume of injected CO2 can be simulated.

[0035] Example 2

[0036] This embodiment mainly relates to a method for determining the amount of gaseous-supercritical CO2 in aquatic layers, taking into account the effects of temperature, pressure, and salinity. This embodiment is based on Example 1.

[0037] The meaning of gaseous supercritical CO2 is also the same as in Example 1. Example 2 includes all the contents of Example 1, and the beneficial effects of Example 1 can also be applied to Example 2.

[0038] The determination method includes: (1) Simulate the pressure of the overlying rock strata and surrounding rock of the actual water layer. In specific operation, a preset axial pressure is applied to the model sand body injected into the model body 1 through the axial pressure loading system 2 to simulate the pressure of the overlying rock layer and surrounding rock of the actual water layer.

[0039] The model sand injected into the main body 1 can be of a suitable mesh size, such as quartz sand, and the main body 1 is filled using a dry method. That is, the main body 1 can also be understood as a CO2 burial model.

[0040] (2) Preparation of simulated formation water and saturated CO2 formation water 1) Preparation of simulated formation water In practice, a first preset volume of deionized water can be selected, distilled and purified to remove electrolytes, non-electrolytes and dissolved CO2, and then injected into a first storage tank for sealed storage to obtain simulated water. A second storage tank can be vacuumed, and then a second preset volume of simulated water can be injected and the corresponding mass of mineral salts can be added. The mixture can be magnetically stirred evenly to prepare simulated formation water with the same mineral composition and mineralization as the target buried water layer.

[0041] 2) Preparation of saturated CO2 formation water Inside the constant temperature chamber, the formation temperature T is maintained. Excess CO2 is injected into the second storage tank containing simulated formation water, and the pressure inside the second storage tank is raised to the experimental set pressure P. The tank is then rotated slowly and continuously (e.g., for 24 hours) to allow the CO2 to fully contact and dissolve with the simulated formation water until it reaches saturation. The second storage tank is then reset and the excess gaseous CO2 is discharged. At the same time, a backpressure system is used to maintain the pressure inside the storage tank at the experimental set pressure P, thus completing the preparation of saturated CO2 formation water.

[0042] 3) Physical property determination of model sand body A vacuum saturation method was used to saturate the CO2 burial model to simulate formation water, and the model's porosity was measured. Then, simulated formation water was injected into the model at a constant rate using a displacement method. Pressure changes at both the injection and production ends of the model were monitored and recorded, and the model's water permeability was calculated. This allows for comparison of the differences in porosity and permeability between the sand body in the indoor CO2 burial model and the target burial aquifer, ensuring that both are within a reasonable error range (thus determining whether the sand body porosity and permeability match the actual field reservoir). The CO2 burial model is the experimental apparatus provided in Example 1 for measuring the burial amount of gaseous supercritical and dissolved CO2 in the aquifer.

[0043] More specifically, saturated simulated formation water was injected into the lower injection port 42 of the CO2 burial model using a vacuum saturation method, and the porosity of the CO2 burial model was measured. Then, simulated formation water was injected into the lower injection port 42 at a constant rate using a displacement method. Pressure changes at multiple monitoring ports 13 of the CO2 burial model were monitored and recorded, and the water permeability of the CO2 burial model was calculated. The differences in porosity and permeability between the sand body of the CO2 burial model and the target burial aquifer were compared to ensure that both were within a reasonable error range.

[0044] 4) Eliminate the influence of CO2 dissolution on the measurement results of gaseous-supercritical CO2 storage. The pressure of the overlying strata above the target buried aquifer is P. RBased on this, the CO2 burial model was maintained at the experimentally set temperature T, and the pressure of the axial compression loading system 2 of the CO2 burial model was set to P. R Saturated CO2 formation water was injected into the CO2 storage model via injection port 42 using a displacement method. The back pressure at the model outlet was set to P, and CO2-free formation water was extracted from the production port 23. Typically, saturated CO2 formation water replacement is completed after a cumulative injection of 10.0 PV of saturated CO2 formation water. This eliminates the influence of CO2 dissolution on the measurement results of gaseous-supercritical CO2 storage.

[0045] 5) Eliminate the influence of mineral precipitation caused by CO2 geochemical reactions on the measurement results of gaseous-supercritical CO2 burial volume. After completing the saturated CO2 formation water replacement process in step 4), the CO2 burial model was pressurized (the set pressure P of the axial pressure loading system 2) under the experimentally set temperature T. R The model is allowed to stand (e.g., for 48 hours) at a set pressure P at the outlet, allowing the model sand body and dissolved CO2 in the CO2 storage model to fully react. Saturated CO2 formation water is then re-injected from the lower injection port 42 of the CO2 storage model using a displacement method, and the CO2-reacted formation water is extracted from the production port 23. During this process, the pressures of the axial compression loading system 2 and the model outlet are set to P. R And P. A cumulative injection of 10.0 PV was carried out to complete the secondary replacement of saturated CO2 formation water, thereby eliminating the influence of mineral precipitation caused by CO2 geochemical reaction on the measurement results of gaseous-supercritical CO2 burial volume.

[0046] 6) Calculation of CO2 stockpile in gaseous-supercritical water layers with closed boundaries For water layers with closed boundaries, an injection-only method is adopted. CO2 is injected into the upper injection port 41 of the CO2 storage model at a constant speed through a gas flow controller at an experimentally set injection rate q. During this process, the extraction port 23 is closed and no drainage is carried out.

[0047] Real-time dynamic monitoring and recording of resistivity and pressure data at multiple monitoring ports 13 (specifically, monitoring can be performed using a monitoring probe integrating an electrode probe and a pressure sensor; in other embodiments, other monitoring devices may also be used). CO2 is continuously injected until the upper injection port 41 and any one of the multiple monitoring ports 13 reach the upper limit pressure P. U Stop the injection and record the injection time t. Let the model stand still (usually for 1 hour). After the fluid and pressure in the model stabilize, read the pressure data at the pressure points of the CO2 burial model (multiple monitoring ports 13, upper injection port 41, and extraction port 23; in this embodiment, the pressure points include 8 pressure monitoring ports 13, upper injection port 41, and extraction port 23). Take the average value as the CO2 burial pressure, denoted as t. .

[0048] For a water layer with a closed boundary, the upper limit of the burial pressure is P. U At that time, the amount of gaseous-supercritical CO2 buried V C for: (1) V C This refers to the amount of gaseous-supercritical CO2 stored, sm 3 (Volume at 20℃ and 1 atm standard conditions, the same below); q represents the CO2 injection rate, sm 3 / min; t represents the CO2 injection time, in minutes; V PVL Let m be the pore volume of the sand body model. 3 ; For buried pressure CO2 solubility sm in simulated formation water 3 / m 3 ; S P The solubility sm of CO2 in simulated formation water when the outlet back pressure is P. 3 / m 3 .

[0049] 7) Calculation of CO2 stockpile in gaseous-supercritical states in aquatic layers with constant pressure boundaries. For a water layer with a constant pressure boundary, the pressure at the model outlet is set to P to simulate the constant pressure boundary condition, and the pressure of the axial compression loading system 2 is set to P. R The pressure of the overlying strata was simulated. CO2 was injected into the CO2 storage model through the upper injection port 41 using a displacement method, and the CO2 injection rate was controlled at q (e.g., controlled by a gas flow controller) and kept constant. Formation water was extracted from the CO2 storage model through the production port 23 to simulate the reverse water intrusion process of formation water flowing into the water body during CO2 storage.

[0050] Real-time dynamic monitoring and recording of resistivity and pressure data at each measuring point (specifically, this can be achieved using a monitoring probe integrating an electrode probe and a pressure sensor; in other embodiments, other monitoring devices may also be used). The sweep pattern of injected CO2 is tracked through resistivity data changes at multiple monitoring ports 13. When the average resistivity monitored at the monitoring port 13 closest to the production outlet 23 drops to 0.5 times the resistivity of the initial saturated formation water, and the injected CO2 has not yet breached the production outlet 23, CO2 injection is stopped, and the production outlet 23 valve is closed. At this point, the injected CO2 reaches or approaches the production outlet 23 but has not yet breached it. This process simulates the actual process of CO2 injected into the aquifer migrating to the interface between the aquifer and the water body but not yet entering the water body.

[0051] Metered cumulative water output V WL Record the CO2 injection time t. Let the model stand for 1 hour until the fluid and pressure in the model stabilize. Then, read the pressure data at each pressure point of the CO2 burial model (multiple monitoring ports 13, upper injection port 41, and extraction port 23; in this embodiment, the pressure points include 8 pressure monitoring ports 13, upper injection port 41, and extraction port 23). Take the average value as the CO2 burial pressure, denoted as t. The gaseous-supercritical CO2 burial quantity V of the water layer with constant pressure boundary is... C for: (2) Where V WL To accumulate the water production, m 3 ; V C This refers to the amount of gaseous-supercritical CO2 stored, sm 3 (Volume at 20℃ and 1 atm standard conditions, the same below); q represents the CO2 injection rate, sm 3 / min; t represents the CO2 injection time, in minutes; V PVL Let m be the pore volume of the sand body model. 3 ; For buried pressure CO2 solubility sm in simulated formation water 3 / m 3 ; S P The solubility sm of CO2 in simulated formation water when the outlet back pressure is P. 3 / m 3 .

[0052] 8) A graph showing the variation of gaseous-supercritical CO2 reserves with temperature and pressure conditions. Using the above method, by varying the experimental temperature and pressure according to different actual CO2 storage conditions in the mine, a series of gaseous-supercritical CO2 storage data can be obtained. By interpolating these data, a graph showing the variation of gaseous-supercritical CO2 storage with temperature and pressure conditions can be obtained, as shown below. Figure 4 As shown.

[0053] 9) Based on the graph showing the variation of gaseous-supercritical CO2 burial volume with temperature and pressure conditions, the burial temperature is T, the burial pressure is P, and the pressure of the overlying strata is P R When the formation water salinity is M, the gaseous-supercritical CO2 burial quantity V is obtained from indoor experiments. C .

[0054] For any actual water layer temperature and pressure conditions on site, a defined chart (e.g.) is used. Figure 4 By using the corresponding indoor experimental measurements of gaseous-supercritical CO2 reserves, one can obtain the corresponding plates. Furthermore, by changing the formation water salinity and repeating the above experimental process, a series of plates can be obtained, ultimately forming a series of plates representing the gaseous-supercritical CO2 reserves in aquifers that consider the effects of temperature, pressure, and salinity.

[0055] In practical field applications, the amount of gaseous-supercritical CO2 stored in aquatic layers, considering the effects of temperature, pressure, and salinity, is denoted as V. C-(P,T,M) Based on the aforementioned indoor experiments, the gaseous-supercritical CO2 burial volume V... C When the burial temperature is T, the burial pressure is P, and the formation water salinity is M, the actual amount of gaseous-supercritical CO2 burial in the mine is V. C-(P,T,M) The calculation method is as follows: (3) V C-(P,T,M) This represents the actual gaseous-supercritical CO2 storage capacity of the aquifer in the mine, sm 3 ; V C To determine the amount of gaseous-supercritical CO2 stored in the laboratory, sm 3 ; V PVL Let m be the pore volume of the sand body model. 3 ; V PVR The actual pore volume of the aquifer in the mine is given in m. 3 .

[0056] The method provided by this invention employs saturated CO2 formation water replacement when determining the amount of gaseous-supercritical CO2, thereby eliminating the influence of CO2 dissolution. By pretreatment, the saturated CO2 formation water is allowed to fully contact and react with the model sand body, and the precipitates generated by the geochemical reaction are discharged from the model through secondary replacement with saturated CO2 formation water, which effectively reduces the intensity of geochemical reaction in the subsequent gaseous-supercritical CO2 sequestration experiment.

[0057] Furthermore, the quartz sand used to fill the CO2 storage model has a single composition, stable properties, and no cementing material. In addition, the experimental time is relatively short. Therefore, the amount of CO2 mineralization and storage during the gaseous-supercritical CO2 storage measurement experiment can be ignored.

[0058] Furthermore, the experimental apparatus provided by this invention for measuring the burial amount of gaseous supercritical and dissolved CO2 in aquatic layers can simulate burial examples such as aquatic layers with inclination angles, aquatic layers connected to open edge and bottom water, and high-injection-low-production gas-injection-drainage, etc., and the burial amount V of gaseous-supercritical CO2. C - (P,T,M) The measurement and calculation methods are similar to those described above, and will not be repeated here.

[0059] Example 3

[0060] To achieve rapid, accurate, and efficient determination of dissolved CO2 levels in formation water, this invention proposes a method for determining and calculating dissolved CO2 levels in formation water based on the resistivity method. CO2 dissolves in formation water to form carbonic acid, which ionizes to form H+. + and HCO3 - The increased ion content in formation water leads to a decrease in its resistivity. Therefore, changes in the resistivity of formation water can reflect changes in the amount of dissolved CO2 stored in the formation water. The method for determining and calculating the amount of dissolved CO2 stored in formation water based on the resistivity method includes the following steps: 1) Model Setup The experimental apparatus provided in Example 1 is rotated 90° counterclockwise by the rotating device 3, so that the injection end (upper injection port 41 and lower injection port 42) is in a vertical position with the extraction port 23 at the top.

[0061] A monitoring probe integrating an electrode probe and a pressure sensor is installed at multiple monitoring ports 13. In this embodiment, there are eight monitoring ports 13, but the number can be adjusted as needed. For ease of explanation, the following description uses a monitoring probe with an integrated electrode probe and pressure sensor installed at one of the monitoring ports 13 as an example.

[0062] 2) Simulated water resistivity calibration Simulated water, after the removal of electrolytes, non-electrolytes, and dissolved CO2, is injected into the lower injection port 42 of the CO2 storage model. Excess simulated water is discharged through the production port 23 of the CO2 storage model. The resistivity of each measuring point is monitored by electrode probes and averaged to serve as the resistivity benchmark value when the formation water salinity is 0, thus completing the calibration of the simulated water resistivity.

[0063] Simulated formation water with a set mineral composition and salinity is injected into the model to replace the simulated water (usually requiring continuous displacement of 10.0 PV). The resistivity of each monitoring port 13 is monitored by electrode probes and used as the resistivity reference value when CO2 solubility is 0, thus completing the calibration of the simulated formation water resistivity.

[0064] For ease of explanation, we will use 8 monitoring ports 13 as an example, but this does not mean that there are only 8 monitoring ports 13. The valve at the production outlet 23 is closed, and a monitoring probe integrating an electrode probe and pressure sensor is installed there, forming a total of 9 monitoring points with the monitoring ports 13 on both sides of the model. During CO2 injection, the axial pressure of the model is maintained at the set overlying stratum pressure P by the axial pressure loading system 2. R The experimental temperature is maintained at the actual temperature T of the buried water layer by using a constant temperature chamber. Specifically, the CO2 burial model can be placed in the constant temperature chamber.

[0065] 3) Calculation of dissolved CO2 storage A predetermined volume ΔV of CO2 is injected into the CO2 storage model through the lower injection port 42 (the injection rate can be controlled by a gas flow controller to maintain a constant injection rate). The resistivity and pressure changes at the production port 23 and multiple monitoring ports 13 are monitored. After injection, the model is allowed to stand for a predetermined time (e.g., 24 hours) to allow the injected CO2 to fully dissolve in the simulated formation water. The dissolved CO2 storage volume is calculated using the known formation water volume and the injected CO2 volume. The resistivity of the formation water after the CO2 has fully dissolved and stabilized is recorded by monitoring the production port 23 and multiple monitoring ports 13.

[0066] A stepped-incremental injection method (i.e., multiple injections) was used to continuously inject ΔV volume of CO2 into the CO2 storage model, repeating the aforementioned experimental process. This allowed for the determination of the resistivity and changes at various measuring points (production outlet 23 and multiple monitoring ports 13) as the dissolved CO2 storage increased. Furthermore, the mapping relationship between the simulated dissolved CO2 storage in formation water and the formation water resistivity data sequences was obtained.

[0067] Furthermore, if a significant resistivity anomaly is observed at the upper measuring point of the model (the measuring point near the production outlet 23), it indicates that CO2 is already completely saturated in the simulated formation water. Subsequent injected CO2, influenced by gravitational differentiation, is distributed in a gaseous or supercritical state in the upper part of the model, leading to an abnormally high resistivity at this location. On one hand, this phenomenon can serve as evidence that CO2 is completely saturated in the simulated formation water; on the other hand, these anomaly points should be removed when calculating the average resistivity.

[0068] 4) Chart showing the variation of dissolved CO2 storage with formation water resistivity and salinity The above experimental procedure was repeated for formation waters with the same mineral composition but different salinity. This allowed the mapping relationship between dissolved CO2 storage and formation water resistivity under different salinity conditions to be obtained. By organizing, summarizing, and interpolating the data on formation water resistivity, formation water salinity, and dissolved CO2 storage, a graph showing the variation of dissolved CO2 storage with formation water resistivity and salinity can be obtained, as shown in the figure. Figure 5 As shown.

[0069] It should be noted that the dissolved CO2 mentioned in this invention refers to CO2 dissolved in mineralized formation water and continuously existing in a dissolved state, the total volume of which is denoted as V. S Based on the resistivity method, the method for determining the amount of dissolved CO2 in formation water through indoor experiments is as follows: (1) Under the target water layer temperature T and overlying rock pressure P R Under the conditions of burial pressure P, formation water mineral composition and salinity, the CO2 burial experiment was carried out using the CO2 burial quantity determination method for closed / constant pressure boundary water layers in Example 2. The difference is that the saturation and secondary replacement used at this time were simulated formation water without CO2; (2) after the CO2 injection was completed and the fluid distribution was stable, the resistivity of the CO2-containing formation water was measured; (3) the formation water resistivity and salinity data were checked. Figure 5 The chart shown provides the dissolved and stored CO2 content (V) in formation water under the corresponding temperature, pressure, and salinity conditions. S .

[0070] 5) Dissolved CO2 storage capacity V S-(P,T,M) Based on the aforementioned chart showing the variation of dissolved CO2 storage capacity with formation water resistivity and salinity, the dissolved CO2 storage capacity V in the indoor experimental sand-filled model was determined. S ; Based on the burial temperature T and the pressure of the overlying strata P R Calculate the dissolved CO2 storage volume V of the actual aquifer in the mine with a burial pressure of P and a formation water salinity of M. S-(P,T,M) The calculation formula is: (4) V S-(P,T,M) The actual dissolved CO2 content in the aquifer of the mine, sm 3 ; V S To determine the amount of dissolved CO2 buried in the laboratory, sm 3 ; V PVL Let m be the pore volume of the sand body model. 3 ; V WL For the cumulative water production of the sand body model, m 3 ; V PVR The actual pore volume of the aquifer in the mine is given in m. 3 ; V WR The actual cumulative discharge of water from the aquifer in the mine, in meters. 3 .

[0071] This invention constructs a chart of dissolved CO2 burial volume as a function of formation water resistivity and salinity based on the resistivity method. Combined with the burial volume calculation formula, it can realize the dissolved CO2 burial volume V under arbitrary burial temperature, pressure, and formation water salinity conditions. S-(P, T, M) Measurement and calculation: It further takes into account the measurement of CO2 storage in both saturated and unsaturated states, and realizes rapid, accurate and efficient measurement and calculation of dissolved CO2 storage in water layers.

[0072] Example 4

[0073] CO2 mineralization and solid-state sequestration is one of the important mechanisms for CO2 storage in aquifers. The geochemical reaction after CO2 injection into the aquifer occurs at a very slow rate, typically requiring decades or even centuries to produce a significant sequestration effect. Therefore, the reactants and products involved in the geochemical reaction are present in trace amounts within a short period, making it quite difficult to determine the amount of CO2 mineralized and sequestered through laboratory experiments.

[0074] Under identical conditions of temperature, pressure, and reactant (rock sample, formation water) composition, one of the main factors affecting geochemical reactions is the contact area between reactants. In underground aquifers, many minerals lack pores to effectively connect with formation water, preventing sufficient contact and thus hindering the full geochemical reaction between dissolved CO2 and rock minerals. Consequently, the rate of geochemical reaction after CO2 injection into the aquifer is quite slow, making laboratory experimental determination of CO2 mineralization and solid sequestration difficult and prone to significant errors. To improve the geochemical reaction rate, rock samples are crushed and ground to form powder, increasing the contact area between mineral particles and formation water. This facilitates laboratory experimental determination of the content and changes in geochemical reaction products. Based on this, the mass of CO2 solid sequestration products from geochemical reactions is calibrated using the same rock mineral specific surface area in laboratory experiments. This allows for the extrapolation and calculation of the actual solid CO2 sequestration under the same temperature, pressure, mineral composition, and mineralization conditions at the mining site.

[0075] Specifically, the present invention provides a method for determining and calculating the amount of mineralized solid CO2 buried by calibrating the specific surface area, which includes: The specific surface area of ​​block and powder samples was determined using the probe gas adsorption isotherm method. Specifically, for the cylindrical rock samples obtained from drilling cores of the target CO2-bearing aquifer, their specific surface area was determined using the probe gas adsorption isotherm method, i.e., the specific surface area of ​​the porous medium of the target aquifer, and denoted as S. C The rock sample was ground into powder with the experimentally determined particle size. The specific surface area of ​​the powdered rock sample was measured using the same method and recorded as S. L .

[0076] More specifically, the measured specific surface area of ​​both block and powder samples includes the measured specific surface area S of the block sample. C Specific surface area S of powdered sample L .

[0077] 2) Determination of the mass of solid products from the geochemical reaction of CO2 in indoor experiments The steps for determining the mass of solid products from the geochemical reaction of CO2 in indoor experiments include: The ground rock sample powder was placed into the reaction vessel; Evacuate the reactor. Simulated formation water is injected into the reactor until the cumulative injected volume reaches a preset multiple of the reactor volume, at which point the injection is stopped. Place the reactor in a constant temperature environment and maintain the temperature of the constant temperature environment at the actual buried water layer temperature T. Inject CO2 into the reactor until the pressure inside the reactor reaches the actual buried water layer pressure P. Then stop the injection and maintain it at the actual buried water layer pressure P. The solid-liquid mixture in the stirred reactor is stirred to ensure full contact and reaction between the mineral powder and the formation water. The changes in the types and contents of ions in the formation water after the reaction are measured. Based on the changes in the types and contents of ions in formation water before and after the CO2 geochemical reaction, the chemical equations and reaction products of the geochemical reaction are deduced, and the mass of solid products of the CO2 geochemical reaction in the laboratory experiment is calculated. Specifically, the ground rock sample powder is placed in a high-temperature reaction vessel (such as...). Figure 6 (As shown). The reactor was evacuated for 2 hours via the air injection and venting lines to eliminate the influence of air inside the reactor. Simulated formation water with the same mineral composition and salinity as the target buried aquifer was prepared using the simulated formation water preparation method described in the above embodiments. Simulated formation water was injected into the reactor via the injection pipeline, and injection was stopped when the cumulative injected volume reached 0.8 times the reactor volume. Place the reactor into a split-type constant temperature chamber and maintain the temperature of the chamber at the actual buried water layer temperature T. Inject CO2 into the reactor through the injection and exhaust lines until the pressure inside the reactor reaches the actual buried water layer pressure P, then stop the injection. Use a pressure tracking pump and pressure sensor to adjust the CO2 injection or discharge to maintain the pressure inside the reactor at the actual buried water layer pressure P throughout the experiment. The solid-fluid mixture in the reactor was stirred at low speed using a magnetic stirrer to ensure full contact and reaction between the mineral powder and formation water. This experiment was conducted continuously for 30 days, with formation water samples taken from the reactor every 5 days via a sampling port. The changes in the types and concentrations of ions in the formation water after the reaction were measured using inductively coupled plasma atomic emission spectrometry (ICP). Based on the changes in the types and contents of ions in formation water before and after the CO2 geochemical reaction, the chemical equations and reaction products of the geochemical reaction are deduced, and the mass of the solid products of the CO2 geochemical reaction in the laboratory experiment is calculated, that is, the mass of the solid CO2 sequestration in the laboratory experiment.

[0078] It should be noted that the reaction vessel can be made of, for example... Figure 6 The reactor shown can also be a conventional reactor; no specific restrictions are imposed here.

[0079] 3) Calculation of mineralized solid CO2 storage volume during actual on-site CO2 storage process The method for calculating the amount of mineralized solid CO2 buried during the actual CO2 burial process at the site specifically includes: Calculate the mass of CO2 solid-state sequestration in the indoor experiment and convert it into gas volume under standard conditions, denoted as G. L That is, the volume of CO2 solid-state sequestration via geochemical reactions measured in the laboratory is G. L ; Based on the measurement results at different times, a curve showing the relationship between the mineralized solid CO2 storage and time can be plotted (e.g., Figure 7 ); By performing regression processing on the curves and data showing the change in mineralized solid CO2 stock over time, a regression formula for the change in CO2 stock over time can be obtained, enabling the prediction of the mineralized solid CO2 stock during the CO2 stocking process.

[0080] It should be noted that the mineralized solid CO2 mentioned in this invention refers to CO2 dissolved in formation water that, through chemical reaction with minerals in reservoir rocks or fluids, forms mineral precipitates and is stored in the reservoir in solid form. Its converted volume is denoted as V. D .

[0081] More specifically, the method of equal surface area is used to apply the amount of mineralized solid CO2 buried in the laboratory experiment to the calculation of the amount of mineralized solid CO2 buried in the actual CO2 water layer in the field. Specifically, based on the measured specific surface area of ​​block and powder samples and the mass of solid products of CO2 geochemical reaction in the laboratory experiment, the amount of mineralized solid CO2 buried in the actual CO2 burial process in the field is calculated. The calculation formula is shown in Equation (5).

[0082] (5) V D This represents the actual amount of mineralized solid CO2 stored during the on-site CO2 storage process, sm 3 ; G L The volume of CO2 solid-state sequestered via geochemical reaction, measured in the laboratory, is sm. 3 ; S L The specific surface area, measured in the laboratory, of the rock sample after it has been ground into powder, is expressed in m². 2 / kg; M L The mass of rock sample powder placed in the high-temperature reactor during the experiment, in kg; S C The specific surface area of ​​the porous medium in the target buried aquifer is m. 2 / kg; M R The mass of the rock skeleton of the target buried water layer, kg.

[0083] Based on the above process, the mineralized solid CO2 stockpile is first calibrated through indoor experiments. Then, the principle of equal surface area is applied to calculate the actual mineralized solid CO2 stockpile in the field, which is the method for determining and calculating the mineralized solid CO2 stockpile calibrated by equal surface area. Using this method, by changing the experimental temperature T, stockpile pressure P, formation water salinity M, and stockpile time t, the mineralized solid CO2 stockpile V corresponding to different stockpile times under the complex temperature, pressure, and mineralized formation water conditions in the field can be obtained. D-(P, T, M, t) .

[0084] Example 5

[0085] In actual mining applications, the total CO2 water content is the sum of the gaseous-supercritical, dissolved, and mineralized solid CO2 contents. Based on the above examples, the method for calculating the total CO2 water content is as follows: (6) V (P, T, M, t) The total CO2 water layer sm 3 ; V C-(P, T, M) This refers to the amount of gaseous-supercritical CO2 stored, sm 3 ; V S-(P, T, M) The amount of dissolved CO2 buried, sm 3 ; V D-(P, T, M, t) For mineralized solid CO2 reserves, sm 3 .

[0086] Formula (6) can be used to calculate the total amount of CO2 water in the burial layer at the time of burial temperature T, burial pressure P, formation water salinity M, and burial time t.

[0087] This invention relates to an experimental apparatus for determining the amount of gaseous supercritical and dissolved CO2 in an aquifer. The model body 1 contains a cylindrical cavity 14 with a first end 11 and a second end 12 at both ends. The cylindrical cavity 14 is used to fill model sand. Multiple monitoring ports 13 are provided on the outer side of the model body 1. An axial pressure loading system 2 is installed at the second end 12, dividing the cylindrical cavity 14 into a first cavity 141 and a second cavity 142. The axial pressure loading system 2 has an axially extending outlet 23, which communicates with the first cavity 141 and extends through the second cavity 142 to the outside. The axial pressure loading system 2 is used to apply overburden pressure to the model sand within the cylindrical cavity 14. Monitoring devices are installed at the multiple monitoring ports 13 to monitor resistivity changes at the monitoring ports 13 to monitor changes in the fluid phase and content within the model sand, or to monitor the monitoring ports 13 themselves. The pressure at the location; the rotating device 3 is installed on the model body 1 to drive the model body 1 to rotate to a preset angle; the upper plug structure 4 is installed on the first end 11 to close the first end 11, the upper plug structure 4 is axially provided with an upper injection port 41 and a lower injection port 42, the upper injection port 41 and the lower injection port 42 are arranged at intervals in the vertical direction; the lower plug structure 5 is installed on the second end 12 to close the second end 12, the lower plug structure 5 is axially provided with a plurality of axial pressure injection ports 51 and axial vent ports arranged in the vertical direction, the lower plug structure 5 is located on the side opposite to the upper plug structure 4 of the axial pressure loading system 2, the axial pressure injection ports 51 and the axial vent ports are respectively connected to the second cavity 142 to inject fluid into the second cavity 142 or release fluid; wherein, the first cavity 141 is filled with the model sand body, so that experiments on the amount of CO2 buried under different storage conditions can be considered.

[0088] Furthermore, this invention provides a method for indoor experimental determination of CO2 storage capacity in gaseous-supercritical, dissolved, and mineralized solid states in CO2-bearing aquifers under the influence of multiple factors such as temperature, pressure, and mineralization, as well as a method for predicting CO2 storage capacity in mining areas. This solves the problem of CO2 storage capacity determination under complex temperature, pressure, and fluid conditions, and achieves accurate determination of CO2 storage capacity in different occurrence states (gase-supercritical, dissolved, and mineralized solid), making the CO2 storage capacity determination method more organized, clear, and systematic. Further applied to the mining field, it enables rapid, accurate, and efficient prediction of CO2 storage capacity in aquifers at any depth. This invention further improves the CO2 storage technology system, providing effective technical support for indoor CO2 storage experiments and field practice.

[0089] Obviously, the embodiments described above are merely some, not all, embodiments of the present invention. Based on the embodiments of the present invention, those skilled in the art can make other variations or modifications without creative effort, and all such variations or modifications should fall within the scope of protection of the present invention.

Claims

1. A method for determining the amount of gaseous-supercritical CO2 stored, characterized in that, Includes the following steps: The CO2 burial model was saturated with simulated formation water using a vacuum saturation method, and the porosity of the model was measured. Then, simulated formation water was injected into the model at a constant rate using a displacement method. The pressure changes at both the injection and production ends of the model were monitored and recorded, and the permeability of the model water was calculated. Eliminating the influence of CO2 dissolution on the measurement results of gaseous-supercritical CO2 burial volume includes defining the overlying strata pressure P above the target burial water layer. R Based on this, the CO2 burial model was maintained at the experimentally set temperature T, and the pressure of the axial compression loading system of the CO2 burial model was set to P. R Saturated CO2 formation water was injected from the lower injection port of the CO2 storage model using a displacement method. The back pressure at the model outlet was set to P, and CO2-free formation water was extracted from the production outlet. The saturated CO2 formation water replacement was completed when 10.0 PV of saturated CO2 formation water was cumulatively injected. To eliminate the influence of mineral precipitation caused by CO2 geochemical reactions on the measurement results of gaseous-supercritical CO2 storage, the following measures were taken: After completing the saturated CO2 formation water replacement process, the CO2 storage model was pressurized and allowed to stand at a set experimental temperature T, allowing the model sand bodies and dissolved CO2 in the CO2 storage model to fully react; saturated CO2 formation water was re-injected from the lower injection port of the CO2 storage model using a displacement method, and the formation water after the CO2 geochemical reaction was extracted from the production port. During this process, the pressure of the axial pressure loading system and the pressure at the model outlet were set to P, respectively. R And P; a cumulative injection of 10.0 PV was completed, achieving secondary replacement of saturated CO2 formation water; For aquatic layers with closed or constant-pressure boundaries, calculate the gaseous-supercritical CO2 burial quantity. Based on the calculated gaseous-supercritical CO2 stockpile, a graph showing the variation of gaseous-supercritical CO2 stockpile with temperature and pressure conditions was constructed. Based on the graph showing the variation of gaseous-supercritical CO2 burial quantity with temperature and pressure conditions, burial temperature T, burial pressure P, and overlying strata pressure P... R When the formation water salinity is M, the gaseous-supercritical CO2 burial quantity V is obtained from indoor experiments. C ; The CO2 storage model includes: A cylindrical model body, the model body having a cylindrical cavity inside, the cylindrical cavity having a first end and a second end located at both ends, the cylindrical cavity being used to fill model sand, and multiple monitoring ports penetrating the outer side of the model body; An axial pressure loading system is installed at the second end and divides the cylindrical cavity into a first cavity and a second cavity. The axial pressure loading system has a sampling outlet along the axial direction. The sampling outlet communicates with the first cavity and extends through the second cavity to the outside. The axial pressure loading system is used to apply overburden pressure to the model sand body in the cylindrical cavity. A monitoring device is installed at the plurality of monitoring ports to monitor the resistivity changes at the monitoring ports in order to monitor the changes in the fluid phase and content within the model sand body, or to monitor the pressure at the monitoring ports. A rotating device, installed on the model body, is used to rotate the model body to a preset angle; An upper plug structure, installed at the first end, is used to seal the first end. The upper plug structure has an upper injection port and a lower injection port extending axially, and the upper and lower injection ports are spaced apart in the vertical direction. The lower plug structure is installed at the second end to close the second end. The lower plug structure has a plurality of axial pressure injection ports and axial vent ports arranged in the vertical direction. The lower plug structure is located on the side opposite to the upper plug structure of the axial pressure loading system. The axial pressure injection ports and axial vent ports are respectively connected to the second cavity to inject fluid into or release fluid into the second cavity. The first cavity is filled with the model sand body; The step of calculating the gaseous-supercritical CO2 stockpile for aquatic layers with closed or constant pressure boundaries includes: For aquatic layers with closed boundaries, a method of injection without extraction is adopted. CO2 is injected into the upper injection port of the CO2 storage model at a constant speed through a gas flow controller at an experimentally set injection rate q. During this process, the extraction port is closed and no water is drained. Real-time dynamic monitoring and recording of resistivity and pressure data at multiple monitoring ports; continuous injection of CO2 until the upper injection port and any one of the multiple monitoring ports reach the upper limit pressure P. U Stop the injection, record the injection time t, let the model stand still, and after the fluid and pressure in the model stabilize, read the pressure points of the CO2 buried model respectively; For a water layer with a closed boundary, the upper limit of the burial pressure is P. U At that time, the amount of gaseous-supercritical CO2 buried V C for: （1） V C This refers to the amount of gaseous-supercritical CO2 stored, sm 3 ; q represents the CO2 injection rate, sm 3 / min; t represents the CO2 injection time, in minutes; V PVL Let m be the pore volume of the sand body model. 3 ; For buried pressure CO2 solubility sm in simulated formation water 3 / m 3 ; S P The solubility sm of CO2 in simulated formation water when the outlet back pressure is P. 3 / m 3 .

2. The method for determining the amount of gaseous-supercritical CO2 as described in claim 1, characterized in that, The axial compression loading system includes: An axial compression loading structure, housed within the cylindrical cavity, divides the cylindrical cavity into a first cavity and a second cavity, the axial compression loading structure having an axially extending outlet; and... A screen pressure plate is installed at the end of the axial pressure loading structure near the first end, and the screen pressure plate covers the outer edge of the extraction outlet to prevent particles of the model sand in the first cavity from entering and blocking the extraction outlet during the extraction process.

3. The method for determining the amount of gaseous-supercritical CO2 as described in claim 1, characterized in that, The number of monitoring ports is eight, and the eight monitoring ports are evenly distributed on the outside of the main body of the model.

4. The method for determining the amount of gaseous-supercritical CO2 as described in claim 1, characterized in that, The monitoring port is equipped with a monitoring probe that integrates an electrode probe and a pressure sensor.

5. The method for determining the amount of gaseous-supercritical CO2 as described in claim 1, characterized in that, The step of calculating the gaseous-supercritical CO2 stockpile for aquatic layers with closed or constant pressure boundaries includes: For a water layer with a constant pressure boundary, the pressure at the model outlet is set to P to simulate the constant pressure boundary condition, and the pressure of the axial compression loading system is set to P. R The pressure of the overlying strata was simulated. CO2 was injected from the upper injection port of the CO2 storage model by displacement, and the CO2 injection rate was controlled to be q and kept constant. Formation water was extracted from the production port of the CO2 storage model to simulate the reverse water intrusion process of formation water flowing to the water body during CO2 storage. Real-time dynamic monitoring and recording of resistivity and pressure data at each measuring point; tracking the sweep pattern of injected CO2 by varying resistivity data from multiple monitoring ports; stopping CO2 injection and closing the production port valve when the average resistivity monitored at the monitoring port closest to the production outlet drops to 0.5 times the resistivity of the initial saturated formation water, and the injected CO2 has not yet broken through the production outlet; at this time, the injected CO2 reaches or approaches the production outlet but has not yet broken through the production outlet. This process is used to simulate the process of CO2 injected into the actual water layer migrating to the interface between the water layer and the water body but not yet entering the water body. Metered cumulative water production V WL Record the CO2 injection time t; let the model stand for 1 h until the fluid and pressure in the model stabilize, then read the pressure data at the pressure points of the CO2 burial model, and take the average value as the CO2 burial pressure, denoted as t. The gaseous-supercritical CO2 burial quantity V of the water layer with constant pressure boundary is... C for: （2） V WL To accumulate the water production, m 3 ; V C This refers to the amount of gaseous-supercritical CO2 stored, sm 3 ; q represents the CO2 injection rate, sm 3 / min; t represents the CO2 injection time, in minutes; V PVL Let m be the pore volume of the sand body model. 3 ; For buried pressure CO2 solubility sm in simulated formation water 3 / m 3 ; S P The solubility sm of CO2 in simulated formation water when the outlet back pressure is P. 3 / m 3 .

6. The method for determining the amount of gaseous-supercritical CO2 as described in claim 1, characterized in that, The chart shows the variation of gaseous-supercritical CO2 burial volume with temperature and pressure conditions, with burial temperature T, burial pressure P, and overlying strata pressure P. R When the formation water salinity is M, the gaseous-supercritical CO2 burial quantity V is obtained from indoor experiments. C Following the steps described above, the determination method further includes: The amount of gaseous-supercritical CO2 stored in an aquifer, taking into account the effects of temperature, pressure, and salinity, is denoted as V. C-(P,T,M) Based on indoor experimental measurements of gaseous-supercritical CO2 burial volume V C When the burial temperature is T, the burial pressure is P, and the formation water salinity is M, the actual amount of gaseous-supercritical CO2 burial in the mine is V. C-(P,T,M) The calculation method is as follows: （3） V C-(P,T,M) This represents the actual gaseous-supercritical CO2 storage capacity of the aquifer in the mine, sm 3 ; V C To determine the amount of gaseous-supercritical CO2 stored in the laboratory, sm 3 ; V PVL Let m be the pore volume of the sand body model. 3 ; V PVR The actual pore volume of the aquifer in the mine is given in m. 3 .

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