CO2-saline water-rock multiple contact reaction simulation device and test method thereof

Abstract

The invention relates to a CO2-salt water-rock multiple contact reaction simulation device and a test method thereof. The device comprises a first high-pressure reaction kettle, a high-pressure kettle with a stirrer, a second high-pressure reaction kettle, a third high-pressure reaction kettle and a fourth high-pressure reaction kettle which are connected in sequence, a thermotank and a CO2 gas cylinder; wherein the first high-pressure reaction kettle, the high-pressure kettle with the stirrer, the second high-pressure reaction kettle, the third high-pressure reaction kettle and the fourth high-pressure reaction kettle are all arranged in the constant-temperature box; the constant temperature box is used for simulating the temperature of a target reservoir; a plurality of small rock core samples and original stratum salt water are arranged in the first high-pressure reaction kettle; an automatic stirrer and a saturated CO2 solution are arranged in the autoclave with the stirrer; and the CO2 gas cylinder is used for injecting CO2 into the high-pressure kettle with the stirrer. The device can simulate that CO2 is injected into salt water to form carbonated water under high-temperature and high-pressure conditions of a stratum, and the carbonated water and stratum rocks are subjected to multiple contact reactions.

Description

Technical Field

[0001] The invention belongs to the technical field of CO2 geological storage research, and in particular relates to a CO2-salt water-rock multiple contact reaction simulation device and a testing method thereof. Background Art

[0002] In recent years, excessive emissions of greenhouse gases, mainly CO2, have caused global temperatures to continue to rise and environmental problems to become increasingly severe. Injecting CO2 into underground saline aquifers for geological storage has become the most promising way to reduce carbon emissions on a large scale. Specifically, CO2 is injected into saline aquifers to undergo mineralization reactions with rocks to form stable minerals for permanent storage, which is the main mechanism for long-term safe storage of CO2. Therefore, studying the reversible reaction of mineral or rock dissolution-precipitation and analyzing its evolution laws are crucial for evaluating the effect of mineralization storage and calculating the mineralization storage cycle and storage volume.

[0003] At present, the CO2-saltwater-rock reaction is mainly based on experimental analysis, and some mineralization reactions can also be numerically simulated by computer. However, numerical simulations are often calculated based on typical chemical reaction equations, so chemical reaction-related parameters such as the activation energy of minerals and reaction surface area are required. These parameters are usually difficult to accurately obtain, resulting in low accuracy and credibility of numerical simulation results.

[0004] There are mainly static and dynamic methods for experimental analysis. The static method generally refers to immersing rock or mineral samples in saline water saturated with CO2, and the reaction is carried out in a high-pressure reactor. The dynamic method generally refers to placing the core in a core holder and displacing it with saline water saturated with CO2. However, the saline water saturated with CO2 in the static method is in a relatively static state and cannot effectively simulate the dynamic change process of CO2 injection in geological storage. Although the dynamic method can simulate the multiple contact process of CO2 injected into the geological body with saline rocks, it has the following shortcomings: First, it can only analyze the multiple contact reaction process of CO2-saline water-rock through the solution flowing out of the outlet of the core holder; second, it must be taken out of the core holder after the displacement experiment is completed, and then the relevant rock physical parameters such as mineral composition are analyzed; this will result in the inability of the post-reaction solution to effectively match the reacting rock, and the evolution process of minerals in the actual reservoir and the reversible reaction of rock dissolution-precipitation cannot be accurately analyzed. Summary of the invention

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows: a CO2-salt water-rock multiple contact reaction simulation device, the device comprises a first high-pressure reactor, a high-pressure reactor with a stirrer, a second high-pressure reactor, a third high-pressure reactor and a fourth high-pressure reactor connected in sequence; and a thermostat and a CO2 gas cylinder; wherein,

[0006] The first autoclave, the autoclave with agitator, the second autoclave, the third autoclave and the fourth autoclave are all placed inside the thermostatic box;

[0007] The thermostatic box is used to simulate the target reservoir temperature;

[0008] The first high-pressure reactor is equipped with a plurality of core samples and original formation salt water;

[0009] The agitator autoclave is equipped with an automatic agitator and a saturated CO2 solution;

[0010] The second high-pressure reactor is equipped with a small core sample and a first CO2-salt water-rock contact reaction solution;

[0011] The third high-pressure reactor is equipped with a small core sample and a second CO2-salt water-rock contact reaction solution;

[0012] The fourth high-pressure reactor is equipped with a small core sample and a third CO2-salt water-rock contact reaction solution;

[0013] The CO2 cylinder is used to inject CO2 into the agitator autoclave.

[0014] Furthermore, the first high-pressure reactor has a first piston built in, the first core sample, the second core sample and the third core sample are placed on the top of the first piston, and the bottom of the first piston is connected to a first constant pressure and constant speed pump;

[0015] The top interface of the first high-pressure reactor is connected to the second valve of the six-way valve.

[0016] Furthermore, the first valve of the six-way valve is connected to the CO2 cylinder via a gas pump; the third valve of the six-way valve is connected to the autoclave with agitator; the fourth valve of the six-way valve is connected to the first fluid outlet; the fifth valve of the six-way valve is connected to the pressure relief valve; and the sixth valve of the six-way valve is connected to a pressure gauge.

[0017] Furthermore, the bottom interface of the agitator autoclave is connected to the first valve of the first three-way valve; the second valve of the first three-way valve is connected to the second fluid outlet; the third valve of the first three-way valve is connected to the first interface on the top of the second autoclave;

[0018] The second high-pressure reactor has a built-in second piston, and the first core sample is placed on the top of the second piston; the bottom of the second high-pressure reactor is connected to a second constant-pressure constant-speed pump; the second interface on the top of the second high-pressure reactor is connected to the first valve of the second three-way valve.

[0019] Furthermore, the second valve of the second three-way valve is connected to the third fluid outlet; the third valve of the second three-way valve is connected to the first interface on the top of the third high-pressure reactor;

[0020] The third high-pressure reactor has a third piston built in, and a second core sample is placed on the top of the third piston; the bottom of the third high-pressure reactor is connected to a third constant-pressure constant-speed pump; the second interface on the top of the third high-pressure reactor is connected to the first valve of a third three-way valve.

[0021] Furthermore, the second valve of the third three-way valve is connected to the fourth fluid outlet; the third valve of the third three-way valve is connected to the first interface on the top of the fourth high-pressure reactor; the second interface on the top of the fourth high-pressure reactor is connected to the fifth fluid outlet; the fourth high-pressure reactor is equipped with a fourth piston, and a third core sample is placed on the top of the fourth piston; the bottom of the fourth high-pressure reactor is connected to a fourth constant pressure and constant speed pump.

[0022] Furthermore, the first fluid outlet end, the second fluid outlet end, the third fluid outlet end, the fourth fluid outlet end, and the fifth fluid outlet end are all connected to a measuring cylinder.

[0023] Furthermore, the thermostat is also connected to a thermostat controller.

[0024] In addition, the present invention also proposes a testing method for a CO2-salt water-rock multiple contact reaction simulation device as described above, the method comprising the following steps:

[0025] Putting the original formation salt water and a plurality of core samples cut from rock samples into a first high-pressure reactor, placing the first high-pressure reactor into a constant temperature box, setting the temperature to the target reservoir temperature through a constant temperature box controller, and controlling the pressure to the target reservoir pressure through a constant pressure and constant speed pump and maintaining the constant pressure;

[0026] A small amount of original formation salt water is collected through the first fluid outlet, and the change of ion concentration in the original formation salt water is analyzed until equilibrium is reached; the first high-pressure reactor is removed from the thermostatic box, and then a plurality of core samples are taken out for drying and thin slices are cut for testing;

[0027] Injecting original formation saline water and CO2 into an autoclave with a stirrer, collecting a solution saturated with CO2 through a second fluid outlet, and analyzing changes in ion concentration in the solution saturated with CO2;

[0028] The first core sample and the saturated CO2 solution are placed in the second high-pressure reactor, the second constant-pressure constant-speed pump is turned on to maintain the target reservoir pressure, the first CO2-salt water-rock contact reaction solution is collected through the third fluid outlet, and the change in ion concentration in the first CO2-salt water-rock contact reaction solution is analyzed; the second high-pressure reactor is removed from the thermostatic box, and then the first core sample is taken out for drying and testing;

[0029] The second core sample and the first CO2-salt water-rock contact reaction solution are placed in a third high-pressure reactor, the third constant-pressure constant-speed pump is turned on to maintain the target reservoir pressure, the second CO2-salt water-rock contact reaction solution is collected through the fourth fluid outlet, and the change in ion concentration in the second CO2-salt water-rock contact reaction solution is analyzed; the third high-pressure reactor is removed from the thermostatic box, and then the second core sample is taken out for drying and testing;

[0030] The third core sample and the second CO2-salty water-rock contact reaction solution were placed in a fourth high-pressure reactor, the fourth constant-pressure constant-speed pump was turned on to maintain the target reservoir pressure, the third CO2-salty water-rock contact reaction solution was collected through the fifth fluid outlet, and the change in ion concentration in the third CO2-salty water-rock contact reaction solution was analyzed; the fourth high-pressure reactor was removed from the constant temperature box, and then the third core sample was taken out for drying and testing.

[0031] Furthermore, the first core sample, the second core sample and the third core sample after drying were tested by X-ray diffractometer, scanning electron microscope and energy spectrometer respectively to analyze the rock mineral composition, rock micromorphology, pore structure and rock surface elements.

[0032] The present invention proposes a CO2-saltwater-rock multiple contact reaction simulation device, which can simulate the injection of CO2 into saltwater under high temperature and high pressure conditions in the formation to form carbonated water, and multiple contact reactions with formation rocks. The present invention proposes a testing method for a CO2-saltwater-rock multiple contact reaction simulation device, which can achieve real-time comparison of rock mineral composition, pore throat structure, and solution ion composition before, during, and after the CO2-saltwater-rock reaction, and provides important technical support for analyzing the reversible dissolution-precipitation reaction in the CO2-saltwater-rock multiple contact reaction process and clarifying the CO2 mineralization and storage mechanism.

[0033] Other features and advantages of the present invention will be described in the following description, and part of them will become obvious from the description, or be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0035] Figure 1 This is the multiple contact reaction pattern diagram of CO2-salt water-rock in the target reservoir;

[0036] Figure 2 A schematic diagram of a CO2-salt water-rock multiple contact reaction simulation device;

[0037] Figure 3 This is a flow chart of the testing method of the CO2-salt water-rock multiple contact reaction simulation device;

[0038] Figure numerals: 1, CO2 gas cylinder; 2-1, first high-pressure reactor; 3-1, second high-pressure reactor; 4-1, third high-pressure reactor; 5-1, fourth high-pressure reactor; 6, high-pressure reactor with stirrer; 7, automatic stirrer; 8-1, first piston; 8-2, second piston; 8-3, third piston; 8-4, fourth piston; 9-1, first constant-pressure constant-speed pump; 9-2, second constant-pressure constant-speed pump; 9-3, third constant-pressure constant-speed pump; 9-4, fourth constant-pressure constant-speed pump; 10. Six-way valve; 11. Pressure gauge; 12. Pressure relief valve; 13. First fluid outlet; 14. Original formation saline water; 15-1. Saturated CO2 solution; 15-2. First CO2-salt water-rock contact reaction solution; 15-3. Second CO2-salt water-rock contact reaction solution; 15-4. Third CO2-salt water-rock contact reaction solution; 16. Constant temperature box; 17. Constant temperature box controller; 18-1. First core sample; 18-2. Second core sample; 18-3, third core sample; 19, gas pump; 20, first three-way valve; 21, second fluid outlet; 22, second three-way valve; 23, third fluid outlet; 24, third three-way valve; 25, fourth fluid outlet; 26, fifth fluid outlet; 27, measuring cylinder; a, first valve of six-way valve 10; b, second valve of six-way valve 10; c, third valve of six-way valve 10; d, fourth valve of six-way valve 10; e, six-way valve 10 The fifth valve of the six-way valve 10; f, the sixth valve of the six-way valve 10; a1, the first valve of the first three-way valve 20; b1, the second valve of the first three-way valve 20; c1, the third valve of the first three-way valve 20; a2, the first valve of the second three-way valve 22; b2, the second valve of the second three-way valve 22; c2, the third valve of the second three-way valve 22; a3, the first valve of the third three-way valve 24; b3, the second valve of the third three-way valve 24; c3, the third valve of the third three-way valve 24. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] like Figure 1The figure shows the multiple contact reaction mode of CO2-salt water-rock in the target reservoir: CO2 is injected into the target reservoir through the soil layer and the cap layer in sequence through the CO2 injection well, and CO2 dissolves in the salt water in the target reservoir, and then repeatedly contacts with the rock during the flow process to produce chemical reactions. Based on this, the present invention proposes a CO2-salt water-rock multiple contact reaction simulation device, such as Figure 2 As shown, the device includes a first high-pressure reactor 2-1, a high-pressure reactor with a stirrer 6, a second high-pressure reactor 3-1, a third high-pressure reactor 4-1 and a fourth high-pressure reactor 5-1, a thermostat 16 and a CO2 gas cylinder 1, which are sequentially connected through pipelines; wherein the CO2 gas cylinder 1 is connected to a gas pump 19 through a pipeline, and the gas pump 19 is connected to a first valve a of a six-way valve 10 through a pipeline; the second valve b of the six-way valve 10 is connected to the top interface of the first high-pressure reactor 2-1 through a pipeline, the third valve c of the six-way valve 10 is connected to the top interface of the high-pressure reactor 6 with a stirrer through a pipeline, and the fourth valve d of the six-way valve 10 is connected to a pipeline as a first fluid outlet 13; the fifth valve e of the six-way valve 10 is connected to a pressure relief valve 12, and the sixth valve f of the six-way valve 10 is connected to a pressure gauge 11.

[0041] Furthermore, the bottom of the first high-pressure reactor 2-1 is connected to the first constant speed constant pressure pump 9-1, and the first piston 8-1 is provided inside the high-pressure reactor 2-1. A rock core sample cut from a rock sample is placed on the first piston 8-1. The number of rock core samples is determined according to the number of CO2-salt water-rock multiple contact reaction experiments. For example, in the embodiment of the present invention, the CO2-salt water-rock multiple contact reaction experiment needs to be carried out three times, so the rock sample is cut into three rock core samples, namely the first rock core sample 18-1, the second rock core sample 18-2 and the third rock core sample 18-3, and they are placed on the first piston 8-1. At the same time, the prepared original formation salt water 14 is injected into the first high-pressure reactor 2-1. The original formation salt water 14 fills the first high-pressure reactor 2-1 as much as possible, which can ensure full contact with multiple rock core samples on the one hand, and ensure sufficient solution for subsequent reactions on the other hand.

[0042] Furthermore, an automatic stirrer 7 is provided inside the stirrer autoclave 6, and the bottom of the stirrer autoclave 6 is connected to the first valve a1 of the first three-way valve 20 through a pipeline. The second valve b1 of the first three-way valve 20 is connected to a pipeline as the second fluid outlet 21; the third valve c1 of the first three-way valve 20 is connected to the first interface at the top of the second high-pressure reactor 3-1 through a pipeline.

[0043] Furthermore, a second piston 8-2 is provided inside the second high-pressure reactor 3-1, and a first core sample 18-1 is placed on the second piston 8-2; a saturated CO2 solution 15-1 is first injected into the second high-pressure reactor 3-1, and after 48 hours of reaction, the solution is the first CO2-salty water-rock contact reaction solution 15-2; the bottom of the second high-pressure reactor 3-1 is connected to a second constant pressure and constant speed pump 9-2; the second interface at the top of the second high-pressure reactor 3-1 is connected to the first valve a2 of the second three-way valve 22 through a pipeline, and the second valve b2 of the second three-way valve 22 is connected to a pipeline as a third fluid outlet 23; the third valve c2 of the second three-way valve 22 is connected to the first interface at the top of the third high-pressure reactor 4-1.

[0044] Furthermore, the third high-pressure reactor 4-1 is provided with a third piston 8-3 inside, and a second core sample 18-2 is placed on the third piston 8-3; the first CO2-salt water-rock contact reaction solution 15-2 is first injected into the third high-pressure reactor 4-1, and the solution after 48 hours of reaction is the second CO2-salt water-rock contact reaction solution 15-3; the bottom of the third high-pressure reactor 4-1 is connected to a third constant pressure constant speed pump 9-3. The first valve a3 of the third three-way valve 24 is connected to the second interface at the top of the third high-pressure reactor 4-1 through a pipeline, and the second valve b3 of the third three-way valve 24 is connected to a pipeline as the fourth fluid outlet 25; the third valve c3 interface of the third three-way valve 24 is connected to the first interface at the top of the fourth high-pressure reactor 5-1.

[0045] Furthermore, the fourth high-pressure reactor 5-1 is provided with a fourth piston 8-4, on which a third core sample 18-3 is placed; the fourth high-pressure reactor 5-1 is first injected with a second CO2-salt water-rock contact reaction solution 15-3, and after 48 hours of reaction, the solution is a third CO2-salt water-rock contact reaction solution 15-4; the bottom of the fourth high-pressure reactor 5-1 is connected to a fourth constant pressure and constant speed pump 9-4. The second interface at the top of the fourth high-pressure reactor 5-1 is directly connected to a pipeline as the fifth fluid outlet 26.

[0046] Furthermore, the first fluid outlet port 13, the second fluid outlet port 21, the third fluid outlet port 23, the fourth fluid outlet port 25, and the fifth fluid outlet port 26 are all connected to a metering cylinder 27, and the metering cylinder 27 is used to accurately collect the solution before the CO2-salt water-rock reaction and after each contact reaction.

[0047] Further, the first autoclave 2-1, the autoclave with agitator 6, the second autoclave 3-1, the third autoclave 4-1 and the fourth autoclave 5-1 are placed inside a thermostatic box 16, and the thermostatic box 16 is adjusted by a thermostatic box controller 17 to simulate the target reservoir temperature.

[0048] In addition, the present invention also proposes a test method for the above-mentioned CO2-salt water-rock multiple contact reaction simulation device, such as Figure 3 As shown, the method comprises the following steps:

[0049] According to the mineralization and ion composition of the formation water in the target reservoir, NaCl, NaHCO3, KHCO3, CaCl2 and MgSO4 are added to the deionized water to prepare the original formation saline water 14;

[0050] Select the target reservoir rock and drill the core. Depending on the size of the rock, the drilled core is generally 25 mm in diameter and 50-70 mm in length. In the embodiment of the present invention, the drilled core is processed into three cylindrical samples with a diameter of 25 mm and a length of 20 mm, namely core sample 18-1, core sample 18-2 and core sample 18-3, to eliminate the differences caused by the heterogeneity of the rock itself as much as possible;

[0051] Put three core samples on the first piston 8-1 inside the first high-pressure reactor 2-1, add the prepared original formation salt water 14 and seal it. Put the first high-pressure reactor 2-1 into the thermostat 16, and set the temperature to the target reservoir temperature through the thermostat controller 17; control the pressure to the target reservoir pressure through the constant pressure and constant speed pump 9-1 and maintain it at a constant pressure;

[0052] The minimum constant pressure maintenance time is no less than 7 days. Every 24 hours, 1-2 mL of original formation salt water 14 is collected through the first fluid outlet port 13 connected to the top of the first high-pressure reactor 2-1, and the ion concentration change of the original formation salt water 14 is analyzed by inductively coupled plasma emission spectrometer until equilibrium is reached. This step is to ensure that the target reservoir rock is in full contact with the formation salt water, and simulate and restore the state of the rock and formation salt water before CO2 is injected into the target reservoir under high temperature and high pressure;

[0053] Open the third valve c of the six-way valve 10, and inject the original formation salt water 14 into the autoclave with agitator 6 at a constant pressure; close the third valve c of the six-way valve 10, close the second valve b of the six-way valve 10, close the constant pressure and constant speed pump 9-1, remove the first high-pressure reactor 2-1 from the thermostat 16, and gradually release the pressure after the temperature drops to room temperature; then take out the three core samples in the first autoclave 2-1 and dry them;

[0054] A 1-2 mm thin slice was cut from the top of each of the three core samples. The samples were prepared according to the requirements of different analytical instruments for test samples. They were tested by X-ray diffractometer (XRD), scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) respectively to analyze the original mineral composition, microscopic morphology, pore structure and surface elements of the rock, and used as the initial reference values ​​of rock-related parameters before the CO2-salt water-rock reaction.

[0055] The remaining first core sample 18-1 is placed on the second piston 8-2 in the second autoclave 3-1, the second core sample 18-2 is placed on the third piston 8-3 in the third autoclave 4-1, and the third core sample 18-3 is placed on the fourth piston 8-4 in the fourth autoclave 5-1;

[0056] CO2 is injected into the agitator autoclave 6 through the CO2 cylinder 1, and the pressure is increased to the target reservoir pressure through the gas pump 19, and the automatic agitator 7 is turned on for stirring to ensure that the original formation salt water 14 is fully saturated with CO2 to achieve dissolution equilibrium. Since CO2 dissolution may cause pressure fluctuations, the sixth valve f of the six-way valve 10 is opened at the same time, and the pressure change is monitored by the pressure gauge 11; when the pressure reaches the target pressure and remains constant, it is considered that the original formation salt water 14 is fully saturated with CO2, forming a saturated CO2 solution 15-1; at this time, the upper part of the agitator autoclave 6 is CO2, and the lower part is a saturated CO2 solution 15-1;

[0057] Open the first valve a1 of the first three-way valve 20 and the second valve b1 of the first three-way valve 20, collect 1-2 mL of saturated CO2 solution 15-1 from the second fluid outlet 21, and analyze the solution ion concentration by inductively coupled plasma emission spectrometry; use the analysis results as initial reference values ​​of solution related parameters before CO2-salt water-rock reaction; at this step, all preparations before CO2-salt water-rock reaction have been completed, and the next step is to carry out multiple contact reactions of CO2-salt water-rock;

[0058] Close the second valve b1 of the first three-way valve 20, open the third valve c1 of the first three-way valve 20, and inject the saturated CO2 solution 15-1 into the second high-pressure reactor 3-1 at a constant pressure; close the third valve c1 of the first three-way valve 20, and open the second constant pressure and constant speed pump 9-2 to maintain the target reservoir pressure; after an interval of 48 hours, the first CO2-salt water-rock contact reaction is completed, and the solution after the reaction is the first CO2-salt water-rock contact reaction solution 15-2. Open the second valve b2 of the second three-way valve 22 and the third valve c2 of the second three-way valve 22, collect 1-2mL of the first CO2-salt water-rock contact reaction solution 15-2 from the third fluid outlet 23, and test the ion concentration of the first CO2-salt water-rock contact reaction solution 15-2 by inductively coupled plasma emission spectrometer analysis;

[0059] Close the second valve b2 of the second three-way valve 22, open the third valve c2 of the second three-way valve 22, and inject the first CO2-salt water-rock contact reaction solution 15-2 into the third high-pressure reactor 4-1 at a constant pressure. Close the third valve c2 of the second three-way valve 22, and open the third constant pressure and constant speed pump 9-3 to maintain the target reservoir pressure; at the same time, withdraw the second high-pressure reactor 3-1 from the thermostat 16, and after the temperature drops to room temperature, perform gradient pressure relief; then take out the first core sample 18-1 in the second high-pressure reactor 3-1, dry it, and perform X-ray diffractometer (XRD), scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) tests on it, analyze the rock mineral composition, rock micromorphology, pore structure and rock surface elements, and use it as the change value of rock-related parameters after the first contact reaction of CO2-salt water-rock;

[0060] After an interval of 48 hours, the second CO2-salt water-rock contact reaction is completed, and the solution after the reaction is the second CO2-salt water-rock contact reaction solution 15-3. Open valve b3 and valve c3, collect 1-2 ml of the second CO2-salt water-rock contact reaction solution 15-3 from the fourth fluid outlet 25, and test the ion concentration of the solution after the second contact reaction by inductively coupled plasma emission spectrometry;

[0061] The second valve b3 of the third three-way valve 24 is closed, and the third valve c3 of the third three-way valve 24 is opened, and the second CO2-salt water-rock contact reaction solution 15-3 is injected into the fourth high-pressure reactor 5-1 at a constant pressure; the third valve c3 of the third three-way valve 24 is closed, and the fourth constant pressure constant speed pump 9-4 is opened to maintain the target reservoir pressure; at the same time, the third high-pressure reactor 4-1 is withdrawn from the constant temperature box 16, and the pressure is gradually relieved after the temperature drops to room temperature; then the second core sample 18-2 in the third high-pressure reactor 4-1 is taken out, and after drying, it is tested by X-ray diffractometer (XRD), scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) respectively, to analyze the rock mineral composition, rock micromorphology, pore structure and rock surface elements, and it is used as the change value of rock related parameters after the second contact reaction of CO2-salt water-rock;

[0062] After an interval of 48 hours, the third CO2-salt water-rock contact reaction is completed, and the solution after the reaction is the third CO2-salt water-rock contact reaction solution 15-4. 1-2 mL of the third CO2-salt water-rock contact reaction solution 15-4 is collected from the fifth fluid outlet 26, and the ion concentration of the solution after the third contact reaction is tested by an inductively coupled plasma emission spectrometer.

[0063] The fourth high-pressure reactor 5-1 is placed outside the thermostat 16, and the pressure is gradually released after the temperature drops to room temperature; then the third core sample 18-3 in the fourth high-pressure reactor 5-1 is taken out, and after drying, it is tested by X-ray diffractometer (XRD), scanning electron microscope (SEM) and energy dispersive spectrometer (EDS), and the rock mineral composition, rock micromorphology, pore structure and rock surface elements are analyzed, and the values ​​are used as the rock-related parameter change values ​​after the third contact reaction of CO2-salt water-rock, and the thermostat 16 is closed, and the experiment ends. At this step, the multiple contact reactions of CO2-salt water-rock have been completed.

[0064] In the above test method, since the CO2-salt water-rock contact reaction time is closely related to pressure, temperature, rock type, and experimental purpose, technical personnel in this field can set the contact reaction time specifically according to the experimental plan.

[0065] In the above test method, CO2 injected into the formation will repeatedly contact with salt water and rock. In the embodiment of the present invention, three contact reaction experiments are set to effectively simulate the repeated multiple contact effects of CO2-salt water-rock in the target reservoir. Those skilled in the art can modify the above device and method according to the experimental plan to increase the number of contact reactions.

[0066] In the above test methods, the inductively coupled plasma emission spectrometer used for solution analysis, and the X-ray diffractometer, scanning electron microscope and energy spectrometer used for rock or mineral analysis can be replaced, increased or reduced by technical personnel in this field according to the conditions of laboratory instruments and equipment.

[0067] In summary, the device designed by the present invention realizes the analysis and testing of CO2-salt water-rock before, at the beginning, during and at the end of the reaction. The dynamic reaction process of CO2-salt water-rock can be inferred by the change of solution ion concentration before and after the reaction, combined with the rock mineral composition, rock micromorphology, pore structure and rock surface element changes. The rock dissolution, precipitation and the reversible reaction between dissolution and precipitation caused by the injection of CO2 into the target reservoir can be intuitively understood and judged, laying a theoretical foundation for the efficient storage of CO2 in the target reservoir.

[0068] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A CO2-salt water-rock multiple contact reaction simulation device, characterized in that: The device comprises a first high-pressure reactor (2-1), a high-pressure reactor with a stirrer (6), a second high-pressure reactor (3-1), a third high-pressure reactor (4-1) and a fourth high-pressure reactor (5-1) which are connected in sequence, as well as a thermostat (16) and a CO2 gas cylinder (1); wherein, The first high-pressure reactor (2-1), the high-pressure reactor with a stirrer (6), the second high-pressure reactor (3-1), the third high-pressure reactor (4-1) and the fourth high-pressure reactor (5-1) are all placed inside the thermostatic box (16); The thermostatic box (16) is used to simulate the target reservoir temperature; The first high-pressure reactor (2-1) contains a plurality of core samples and original formation salt water (14); The agitator autoclave (6) is equipped with an automatic agitator (7) and a saturated CO2 solution (15-1); The second high-pressure reactor (3-1) is equipped with a small core sample and a first CO2-salt water-rock contact reaction solution (15-2); The third high-pressure reactor (4-1) contains a small core sample and a second CO2-salt water-rock contact reaction solution (15-3); The fourth high-pressure reactor (5-1) contains a small core sample and a third CO2-salt water-rock contact reaction solution (15-4); The CO2 cylinder (1) is used to inject CO2 into the agitator autoclave (6).

2. The device according to claim 1, characterized in that The first high-pressure reactor (2-1) has a first piston (8-1) built in, a first core sample (18-1), a second core sample (18-2) and a third core sample (18-3) are placed on the top of the first piston (8-1), and the bottom of the first piston (8-1) is connected to a first constant-pressure and constant-speed pump (9-1); The top interface of the first high-pressure reactor (2-1) is connected to the second valve (b) of the six-way valve (10).

3. The device according to claim 2, characterized in that The first valve (a) of the six-way valve (10) is connected to the CO2 gas cylinder (1) via a gas pump (19); the third valve (c) of the six-way valve (10) is connected to the autoclave with agitator (6); the fourth valve (d) of the six-way valve (10) is connected to the first fluid outlet (13); the fifth valve (e) of the six-way valve (10) is connected to the pressure relief valve (12); and the sixth valve (f) of the six-way valve (10) is connected to the pressure gauge (11).

4. The device according to claim 3, characterized in that The bottom interface of the agitator autoclave (6) is connected to the first valve (a1) of the first three-way valve (20); the second valve (b1) of the first three-way valve (20) is connected to the second fluid outlet (21); the third valve (c1) of the first three-way valve (20) is connected to the first interface at the top of the second autoclave (3-1); The second high-pressure reactor (3-1) has a second piston (8-2) built in, and a first core sample (18-1) is placed on the top of the second piston (8-2); the bottom of the second high-pressure reactor (3-1) is connected to a second constant-pressure constant-speed pump (9-2); and the second interface at the top of the second high-pressure reactor (3-1) is connected to the first valve (a2) of the second three-way valve (22).

5. The device according to claim 4, characterized in that The second valve (b2) of the second three-way valve (22) is connected to the third fluid outlet port (23); the third valve (c2) of the second three-way valve (22) is connected to the first interface at the top of the third high-pressure reactor (4-1); The third high-pressure reactor (4-1) has a third piston (8-3) built in, and a second core sample (18-2) is placed on the top of the third piston (8-3); the bottom of the third high-pressure reactor (4-1) is connected to a third constant-pressure constant-speed pump (9-3); and the second interface at the top of the third high-pressure reactor (4-1) is connected to the first valve (a3) ​​of the third three-way valve (24).

6. The device according to claim 5, characterized in that The second valve (b3) of the third three-way valve (24) is connected to the fourth fluid outlet port (25); the third valve (c3) of the third three-way valve (24) is connected to the first interface at the top of the fourth high-pressure reactor (5-1); the second interface at the top of the fourth high-pressure reactor (5-1) is connected to the fifth fluid outlet port (26); the fourth high-pressure reactor (5-1) has a fourth piston (8-4) built in, and a third core sample (18-3) is placed on the top of the fourth piston (8-4); the bottom of the fourth high-pressure reactor (5-1) is connected to a fourth constant-pressure and constant-speed pump (9-4).

7. The device according to claim 6, characterized in that The first fluid outlet end (13), the second fluid outlet end (21), the third fluid outlet end (23), the fourth fluid outlet end (25), and the fifth fluid outlet end (26) are all connected to a measuring cylinder (27).

8. The device according to any one of claims 1 to 7, characterized in that: The thermostat (16) is also connected to a thermostat controller (17).

9. A method for testing a CO2-salt water-rock multiple contact reaction simulation device according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: Putting the original formation salt water (14) and a plurality of core samples cut from rock samples into a first high-pressure reactor (2-1), placing the first high-pressure reactor (2-1) into a constant temperature box (16), setting the temperature to the target reservoir temperature through a constant temperature box controller (17), and controlling the pressure to the target reservoir pressure through a constant pressure and constant speed pump (9-1) and maintaining the pressure at a constant level; A small amount of original formation salt water (14) is collected through the first fluid outlet (13), and the change in ion concentration in the original formation salt water (14) is analyzed until equilibrium is reached; the first high-pressure reactor (2-1) is removed from the thermostatic box (16), and then a plurality of core samples are taken out, dried, and sliced ​​for testing; Injecting original formation salt water (14) and CO2 into an autoclave (6) with a stirrer, collecting a CO2-saturated solution (15-1) through a second fluid outlet (21), and analyzing changes in ion concentration in the CO2-saturated solution (15-1); The first core sample (18-1) and the saturated CO2 solution (15-1) are placed in a second high-pressure reactor (3-1), and the second constant-pressure constant-speed pump (9-2) is turned on to maintain the target reservoir pressure. The first CO2-salt water-rock contact reaction solution (15-2) is collected through the third fluid outlet (23), and the change in ion concentration in the first CO2-salt water-rock contact reaction solution (15-2) is analyzed; the second high-pressure reactor (3-1) is removed from the thermostatic box (16), and then the first core sample (18-1) is taken out, dried, and tested; The second core sample (18-2) and the first CO2-salt water-rock contact reaction solution (15-2) are placed in a third high-pressure reactor (4-1), the third constant-pressure constant-speed pump (9-3) is turned on to maintain the target reservoir pressure, the second CO2-salt water-rock contact reaction solution (15-3) is collected through the fourth fluid outlet (25), and the change in ion concentration in the second CO2-salt water-rock contact reaction solution (15-3) is analyzed; the third high-pressure reactor (4-1) is removed from the thermostatic box (16), and then the second core sample (18-2) is taken out, dried and tested; The third core sample (18-3) and the second CO2-salt water-rock contact reaction solution (15-3) are placed in a fourth high-pressure reactor (5-1), the fourth constant pressure constant speed pump (9-4) is turned on to maintain the target reservoir pressure, the third CO2-salt water-rock contact reaction solution (15-4) is collected through the fifth fluid outlet port (26), and the change in ion concentration in the third CO2-salt water-rock contact reaction solution (15-4) is analyzed; the fourth high-pressure reactor (5-1) is removed from the constant temperature box (16), and then the third core sample (18-3) is taken out, dried and tested.

10. The method according to claim 9, characterized in that The first core sample (18-1), the second core sample (18-2) and the third core sample (18-3) after drying were tested by X-ray diffractometer, scanning electron microscope and energy spectrometer respectively to analyze the rock mineral composition, rock micromorphology, pore structure and rock surface elements.

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