Carbon dioxide displacement of crude oil simulation apparatus

Abstract

The embodiment of the application provides a carbon dioxide displacement crude oil simulation device, and relates to the technical field of oil and gas development.The device comprises a simulation mechanism and an injection mechanism;the injection mechanism is connected with a first simulation component in a plurality of simulation components through a conduit, and the injection mechanism is used for injecting CO2 gas or crude oil into the plurality of simulation components;the simulation component comprises a holder, a gas-liquid separation component, a gas-liquid mixing component and a booster pump, which are sequentially connected through the conduit; a gas flow meter and a liquid flow meter are arranged on the gas-liquid separation component; the last simulation component in the plurality of simulation components only comprises the holder; an outlet pipe of the holder of the last simulation component is communicated with an inlet of a back pressure valve; a measuring bottle is communicated with an outlet of the back pressure valve through a first conduit; an inlet of a gas meter is communicated with the measuring bottle through a second conduit; and the technical scheme provided by the embodiment of the application can improve the accuracy of the measured CO2 oil displacement efficiency of each core.

Description

Technical Field

[0001] This application relates to the field of oil and gas development technology, and in particular to a carbon dioxide displacement crude oil simulation device. Background Technology

[0002] CO2 (Carbondioxide) flooding technology can improve the oil recovery rate of an oil field by injecting CO2 into the oil reservoir.

[0003] In related technologies, long core displacement experiments are conducted by axially splicing multiple core samples to form a long core of a certain length. The long core is then loaded into a core holder, and various fluids are injected into the core holder through an injection mechanism to simulate the CO2 oil displacement process. This allows for the study of various factors affecting the efficiency of CO2 oil displacement.

[0004] Among the aforementioned related technologies, long core displacement experiments can only measure macroscopic parameters such as outlet back pressure and recovery rate. Since long cores are heterogeneous, the CO2 oil displacement efficiency of each core measured by long core displacement experiments is not accurate enough. Summary of the Invention

[0005] This application provides a carbon dioxide displacement crude oil simulation device, which can improve the accuracy of the measured CO2 oil displacement efficiency of each core sample. The technical solution provided by this application is as follows:

[0006] According to one aspect of the embodiments of this application, a carbon dioxide displacement crude oil simulation device is provided, the device comprising a simulation mechanism and an injection mechanism; wherein...

[0007] The simulation mechanism includes multiple simulation components, a back pressure valve, a metering bottle, a gas meter, a first conduit, and a second conduit, with adjacent simulation components connected by a connecting pipe.

[0008] The injection mechanism is connected to the first of the plurality of simulation components via a conduit, and the injection mechanism is used to inject CO2 gas or crude oil into the plurality of simulation components;

[0009] The simulation component includes a clamp, a gas-liquid separation component, a gas flow meter, a liquid flow meter, a gas-liquid mixing component, a booster pump, and the connecting pipe. The clamp, the gas-liquid separation component, the gas-liquid mixing component, and the booster pump are sequentially connected through conduits. The gas flow meter and the liquid flow meter are mounted on the gas-liquid separation component.

[0010] The last of the plurality of simulation components includes only the clamp, the outlet pipe of the clamp of the last simulation component is connected to the inlet of the back pressure valve, the metering bottle is connected to the outlet of the back pressure valve via the first conduit, and the inlet of the gas meter is connected to the metering bottle via the second conduit.

[0011] In some embodiments, the clamp includes a cylinder, a cover plate, an inlet pipe, an outlet pipe, and an airbag sleeve;

[0012] The cylinder has a cylindrical inner cavity for holding the rock core, one end of the cylinder is open, and the other end of the cylinder has a liquid outlet hole.

[0013] The cover plate is used to cover one end of the opening of the cylinder;

[0014] The cover plate has a liquid inlet hole, and one end of the inlet pipe is connected to the liquid inlet hole;

[0015] One end of the outlet pipe is connected to the liquid outlet hole;

[0016] The airbag sleeve is built into the cylinder and is used to fit onto the rock core. An inflation port is formed on the airbag sleeve, which is connected to the inner cavity of the airbag sleeve.

[0017] In some embodiments, the clamp further includes at least one locking screw, and the cover plate is detachably connected to the cylinder via the at least one locking screw.

[0018] In some embodiments, the clamp further includes an inlet flow meter, an inlet pressure gauge, and an outlet pressure gauge; wherein...

[0019] The inlet flow meter and the inlet pressure gauge are installed on the inlet pipe;

[0020] The liquid outlet pressure gauge is installed on the outlet pipe.

[0021] In some embodiments, the injection mechanism includes a first container, a second container, a first piston, a second piston, a first air injection pipe, a second air injection pipe, a displacement pump, a liquid outlet pipe, an air outlet pipe, and a constant temperature chamber; wherein,

[0022] The first piston seal is slidably disposed inside the first container and divides the first container into a first upper receiving cavity and a first lower receiving cavity, the first upper receiving cavity being used to hold crude oil;

[0023] The second piston is slidably disposed within the second container and divides the second container into a second upper receiving chamber and a second lower receiving chamber. The second upper receiving chamber is used to hold the CO2 gas.

[0024] One end of the first air injection pipe is connected to the outlet of the displacement pump, and the other end of the first air injection pipe is connected to the first lower receiving cavity. A first control valve is provided on the first air injection pipe.

[0025] One end of the second air injection pipe is connected to the outlet of the displacement pump, and the other end of the second air injection pipe is connected to the second lower receiving cavity. A second control valve is provided on the second air injection pipe.

[0026] One end of the liquid outlet pipe is connected to the first upper accommodating cavity, and the other end of the liquid outlet pipe is connected to the other end of the inlet pipe of the first simulation component. A liquid outlet valve is provided on the liquid outlet pipe.

[0027] One end of the vent pipe is connected to the second upper accommodating cavity, and the other end of the vent pipe is connected to the other end of the inlet pipe of the first simulation component. An vent valve is provided on the vent pipe.

[0028] Both the first container and the second container are placed inside the constant temperature chamber, which is used to bring the fluid temperature in the first container and the second container up to the formation temperature.

[0029] In some embodiments, the gas-liquid separation assembly includes a separation tube, a gas guide tube, and a liquid guide tube; wherein,

[0030] The separation tube is vertically arranged, and a first through hole is provided on the side wall of the separation tube. The first through hole is connected to one end of the outlet tube of the clamp. The upper end of the separation tube is connected to one end of the gas guide tube, and the lower end of the separation tube is connected to one end of the liquid guide tube.

[0031] A first check valve is provided on the air duct;

[0032] A second one-way valve is installed on the liquid guide tube.

[0033] In some embodiments, the gas flow meter is disposed on the gas guide pipe, and the liquid flow meter is disposed on the liquid guide pipe.

[0034] In some embodiments, the gas-liquid mixing assembly includes a mixing pipe and a converging pipe; wherein,

[0035] The upper end of the mixing tube is connected to the other end of the gas guiding tube, the lower end of the mixing tube is connected to the other end of the liquid guiding tube, a second perforation is provided on the side wall of the mixing tube, and one end of the converging tube is connected to the second perforation.

[0036] In some embodiments, the inlet of the booster pump is connected to the other end of the manifold.

[0037] In some embodiments, one end of the connecting pipe is connected to the outlet of the booster pump.

[0038] The technical solutions provided in this application embodiment may have the following beneficial effects:

[0039] By setting up multiple simulation components connected in sequence, each simulation component includes a clamp, a gas-liquid separation component, a gas flow meter, a liquid flow meter, a gas-liquid mixing component, a booster pump, and connecting pipes. The clamp is used to hold the core, and the gas-liquid separation component is used to separate the CO2 gas discharged from the core from the crude oil, so that the volume of crude oil discharged from the core can be measured by the liquid flow meter. The gas-liquid mixing component then mixes the CO2 gas with the crude oil, pressurizes it, and discharges it into the next simulation component. In this way, the volume of crude oil discharged from the core can be measured by the liquid flow meter of each simulation component, so that the volume of crude oil discharged from each core can be quantitatively measured, and the oil displacement efficiency of each core can be obtained, thus improving the accuracy of the measured CO2 oil displacement efficiency of each core.

[0040] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a schematic diagram of the structure of a CO2 displacement crude oil simulation device provided in one embodiment of this application;

[0043] Figure 2 This is a schematic diagram of the structure of a CO2 displacement crude oil simulation device provided in another embodiment of this application;

[0044] Figure 3 This is a schematic diagram of the structure of a simulation component provided in one embodiment of this application;

[0045] Figure 4 This is a schematic diagram of the structure of a clamp provided in one embodiment of this application;

[0046] Figure 5 This is a schematic diagram of the structure of a gas-liquid separation component and a gas-liquid mixing component provided in one embodiment of this application;

[0047] Figure 6 This is a schematic diagram of the back pressure valve, metering bottle, and gas meter provided in one embodiment of this application;

[0048] Figure 7 This is a schematic diagram of the injection mechanism provided in one embodiment of this application.

[0049] Legend:

[0050] 1-Simulation mechanism 11-Simulation components

[0051] 111-Clamping device 1111-Cylinder body

[0052] 1112-Cover plate 1113-Inlet pipe

[0053] 11131 - Inlet flow meter; 11132 - Inlet pressure gauge

[0054] 1114-Outlet pipe; 11141-Outlet pressure gauge

[0055] 1115-Airbag Cover 11151-Inflation Port

[0056] 1116 - Locking screw; 112 - Gas-liquid separation assembly

[0057] 1121-Separation tube 1122-Gas delivery tube

[0058] 1123-Liquid delivery tube; 1124-First check valve

[0059] 1125 - Second check valve; 113 - Gas flow meter

[0060] 114-Liquid Flow Meter 115-Gas-Liquid Mixing Component

[0061] 1151 - Mixing pipe; 1152 - Converging pipe

[0062] 116-Boost pump 117-Connecting pipe

[0063] 12-Back pressure valve 13-Metering bottle

[0064] 14-Gas meter 15-First guide tube

[0065] 16-Second catheter 2-Injection mechanism

[0066] 21-First container 22-Second container

[0067] 23-First Piston 24-Second Piston

[0068] 25-First air injection pipe; 251-First control valve

[0069] 26-Second air injection pipe; 261-Second control valve

[0070] 27-Displacement pump 28-Discharge pipe

[0071] 281-Liquid outlet valve 29-Gas outlet pipe

[0072] 291 - Exhaust valve; 210 - Thermostatic chamber

[0073] 3-core Detailed Implementation

[0074] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of methods consistent with some aspects of this application as detailed in the appended claims.

[0075] CO2 enhanced oil recovery (EOR) is an innovative oilfield development technology that enhances oil recovery by injecting CO2 into the reservoir. CO2 EOR not only improves crude oil recovery but also locks up CO2 in underground reservoirs, reducing greenhouse gas emissions.

[0076] The core of CO2 enhanced oil recovery (EOR) technology is to inject CO2 into the oil reservoir. By reducing the viscosity of the crude oil and increasing the permeability of the reservoir, it improves the fluidity of the crude oil, thereby increasing the production of the oil well. At the same time, the injected CO2 reacts with the hydrocarbons in the crude oil to form a mixed phase, making the crude oil easier to extract.

[0077] In CO2 enhanced oil recovery (EOR), the injected CO2 is trapped underground, forming a long-term stable storage state. This method of CO2 trapping is more environmentally friendly and safer than releasing CO2 into the atmosphere. Furthermore, due to the complexity and diversity of oilfield geological conditions, CO2 EOR technology can employ different injection methods and parameters based on different reservoir types and characteristics to achieve more efficient and economical CO2 trapping.

[0078] Factors affecting CO2 enhanced oil recovery efficiency include: pressure ratio, effective formation thickness, formation depth, formation crude oil viscosity, surface crude oil density, residual oil saturation, reservoir temperature, porosity, and permeability.

[0079] CO2 displacement efficiency is closely related to the distance from the injection point. Areas closer to the injection point may have a better displacement effect, while areas farther away from the injection point may not have a sufficient displacement effect. However, the specific impact of the injection point distance on CO2 displacement efficiency is currently unclear.

[0080] Please refer to Figure 1 This illustrates a schematic diagram of a CO2-driven crude oil displacement simulation device provided in one embodiment of this application. Figure 1 As shown, the device may include a simulation mechanism 1 and an injection mechanism 2.

[0081] like Figure 2 As shown, the simulation mechanism 1 includes multiple simulation components 11, a back pressure valve 12, a metering bottle 13, a gas meter 14, a first conduit 15 and a second conduit 16, and adjacent simulation components 11 are connected by a connecting pipe 117.

[0082] The injection mechanism 2 is connected to the first of the multiple simulation components 11 via a conduit. The injection mechanism 2 is used to inject CO2 gas or crude oil into the multiple simulation components 11.

[0083] In some embodiments, multiple simulation components 11 are connected end-to-end via conduits. For example, each simulation component 11 before the last one has an inlet pipe 1113 at one end and a connecting pipe 117 at the other end. The connecting pipe 117 of each simulation component 11 is connected to the inlet pipe 1113 of the next simulation component 11. That is, the other end of the connecting pipe 117 of the first simulation component 11 is connected to the other end of the inlet pipe 1113 of the second simulation component 11, the other end of the connecting pipe 117 of the second simulation component 11 is connected to the other end of the inlet pipe 1113 of the third simulation component 11, the other end of the connecting pipe 117 of the third simulation component 11 is connected to the other end of the inlet pipe 1113 of the fourth simulation component 11, and so on, with the other end of the connecting pipe 117 of each simulation component 11 connected to the other end of the inlet pipe 1113 of the next simulation component 11. Figure 1 , 2 Only five simulation components 11 are shown in this embodiment. In other alternative embodiments, the number of simulation components 11 can be adjusted as needed.

[0084] In some embodiments, the other end of the outlet pipe 28 of the injection mechanism 2 is connected to the inlet pipe 1113 of the first simulation component 11, so that CO2 gas or crude oil can be injected into multiple simulation components 11 through the injection mechanism 2.

[0085] like Figure 3 As shown, the simulation component 11 includes a clamp 111, a gas-liquid separation component 112, a gas flow meter 113, a liquid flow meter 114, a gas-liquid mixing component 115, a booster pump 116, and a connecting pipe 117. The clamp 111, the gas-liquid separation component 112, the gas-liquid mixing component 115, and the booster pump 116 are connected sequentially through conduits. The gas flow meter 113 and the liquid flow meter 114 are mounted on the gas-liquid separation component 112.

[0086] In some embodiments, such as Figure 4As shown, the clamp 111 includes a cylinder 1111, a cover plate 1112, an inlet pipe 1113, an outlet pipe 1114, and an airbag sleeve 1115. The cylinder 1111 has a cylindrical inner cavity for inserting the core 3. One end of the cylinder 1111 is open, and the other end of the cylinder 1111 has a liquid outlet hole. The cover plate 1112 is used to cover the open end of the cylinder 1111. The cover plate 1112 has a liquid inlet hole, and one end of the inlet pipe 1113 is connected to the liquid inlet hole. One end of the outlet pipe 1114 is connected to the liquid outlet hole. The airbag sleeve 1115 is built inside the cylinder 1111 and is used to be fitted onto the core 3. An inflation port 11151 is formed on the airbag sleeve 1115, which is connected to the inner cavity of the airbag sleeve 1115.

[0087] In some embodiments, the clamp 111 is used as follows: first, open the cover plate 1112, then put the core 3 into the cylinder 1111 and let the core 3 pass through the airbag sleeve 1115, then cover the cover plate 1112 and fix it with multiple locking screws 1116, then connect the inflation port 11151 to the outlet of the air pump (not shown), and inflate the airbag sleeve 1115 with the air pump, so that the airbag sleeve 1115 can apply confining pressure to the core 3 to simulate the confining pressure of the underground reservoir.

[0088] In some embodiments, such as Figure 4 As shown, the clamp 111 also includes at least one locking screw 1116. The cover plate 1112 is detachably connected to the cylinder 1111 by at least one locking screw 1116, thereby facilitating the removal and installation of the core 3 and preventing the core 3 from falling out of the clamp 111.

[0089] In some embodiments, the number of locking screws 1116 can be 4, 5, 6, 8, etc. The specific number of locking screws 1116 can be set by relevant technicians according to the actual situation, and this application embodiment does not specifically limit it.

[0090] In some embodiments, such as Figure 3 As shown, the clamp 111 also includes an inlet flow meter 11131, an inlet pressure gauge 11132, and an outlet pressure gauge 11141; wherein, the inlet flow meter 11131 and the inlet pressure gauge 11132 are installed on the inlet pipe 1113; and the outlet pressure gauge 11141 is installed on the outlet pipe 1114.

[0091] In some embodiments, the inlet flow meter 11131 is used to measure the flow rate of the liquid flowing through the inlet pipe 1113, the inlet pressure gauge 11132 is used to measure the pressure of the liquid flowing through the inlet pipe 1113, and the outlet pressure gauge 11141 is used to measure the pressure of the liquid flowing through the outlet pipe 1114.

[0092] In some embodiments, such as Figure 5 As shown, the gas-liquid separation assembly 112 includes a separation tube 1121, a gas guide tube 1122, and a liquid guide tube 1123. The separation tube 1121 is vertically arranged, and a first through hole is formed on the side wall of the separation tube 1121. The first through hole is connected to one end of the outlet tube 1114 of the clamp. The upper end of the separation tube 1121 is connected to one end of the gas guide tube 1122, and the lower end of the separation tube 1121 is connected to one end of the liquid guide tube 1123. A first one-way valve 1124 is provided on the gas guide tube 1122, and a second one-way valve 1125 is provided on the liquid guide tube 1123.

[0093] In some embodiments, a first perforation is provided on the side wall of the separator 1121, which communicates with the other end of the outlet pipe 1114. The separator 1121 is vertically arranged, with its upper end connected to one end of the gas guide pipe 1122 and its lower end connected to one end of the liquid guide pipe 1123. In some embodiments, a first one-way valve 1124 is provided on the gas guide pipe 1122, and a second one-way valve 1125 is provided on the liquid guide pipe 1123 to prevent reverse flow of fluid. That is, the first one-way valve 1124 is used to prevent gas from flowing in the opposite direction to the separator, and the second one-way valve 1125 is used to prevent fluid from flowing in the opposite direction to the separator.

[0094] In some embodiments, the working principle of the gas-liquid separation component 112 is as follows: after the gas-liquid mixture enters the separation pipe 1121, under the action of gravity, the liquid in the gas-liquid mixture descends and enters the liquid guide pipe 1123, while the gas in the gas-liquid mixture rises and enters the gas guide pipe 1122, thereby realizing the function of gas-liquid separation.

[0095] In some embodiments, the length of the separation tube 1121 is greater than or equal to a first length threshold. In some embodiments, the length of the separation tube 1121 can be 20 cm, 30 cm, 40 cm, etc. Of course, the length of the separation tube 1121 can also have other values. The specific length of the separation tube 1121 can be set by relevant technicians according to the actual situation. This application embodiment does not make specific limitations in this regard.

[0096] In some embodiments, such as Figure 5 As shown, the gas flow meter 113 is installed on the gas guide pipe 1122, and the liquid flow meter 114 is installed on the liquid guide pipe 1123.

[0097] In some embodiments, on the gas delivery pipe 1122, the gas flow meter 113 is located closer to the end of the gas delivery pipe 1122 that connects to the separator pipe 1121, compared to the first one-way valve 1124. On the liquid delivery pipe 1123, the liquid flow meter 114 is located closer to the end of the liquid delivery pipe 1123 that connects to the separator pipe 1121, compared to the second one-way valve 1125. This improves the accuracy of the measurement results from the gas flow meter 113 and the liquid flow meter 114.

[0098] In some embodiments, such as Figure 5 As shown, the gas-liquid mixing assembly 115 includes a mixing pipe 1151 and a converging pipe 1152; wherein, the upper end of the mixing pipe 1151 is connected to the other end of the gas guiding pipe 1122, the lower end of the mixing pipe 1151 is connected to the other end of the liquid guiding pipe 1123, a second perforation is provided on the side wall of the mixing pipe 1151, and one end of the converging pipe 1152 is connected to the second perforation.

[0099] In some embodiments, such as Figure 3 As shown, the inlet of the booster pump 116 is connected to the other end of the manifold 1152.

[0100] In some embodiments, the booster pump 116 is used to compensate for the pressure drop caused by the gas-liquid separation assembly 112 and the gas-liquid mixing assembly 115. Specifically, the pressure at the outlet of the booster pump 116 should be approximately equal to the pressure of the corresponding outlet pressure gauge 11141.

[0101] In some embodiments, one end of the connecting pipe 117 is connected to the outlet of the booster pump 116. The connecting pipe 117 is used to connect two adjacent simulation components 11, allowing fluid to flow between multiple simulation components 11.

[0102] like Figure 2 As shown, the last simulation component 11 among the multiple simulation components 11 includes only a clamp 111. The outlet pipe 1114 of the clamp 111 of the last simulation component 11 is connected to the inlet of the back pressure valve 12. The metering bottle 13 is connected to the outlet of the back pressure valve 12 via the first conduit 15. The inlet of the gas meter 14 is connected to the metering bottle 13 via the second conduit 16.

[0103] In some embodiments, such as Figure 6 As shown, the last simulation component 11 only includes the clamp 111, and does not include the gas-liquid separation component 112, gas flow meter 113, liquid flow meter 114, gas-liquid mixing component 115, booster pump 116, or connecting pipe 117.

[0104] In some embodiments, during use, after the gas-liquid mixture is discharged from the outlet of the back pressure valve 12, it enters the metering bottle 13 via the first conduit 15. The liquid accumulates in the metering bottle 13, and the gas enters the gas meter 14 via the second conduit 16. Therefore, the metering bottle 13 can measure the liquid volume, while the gas meter 14 can measure the gas volume. In some embodiments, the back pressure valve 12 is used to maintain the pressure inside the pipeline.

[0105] In some embodiments, such as Figure 7 As shown, the injection mechanism 2 includes a first container 21, a second container 22, a first piston 23, a second piston 24, a first gas injection pipe 25, a second gas injection pipe 26, a displacement pump 27, a liquid outlet pipe 28, a gas outlet pipe 29, and a constant temperature chamber 210. The first piston 23 is slidably and sealed within the first container 21, dividing the first container 21 into a first upper cavity and a first lower cavity, the first upper cavity being used to hold crude oil. The second piston 24 is slidably and sealed within the second container 22, dividing the second container 22 into a second upper cavity and a second lower cavity, the second upper cavity being used to hold CO2 gas. One end of the first gas injection pipe 25 is connected to the outlet of the displacement pump 27, and the other end of the first gas injection pipe 25 is connected to the first lower cavity. A first control valve is provided on the first gas injection pipe 25. Valve 251; one end of the second air injection pipe 26 is connected to the outlet of the displacement pump 27, and the other end of the second air injection pipe 26 is connected to the second lower accommodating cavity. A second control valve 261 is provided on the second air injection pipe 26; one end of the liquid outlet pipe 28 is connected to the first upper accommodating cavity, and the other end of the liquid outlet pipe 28 is connected to the other end of the inlet pipe 1113 of the first simulation component 11. A liquid outlet valve 281 is provided on the liquid outlet pipe 28; one end of the air outlet pipe 29 is connected to the second upper accommodating cavity, and the other end of the air outlet pipe 29 is connected to the other end of the inlet pipe 1113 of the first simulation component 11. An air outlet valve 291 is provided on the air outlet pipe 29; the first container 21 and the second container 22 are both placed in a constant temperature chamber 210. The constant temperature chamber 210 is used to make the fluid temperature in the first container 21 and the second container 22 reach the formation temperature.

[0106] In some embodiments, the constant temperature chamber 210 can be heated to the formation temperature, thereby causing the fluid temperature in the first container 21 and the second container 22 to reach the formation temperature.

[0107] In some embodiments, when crude oil needs to be injected, the first control valve 251 and the liquid outlet valve 281 are opened, the second control valve 261 and the gas outlet valve 291 are closed, and then the displacement pump 27 is turned on. The displacement pump 27 fills the first lower receiving chamber with gas, thereby pushing the first piston 23 upward. The first piston 23 pushes the crude oil in the first upper receiving chamber into the inlet pipe 1113 of the first simulation component 11, thereby entering each simulation component 11 in sequence. When CO2 gas needs to be injected, the second control valve 261 and the gas outlet valve 291 are opened, the first control valve 251 and the liquid outlet valve 281 are closed, and then the displacement pump 27 is turned on. The displacement pump 27 fills the second lower receiving chamber with gas, thereby pushing the second piston 24 upward. The second piston 24 pushes the CO2 gas in the second upper receiving chamber into the inlet pipe 1113 of the first simulation component 11, thereby entering each simulation component 11 in sequence.

[0108] In summary, the technical solution provided in this application provides a method by setting up multiple simulation components 11 connected in sequence. Each simulation component 11 includes a clamp 111, a gas-liquid separation component 112, a gas flow meter 113, a liquid flow meter 114, a gas-liquid mixing component 115, a booster pump 116, and a connecting pipe 117. The clamp 111 is used to clamp the core 3. The gas-liquid separation component 112 is used to separate the CO2 gas discharged from the core 3 from the crude oil, so that the volume of crude oil discharged from the core 3 can be measured by the liquid flow meter 114. The gas-liquid mixing component 115 then mixes the CO2 gas with the crude oil, pressurizes it, and discharges it into the next simulation component 11. In this way, the volume of crude oil discharged from the core 3 can be measured by the liquid flow meter 114 of each simulation component 11, so that the volume of crude oil discharged from each core 3 can be quantitatively measured, and the oil displacement efficiency of each core 3 can be obtained, thus improving the accuracy of the measured CO2 oil displacement efficiency of each core.

[0109] In some implementations, the carbon dioxide displacement crude oil simulation device is used as follows:

[0110] 1. Dry multiple core samples 3 of the same length, volume, and lithology at 105℃ for 24 hours, and then test the porosity, permeability, density, and other parameters of each core sample 3 to ensure that the porosity, permeability, density, and other parameters of each core sample 3 are approximately the same.

[0111] 2. Vacuum each core sample 3, saturate it with a mineralization of 40000 mg / L to simulate formation water for 24 hours, then pressurize it to 20 MPa for 8 hours.

[0112] 3. After the water is saturated, each core 3 is put into each clamp 111. The air inlet 11151 of each clamp 111 is connected to an air pump. The air pump inflates each air bladder 1115, and the air bladder 1115 squeezes the core 3 to simulate the confining pressure on the core 3.

[0113] 4. Inject crude oil into each simulation component 11. Specifically, open the first control valve 251 and the liquid outlet valve 281, close the second control valve 261 and the gas outlet valve 291, and then turn on the displacement pump 27. The displacement pump 27 fills the first lower receiving chamber with gas, thereby pushing the first piston 23 upward. The first piston 23 pushes the crude oil in the first upper receiving chamber into the inlet pipe 1113 of the first simulation component 11. The crude oil enters the cylinder 1111 of the first simulation component 11 through the inlet pipe 1113, passes through the first core 3 and displaces the water in the core 3. The mixture of crude oil and the displaced water exits from the outlet pipe 1111 of the first simulation component 11. The water is discharged from 114 and then sequentially enters the separation pipe 1121, the guide pipe 1123, the mixing pipe 1151, the converging pipe 1152 and the booster pump 116. Then it enters the inlet pipe 1113 of the second simulation component 11 through the connecting pipe 117. It enters each simulation component 11 in sequence, and then is discharged from the back pressure valve 12 and enters the metering bottle 13. After a period of time, the volume of water and crude oil collected in the metering bottle 13 is observed (water and crude oil will be separated by density). When the volume of water no longer increases, it indicates that the oil-water displacement process has reached its limit, and the displacement pump 27 is stopped. At this time, the pores of the core 3 in each cylinder 1111 contain only a small amount of bound water and a large amount of crude oil.

[0114] In some embodiments, the total crude oil volume Voil in each core 3 can be calculated using the following formula (1).

[0115]

[0116] Wherein, Vin1 is the total volume of crude oil entering as detected by the inlet flow meter 11131 of the first simulation component 11, Vout1 is the total volume of crude oil collected in the metering bottle 13, Vpipeline is the volume of all pipelines between the inlet flow meter 11131 of the first simulation component 11 and the metering bottle 13, which can be measured in advance, and n is the number of cores 3.

[0117] The principle of the above formula (1) is as follows: Since each core 3 can be regarded as completely identical, the crude oil volume in each core 3 should be equal. The total volume of crude oil entering detected by the inlet flow meter 11131 of the first simulation component 11 minus the total volume of crude oil collected in the metering bottle 13 is the volume of crude oil reduced. The volume of crude oil reduced is distributed in two locations: one is in each core 3, and the other is in the pipeline. Therefore, subtracting the total volume in the pipeline gives the crude oil volume in the core 3. Dividing by the number of cores 3 gives the crude oil volume in each core 3.

[0118] 5. Inject CO2 gas into each simulation component 11. The specific process is as follows: Empty the metering bottle 13, open the second control valve 261 and the gas outlet valve 291, close the first control valve 251 and the liquid outlet valve 281, and then turn on the displacement pump 27; the displacement pump 27 fills the second lower receiving chamber with gas, thereby pushing the second piston 24 upward, and the second piston 24 pushes the CO2 gas in the second upper receiving chamber to the inlet pipe 1113 of the first simulation component 11; the CO2 gas enters the cylinder 1111 of the first simulation component 11 through the inlet pipe 1113, passes through the first core 3 and displaces the crude oil in the core 3, and the mixture of CO2 gas and the displaced crude oil is discharged from the outlet pipe 1114 of the first simulation component 11 and then enters the separation pipe 1121; in the separation pipe 1121, CO2 The gas and crude oil separate. The crude oil flows downward through the liquid guide pipe 1123 into the mixing pipe 1151, while the CO2 gas flows through the gas guide pipe 1122 into the mixing pipe 1151. Finally, the two converge and mix in the converging pipe 1152. The gas-liquid mixture then enters the booster pump 116 and then enters the inlet pipe 1113 of the second simulation component 11 through the connecting pipe 117. This process continues, entering each simulation component 11 in sequence. Afterward, the mixture is discharged from the back pressure valve 12 and then enters the metering bottle 13, where the crude oil is collected. The CO2 gas enters the gas meter 14 through the second conduit 16. After a period of time, the volume of crude oil collected in the metering bottle 13 is observed. When the volume of crude oil no longer increases, it indicates that the CO2 displacement of crude oil has reached its limit, and the displacement pump 27 is stopped.

[0119] The volume of crude oil displaced by CO2 gas in each core 3, Voil_drive_i, can be calculated using the following formula (2).

[0120] Voil_drive_i = V_out_i – V_out_i-1 – V_pipe_i (2)

[0121] Wherein, Voil_drive_i is the volume of crude oil displaced by the i-th core, V_out_i is the volume of crude oil measured by the liquid flow meter 114 corresponding to the i-th core, V_out_i-1 is the volume of crude oil measured by the liquid flow meter 114 corresponding to the (i-1)-th core, and V_pipe_i is the volume of the pipe between the liquid flow meter 114 corresponding to the i-th core and the liquid flow meter 114 corresponding to the (i-1)-th core.

[0122] The calculation formula (3) for the volume of crude oil displaced by CO2 gas in the first core, Voil_drive1, is as follows.

[0123] Voil drive 1 = V outlet 1 – V pipe 1 (3)

[0124] Wherein, Voil_drive1 is the volume of crude oil displaced by the first core, V_out1 is the volume of crude oil measured by the liquid flow meter 114 corresponding to the first core, and V_pipeline1 is the volume of the pipeline between the liquid flow meter 114 corresponding to the first core and the gas outlet pipe 29.

[0125] The principle of the above formula (3) is: the difference in crude oil volume measured by two adjacent liquid flow meters 114 should be the sum of the crude oil displaced by the next core and the volume of the pipe between the two adjacent liquid flow meters 114. Therefore, subtracting the volume of the pipe between the two adjacent liquid flow meters 114 gives the volume of crude oil displaced by the next core.

[0126] Therefore, the calculation formula (4) for the oil displacement efficiency Ei of each core 3 is as follows.

[0127] Ei = Voil_drive_i / Voil_total (4)

[0128] Where Ei is the oil displacement efficiency of the i-th core, Voil_displaced_i is the volume of crude oil displaced from the i-th core, and Voil_total is the total volume of crude oil in each core.

[0129] 6. Compare the oil displacement efficiency of each core 3 to determine the specific impact of the injection point distance on the CO2 oil displacement efficiency.

[0130] This application embodiment obtains the crude oil volume discharged from each core 3 quantitatively, thereby obtaining the oil displacement efficiency of each core 3, and thus studying the specific impact of injection point distance on CO2 oil displacement efficiency. This solves the problem that existing long core displacement experiments cannot quantitatively obtain the CO2 oil displacement efficiency of each core, thus helping to analyze the specific impact of injection point distance on CO2 oil displacement efficiency.

[0131] It should be understood that "multiple" as used in this article refers to two or more.

[0132] The above description is merely an exemplary embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A carbon dioxide displacement crude oil simulation device, characterized in that, The device includes a simulation mechanism and an injection mechanism; wherein... The simulation mechanism includes multiple simulation components, a back pressure valve, a metering bottle, a gas meter, a first conduit, and a second conduit, with adjacent simulation components connected by a connecting pipe. The injection mechanism is connected to the first of the plurality of simulation components via a conduit, and the injection mechanism is used to inject CO2 gas or crude oil into the plurality of simulation components; The simulation component includes a clamp, a gas-liquid separation component, a gas flow meter, a liquid flow meter, a gas-liquid mixing component, a booster pump, and the connecting pipe. The clamp, the gas-liquid separation component, the gas-liquid mixing component, and the booster pump are sequentially connected through conduits. The gas flow meter and the liquid flow meter are mounted on the gas-liquid separation component. The last of the plurality of simulation components includes only the clamp, the outlet pipe of the clamp of the last simulation component is connected to the inlet of the back pressure valve, the metering bottle is connected to the outlet of the back pressure valve via the first conduit, and the inlet of the gas meter is connected to the metering bottle via the second conduit.

2. The apparatus according to claim 1, characterized in that, The clamp includes a cylinder, a cover plate, an inlet pipe, an outlet pipe, and an airbag sleeve; The cylinder has a cylindrical inner cavity for inserting the rock core, one end of the cylinder is open, and the other end of the cylinder has a liquid outlet hole. The cover plate is used to cover one end of the opening of the cylinder; The cover plate has a liquid inlet hole, and one end of the inlet pipe is connected to the liquid inlet hole; One end of the outlet pipe is connected to the liquid outlet hole; The airbag sleeve is built into the cylinder and is used to fit onto the rock core. An inflation port is formed on the airbag sleeve, which is connected to the inner cavity of the airbag sleeve.

3. The apparatus according to claim 2, characterized in that, The clamp also includes at least one locking screw, and the cover plate is detachably connected to the cylinder via the at least one locking screw.

4. The apparatus according to claim 2, characterized in that, The clamp also includes an inlet flow meter, an inlet pressure gauge, and an outlet pressure gauge; wherein... The inlet flow meter and the inlet pressure gauge are installed on the inlet pipe; The liquid outlet pressure gauge is installed on the outlet pipe.

5. The apparatus according to claim 1, characterized in that, The injection mechanism includes a first container, a second container, a first piston, a second piston, a first air injection pipe, a second air injection pipe, a displacement pump, a liquid outlet pipe, an air outlet pipe, and a constant temperature chamber; wherein, The first piston seal is slidably disposed inside the first container and divides the first container into a first upper receiving cavity and a first lower receiving cavity, the first upper receiving cavity being used to hold crude oil; The second piston is slidably disposed within the second container and divides the second container into a second upper receiving chamber and a second lower receiving chamber. The second upper receiving chamber is used to hold the CO2 gas. One end of the first air injection pipe is connected to the outlet of the displacement pump, and the other end of the first air injection pipe is connected to the first lower receiving cavity. A first control valve is provided on the first air injection pipe. One end of the second air injection pipe is connected to the outlet of the displacement pump, and the other end of the second air injection pipe is connected to the second lower receiving cavity. A second control valve is provided on the second air injection pipe. One end of the liquid outlet pipe is connected to the first upper accommodating cavity, and the other end of the liquid outlet pipe is connected to the other end of the inlet pipe of the first simulation component. A liquid outlet valve is provided on the liquid outlet pipe. One end of the vent pipe is connected to the second upper accommodating cavity, and the other end of the vent pipe is connected to the other end of the inlet pipe of the first simulation component. An vent valve is provided on the vent pipe. Both the first container and the second container are placed inside the constant temperature chamber, which is used to bring the fluid temperature in the first container and the second container up to the formation temperature.

6. The apparatus according to claim 1, characterized in that, The gas-liquid separation assembly includes a separation tube, a gas guide tube, and a liquid guide tube; wherein... The separation tube is vertically arranged, and a first through hole is provided on the side wall of the separation tube. The first through hole is connected to one end of the outlet tube of the clamp. The upper end of the separation tube is connected to one end of the gas guide tube, and the lower end of the separation tube is connected to one end of the liquid guide tube. A first check valve is provided on the air duct; A second one-way valve is installed on the liquid guide tube.

7. The apparatus according to claim 6, characterized in that, The gas flow meter is installed on the gas guide pipe, and the liquid flow meter is installed on the liquid guide pipe.

8. The apparatus according to claim 6, characterized in that, The gas-liquid mixing assembly includes a mixing pipe and a converging pipe; wherein... The upper end of the mixing tube is connected to the other end of the gas guiding tube, the lower end of the mixing tube is connected to the other end of the liquid guiding tube, a second perforation is provided on the side wall of the mixing tube, and one end of the converging tube is connected to the second perforation.

9. The apparatus according to claim 8, characterized in that, The inlet of the booster pump is connected to the other end of the converging pipe.

10. The apparatus according to any one of claims 1 to 9, characterized in that, One end of the connecting pipe is connected to the outlet of the booster pump.

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