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

Abstract

The present application relates to a kind of CO2-salt water-rock multiple contact reaction simulation device and its testing method, the device includes first high-pressure reactor, high-pressure reactor with agitator, second high-pressure reactor, third high-pressure reactor and fourth high-pressure reactor connected in sequence;And thermostat and CO2 gas cylinder;Wherein, the first high-pressure reactor, high-pressure reactor with agitator, second high-pressure reactor, third high-pressure reactor and fourth high-pressure reactor are all placed in the thermostat interior;The thermostat is used to simulate target reservoir temperature;Multiple core samples and original formation salt water are built-in the first high-pressure reactor;Automatic agitator and saturated CO2 solution are built-in the high-pressure reactor with agitator;The CO2 gas cylinder is used to inject CO2 into the high-pressure reactor with agitator.The device can simulate the high temperature and high pressure condition of formation, CO2 is injected into salt water to form carbonic acid water, and multiple contact reactions occur with formation rock.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of CO2 geological storage research, and particularly relates to a CO2-saline water-rock multiple contact reaction simulation device and a testing method thereof. BACKGROUND

[0002] In recent years, the excessive emission of greenhouse gases dominated by CO2 has caused the continuous rise of global temperature and the increasingly serious environmental problems. CO2 injection into the underground saline aquifer for geological storage has become the most promising large-scale carbon reduction approach. Specifically, CO2 is injected into the saline aquifer to form stable minerals through mineralization reaction with rocks, which is the main mechanism for the long-term and safe storage of CO2. Therefore, the research on the dissolution-deposition reversible reaction of minerals or rocks and the analysis of the evolution law thereof are crucial for the evaluation of the mineralization storage effect and the calculation of the mineralization storage period and storage capacity.

[0003] At present, the CO2-saline water-rock reaction is mainly analyzed by experiments, and part of the mineralization reaction can also be simulated by computers. However, the numerical simulation is usually calculated according to the typical chemical reaction equation, and thus the chemical reaction parameters such as the activation energy of the mineral and the reaction surface area are required. However, these parameters are usually difficult to accurately obtain, resulting in low accuracy and reliability of the numerical simulation results.

[0004] The experimental analysis mainly includes static method and dynamic method. The static method generally refers to immersing the rock or mineral sample into the saturated CO2 saline water, and the reaction is carried out in a high-pressure reaction kettle. The dynamic method generally refers to placing the core in a core holder and displacing it through the saturated CO2 saline water. However, the saturated CO2 saline water in the static method is in a relatively static state, and the dynamic change process of CO2 injection in the geological storage cannot be effectively simulated. Although the dynamic method can simulate the multiple contact process of CO2 injection into the geological body and the saline water and rock, it has the following disadvantages: first, it can only analyze the multiple contact reaction process of CO2-saline water-rock through the solution flowing out of the outlet end of the core holder; second, the core in the core holder can be taken out only after the displacement experiment is completed, and then the mineral composition and other related rock physical parameters are analyzed; this will result in the fact that the solution after the reaction cannot be effectively matched with the rock after the reaction, and the evolution process of the minerals in the actual reservoir and the dissolution-deposition reversible reaction of the rock cannot be accurately analyzed. SUMMARY

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

[0006] The first high-pressure reactor is provided with a stirrer, and the second, third and fourth high-pressure reactors are arranged in the thermostat.

[0007] The thermostat is used for simulating the temperature of a target reservoir.

[0008] The first high-pressure reactor is provided with multiple core samples and original saline water.

[0009] The high-pressure reactor with a stirrer is provided with an automatic stirrer and a saturated CO2 solution.

[0010] The second high-pressure reactor is provided with a core sample and a first CO2-saline water-rock contact reaction solution.

[0011] The third high-pressure reactor is provided with a core sample and a second CO2-saline water-rock contact reaction solution.

[0012] The fourth high-pressure reactor is provided with a core sample and a third CO2-saline water-rock contact reaction solution.

[0013] The CO2 cylinder is used for injecting CO2 into the high-pressure reactor with a stirrer.

[0014] Further, the first high-pressure reactor is provided with a first piston, the top of the first piston is arranged with a first core sample, a second core sample and a third core sample, and the bottom of the first piston is connected with a first constant-pressure constant-speed pump.

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

[0016] Further, a first valve of the six-way valve is connected with the CO2 cylinder through a gas pump, a third valve of the six-way valve is connected with the high-pressure reactor with a stirrer, a fourth valve of the six-way valve is connected with a first fluid outlet end, a fifth valve of the six-way valve is connected with a pressure relief valve, and a sixth valve of the six-way valve is connected with a pressure gauge.

[0017] Further, the bottom of the high-pressure reactor with a stirrer is connected with a first valve of a first three-way valve, a second valve of the first three-way valve is connected with a second fluid outlet end, and a third valve of the first three-way valve is connected with a first interface at the top of the second high-pressure reactor.

[0018] The second high-pressure reactor is provided with a second piston, the top of the second piston is arranged with a first core sample, the bottom of the second high-pressure reactor is connected with a second constant-pressure constant-speed pump, and a second interface at the top of the second high-pressure reactor is connected with a first valve of a second three-way valve.

[0019] Further, the second valve of the second three-way valve is connected with a third fluid outlet end; the third valve of the second three-way valve is connected with the top first interface of the third high-pressure reactor;

[0020] The third high-pressure reactor is internally provided with a third piston, the top of the third piston is placed with a second core sample, the bottom of the third high-pressure reactor is connected with a third constant-pressure constant-speed pump, and the top second interface of the third high-pressure reactor is connected with the first valve of a third three-way valve.

[0021] Further, the second valve of the second three-way valve is connected with a third fluid outlet end; the third valve of the second three-way valve is connected with the top first interface of the third high-pressure reactor;

[0022] Further, 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 with a metering cylinder.

[0023] Further, the thermostat is also connected with a thermostat controller.

[0024] In addition, the application also provides a test method of the CO2-saline rock multiple contact reaction simulation device.

[0025] The original formation saline and a plurality of core samples cut from the rock sample are placed in the first high-pressure reactor, the first high-pressure reactor is placed in the thermostat, the temperature is set as the target reservoir temperature through the thermostat controller, and the pressure is controlled as the target reservoir pressure through the constant-pressure constant-speed pump and is maintained at a constant pressure;

[0026] A small amount of original formation saline is collected through the first fluid outlet end, and the ion concentration change in the original formation saline is analyzed until equilibrium is reached; the first high-pressure reactor is removed from the thermostat, then the plurality of core samples are dried and cut into thin sections for testing;

[0027] The original formation saline and CO2 are injected into the high-pressure reactor with a stirrer, a saturated CO2 solution is collected through the second fluid outlet end, and the ion concentration change in the saturated CO2 solution is analyzed;

[0028] Put the first core sample and saturated CO2 solution into the second high-pressure reactor, open the second constant pressure constant speed pump to maintain the target reservoir pressure, collect the first CO2-salt water-rock contact reaction solution through the third fluid outlet end, and analyze the ion concentration change in the first CO2-salt water-rock contact reaction solution; the second high-pressure reactor is taken out of the thermostat, then the first core sample is dried and tested;

[0029] Put the second core sample and the first CO2-salt water-rock contact reaction solution into the third high-pressure reactor, open the third constant pressure constant speed pump to maintain the target reservoir pressure, collect the second CO2-salt water-rock contact reaction solution through the fourth fluid outlet end, and analyze the ion concentration change in the second CO2-salt water-rock contact reaction solution; the third high-pressure reactor is taken out of the thermostat, then the second core sample is dried and tested;

[0030] Put the third core sample and the second CO2-salt water-rock contact reaction solution into the fourth high-pressure reactor, open the fourth constant pressure constant speed pump to maintain the target reservoir pressure, collect the third CO2-salt water-rock contact reaction solution through the fifth fluid outlet end, and analyze the ion concentration change in the third CO2-salt water-rock contact reaction solution; the fourth high-pressure reactor is taken out of the thermostat, then the third core sample is dried and tested.

[0031] Further, the dried first core sample, the second core sample and the third core sample are respectively tested by X-ray diffractometer, scanning electron microscope and energy spectrometer, and the rock mineral composition, rock micro-morphology, pore structure and rock surface elements are analyzed.

[0032] The CO2-salt water-rock multiple contact reaction simulation device provided by the application can simulate the formation of carbonic acid water by injecting CO2 into salt water under high temperature and high pressure conditions of the formation, and the multiple contact reaction with the formation rock.

[0033] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art upon examination of the following or can be learned by practice of the application. The objects and other advantages of the application can be realized and attained by the methods and instrumentalities particularly pointed out in the written description and claims. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0035] Figure 1 A CO2-brine-rock multiple-contact reaction mode diagram for a target reservoir;

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

[0037] Figure 3 A flowchart of a test method of a CO2-brine-rock multiple-contact reaction simulation device;

[0038] Reference: 1, CO2 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 end; 14, original formation salt 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 end; 22, second three-way valve; 23, third fluid outlet end; 24, third three-way valve; 25, fourth fluid outlet end; 26, fifth fluid outlet end; 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, fifth valve of six-way valve 10; f, sixth valve of six-way valve 10; a1, first valve of first three-way valve 20; b1, second valve of first three-way valve 20; c1, third valve of first three-way valve 20; a2, first valve of second three-way valve 22; b2, second valve of second three-way valve 22; c2, third valve of second three-way valve 22; a3, first valve of third three-way valve 24; b3, second valve of third three-way valve 24; c3, third valve of third three-way valve 24. DETAILED DESCRIPTION

[0039] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort belong to the scope of the present application.

[0040] As Figure 1The target reservoir CO2-salt water-rock multiple contact reaction mode is shown: CO2 is injected into the target reservoir through the CO2 injection well, and then injected into the target reservoir through the soil layer and the cap rock, and then dissolved in the salt water in the target reservoir, and then chemically reacted with the rock in the flow process. Based on this, the application provides a CO2-salt water-rock multiple contact reaction simulation device, as shown in the figure Figure 2 As shown, the device comprises a first high-pressure reaction kettle 2-1, a high-pressure kettle with a stirrer 6, a second high-pressure reaction kettle 3-1, a third high-pressure reaction kettle 4-1, and a fourth high-pressure reaction kettle 5-1 connected in sequence through pipelines, a thermostat 16, and a CO2 gas cylinder 1; wherein the CO2 gas cylinder 1 is connected with a gas pump 19 through a pipeline, the gas pump 19 is connected with a first valve a of a six-way valve 10 through a pipeline; a second valve b of the six-way valve 10 is connected with a top interface of the first high-pressure reaction kettle 2-1 through a pipeline, a third valve c of the six-way valve 10 is connected with a top interface of the high-pressure kettle with a stirrer 6 through a pipeline, a fourth valve d of the six-way valve 10 is connected with a pipeline as a first fluid outlet end 13; a fifth valve e of the six-way valve 10 is connected with a pressure relief valve 12, and a sixth valve f of the six-way valve 10 is connected with a pressure gauge 11.

[0041] Further, the first high-pressure reaction kettle 2-1 is connected with a first constant-speed constant-pressure pump 9-1 at the bottom, and a first piston 8-1 is arranged in the high-pressure reaction kettle 2-1, and a rock core sample cut from a rock sample is placed on the first piston 8-1, and the number of the rock core sample is determined according to the number of CO2-salt water-rock multiple contact reaction experiments, for example, in the embodiment of the application, 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, which are a first rock core sample 18-1, a second rock core sample 18-2, and a third rock core sample 18-3, and are placed on the first piston 8-1. At the same time, the original formation salt water 14 is injected into the first high-pressure reaction kettle 2-1, and the original formation salt water 14 fills the first high-pressure reaction kettle 2-1 as much as possible, which can ensure sufficient contact with the multiple rock core samples and sufficient solution for subsequent reaction.

[0042] Further, an automatic stirrer 7 is arranged in the high-pressure kettle with a stirrer 6, and the bottom of the high-pressure kettle with a stirrer 6 is connected with a first valve a1 of a first three-way valve 20 through a pipeline. A second valve b1 of the first three-way valve 20 is connected with a pipeline as a second fluid outlet end 21; a third valve c1 of the first three-way valve 20 is connected with a first interface at the top of the second high-pressure reaction kettle 3-1 through a pipeline.

[0043] Furthermore, a second piston 8-2 is installed 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 reacting for 48 hours, the solution becomes the first CO2-saltwater-rock contact reaction solution 15-2; a second constant pressure and constant speed pump 9-2 is connected to the bottom of the second high-pressure reactor 3-1; the second port 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 the third fluid outlet 23; the third valve c2 of the second three-way valve 22 is connected to the first port at the top of the third high-pressure reactor 4-1.

[0044] Furthermore, the third high-pressure reactor 4-1 is equipped with a third piston 8-3, on which a second core sample 18-2 is placed; the third high-pressure reactor 4-1 is first injected with a first CO2-saline water-rock contact reaction solution 15-2, and after 48 hours of reaction, the solution becomes a second CO2-saline water-rock contact reaction solution 15-3; the bottom of the third high-pressure reactor 4-1 is connected to a third constant pressure and 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 via a pipeline, and the second valve b3 of the third three-way valve 24 is connected to a pipeline as a 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 equipped 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-saline water-rock contact reaction solution 15-3, and after 48 hours of reaction, the solution becomes a third CO2-saline water-rock contact reaction solution 15-4. The bottom of the fourth high-pressure reactor 5-1 is connected to a fourth constant-pressure, 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 a fifth fluid outlet 26.

[0046] Furthermore, the first fluid outlet 13, the second fluid outlet 21, the third fluid outlet 23, the fourth fluid outlet 25, and the fifth fluid outlet 26 are all connected to measuring cylinders 27, which are used to accurately collect the solution before the CO2-saltwater-rock reaction and after each contact reaction.

[0047] Furthermore, the first high-pressure reactor 2-1, the high-pressure reactor 6 with a stirrer, the second high-pressure reactor 3-1, the third high-pressure reactor 4-1, and the fourth high-pressure reactor 5-1 are placed inside the constant temperature chamber 16, which is adjusted by the constant temperature chamber controller 17 to simulate the target reservoir temperature.

[0048] Further, the application also provides a test method of the CO2-saline water-rock multiple contact reaction simulation device. Figure 3 As shown in the figure, the method comprises the following steps:

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

[0050] The target reservoir rock is selected, and the core is drilled. According to the size of the rock, the size of the drilled core is generally 25 mm in diameter and 50-70 mm in length. In the embodiment of the application, the drilled core is processed into three cylindrical small samples with a diameter of 25 mm and a length of 20 mm, which are core sample 18-1, core sample 18-2 and core sample 18-3, respectively, to eliminate the differences caused by the heterogeneity of the rock as much as possible.

[0051] The three core samples are placed on the first piston 8-1 inside the first high-pressure reaction kettle 2-1, the prepared original formation saline water 14 is added and sealed. The first high-pressure reaction kettle 2-1 is placed in the constant temperature box 16, and the temperature is set to the target reservoir temperature by the constant temperature box controller 17; the pressure is controlled to the target reservoir pressure by the constant pressure constant speed pump 9-1 and maintained at a constant pressure.

[0052] The constant pressure maintaining time is not less than 7 days, 1-2 mL of the original formation saline water 14 is collected through the first fluid outlet end 13 connected to the top of the first high-pressure reaction kettle 2-1 every 24 h, and the ion concentration change of the original formation saline water 14 is analyzed by an 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 saline water, simulating and restoring the state of the rock and the formation saline water before the injection of CO2 at high temperature and high pressure in the target reservoir;

[0053] The third valve c of the six-way valve 10 is opened, and the original formation saline water 14 is injected into the high-pressure kettle 6 with a stirrer at a constant pressure; the third valve c of the six-way valve 10 is closed, the second valve b of the six-way valve 10 is closed, the constant pressure constant speed pump 9-1 is closed, the first high-pressure reaction kettle 2-1 is taken out of the constant temperature box 16, and the temperature is lowered to room temperature before gradient pressure relief; then the three core samples in the first high-pressure kettle 2-1 are taken out and dried;

[0054] A 1-2 mm core slice is cut from the top of each of the three core samples, and the samples are prepared according to the requirements of different analysis instruments for test samples, and are tested by X-ray diffractometer (XRD), scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) respectively, to analyze the original mineral composition of the rock, the microstructure of the rock, the pore structure and the elements on the surface of the rock, and to take them as the initial reference values of the related parameters of the rock before the CO2-saline water-rock reaction.

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

[0056] CO2 is injected into the stirred autoclave 6 through the CO2 cylinder 1, and the target reservoir pressure is reached by boosting the pressure through the gas pump 19, while the automatic stirrer 7 is turned on for stirring to ensure that the original formation brine 14 is fully saturated with CO2 to reach dissolution equilibrium. Since CO2 dissolution may cause fluctuations in pressure, the sixth valve f of the six-way valve 10 is also opened, and the pressure changes are monitored through the pressure gauge 11; when the pressure reaches the target pressure and remains constant, it is considered that the original formation brine 14 has been fully saturated with CO2, forming a saturated CO2 solution 15-1; at this time, the upper part of the stirred autoclave 6 is CO2, and the lower part is the saturated CO2 solution 15-1;

[0057] The first valve a1 of the first three-way valve 20 and the second valve b1 of the first three-way valve 20 are opened, and 1-2 mL of the saturated CO2 solution 15-1 is collected from the second fluid outlet end 21, and the ion concentration of the solution is analyzed by an inductively coupled plasma emission spectrometer; the analysis results are used as the initial reference value of the solution related parameters before the CO2-brine-rock reaction; up to this step, all the preparations before the CO2-brine-rock reaction have been completed, and the next step is to carry out the CO2-brine-rock multiple contact reaction;

[0058] The second valve b1 of the first three-way valve 20 is closed, and the third valve c1 of the first three-way valve 20 is opened, and the saturated CO2 solution 15-1 is injected into the second high-pressure reaction kettle 3-1 at a constant pressure; the third valve c1 of the first three-way valve 20 is closed, and the second constant-pressure constant-speed pump 9-2 is opened to maintain the target reservoir pressure; after 48 hours, the first CO2-brine-rock contact reaction is completed, and the reacted solution is the first CO2-brine-rock contact reaction solution 15-2. The second valve b2 of the second three-way valve 22 and the third valve c2 of the second three-way valve 22 are opened, 1-2 mL of the first CO2-brine-rock contact reaction solution 15-2 is collected from the third fluid outlet end 23, and the ion concentration of the first CO2-brine-rock contact reaction solution 15-2 is tested by an inductively coupled plasma emission spectrometer;

[0059] The second valve b2 of the second three-way valve 22 is closed, the third valve c2 of the second three-way valve 22 is opened, and the first CO2-saline water-rock contact reaction solution 15-2 is injected into the third high-pressure reactor 4-1 at a constant pressure. The third valve c2 of the second three-way valve 22 is closed, the third constant-pressure constant-speed pump 9-3 is opened to maintain the target reservoir pressure; at the same time, the second high-pressure reactor 3-1 is removed from the thermostat 16, and after the temperature drops to room temperature, the pressure is gradually released; then the first core sample 18-1 in the second high-pressure reactor 3-1 is taken out, dried, and then tested by X-ray diffractometer (XRD), scanning electron microscope (SEM) and energy spectrometer (EDS) respectively to analyze the mineral composition of the rock, the micro-morphology of the rock, the pore structure and the surface elements of the rock, and the changes of the related parameters of the rock after the first CO2-saline water-rock contact reaction are taken as the first CO2-saline water-rock contact reaction solution 15-2.

[0060] After 48 hours, the second CO2-saline water-rock contact reaction is completed, the reacted solution is the second CO2-saline water-rock contact reaction solution 15-3, the valves b3 and c3 are opened, 1-2ml of the second CO2-saline water-rock contact reaction solution 15-3 is collected from the fourth fluid outlet end 25, and the ion concentration of the solution after the second contact reaction is tested by inductively coupled plasma emission spectrometer.

[0061] The second valve b3 of the third three-way valve 24 is closed, the third valve c3 of the third three-way valve 24 is opened, and the second CO2-saline 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, 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 removed from the thermostat 16, and after the temperature drops to room temperature, the pressure is gradually released; then the second core sample 18-2 in the third high-pressure reactor 4-1 is taken out, dried, and then tested by X-ray diffractometer (XRD), scanning electron microscope (SEM) and energy spectrometer (EDS) respectively to analyze the mineral composition of the rock, the micro-morphology of the rock, the pore structure and the surface elements of the rock, and the changes of the related parameters of the rock after the second CO2-saline water-rock contact reaction are taken as the second CO2-saline water-rock contact reaction solution 15-3.

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

[0063] The fourth high-pressure reactor 5-1 is taken out of the thermostat 16, and after the temperature drops to room temperature, the pressure is gradually released; then the third core sample 18-3 in the fourth high-pressure reactor 5-1 is taken out, dried, and then tested by X-ray diffractometer (XRD), scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) to analyze the mineral composition of the rock, the micro-morphology of the rock, the pore structure of the rock and the surface elements of the rock, and the changes of the related parameters of the rock after the third contact reaction of CO2-saline water-rock are taken as the changes of the related parameters of the rock after the third contact reaction of CO2-saline water-rock, the thermostat 16 is closed, and the experiment is ended. At this step, the multiple contact reactions of CO2-saline water-rock have been completed.

[0064] In the above test method, the contact reaction time of CO2-saline water-rock is closely related to pressure, temperature, rock type and experimental purpose, and the person skilled in the art can set the contact reaction time according to the experimental scheme.

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

[0066] In the above test method, the inductively coupled plasma emission spectrometer used for solution analysis, the X-ray diffractometer, the scanning electron microscope and the energy dispersive spectrometer used for rock or mineral analysis can be replaced, increased or reduced by the person skilled in the art according to the laboratory instrument equipment.

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

[0068] Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced by equivalents; and these modifications or replacements 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 application.

Claims

1. A CO2-brine-rock multiple-contact reaction simulation apparatus, characterized by, 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) connected in sequence, a thermostat (16), and a CO2 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 thermostat (16); The thermostat (16) is used to simulate the target reservoir temperature; The first high-pressure reactor (2-1) is internally provided with multiple core samples and original formation salt water (14); The high-pressure reactor with a stirrer (6) is internally provided with an automatic stirrer (7) and a CO2-saturated solution (15-1); The second high-pressure reactor (3-1) is internally provided with a core sample and a first CO2-salt water-rock contact reaction solution (15-2); The third high-pressure reactor (4-1) is internally provided with a core sample and a second CO2-salt water-rock contact reaction solution (15-3); The fourth high-pressure reactor (5-1) is internally provided with a 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 high-pressure reactor with a stirrer (6); The first high-pressure reactor (2-1) is internally provided with a first piston (8-1), and the top of the first piston (8-1) is placed with a first core sample (18-1), a second core sample (18-2), and a third core sample (18-3); The second high-pressure reactor (3-1) is internally provided with a second piston (8-2), and the top of the second piston (8-2) is placed with the first core sample (18-1); The third high-pressure reactor (4-1) is internally provided with a third piston (8-3), and the top of the third piston (8-3) is placed with the second core sample (18-2); The fourth high-pressure reactor (5-1) is internally provided with a fourth piston (8-4), and the top of the fourth piston (8-4) is placed with the third core sample (18-3).

2. The apparatus of claim 1, wherein, The bottom of the first piston (8-1) is connected with a first constant-pressure constant-speed pump (9-1); The top interface of the first high-pressure reactor (2-1) is connected with a second valve (b) of a six-way valve (10).

3. The apparatus of claim 2, wherein, The first valve (a) of the six-way valve (10) is connected with the CO2 cylinder (1) through a gas pump (19); the third valve (c) of the six-way valve (10) is connected with the high-pressure reactor with a stirrer (6); the fourth valve (d) of the six-way valve (10) is connected with a first fluid outlet end (13); the fifth valve (e) of the six-way valve (10) is connected with a pressure relief valve (12); The sixth valve (f) of the six-way valve (10) is connected with a pressure gauge (11).

4. The apparatus of claim 3, wherein, 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 end (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). The bottom of the second high-pressure reactor (3-1) is connected to the second constant-pressure 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).

5. The apparatus of claim 4, wherein, The second valve (b2) of the second three-way valve (22) is connected to the third fluid outlet end (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 bottom of the third high-pressure reactor (4-1) is connected to the third constant-pressure constant-speed pump (9-3); 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). The second valve (b3) of the third three-way valve (24) is connected to the fourth fluid outlet end (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 end (26); the bottom of the fourth high-pressure reactor (5-1) is connected to the fourth constant-pressure constant-speed pump (9-4).

6. The apparatus of claim 5, wherein, 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).

7. The apparatus of claim 6, wherein, The thermostat (16) is also connected to a thermostat controller (17).

8. The device of any one of claims 1-7, wherein, The method comprises the following steps:

9. A method of testing a CO2-brine-rock multiple contact reaction simulation device according to any one of claims 1 to 8, wherein, Put the original formation brine (14) and a plurality of core samples cut from the rock sample into the first high-pressure reactor (2-1), put the first high-pressure reactor (2-1) into the thermostat (16), set the temperature to the target reservoir temperature through the thermostat controller (17), and control the pressure to the target reservoir pressure through the constant-pressure constant-speed pump (9-1) and maintain constant pressure; Collect a small amount of original formation brine (14) through the first fluid outlet end (13), and analyze the ion concentration change in the original formation brine (14) until equilibrium is reached; remove the first high-pressure reactor (2-1) from the thermostat (16), then dry and cut the plurality of core samples into thin sections for testing; Inject the original formation brine (14) and CO2 into the agitator autoclave (6), collect the CO2-saturated solution (15-1) through the second fluid outlet end (21), and analyze the ion concentration change in the CO2-saturated solution (15-1); Put the first core sample (18-1) and the CO2-saturated solution (15-1) into the second high-pressure reactor (3-1), and set the temperature to the target reservoir temperature through the thermostat controller (17), and control the pressure to the target reservoir pressure through the constant-pressure constant-speed pump (9-2) and maintain constant pressure; Collect a small amount of CO2-saturated solution (15-1) through the second fluid outlet end (21), and analyze the ion concentration change in the CO2-saturated solution (15-1) until equilibrium is reached; remove the second high-pressure reactor (3-1) from the thermostat (16), then dry and cut the first core sample (18-1) into thin sections for testing; Put the second core sample (18-2) and the CO2-saturated solution (15-1) into the third high-pressure reactor (4-1), and set the temperature to the target reservoir temperature through the thermostat controller (17), and control the pressure to the target reservoir pressure through the constant-pressure constant-speed pump (9-3) and maintain constant pressure; Collect a small amount of CO2-saturated solution (15-1) through the third fluid outlet end (23), and analyze the ion concentration change in the CO2-saturated solution (15-1) until equilibrium is reached; remove the third high-pressure reactor (4-1) from the thermostat (16), then dry and cut the second core sample (18-2) into thin sections for testing; Put the third core sample (18-3) and the CO2-saturated solution (15-1) into the fourth high-pressure reactor (5-1), and set the temperature to the target reservoir temperature through the thermostat controller (17), and control the pressure to the target reservoir pressure through the constant-pressure constant-speed pump (9-4) and maintain constant pressure; Collect a small amount of CO2-saturated solution (15-1) through the fourth fluid outlet end (25), and analyze the ion concentration change in the CO2-saturated solution (15-1) until equilibrium is reached; remove the fourth high-pressure reactor (5-1) from the thermostat (16), then dry and cut the third core sample (18-3) into thin sections for testing. In (3-1), the second constant pressure constant speed pump (9-2) is opened to maintain the target reservoir pressure, the first CO2-saline water-rock contact reaction solution (15-2) is collected through the third fluid outlet end (23), and the ion concentration change in the first CO2-saline water-rock contact reaction solution (15-2) is analyzed; The second high-pressure reactor (3-1) is taken out of the thermostat (16), and then the first core sample (18-1) is dried and tested; The second core sample (18-2) and the first CO2-saline water-rock contact reaction solution (15-2) are placed in the third high-pressure reactor (4-1), the third constant pressure constant speed pump (9-3) is opened to maintain the target reservoir pressure, the second CO2-saline water-rock contact reaction solution (15-3) is collected through the fourth fluid outlet end (25), and the ion concentration change in the second CO2-saline water-rock contact reaction solution (15-3) is analyzed; The third high-pressure reactor (4-1) is taken out of the thermostat (16), and then the second core sample (18-2) is dried and tested; the third core sample (18-3) and the second CO2-saline water-rock contact reaction solution (15-3) are placed in the fourth high-pressure reactor (5-1), the fourth constant pressure constant speed pump (9-4) is opened to maintain the target reservoir pressure, the third CO2-saline water-rock contact reaction solution (15-4) is collected through the fifth fluid outlet end (26), and the ion concentration change in the third CO2-saline water-rock contact reaction solution (15-4) is analyzed; the fourth high-pressure reactor (5-1) is taken out of the thermostat (16), and then the third core sample (18-3) is dried and tested.

10. The method of claim 9, wherein, The dried first core sample (18-1), the second core sample (18-2) and the third core sample (18-3) are respectively tested by X-ray diffractometer, scanning electron microscope and energy spectrometer to analyze the mineral composition of the rock, the microstructure of the rock, the pore structure and the elements on the surface of the rock.

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