High temperature and high pressure supercritical carbon dioxide imbibition experimental device for shale core

Abstract

This invention discloses a high-temperature, high-pressure supercritical carbon dioxide percolation experimental apparatus for shale core samples, relating to the field of shale oil development technology. The apparatus includes a CNC housing and a high-temperature, high-pressure percolation reactor; a weighing mechanism is installed at the bottom center of the reactor. Through the coordinated operation of the high-temperature, high-pressure percolation reactor, intermediate container, gas filling mechanism, high-pressure plunger pump, gas supply mechanism, heating resistor, and insulation shell, the high-pressure plunger pump precisely regulates the system pressure, ensuring high accuracy of the experimental pressure conditions. The heating resistor creates the required high-temperature environment inside the percolation reactor. These two components work together with the high-temperature, high-pressure percolation reactor to simulate a high-temperature, high-pressure reservoir environment, covering the high-temperature, high-pressure conditions required for shale oil development. The experimental adjustment range is large, allowing for accurate measurement of the supercritical carbon dioxide percolation oil recovery efficiency under different temperature and pressure conditions, ensuring the authenticity and reliability of the experimental simulation results.

Description

Technical Field

[0001] This invention relates to the field of shale oil development technology, specifically to a high-temperature, high-pressure supercritical carbon dioxide percolation experimental apparatus for shale core samples. Background Technology

[0002] The effective development of shale oil still faces many problems and challenges. Shale is a low-porosity and low-permeability reservoir, and common water-drive development methods cannot achieve good results. In addition, my country's shale oil has high viscosity and poor mobility. The lithology of shale oil-rich strata is weak, with high clay mineral content and high water sensitivity. Although the shale strata have the best oil-bearing properties, they are thin and have high soluble salt content. The crystallization of soluble salts can easily clog the wellbore. These are all important factors restricting the development of shale oil in my country.

[0003] Chinese patent CN209432826U discloses a visual automatic percolation test device for shale cores. This device solves the problem of core shaking in the initial testing phase by connecting the core with a rigid rod and slowly adding water into a container until the liquid surface contacts the core. A flexible seal above the core prevents water evaporation and frictional resistance from affecting the balance's weighing, allowing for direct and accurate real-time measurement of core percolation. It accurately measures the percolation characteristics during the contact process between the core and the liquid surface, addressing the limitation of traditional percolation experiments in measuring initial percolation. The device automatically monitors various phenomena on the core surface in real time and collects data to determine whether the percolation process is unidirectional or counter-directional.

[0004] Existing experimental setups have a narrow range of temperature and pressure regulation during use. The temperature range they can achieve is usually insufficient to cover the high-temperature environment of actual shale oil development formations, and the pressure conditions they can provide are far lower than the high-pressure conditions of the formations on site. They cannot reproduce the real state of crude oil viscosity changes and supercritical carbon dioxide dissolution characteristics under high formation temperatures, nor can they simulate the actual performance of shale reservoir pore structure and fluid seepage laws under high pressure, resulting in insufficient realism in experimental simulations. Summary of the Invention

[0005] The purpose of this invention is to provide a high-temperature and high-pressure supercritical carbon dioxide percolation experimental device for shale cores, so as to solve the problem that the existing technology cannot simulate the high-temperature and high-pressure formation environment during actual shale oil development.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a high-temperature and high-pressure supercritical carbon dioxide percolation experimental device for shale cores, comprising a CNC housing and a high-temperature and high-pressure percolation reactor;

[0007] A weighing mechanism is installed at the bottom center of the high-temperature and high-pressure percolation reactor;

[0008] The intermediate container is vertically installed between the middle of the top inner wall and the middle of the bottom inner wall of the CNC housing;

[0009] An inflation mechanism is installed between the top of the intermediate container and the high-temperature and high-pressure percolation reactor;

[0010] A high-pressure plunger pump is installed on the right side of the bottom inner wall of the CNC housing. The air inlet end of the high-pressure plunger pump is equipped with an air extraction pipe, and the other end of the air extraction pipe is installed on the lower side of the outer wall of the intermediate container. The air outlet end of the high-pressure plunger pump is equipped with an air venting pipe, and the other end of the air venting pipe is installed on the middle side of the outer wall of the intermediate container.

[0011] The air supply mechanism is installed on the left side of the bottom inner wall of the CNC housing;

[0012] A heating resistor is installed in the middle of the outer wall of the high-temperature and high-pressure percolation reactor;

[0013] The heat-insulating shell is installed on the outer wall of the high-temperature and high-pressure percolation reactor, and the heat-insulating shell is sleeved on the outer surface of the heating resistor.

[0014] Furthermore, the interior of the high-temperature and high-pressure percolation reactor is optionally equipped with a first core percolation chamber or a second core percolation chamber. The interior of the first core percolation chamber and the second core percolation chamber are each provided with multiple core cavities, and core samples are placed inside the multiple core cavities.

[0015] Furthermore, the high-temperature and high-pressure percolation reactor includes a percolation reactor body and a percolation reactor cover. The percolation reactor cover is installed on the top of the percolation reactor body, and the percolation reactor cover and the percolation reactor body are connected by a flange seal.

[0016] Furthermore, the weighing mechanism includes a flexible and rigid pipe connector, multiple discharge pipes, multiple tension sensing hoses, multiple oil absorption collection pipes, and multiple oil drain pipes. The multiple discharge pipes are all installed at the top of the flexible and rigid pipe connector and are embedded in the bottom of the absorption vessel body. The multiple tension sensing hoses are respectively installed at the bottom of the multiple discharge pipes. The multiple oil absorption collection pipes are respectively installed at the bottom of the multiple tension sensing hoses. The multiple oil drain pipes are respectively installed at the middle of the bottom of the multiple oil absorption collection pipes.

[0017] Furthermore, the inflation mechanism includes an inflation pipe, an inflation valve, a diversion pipe, and multiple inflation pipes. One end of the inflation pipe penetrates the top inner wall of the CNC housing and is installed at the top of the intermediate container through a sealing joint. The inflation valve is located on the lower side of the outer wall of the inflation pipe. The diversion pipe is installed at the other end of the inflation pipe. All the multiple inflation pipes are installed at the bottom end of the diversion pipe, and all the multiple inflation pipes are embedded in the top of the percolation reactor lid.

[0018] Furthermore, the gas supply mechanism includes a gas cylinder base, multiple gas cylinder slots, multiple carbon dioxide cylinders, multiple gas cylinder valves, multiple connecting pipes, and a gas collecting pipe. The gas cylinder base is installed on the left side of the bottom inner wall of the CNC housing. The multiple gas cylinder slots are all opened at the top of the gas cylinder base. The multiple carbon dioxide cylinders are respectively placed inside the multiple gas cylinder slots. The multiple gas cylinder valves are respectively set at the top of the multiple carbon dioxide cylinders. The multiple connecting pipes are respectively installed on the multiple gas cylinder valves. The gas collecting pipe is installed between the other ends of the multiple connecting pipes and is installed on the upper side of the outer wall of the intermediate container.

[0019] Furthermore, a sealed door is installed in the middle of the outer wall of the CNC housing via a hinge, a controller is installed in the middle of the outer wall of the sealed door, and multiple support feet are installed around the bottom of the high-temperature and high-pressure percolation reactor.

[0020] Furthermore, both the first and second core permeation chambers are made of titanium alloy, the intermediate container is made of high-strength pressure-resistant glass or Hastelloy, the heating resistor is a ring-shaped armored heating element, and the insulation shell is a composite structure of double-layer aluminum silicate insulation cotton and stainless steel shell.

[0021] Furthermore, the upper inner wall of the discharge pipe is configured as a funnel structure, the oil absorption collection pipe is made of transparent borosilicate glass, valves are provided on the upper part of the oil discharge pipe and the lower part of the outer surface of the discharge pipe, and the bottom end of the oil discharge pipe is higher than the bottom end of the CNC box. The tension sensing hose has a built-in high-precision tension sensor.

[0022] Furthermore, the gas cylinder valve is configured as a solenoid valve, a quick connector is provided at the connection between the connecting pipe and the gas cylinder valve, a one-way valve is provided on the gas collecting pipe, and an ultra-high pressure hose is used for the gas delivery pipe.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] (1) This invention utilizes the coordinated operation of a high-temperature and high-pressure percolation vessel, an intermediate container, an air filling mechanism, a high-pressure plunger pump, an air supply mechanism, a heating resistor, and an insulation shell. The high-pressure plunger pump can precisely adjust the system pressure to ensure the high accuracy of the experimental pressure conditions. The heating resistor creates the required high-temperature environment inside the percolation vessel. The two components work together with the high-temperature and high-pressure percolation vessel to simulate the high-temperature and high-pressure reservoir environment, covering the high-temperature and high-pressure conditions required for shale oil development. The experimental adjustment range is large, and the percolation efficiency of supercritical carbon dioxide under different temperature and pressure conditions can be accurately measured, ensuring the authenticity and reliability of the experimental simulation results.

[0025] (2) Through the coordinated work of the first core permeation chamber, the second core permeation chamber, the core cavity and the weighing mechanism, the first core permeation chamber and the second core permeation chamber can simultaneously carry out the permeation process on multiple core samples, and the core samples do not interfere with each other, effectively avoiding the generation of experimental errors and greatly improving experimental efficiency. The weighing mechanism can automatically measure the mass of shale oil obtained by carbon dioxide fluid permeation according to the change of tension, and then calculate the recovery rate of supercritical carbon dioxide permeation.

[0026] (3) The present invention integrates multiple devices into the CNC housing through the collaborative work of the CNC housing and the controller, which facilitates circuit planning, improves safety, greatly reduces the size of the experimental device, facilitates transportation and layout, and is more aesthetically pleasing. In addition, the controller enables the entire experimental device to have automatic data acquisition and automatic calculation output functions, which significantly improves the automation level of the experimental device. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0028] Figure 1 This is a schematic diagram of the overall structure provided for an embodiment of the present invention;

[0029] Figure 2 A structural cross-sectional view of the CNC housing is provided for embodiments of the present invention;

[0030] Figure 3 A schematic diagram of the gas supply mechanism is provided for embodiments of the present invention;

[0031] Figure 4 A structural cross-sectional view of a high-temperature and high-pressure percolation reactor is provided for embodiments of the present invention;

[0032] Figure 5 A schematic diagram of the structure of the first core permeation chamber is provided for an embodiment of the present invention;

[0033] Figure 6 A schematic diagram of the structure of the second core permeation chamber is provided for an embodiment of the present invention;

[0034] Figure 7 A schematic diagram of the inflation mechanism is provided for embodiments of the present invention;

[0035] Figure 8 A structural schematic diagram of the weighing mechanism is provided for an embodiment of the present invention.

[0036] Explanation of reference numerals in the attached figures:

[0037] 1. CNC housing; 2. High-temperature and high-pressure percolation reactor; 3. Weighing mechanism; 4. Intermediate container; 5. Gas filling mechanism; 6. High-pressure plunger pump; 7. Gas supply mechanism; 8. Sealed door; 9. Controller; 10. Support legs; 11. First core percolation chamber; 12. Second core percolation chamber; 13. Core cavity; 14. Core sample; 15. Heating resistor; 16. Insulated outer shell; 21. Percolation reactor body; 22. 31. Percolation reactor lid; 32. Flexible and rigid pipe connectors; 33. Discharge pipe; 34. Tensile sensing hose; 35. Percolation oil collection pipe; 56. Oil discharge pipe; 57. Gas supply pipe; 58. Gas filling valve; 59. Diverter pipe; 50. Gas filling pipe; 61. Gas extraction pipe; 62. Gas release pipe; 71. Gas cylinder holder; 72. Gas cylinder trough; 73. Carbon dioxide gas cylinder; 74. Gas cylinder valve; 75. Connecting pipe; 76. Gas collection pipe. Detailed Implementation

[0038] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0039] As attached Figure 1 To be continued Figure 8 As shown:

[0040] Example 1:

[0041] This invention provides a high-temperature and high-pressure supercritical carbon dioxide percolation experimental device for shale cores, including a CNC housing 1 and a high-temperature and high-pressure percolation vessel 2. The CNC housing 1 is made of 304 stainless steel and welded together. It has a reserved equipment installation cavity and a wiring storage channel inside, and an information acquisition card is installed inside the CNC housing 1.

[0042] Weighing mechanism 3 is installed at the bottom center of the high temperature and high pressure seepage reactor 2. It is used to measure the mass of shale oil carried by supercritical carbon dioxide in real time, providing accurate data support for subsequent recovery rate calculation.

[0043] The intermediate container 4 is vertically installed between the middle of the top inner wall and the middle of the bottom inner wall of the CNC housing 1, and is used to accurately transport the high-pressure carbon dioxide fluid in the intermediate container 4 to the high-temperature and high-pressure percolation reactor 2.

[0044] The inflation mechanism 5 is installed between the top of the intermediate container 4 and the high-temperature and high-pressure percolation reactor 2;

[0045] A high-pressure plunger pump 6 is installed on the right side of the bottom inner wall of the CNC housing 1. The air inlet end of the high-pressure plunger pump 6 is equipped with an air extraction pipe 61, and the other end of the air extraction pipe 61 is installed on the lower side of the outer wall of the intermediate container 4. The air outlet end of the high-pressure plunger pump 6 is equipped with an air vent pipe 62, and the other end of the air vent pipe 62 is installed on the middle side of the outer wall of the intermediate container 4. Both the air extraction pipe 61 and the air vent pipe 62 are made of high-pressure stainless steel corrugated pipe.

[0046] The gas supply mechanism 7 is installed on the left side of the bottom inner wall of the CNC housing 1, providing a high-purity carbon dioxide gas source for the device to meet the gas source requirements of the supercritical carbon dioxide percolation experiment.

[0047] Heating resistor 15 is installed in the middle of the outer wall of the high temperature and high pressure percolation reactor 2. It adopts a segmented winding and fixing method to fit tightly with the outer wall of the percolation reactor, ensuring uniform heating.

[0048] The heat insulation shell 16 is installed on the outer wall of the high temperature and high pressure percolation vessel 2, and the heat insulation shell 16 is fitted on the outer surface of the heating resistor 15. The heating resistor 15 and the heat insulation shell 16 integrate a PID temperature control component with self-tuning function, which generates heat when powered on and can adjust and control the temperature by input parameters.

[0049] The high-temperature and high-pressure permeation vessel 2 has either a first core permeation chamber 11 or a second core permeation chamber 12 installed inside. The first core permeation chamber 11 and the second core permeation chamber 12 each have multiple core cavities 13, and core samples 14 are placed inside the multiple core cavities 13.

[0050] The high-temperature and high-pressure percolation reactor 2 includes a percolation reactor body 21 and a percolation reactor cover 22. The percolation reactor cover 22 is installed on the top of the percolation reactor body 21. The percolation reactor body 21 is made of forged 316L stainless steel, which can simulate the high-temperature and high-pressure environment of shale oil reservoirs. The percolation reactor cover 22 and the percolation reactor body 21 are connected by a flange seal. A copper sealing gasket is set at the flange connection to ensure high-pressure sealing performance. Multiple interfaces are reserved at the top of the percolation reactor cover 22 for the installation of gas pipelines, temperature sensors and pressure sensors.

[0051] A sealed door 8 is installed in the middle of the outer wall of the CNC housing 1 via a hinge. A controller 9 is installed in the middle of the outer wall of the sealed door 8. Multiple support feet 10 are installed around the bottom of the high temperature and high pressure percolation reactor 2.

[0052] Both the first core percolation chamber 11 and the second core percolation chamber 12 are made of titanium alloy. Titanium alloy has high compressive strength and excellent corrosion resistance, which can prevent chemical reactions with carbon dioxide and shale oil, ensuring a stable experimental environment. The intermediate container 4 is made of high-strength pressure-resistant glass or Hastelloy. High-strength pressure-resistant glass facilitates observation of the internal carbon dioxide state, while Hastelloy is suitable for higher pressure scenarios, both of which can meet high pressure requirements. The heating resistor 15 is a ring-shaped armored heating element. The armored structure has good insulation and temperature resistance, and a long service life. The heat insulation shell 16 adopts a composite structure of double-layer aluminum silicate insulation cotton and stainless steel shell, which can minimize heat loss, maintain the internal temperature of the percolation vessel, and reduce energy consumption.

[0053] Working principle: Before loading the core sample 14, key parameters such as the total mass (or equivalent volume) of saturated oil and the oil saturation of the core need to be recorded. Then, the lid 22 of the percolation reactor is opened, and the core sample 14 saturated with shale oil is loaded into the core cavity 13 of the first core percolation chamber 11 or the second core percolation chamber 12 of the percolation reactor body 21. The first core percolation chamber 11 and the second core percolation chamber 12 can be selected and installed in the high-temperature and high-pressure percolation reactor 2 according to experimental requirements. Multiple core cavities 13 can simultaneously carry out the percolation process on multiple core samples 14, and the core samples 14 do not interfere with each other, effectively avoiding experimental errors. The generation of carbon dioxide significantly improves experimental efficiency. Next, carbon dioxide gas is supplied through the gas supply mechanism 7 and delivered to the intermediate container 4. Subsequently, the high-pressure plunger pump 6 draws gas from the intermediate container 4 through the extraction pipe 61, and then pressurizes and delivers the gas back to the intermediate container 4 through the vent pipe 62. The high-pressure plunger pump 6 can precisely regulate the system pressure, ensuring highly accurate experimental pressure conditions. Afterwards, the high-pressure carbon dioxide gas in the intermediate container 4 is delivered to the high-temperature, high-pressure percolation reactor 2 through the gas filling mechanism 5. High-pressure carbon dioxide can be slowly injected into the reactor. Simultaneously, the high-temperature, high-pressure percolation reactor 2 has an external heat preservation and heating function. The retaining element 15 creates the required high-temperature environment inside the percolation reactor, while the insulating outer shell 16 reduces heat loss to maintain temperature stability. Once the pressure inside the reactor reaches the specified pressure and temperature, a supercritical carbon dioxide state is achieved. Gas injection is then stopped and the outlet valve is closed. Multiple core samples 14 then undergo supercritical carbon dioxide percolation experiments under the set temperature and pressure conditions, initiating a five-hour supercritical carbon dioxide percolation process. This simulates the high-temperature, high-pressure reservoir environment, essentially covering the high-temperature, high-pressure conditions required for shale oil development. The experimental device has a wide adjustment range and can construct a stable and fully compliant environment for shale core samples. Under the high-temperature and high-pressure environment required for experiments, the device accurately simulates and efficiently conducts experiments on the supercritical carbon dioxide percolation of shale cores. It can not only accurately reproduce the high-temperature and high-pressure environment of actual shale oil development formations, the dissolution characteristics of supercritical carbon dioxide, and the true state of shale reservoir pore structure and fluid flow patterns, but also present the actual manifestation of shale reservoir pore structure and fluid flow patterns under high pressure. Through this series of simulations, the device can accurately measure the percolation oil recovery efficiency of supercritical carbon dioxide under different temperature and pressure conditions, effectively ensuring the authenticity and reliability of the experimental simulation results.

[0054] Example 2:

[0055] This embodiment is basically the same as the previous embodiment, except that the inflation mechanism 5 includes an inflation pipe 51, an inflation valve 52, a diversion pipe 53, and multiple inflation pipes 54. One end of the inflation pipe 51 penetrates the top inner wall of the CNC box 1 and is installed on the top of the intermediate container 4 through a sealing joint. The inflation valve 52 is located on the lower side of the outer wall of the inflation pipe 51. The inflation valve 52 is a high-pressure electromagnetic ball valve, which can be remotely controlled by the controller 9 to automate the inflation process. The diversion pipe 53 is installed at the other end of the inflation pipe 51. Multiple inflation pipes 54 are installed at the bottom end of the diversion pipe 53 and are embedded in the top of the percolation vessel cover 22. The number of inflation pipes 54 corresponds one-to-one with the core chamber 13. The bottom end extends to the top of the core percolation chamber to ensure that the carbon dioxide fluid evenly covers the surface of the core sample 14.

[0056] The gas supply mechanism 7 includes a gas cylinder seat 71, multiple gas cylinder slots 72, multiple carbon dioxide gas cylinders 73, multiple gas cylinder valves 74, multiple connecting pipes 75, and a gas collecting pipe 76. The gas cylinder seat 71 is installed on the left side of the bottom inner wall of the CNC housing 1. Multiple gas cylinder slots 72 are all opened at the top of the gas cylinder seat 71. Multiple carbon dioxide gas cylinders 73 are placed inside the multiple gas cylinder slots 72 respectively. Multiple gas cylinder valves 74 are respectively set at the top of the multiple carbon dioxide gas cylinders 73. Multiple connecting pipes 75 are respectively installed on the multiple gas cylinder valves 74. The gas collecting pipe 76 is installed between the other ends of the multiple connecting pipes 75 and is installed on the upper side of the outer wall of the intermediate container 4.

[0057] The gas cylinder valve 74 is a solenoid valve, which can be remotely controlled by the controller 9 to achieve automated supply and cut-off of gas source without manual operation, thus improving the automation and safety of the experiment. A quick connector is set at the connection between the connecting pipe 75 and the gas cylinder valve 74. The quick connector facilitates the replacement of carbon dioxide cylinder 73, reduces cylinder replacement time, and ensures continuous experimentation. A one-way valve is set on the gas collecting pipe 76. The one-way valve can prevent the high-pressure carbon dioxide in the intermediate container 4 from flowing back into the gas cylinder, avoiding overpressure of the gas cylinder and ensuring experimental safety. The gas delivery pipe 51 is an ultra-high pressure hose. The ultra-high pressure hose has good flexibility, can adapt to the installation space inside the CNC cabinet 1, meets the requirements of high-pressure carbon dioxide delivery, and has excellent sealing performance with no risk of leakage.

[0058] Working principle: During the gas supply process, first open the cylinder valve 74 on the carbon dioxide cylinder 73, allowing the carbon dioxide gas in the cylinder 73 to flow into the connecting pipe 75, and then be transported to the intermediate container 4 through the gas collecting pipe 76. Then, close the cylinder valve 74. Next, the high-pressure plunger pump 6 pressurizes the carbon dioxide gas in the intermediate container 4 through the suction pipe 61 and the vent pipe 62. After pressurization, open the filling valve 52 on the gas supply pipe 51. This filling valve 52 can adjust the gas flow rate according to experimental requirements, allowing the high-pressure carbon dioxide gas to be distributed through the distributor pipe 53. Up to one gas filling tube 54 is used to uniformly fill each core cavity 13 of the high-temperature and high-pressure percolation reactor 2, thereby achieving uniform input of high-pressure gas. At this time, the core sample 14 placed in the core cavity 13 carries out a supercritical carbon dioxide percolation experiment under the set temperature and pressure conditions. During the entire experiment, the high-pressure carbon dioxide gas and the high-temperature environment created by the heating resistor 15 work together to achieve accurate simulation and efficient measurement of the supercritical carbon dioxide percolation process of shale core under high temperature and high pressure conditions, further improving the stability and experimental efficiency of the experimental device.

[0059] Example 3:

[0060] This embodiment is basically the same as the previous embodiment, except that the weighing mechanism 3 includes a flexible and rigid pipe connector 31, multiple discharge pipes 32, multiple tension sensing hoses 33, multiple percolation oil collection pipes 34, and multiple oil discharge pipes 35. The multiple discharge pipes 32 are all installed at the top of the flexible and rigid pipe connector 31, and the multiple discharge pipes 32 are all embedded in the bottom of the percolation vessel body 21. The number of discharge pipes 32 corresponds one-to-one with the core cavity 13 to ensure that the percolation produced liquid of each path is collected independently and welded and sealed with the percolation vessel body 21. The multiple tension sensing hoses 33 are respectively installed at the bottom of the multiple discharge pipes 32, and the multiple percolation oil collection pipes 34 are respectively installed at the bottom of the multiple tension sensing hoses 33. The percolation oil collection pipes 34 are convenient for observing the state of the produced liquid, and the outer wall is provided with volume scale lines to assist in reading the volume. The multiple oil discharge pipes 35 are respectively installed in the middle of the bottom of the multiple percolation oil collection pipes 34.

[0061] The upper inner wall of the discharge pipe 32 is designed with a funnel structure. This funnel structure guides the shale oil carried by supercritical carbon dioxide to flow quickly and completely into the seepage oil collection pipe 34, preventing residue from remaining on the inner wall of the discharge pipe 32 and improving measurement accuracy. The seepage oil collection pipe 34 is made of transparent borosilicate glass. The transparency allows for direct observation of the collected shale oil quantity and state. Borosilicate glass is resistant to high temperatures and pressures and has strong chemical stability, so it will not react with shale oil. Valves are installed on both the oil discharge pipe 35 and the lower outer surface of the discharge pipe 32. The valve on the oil discharge pipe 35 is used for experiments. After the experiment is completed, the shale oil discharge is controlled. The valve on the discharge pipe 32 can be closed separately after the end of a single group of experiments without affecting the operation of other groups of experiments. The bottom end of the discharge pipe 35 is higher than the bottom end of the CNC box 1 to avoid the discharge pipe 35 directly contacting the ground and causing wear or affecting the weighing accuracy. At the same time, it is convenient to place a container under the discharge pipe 35 to receive the discharged shale oil. The tension sensing hose 33 has a built-in high-precision tension sensor. The tension sensor can convert the gravity change of the seepage oil collection pipe 34 into a tension signal in real time and transmit it to the controller 9 to calculate the shale oil mass.

[0062] Working Principle: During operation, after the core sample 14 in the high-temperature, high-pressure percolation reactor 2 has completed percolation, the valve on the discharge pipe 32 is opened. The percolated oil flows through the funnel structure of the discharge pipe 32 into the tension sensing hose 33, and then into the percolation oil collection pipe 34. The percolation oil collection pipe 34 mainly collects the percolated oil and related substances until the pressure of the high-temperature, high-pressure percolation reactor 2 becomes zero. At this time, the valve on the discharge pipe 32 is closed. At this time, the high-precision tension sensor built into the tension sensing hose 33 monitors and records the mass change of the oil in real time, calculates the mass of the collected percolation substances (including percolation oil), and then automatically... Subtracting the mass of injected carbon dioxide yields the mass of the absorbed oil, from which the recovery rate is calculated. Simultaneously, the information acquisition card collects temperature and pressure data throughout the process. This data serves as supplementary analysis, further verifying and optimizing the calculation results of the supercritical carbon dioxide absorbed shale oil recovery rate. Afterward, the relevant data and images are output to controller 9. After the experiment, the absorbed oil can be discharged by opening the valve on the drain pipe 35. This series of operations helps improve the accuracy of the absorption measurement, enhances experimental efficiency, and facilitates observation and operation during the experiment, providing strong experimental support for shale oil development research.

[0063] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A high temperature and high pressure supercritical carbon dioxide imbibition experimental device for shale cores, characterized in that, include: CNC housing (1) and high temperature and high pressure percolation reactor (2); Weighing mechanism (3) is installed at the bottom center of the high temperature and high pressure percolation reactor (2); The intermediate container (4) is vertically installed between the middle of the top inner wall and the middle of the bottom inner wall of the CNC housing (1); An inflation mechanism (5) is installed between the top of the intermediate container (4) and the high-temperature and high-pressure percolation vessel (2); A high-pressure plunger pump (6) is installed on the right side of the bottom inner wall of the CNC housing (1). The air inlet end of the high-pressure plunger pump (6) is equipped with an air extraction pipe (61), and the other end of the air extraction pipe (61) is installed on the lower side of the outer wall of the intermediate container (4). The air outlet end of the high-pressure plunger pump (6) is equipped with an air release pipe (62), and the other end of the air release pipe (62) is installed on the middle side of the outer wall of the intermediate container (4). An air supply mechanism (7) is installed on the left side of the bottom inner wall of the CNC housing (1); A heating resistor (15) is installed in the middle of the outer wall of the high-temperature and high-pressure percolation vessel (2); The heat-insulating shell (16) is installed on the outer wall of the high-temperature and high-pressure percolation vessel (2), and the heat-insulating shell (16) is sleeved on the outer surface of the heating resistor (15).

2. The high temperature and high pressure supercritical carbon dioxide imbibition experimental device for shale core according to claim 1, characterized in that, The high-temperature and high-pressure permeation vessel (2) is equipped with either a first core permeation chamber (11) or a second core permeation chamber (12). The first core permeation chamber (11) and the second core permeation chamber (12) are each provided with multiple core cavities (13). Core samples (14) are placed inside each of the multiple core cavities (13). 3.The high temperature and high pressure supercritical carbon dioxide imbibition experimental device for shale core according to claim 1, characterized in that, The high-temperature and high-pressure percolation reactor (2) includes a percolation reactor body (21) and a percolation reactor cover (22). The percolation reactor cover (22) is installed on the top of the percolation reactor body (21), and the percolation reactor cover (22) and the percolation reactor body (21) are connected by a flange seal.

4. The high temperature and high pressure supercritical carbon dioxide imbibition experimental device for shale core according to claim 3, characterized in that, The weighing mechanism (3) includes a flexible and rigid pipe connector (31), multiple discharge pipes (32), multiple tension sensing hoses (33), multiple oil absorption collection pipes (34), and multiple oil drain pipes (35). The multiple discharge pipes (32) are all installed at the top of the flexible and rigid pipe connector (31), and the multiple discharge pipes (32) are all embedded in the bottom of the absorption vessel body (21). The multiple tension sensing hoses (33) are respectively installed at the bottom of the multiple discharge pipes (32). The multiple oil absorption collection pipes (34) are respectively installed at the bottom of the multiple tension sensing hoses (33). The multiple oil drain pipes (35) are respectively installed at the middle of the bottom of the multiple oil absorption collection pipes (34).

5. The high temperature and high pressure supercritical carbon dioxide imbibition experimental device for shale core according to claim 3, characterized in that, The inflation mechanism (5) includes an inflation pipe (51), an inflation valve (52), a diversion pipe (53), and multiple inflation pipes (54). One end of the inflation pipe (51) penetrates the top inner wall of the CNC housing (1) and is installed on the top of the intermediate container (4) through a sealing joint. The inflation valve (52) is located on the lower side of the outer wall of the inflation pipe (51). The diversion pipe (53) is installed on the other end of the inflation pipe (51). Multiple inflation pipes (54) are installed at the bottom end of the diversion pipe (53), and multiple inflation pipes (54) are embedded in the top of the infiltration vessel lid (22).

6. The high-temperature, high-pressure supercritical carbon dioxide percolation experimental apparatus for shale cores according to claim 5, characterized in that, The gas supply mechanism (7) includes a gas cylinder seat (71), multiple gas cylinder slots (72), multiple carbon dioxide cylinders (73), multiple gas cylinder valves (74), multiple connecting pipes (75), and a gas collecting pipe (76). The gas cylinder seat (71) is installed on the left side of the bottom inner wall of the CNC housing (1). Multiple gas cylinder slots (72) are opened at the top of the gas cylinder seat (71). Multiple carbon dioxide cylinders (73) are placed inside the multiple gas cylinder slots (72). Multiple gas cylinder valves (74) are respectively set at the top of the multiple carbon dioxide cylinders (73). Multiple connecting pipes (75) are respectively installed on the multiple gas cylinder valves (74). The gas collecting pipe (76) is installed between the other ends of the multiple connecting pipes (75) and is installed on the upper side of the outer wall of the intermediate container (4).

7. The high-temperature, high-pressure supercritical carbon dioxide percolation experimental apparatus for shale cores according to claim 1, characterized in that, The outer wall of the CNC housing (1) is fitted with a sealed door (8) via a hinge. The outer wall of the sealed door (8) is fitted with a controller (9). The bottom periphery of the high-temperature and high-pressure percolation reactor (2) is fitted with multiple support feet (10).

8. The high-temperature, high-pressure supercritical carbon dioxide percolation experimental apparatus for shale cores according to claim 2, characterized in that, The first core infiltration chamber (11) and the second core infiltration chamber (12) are both made of titanium alloy. The intermediate container (4) is made of high-strength pressure-resistant glass or Hastelloy. The heating resistor (15) is a ring-shaped armored heating element. The heat insulation shell (16) is a composite structure of double-layer aluminum silicate insulation cotton and stainless steel shell.

9. The high-temperature and high-pressure supercritical carbon dioxide percolation experimental apparatus for shale cores according to claim 4, characterized in that, The inner wall of the discharge pipe (32) is configured as a funnel structure. The oil collection pipe (34) is made of transparent borosilicate glass. Valves are provided on the oil drain pipe (35) and the lower part of the outer surface of the discharge pipe (32). The bottom end of the oil drain pipe (35) is higher than the bottom end of the CNC box (1). The tension sensing hose (33) has a built-in high-precision tension sensor.

10. The high-temperature, high-pressure supercritical carbon dioxide percolation experimental apparatus for shale cores according to claim 6, characterized in that, The gas cylinder valve (74) is a solenoid valve, a quick connector is provided at the connection between the connecting pipe (75) and the gas cylinder valve (74), a one-way valve is provided on the gas collecting pipe (76), and the gas delivery pipe (51) is an ultra-high pressure hose.

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