A CO2-water core flooding experimental operation method

Abstract

The present invention discloses a CO2-water core displacement experiment operation method, which belongs to the technical field of displacement experiment methods. The method includes the following steps: S1: first completing the limiting of the first fixed sleeve; S2: injecting hydraulic oil of corresponding pressure into the elastic bag and starting the heating ring and the detection unit to complete the preparation before the test; S3: completing the test of the object to be measured, wherein the detection unit records the test data; S4: after the test is completed, the heating ring and the detection unit are turned off in sequence, and the elastic bag is controlled to reset, and then the first fixed sleeve is opened by the first power member, the object to be measured is taken out, and the first power member is subsequently controlled to reset to complete the test experiment. The present invention facilitates the elastic bag to cling to the side wall of the object to be measured through the elastic deformation of the elastic bag, thereby ensuring that the medium penetrates into the object to be measured; the present invention can also make the medium penetrate into the object to be measured with a stable pressure through the limiting effect of the second sliding column and the fifth spring, thereby improving the accuracy of the experimental data.

Description

Technical Field

[0001] The invention belongs to the technical field of displacement experimental methods, and specifically proposes a CO2-water core displacement experimental operation method. Background Art

[0002] CO2-water two-phase flow displacement experiments simulate the flow and interaction of carbon dioxide (CO2) and water in porous media (such as rock and soil) under laboratory conditions. Such experiments are crucial for understanding CO2 geological storage, enhancing oil recovery, and evaluating subsurface fluid dynamics.

[0003] In the existing core displacement experiment, the core sample must first be placed in a core holder, and then CO2 is injected into one end of the core sample to test the gas-water relative permeability of the core. During this process, CO2 is likely to overflow from the gap between the core sample and the core holder, affecting the accuracy of the test results. In addition, when testing core samples of different sizes, it is difficult to control the sealing and extrusion pressure between the core holder and the core samples of different sizes. If the extrusion pressure is too large, the core sample may be easily broken, causing CO2 to overflow from the cracks in the core sample, resulting in large deviations in the test results. Summary of the Invention

[0004] In order to overcome the above-mentioned technical problems, the present invention provides a CO2-water two-phase flow displacement experimental device and method.

[0005] The technical solution of the present invention is:

[0006] A CO2-water two-phase flow displacement experimental device includes a workbench, a first fixed seat embedded in the middle of the workbench, a side wall of the first fixed seat connected to an exhaust pipe, a switch valve installed in the exhaust pipe, a symmetrical first power member fixed to the workbench, the symmetrical first power members jointly installed with a first fixed shell, the first fixed shell is provided with a first fixed sleeve, the inner diameter of the first fixed sleeve is longer than the maximum diameter of the first fixed seat, a second fixed seat is fixed to the upper part of the first fixed sleeve, the side wall of the second fixed seat is connected to a filling pipe for installing the switch valve, an elastic bag is fixed in the first fixed sleeve, a heating ring and evenly distributed detection units are fixed to the side wall of the first fixed sleeve, second fixed sleeves are fixed to the facing sides of the first and second fixed seats, and the two second fixed sleeves are jointly provided with a centering mechanism for locating the object to be measured in the middle of the elastic bag.

[0007] More preferably, the elastic bag is embedded with evenly distributed elastic rings, and the cross section of the elastic ring is an isosceles trapezoid.

[0008] More preferably, the centering mechanism includes two first sliding shells that are symmetrical in upper and lower directions, and the two first sliding shells are respectively slidably arranged on adjacent second fixed sleeves, and the side walls of the first sliding shells are fixed with first springs fixed to the adjacent second fixed sleeves.

[0009] More preferably, a sliding ring is slidably provided in the first fixed sleeve, the sliding ring is located on the lower side of the elastic bag and is fixed thereto, and a plurality of concentric elastic convex rings are provided on the lower side of the sliding ring, and the first fixed seat is provided with a plurality of concentric annular grooves, and the annular grooves of the first fixed seat are squeezed and fitted with the adjacent elastic convex rings on the sliding ring to improve the sealing between the first fixed seat and the sliding ring.

[0010] More preferably, it also includes a locking mechanism for locking the first fixing sleeve, the locking mechanism being arranged on the workbench, the first fixing shell slidingly cooperating with the first fixing sleeve, the locking mechanism including a fixing ring, the fixing ring being fixedly connected to the upper surface of the workbench, the fixing ring being provided with a centrally symmetrical limiting groove, the lower portion of the first fixing sleeve being rotatably provided with a rotating ring, the lower surface of the rotating ring being fixedly connected with a symmetrical L-shaped rod, the L-shaped rod being limitedly cooperating with the adjacent limiting groove on the fixing ring, the side wall of the first fixing sleeve being fixedly connected to a fixing plate, the fixing plate being installed between the fixing plate and the rotating ring, a torsion spring being fixedly connected between the first fixing shell and the first fixing sleeve, the upper surface of the rotating ring being fixedly connected with symmetrical guide rods, the first fixing shell being provided with a centrally symmetrical guide groove, the guide rods being slidably cooperating with the adjacent guide grooves on the first fixing shell.

[0011] More preferably, a pressurizing mechanism is further included for strengthening the sealing between the elastic bag and the object to be measured, the pressurizing mechanism is arranged on the elastic bag, and the elastic bag is provided with uniformly distributed grooves, the pressurizing mechanism includes uniformly distributed annular sleeves, the uniformly distributed annular sleeves are all fixed in the elastic bag, and the annular sleeves are opposite to the adjacent grooves on the elastic bag, the annular sleeves and the elastic bag cooperate to form an annular cavity filled with hydraulic oil, the elastic bag is fixed with multiple uniformly distributed groups of second fixed shells, each group of the second fixed shells includes multiple second fixed shells distributed equidistantly in the circumferential direction, the number of groups of the multiple second fixed shells is one less than the number of uniformly distributed grooves on the elastic bag, and the multiple groups of the second fixed shells are respectively located in adjacent grooves on the elastic bag, the second fixed shell is slidably provided with a first sliding column that penetrates the elastic bag and is slidably connected thereto, the second fixed shell is connected with a first conduit, the first conduit penetrates the adjacent annular sleeve and is fixed thereto, and the first conduit is connected to the annular sleeve on its lower side.

[0012] More preferably, it also includes a uniform exhaust mechanism for controlling the pressure environment of the object to be measured, the uniform exhaust mechanism is arranged on the first fixed seat, the uniform exhaust mechanism includes a second sliding shell, the second sliding shell is slidably arranged in the first fixed seat, a first sliding plate is slidably arranged in the first fixed seat, a third spring is fixed between the first sliding plate and the second sliding shell, a limit ring is fixed in the first fixed seat for limiting the movement of the second sliding shell, the second sliding shell is connected to a second conduit for installing a switch valve, the second conduit penetrates the first sliding plate and the first fixed seat and slides with the two, the second sliding shell is provided with a circular hole for communicating with the exhaust pipe, the first fixed seat is threaded with a first threaded rod, and the first threaded rod is rotatably connected to the first sliding plate. More preferably, it further includes a pressing mechanism for uniformly squeezing the medium in the second fixed seat, the pressing mechanism is arranged on the second fixed seat, a switch valve is installed in the second fixed seat, the pressing mechanism includes a second power member, the second power member is installed on the second fixed seat, a third sliding shell is slidably arranged in the second fixed seat, a fourth sliding shell connected to the second power member is slidably arranged on the third sliding shell, a fourth spring is installed between the fourth sliding shell and the third sliding shell, and the fourth sliding shell is provided with a uniform component for constantly discharging the medium in the second fixed seat.

[0013] More preferably, the uniform component includes a third fixed shell, the third fixed shell is fixedly connected to the fourth sliding shell, and the third fixed shell is communicated with the fourth sliding shell, a second sliding column is slidably provided in the third fixed shell, the second sliding column is provided with an L-shaped hole, the third fixed shell is threadedly provided with a second threaded rod, the second threaded rod is rotatably provided with a second sliding plate that slides in the third fixed shell, a fifth spring is fixed between the second sliding plate and the second sliding column, a side wall of the third fixed shell is communicated with a third conduit, the third conduit is communicated and cooperated with the L-shaped hole on the second sliding column, and a third sliding plate is slidably provided in the third conduit.

[0014] The present invention also provides an operating method for a CO2-water two-phase flow displacement experiment, based on the above-mentioned CO2-water two-phase flow displacement experimental device, which specifically includes the following steps:

[0015] S1: First, the first power member is activated to move the first fixing sleeve upward, wherein the limiting groove of the fixing ring releases the limit on the L-shaped rod, and then the object to be measured is placed on the corresponding first sliding shell. Then, the first power member is activated to move the first fixing sleeve downward and reset, and at the same time, the L-shaped rod slides back into the limiting groove of the fixing ring, completing the limiting of the first fixing sleeve;

[0016] S2: After the object to be measured enters the first fixing sleeve, hydraulic oil of corresponding pressure is injected into the elastic bladder, and the heating ring and detection unit are activated. The elastic bladder tightly wraps the object to be measured under the pressure of the hydraulic oil, and the heating ring keeps the object to be measured at the set temperature, completing the preparation before the test;

[0017] S3: After completing the preparations before the test, a medium at a specified pressure is injected into the first fixed sleeve through the filling pipe. At the same time, the first threaded rod and the second threaded rod are adjusted according to the corresponding experimental data. Then, the second power member is started. The reciprocating movement of the second sliding column causes the third sliding shell to move, causing the medium in the first fixed sleeve to penetrate into the object to be measured at the specified pressure. The reciprocating movement of the second sliding shell maintains the specified pressure in the first fixed seat, completing the test of the object to be measured. The detection unit records the test data.

[0018] S4: After the test is completed, the heating ring and the detection unit are closed in sequence, and the elastic bag is controlled to reset. Then, the first fixing sleeve is opened by the first power member, and the object to be measured is taken out. Subsequently, the first power member is controlled to reset to complete the test experiment.

[0019] The beneficial technical effects of the present invention are as follows:

[0020] The present invention facilitates the elastic deformation of the elastic bag to facilitate the elastic bag to cling to the side wall of the object to be measured, ensures the penetration of the medium into the object to be measured, and improves the accuracy of experimental data. The first springs on the two first sliding shells facilitate the object to be measured to be centered in the middle of the elastic bag, and facilitate the elastic bag to apply a uniform and stable extrusion force to the object to be measured. The cooperation of multiple elastic rings on the sliding ring and multiple annular grooves on the first fixed seat improves the sealing performance of the device and prevents the medium from leaking to the outside. The cooperation of the L-shaped rod and the upper limit groove of the fixed ring improves the limitation of the first fixed sleeve and further prevents the medium from leaking to the outside. The limiting action of the second sliding shell and the third spring facilitates maintaining a stable pressure on one end of the object to be measured. In combination with the operation of the second power member and the limiting action of the second sliding column and the fifth spring, the medium penetrates into the object to be measured with a stable pressure, thereby improving the accuracy of the experimental data of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention;

[0022] Figure 2 This is a schematic structural diagram of the components in the first fixed sleeve of the present invention;

[0023] Figure 3 It is a cross-sectional view of the components of the first fixing sleeve and the elastic bag of the present invention;

[0024] Figure 4A cross-sectional view of components at the first fixing seat and the second fixing seat of the present invention;

[0025] Figure 5 is a cross-sectional view of the centering mechanism of the present invention;

[0026] Figure 6 An exploded view of the locking mechanism of the present invention;

[0027] Figure 7 is a cross-sectional view of the pressurizing mechanism of the present invention;

[0028] Figure 8 is a cross-sectional view of the uniform exhaust mechanism of the present invention;

[0029] Figure 9 It is a cross-sectional view of the pressing mechanism of the present invention.

[0030] The following are marked in the figure:

[0031] 1. Workbench, 11. First fixing seat, 111. Exhaust pipe, 12. First power member, 13. First fixing shell, 14. First fixing sleeve, 141. Second fixing seat, 142. Filling tube, 15. Elastic capsule, 16. Heating ring, 17. Detection unit, 18. Second fixing sleeve;

[0032] 2. Elastic ring;

[0033] 3. First sliding housing, 31. First spring;

[0034] 4. Sliding ring;

[0035] 5. Fixed ring, 51. Rotating ring, 511. L-shaped rod, 52. Fixed plate, 53. Torsion spring, 54. Second spring, 55. Guide rod;

[0036] 6. annular sleeve, 61. second fixed shell, 62. first sliding column, 63. first guide tube;

[0037] 7. Second sliding housing, 71. First sliding plate, 72. Third spring, 73. Limiting ring, 74. Second guide tube, 75. First threaded rod;

[0038] 8. Second power member, 81. Third sliding housing, 82. Fourth sliding housing, 83. Fourth spring;

[0039] 9. Third fixed housing, 91. Second sliding column, 92. Second threaded rod, 93. Second sliding plate, 94. Fifth spring, 95. Third guide tube, 96. Third sliding plate. DETAILED DESCRIPTION

[0040] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. The first power member and the second power member are both hydraulic push rods.

[0041] Example 1

[0042] A CO2-water two-phase flow displacement experimental device, such as Figure 1-Figure 4 As shown, it includes a workbench 1, the front side of the workbench 1 is fixedly connected to a control panel, the middle part of the workbench 1 is embedded with a first fixed seat 11, the right side of the first fixed seat 11 is connected to an exhaust pipe 111, and a switch valve is installed in the exhaust pipe 111, and two first power members 12 symmetrically connected to the workbench 1 are fixed, and the two first power members 12 are electrically connected to the control panel, and the telescopic ends of the two first power members 12 are jointly installed with a first fixed shell 13, and a first fixed sleeve 14 is provided in the first fixed shell 13. The length of the inner diameter of the first fixed sleeve 14 is greater than the length of the maximum diameter of the first fixed seat 11, so that the first fixed seat 11 is conveniently inserted into the first fixed sleeve 14, and the upper part of the first fixed sleeve 14 is fixed with a second fixed seat 141, and the left side of the second fixed seat 141 is connected to a stuffing pipe 142 for installing the switch valve, and the first fixed sleeve 14 is fixed with an elastic bag 15, which is resistant to High-temperature material, the elastic capsule 15 is embedded with evenly distributed elastic rings 2, the cross-section of the elastic ring 2 is an isosceles trapezoid, the elastic coefficient of the elastic ring 2 is greater than the elastic coefficient of the elastic capsule 15, the elastic capsule 15 is provided with a pipe penetrating the first fixed sleeve 14, the pipe is connected to the external hydraulic pump, and the external hydraulic pump is electrically connected to the control panel, the side wall of the first fixed sleeve 14 is fixed with a heating ring 16 and three evenly distributed detection units 17, the detection unit 17 is used to detect the penetration efficiency of CO2 in the core sample, the heating ring 16 and the three detection units 17 are all electrically connected to the control panel, the first fixed seat 11 and the second fixed seat 141 are fixed with second fixed sleeves 18 on the opposite sides, the two second fixed sleeves 18 are jointly provided with a centering mechanism, the centering mechanism is used to locate the object to be measured in the middle of the elastic capsule 15, the switch valve on the exhaust pipe 111 and the switch valve of the filling pipe 142 are both electrically connected to the control panel.

[0043] like Figure 4 and Figure 5As shown, the centering mechanism includes two first sliding shells 3 that are symmetrical in the upper and lower parts. The two first sliding shells 3 are respectively slidably set on the adjacent second fixed sleeves 18. The side walls of the first sliding shells 3 are fixed with first springs 31 fixed with the adjacent second fixed sleeves 18. The elastic action of the two first springs 31 is used to keep the core sample centered in the elastic bag 15, so that the elastic bag 15 can apply uniform extrusion pressure to the core sample. A sliding ring 4 is slidably set in the lower part of the first fixed sleeve 14. The sliding ring 4 is located on the lower side of the elastic bag 15 and is fixed thereto, and a plurality of concentric elastic convex rings are provided on the lower side of the sliding ring 4. The first fixed seat 11 is provided with a plurality of concentric annular grooves. The annular grooves of the first fixed seat 11 are squeezed and matched with the adjacent elastic convex rings on the sliding ring 4, so that the fitting surface forms a wavy sealing fitting surface, thereby improving the sealing between the first fixed seat 11 and the sliding ring 4 and preventing CO2 from leaking from the first fixed sleeve 14.

[0044] When conducting the CO2-water two-phase flow displacement experiment, the operator first dried the core sample for 24 hours, then placed the core sample in a vacuum saturation device and evacuated it for 3 hours, and then pressurized it to 25MPa with distilled water and maintained it for 24 hours to fill the core sample with distilled water.

[0045] After the preliminary operation and processing of the core sample is completed, the operator controls the two first power members 12 to fully extend through the control panel on the workbench 1. The telescopic end of the first power member 12 drives the first fixed shell 13 and the first fixed sleeve 14 to move upward. Then the operator places the core sample on the upper surface of the lower first sliding shell 3. Subsequently, the operator controls the two first power members 12 to retract and reset through the control panel on the workbench 1. The two first power members 12 drive the first fixed sleeve 14 to move downward through the first fixed shell 13, so that the core sample is located in the elastic bag 15. The elastic bag 15 expands and squeezes the sliding ring 4 to move. The sliding ring 4 moves and is close to the upper surface of the first fixed seat 11. At the same time, under the elastic force of the first springs 31 on the two first sliding shells 3, the two first sliding shells 3 clamp the core sample in the center, thereby ensuring that the core sample is centered in the elastic bag 15, which is convenient for the subsequent elastic bag 15 to apply uniform circumferential extrusion force to the core sample.

[0046] After the first power member 12 is reset, the operator starts the external hydraulic pump, the heating ring 16 and the detection unit 17 through the control panel. The external hydraulic pump works to inject hydraulic oil into the elastic bag 15 through the pipeline. As the hydraulic oil enters, the elastic bag 15 will gradually expand. The expanded elastic bag 15 will fully wrap the core sample. At this time, the external hydraulic pump works to make the elastic bag 15 apply a confining pressure of 20 MPa to the core sample. The heating ring 16 works to maintain 40°C in the first fixing sleeve 14. The elastic bag 15 expands and squeezes the sliding ring 4 downward and close to the upper surface of the first fixing seat 11. At this time, the confining pressure application operation on the core sample is completed.

[0047] After completing the confining pressure application operation, the operator opens the on-off valve on the exhaust pipe 111 and the on-off valve on the filling pipe 142. The operator then connects the tank filled with high-pressure supercritical CO2 to the filling pipe 142. The supercritical CO2 then flows gradually through the filling pipe 142 to the upper side of the core sample under the action of high pressure. Under the action of pressure, the supercritical CO2 gradually penetrates into the core sample. The infiltrated supercritical CO2 drives the distilled water in the core sample to gradually seep downward. During this process, the detection unit 17 operates to record data such as the displacement time, displacement pressure difference, cumulative fluid production, cumulative water production, and initial gas breakthrough point at each moment. The gas-liquid relative permeability is subsequently calculated through the control panel, thereby completing the CO2-water two-phase flow displacement experiment. During this process, the separation effect of the multiple elastic rings 2 separates the contact surface between the elastic bladder 15 and the core sample into multiple layers, preventing supercritical CO2 from flowing downward through the gap between the elastic bladder 15 and the core sample during the experiment, thereby improving the accuracy of the experimental data.

[0048] After the measurement is completed, the operator controls the elastic bag 15 to reset by controlling the external hydraulic pump, and at the same time starts the two first power members 12 to fully extend through the control panel. The operator then takes out the core sample, and then controls the two first power members 12 to work in the reverse direction and reset through the control panel. At the same time, the operator turns off the heating ring 16 and the detection unit 17 through the control panel.

[0049] Example 2

[0050] On the basis of Example 1, Figure 5 and Figure 6As shown, it also includes a locking mechanism, which is arranged on the workbench 1, and is used to lock the first fixed sleeve 14. The first fixed shell 13 slides with the first fixed sleeve 14, and the locking mechanism includes a fixing ring 5, which is fixed to the upper surface of the workbench 1, and the center line of the fixing ring 5 coincides with the center line of the first fixed sleeve 14. The fixing ring 5 is provided with two centrally symmetrical limiting grooves, and the limiting grooves are divided into two sections, which are respectively a vertical section and a horizontal section. The lower part of the first fixed sleeve 14 is rotatably provided with a rotating ring 51, and the lower surface of the rotating ring 51 is fixed with two left-right symmetrical L-shaped rods 511, and the L-shaped rods 511 are limitedly matched with the adjacent limiting grooves on the fixing ring 5, and the side wall of the first fixed sleeve 14 is fixed A fixed plate 52 is connected, and the fixed plate 52 is located above the rotating ring 51. A torsion spring 53 fixed to the lower side of the fixed plate 52 is fixed to the upper side of the rotating ring 51. A second spring 54 is fixed between the first fixed shell 13 and the first fixed sleeve 14. Two guide rods 55 symmetrical in front and back are fixed to the upper surface of the rotating ring 51. The first fixed shell 13 is provided with two centrally symmetrical guide grooves, which are approximately horizontally V-shaped. The guide rods 55 slide in the adjacent guide grooves on the first fixed shell 13. The upper limit groove on the fixed ring 5 is used to limit the two L-shaped rods 511, thereby improving the sealing between the sliding ring 4 and the first fixed seat 11, keeping the core sample in a high-pressure state, and further preventing CO2 leakage.

[0051] like Figure 4 and Figure 7 As shown, it also includes a pressurizing mechanism, which is arranged on the elastic bag 15. The pressurizing mechanism is used to strengthen the sealing between the elastic bag 15 and the object to be measured. Six evenly distributed grooves are provided in the elastic bag 15. The pressurizing mechanism includes six evenly distributed annular sleeves 6. The annular sleeves 6 are made of elastic material. The elastic coefficient of the annular sleeves 6 is greater than the elastic coefficient of the elastic bag 15. The six annular sleeves 6 are all fixed to the inner wall of the elastic bag 15. The annular sleeves 6 and the elastic bag 15 cooperate to form an annular cavity filled with hydraulic oil. The elastic bag 15 is fixed with five evenly distributed groups of second fixed shells 61. Each group of second fixed shells 61 includes six second fixed shells 61 distributed equidistantly in the circumferential direction. The five groups of second The fixed shells 61 are respectively located at the five grooves on the upper side of the elastic bag 15. The second fixed shell 61 is slidably provided with a first sliding column 62 that penetrates the elastic bag 15 and is slidably connected thereto. The second fixed shell 61 is connected to a first conduit 63. The first conduit 63 penetrates the adjacent annular sleeve 6 and is fixed thereto, and the first conduit 63 is connected to the annular sleeve 6 on the lower side. Under the separating action of the elastic ring 2, when CO2 penetrates into the gap between the elastic bag 15 and the core sample, CO2 will squeeze the corresponding first sliding column 62 to move, so that the elastic bag 15 at the lower annular sleeve 6 increases the extrusion force with the core sample, which is convenient for accurately measuring the penetration efficiency of CO2 in the core sample.

[0052] During the displacement experiment, in the initial state, the L-shaped rod 511 is located at one end of the horizontal section of the adjacent limit groove on the fixed ring 5 away from its vertical section, and the guide rod 55 is located in the middle of the V-shaped guide groove on the first fixed shell 13. As the two first power members 12 work and drive the first fixed shell 13 to move upward, the first fixed shell 13 moves upward to compress the second spring 54. At the same time, the lower half of the two guide grooves on the first fixed shell 13 squeeze the two guide rods 55. The two guide rods 55 are squeezed and drive the rotating ring 51 to rotate clockwise. The rotating ring 51 rotates and twists the torsion spring 53, and The rotation of the rotating ring 51 drives the two L-shaped rods 511 to rotate in the two limit grooves of the fixed ring 5. When the L-shaped rods 511 rotate to the vertical section of the adjacent limit grooves on the fixed ring 5, the two limit grooves of the fixed ring 5 release the limit on the two L-shaped rods 511. At this time, under the elastic force of the second spring 54, the rotating ring 51 drives the two L-shaped rods 511 to move upward. After the two L-shaped rods 511 are out of contact with the fixed ring 5, the torsion spring 53 and the second spring 54 return to their initial state. The above operation is repeated subsequently to place the core sample on the upper surface of the lower first sliding shell 3.

[0053] After the core sample is placed, the operator starts the reset of the two first power parts 12 through the control panel, so that the two L-shaped rods 511 contact the upper surface of the fixing ring 5, and then squeezes the two guide rods 55 in the upper half of the two guide grooves on the first fixing shell 13, so that the two guide rods 55 drive the rotating ring 51 and the two L-shaped rods 511 to rotate clockwise and twist the torsion spring 53, so that the two L-shaped rods 511 are respectively facing the vertical sections of the adjacent limit grooves on the fixing ring 5, and then under the torsion force of the torsion spring 53, the two L-shaped rods 511 are reinserted into the two limit grooves on the fixing ring 5, restoring the initial state, and re-completing the limitation of the first fixing sleeve 14.

[0054] After the core sample enters the first fixed sleeve 14, the operator activates the external air pressure pump, heating ring 16 and detection unit 17 through the control panel, and simultaneously continuously injects high-pressure supercritical CO2 into the filling tube 142 to conduct a CO2-water two-phase flow displacement experiment. During the above experiment, when the supercritical CO2 flows into the gap between the elastic capsule 15 and the core sample, the supercritical CO2 will first squeeze the adjacent first sliding column 62 to move due to the separation effect of the corresponding elastic ring 2. The first sliding column 62 moves to squeeze the hydraulic oil in the adjacent second fixed shell 61 through the adjacent first conduit 63 and enter the lower annular sleeve 6. The hydraulic oil squeezes the annular sleeve 6 at this location, causing the area of ​​the annular sleeve 6 facing the elastic capsule 15 to further squeeze the core sample, further improving the sealing between the elastic capsule 15 and the core sample, ensuring the flow of supercritical CO2 in the core sample, and further improving the accuracy of the experimental data. After the test is completed, the operator repeats the above operation to remove the core sample.

[0055] Example 3

[0056] On the basis of Example 2, Figure 4 and Figure 8 As shown, it also includes a uniform exhaust mechanism, which is arranged on the first fixed seat 11. The uniform exhaust mechanism is used to control the pressure environment of the object to be measured. The uniform exhaust mechanism includes a second sliding shell 7, which is slidably arranged at the lower part of the first fixed seat 11. A first sliding plate 71 is slidably arranged in the first fixed seat 11. The first sliding plate 71 is located below the second sliding shell 7. A third spring 72 is fixed between the first sliding plate 71 and the second sliding shell 7. A limiter for limiting the movement of the second sliding shell 7 is fixed in the first fixed seat 11. The positioning ring 73 has an upper surface in the shape of a truncated cone. The lower side of the second sliding shell 7 is connected to a second conduit 74 for installing a switch valve. The switch valve is electrically connected to the control panel. The second conduit 74 penetrates the first sliding plate 71 and the first fixed seat 11 and slides with the two. The second sliding shell 7 is provided with a circular hole for communicating with the exhaust pipe 111. The first fixed seat 11 is threadedly provided with a first threaded rod 75 rotatably connected to the first sliding plate 71. The spring force of the third spring 72 is used to regulate the pressure in the first fixed seat 11 to improve the accuracy of the test results.

[0057] like Figure 4 and Figure 9 As shown, it also includes a pressing mechanism, which is arranged on the second fixed seat 141. The pressing mechanism is used to uniformly squeeze the CO2 in the second fixed seat 141. A switch valve electrically connected to the control panel is installed in the second fixed seat 141. The pressing mechanism includes a second power member 8 electrically connected to the control panel. The second power member 8 is installed at the rear of the upper surface of the second fixed seat 141. A third sliding shell 81 is slidably arranged in the second fixed seat 141. A sealing ring with a triangular cross section is fixed to the lower surface of the third sliding shell 81 to improve the sealing performance of the third sliding shell 81 and the second fixed seat. The sealing between the seats 141, the upper sliding shell 81 is slidingly provided with a fourth sliding shell 82 fixedly connected to the telescopic end of the second power member 8, a fourth spring 83 is installed between the fourth sliding shell 82 and the third sliding shell 81, and the fourth sliding shell 82 and the third sliding shell 81 are filled with hydraulic oil. The fourth sliding shell 82 is provided with a uniform component for constantly discharging CO2 in the second fixed seat 141. The relative sliding of the fourth sliding shell 82 and the third sliding shell 81 is utilized to make CO2 penetrate into the core sample at a constant pressure, thereby improving the stability of the experimental data.

[0058] like Figure 9As shown, the uniform component includes a third fixed shell 9, which is fixed to the upper surface of the fourth sliding shell 82 and is connected to the fourth sliding shell 82. A second sliding column 91 is slidably arranged in the third fixed shell 9, and the third fixed shell 9 is provided with a convex ring for limiting the movement of the second sliding column 91. An L-shaped hole is provided in the second sliding column 91. The upper part of the third fixed shell 9 is threaded with a second threaded rod 92, and the lower part of the second threaded rod 92 is rotatably provided with a second sliding plate 93 sliding in the third fixed shell 9. The lower surface of the second sliding plate 93 is fixed with a fifth spring 94 fixed to the upper side of the second sliding column 91. The side wall of the third fixed shell 9 is fixed and connected with a third conduit 95. The third conduit 95 is communicated with the L-shaped hole on the second sliding column 91. A third sliding plate 96 is slidably arranged in the upper part of the third conduit 95. The elastic force of the fifth spring 94 is adjusted by rotating the second threaded rod 92, which facilitates the control of CO2 penetration into the core sample at different pressures and improves the comprehensiveness of the experimental data.

[0059] When conducting a CO2-water two-phase flow displacement experiment on a core sample, the operator repeats the above operation so that the core sample is circumferentially wrapped by the elastic bag 15. The operator then opens the switch valve on the filling tube 142 and the switch valve on the exhaust pipe 111, wherein the switch valve in the second fixed seat 141 is in a closed state. The operator then injects supercritical CO2 into the second fixed seat 141 through the filling tube 142 and maintains the set pressure intensity of the supercritical CO2 in the second fixed seat 141.

[0060] After the supercritical CO2 is added, the operator closes the switch valve on the filling tube 142 and opens the switch valve in the second fixed seat 141 through the control panel. The control panel simultaneously controls the operation of the second power member 8. The second power member 8 drives the third sliding shell 81 to move downward at a uniform speed through the fourth sliding shell 82 and the fourth spring 83. The movement of the third sliding shell 81 pushes the supercritical CO2 in the second fixed seat 141 to penetrate into the fixed core sample at a stable pressure.

[0061] When the penetration efficiency of supercritical CO2 is slow, the second power part 8 works, and the pressure of the supercritical CO2 squeezes the third sliding shell 81 to move upward relative to the fourth sliding shell 82 and compresses the adjacent fourth spring 83. At the same time, the hydraulic oil in the third sliding shell 81 and the fourth sliding shell 82 squeezes the second sliding column 91 to move upward along the third fixed shell 9 and compresses the fifth spring 94. When the second sliding column 91 moves so that its L-shaped hole is connected to the third conduit 95, the hydraulic oil in the third sliding shell 81 and the fourth sliding shell 82 enters the third conduit 95 through the L-shaped hole of the second sliding column 91. The hydraulic oil will squeeze the third sliding plate 96 upward, so that the supercritical CO2 squeezed on the lower side of the third sliding shell 81 penetrates into the core sample with a stable pressure, thereby improving the stability and accuracy of the testing device.

[0062] Before the test, the operator rotates the second threaded rod 92, which drives the second sliding plate 93 to move, thereby changing the elastic force of the fifth spring 94 in the initial state, thereby facilitating the control of supercritical CO2 to penetrate into the core sample at different pressures, thereby improving the diversity of the test of the device, further simulating the core sample under different pressure states, and further improving the accuracy of the test of the device.

[0063] Supercritical CO2 squeezes the water vapor in the core sample into the first fixed seat 11, causing the pressure in the first fixed seat 11 to gradually increase. After the pressure increases, the second sliding shell 7 is squeezed downward and the third spring 72 is compressed. After the through hole on the second sliding shell 7 is connected to the exhaust pipe 111, the high-pressure gas is gradually discharged from the first fixed seat 11, so that the lower pressure of the core sample remains stable. In this process, the operator changes the spring force between the first sliding plate 71 and the second sliding shell 7 in the initial state by rotating and adjusting the first threaded rod 75, which makes it easier for the operator to simulate the upper and lower sides of the core sample to conduct CO2-water two-phase flow displacement experiments under different pressure conditions, making the experimental data more comprehensive and further improving the accuracy of the experiment. After the test is completed, the operator repeats the above operation to take out the core sample.

[0064] Example 4

[0065] On the basis of Example 3, the present invention further provides an operating method for a CO2-water two-phase flow displacement experiment, based on the above-mentioned CO2-water two-phase flow displacement experimental device, which specifically includes the following steps:

[0066] S1: First, the first power member 12 is started to move the first fixing sleeve 14 upward, wherein the limiting groove of the fixing ring 5 releases the limit on the L-shaped rod 511, and then the object to be measured is placed on the corresponding first sliding shell 3, and then the first power member 12 is started to move the first fixing sleeve 14 downward and reset, and at the same time, the L-shaped rod 511 slides back into the limiting groove of the fixing ring 5, completing the limiting of the first fixing sleeve 14.

[0067] S2: After the object to be measured enters the first fixing sleeve 14, hydraulic oil of corresponding pressure is injected into the elastic bladder 15 and the heating ring 16 and the detection unit 17 are started. The elastic bladder 15 tightly wraps the object to be measured under the pressure of the hydraulic oil, and the heating ring 16 keeps the object to be measured at the set temperature, completing the preparation before the test.

[0068] S3: After completing the preparations before the test, a medium of a specified pressure is injected into the first fixed sleeve 14 through the filling tube 142. At the same time, the first threaded rod 75 and the second threaded rod 92 are adjusted according to the corresponding experimental data. Then, the second power member 8 is started to work. The reciprocating movement of the second sliding column 91 causes the third sliding shell 81 to move and the medium in the first fixed sleeve 14 to penetrate into the object to be measured at a set pressure. Under the action of the reciprocating movement of the second sliding shell 7, the set pressure is maintained in the first fixed seat 11, and the test of the object to be measured is completed. The detection unit 17 records the test data.

[0069] S4: After the test is completed, the heating ring 16 and the detection unit 17 are closed in sequence, and the elastic bag 15 is controlled to reset. Then, the first fixing sleeve 14 is opened by the first power member 12, and the object to be measured is taken out. Subsequently, the first power member 12 is controlled to reset to complete the test experiment.

[0070] The above description of the specific embodiments of the present invention with reference to the accompanying drawings does not limit the scope of the present invention. Any modifications, equivalent substitutions and improvements made by those skilled in the art without departing from the scope and essence of the present invention should be within the scope of the present invention.

Claims

1. A CO2-water core flooding experimental operation method, characterized in that: A CO2-water two-phase flow displacement experimental device is used, which includes a workbench, a first fixed seat is embedded in the middle of the workbench, the side wall of the first fixed seat is connected to an exhaust pipe, a switch valve is installed in the exhaust pipe, a symmetrical first power member is fixed to the workbench, and the symmetrical first power members are jointly installed with a first fixed shell, the first fixed shell is provided with a first fixed sleeve, the inner diameter of the first fixed sleeve is longer than the maximum diameter of the first fixed seat, a second fixed seat is fixed to the upper part of the first fixed sleeve, the side wall of the second fixed seat is connected to a filling pipe for installing the switch valve, an elastic bag is fixed in the first fixed sleeve, a heating ring and evenly distributed detection units are fixed to the side wall of the first fixed sleeve, second fixed sleeves are fixed to the facing sides of the first and second fixed seats, and the two second fixed sleeves are jointly provided with a centering mechanism for locating the object to be measured in the middle of the elastic bag; The elastic bag is embedded with uniformly distributed elastic rings, and the cross section of the elastic ring is an isosceles trapezoid; The centering mechanism includes two first sliding shells symmetrically arranged in an upper and lower direction, wherein the two first sliding shells are respectively slidably arranged on adjacent second fixing sleeves, and a first spring fixed to the adjacent second fixing sleeve is fixed to the side wall of the first sliding shell; The device also includes a uniform exhaust mechanism for controlling the pressure environment of the object to be measured, the uniform exhaust mechanism being arranged on the first fixed seat, the uniform exhaust mechanism including a second sliding shell, the second sliding shell being slidably arranged in the first fixed seat, a first sliding plate being slidably arranged in the first fixed seat, a third spring being fixedly connected between the first sliding plate and the second sliding shell, a limiting ring being fixedly connected in the first fixed seat for limiting the movement of the second sliding shell, the second sliding shell being connected to a second conduit for installing a switch valve, the second conduit penetrating the first sliding plate and the first fixed seat and slidingly cooperating with the two, the second sliding shell being provided with a circular hole for communicating with the exhaust pipe, the first fixed seat being threaded with a first threaded rod, and the first threaded rod being rotatably connected to the first sliding plate; The device also includes a pressing mechanism for uniformly squeezing the medium in the second fixed seat, the pressing mechanism being arranged on the second fixed seat, a switch valve being installed in the second fixed seat, the pressing mechanism including a second power member, the second power member being installed on the second fixed seat, a third sliding shell being slidably arranged in the second fixed seat, a fourth sliding shell being slidably arranged on the third sliding shell and connected to the second power member, a fourth spring being installed between the fourth sliding shell and the third sliding shell, and the fourth sliding shell being provided with a uniform component for constantly discharging the medium in the second fixed seat; The uniform assembly includes a third fixed shell, the third fixed shell is fixedly connected to the fourth sliding shell, and the third fixed shell is communicated with the fourth sliding shell, a second sliding column is slidably provided in the third fixed shell, the second sliding column is provided with an L-shaped hole, the third fixed shell is threadedly provided with a second threaded rod, the second threaded rod is rotatably provided with a second sliding plate that slides in the third fixed shell, a fifth spring is fixed between the second sliding plate and the second sliding column, a side wall of the third fixed shell is communicated with a third conduit, the third conduit is communicated and matched with the L-shaped hole on the second sliding column, and the third sliding plate is slidably provided in the third conduit; The method specifically comprises the following steps: S1: First, the first power member is activated to move the first fixing sleeve upward, wherein the limiting groove of the fixing ring releases the limit on the L-shaped rod, and then the object to be measured is placed on the corresponding first sliding shell. Then, the first power member is activated to move the first fixing sleeve downward and reset, and at the same time, the L-shaped rod slides back into the limiting groove of the fixing ring, completing the limiting of the first fixing sleeve; S2: After the object to be measured enters the first fixing sleeve, hydraulic oil of corresponding pressure is injected into the elastic bladder, and the heating ring and detection unit are activated. The elastic bladder tightly wraps the object to be measured under the pressure of the hydraulic oil, and the heating ring keeps the object to be measured at the set temperature, completing the preparation before the test; S3: After completing the preparations before the test, a medium at a specified pressure is injected into the first fixed sleeve through the filling pipe. At the same time, the first threaded rod and the second threaded rod are adjusted according to the corresponding experimental data. Then, the second power member is started. The reciprocating movement of the second sliding column causes the third sliding shell to move, causing the medium in the first fixed sleeve to penetrate into the object to be measured at the specified pressure. The reciprocating movement of the second sliding shell maintains the specified pressure in the first fixed seat, completing the test of the object to be measured. The detection unit records the test data. S4: After the test is completed, the heating ring and the detection unit are closed in sequence, and the elastic bag is controlled to reset. Then, the first fixing sleeve is opened by the first power member, and the object to be measured is taken out. Subsequently, the first power member is controlled to reset to complete the test experiment.

2. A CO2-water core flooding experimental operation method according to claim 1, characterized in that: A sliding ring is slidingly provided in the first fixed sleeve, and the sliding ring is located on the lower side of the elastic bag and fixed thereto, and a plurality of concentric elastic convex rings are provided on the lower side of the sliding ring, and a plurality of concentric annular grooves are provided on the first fixed seat, and the annular grooves of the first fixed seat are squeezed and fitted with the adjacent elastic convex rings on the sliding ring to improve the sealing between the first fixed seat and the sliding ring.

3. A CO2-water core flooding experimental operation method according to claim 2, characterized in that: The cam is secured to the upper surface of the workbench and is designed to lock the cam, and the cam has a locking mechanism for locking the cam, the locking mechanism being arranged on the workbench, the first fixing shell being slidably engaged with the first fixing sleeve, the locking mechanism comprising a fixing ring, the fixing ring being fixed to the upper surface of the workbench, the fixing ring being provided with a centrally symmetrical limiting groove, the lower portion of the first fixing sleeve being rotatably provided with a rotating ring, the lower surface of the rotating ring being fixed with a symmetrical L-shaped rod, the L-shaped rod being limitedly engaged with the adjacent limiting groove on the fixing ring, the side wall of the first fixing sleeve being fixedly connected to a fixing plate, the fixing plate being installed between the fixing plate and the rotating ring, a torsion spring being fixed between the first fixing shell and the first fixing sleeve, the upper surface of the rotating ring being fixed with symmetrical guide rods, the first fixing shell being provided with a centrally symmetrical guide groove, the guide rod being slidably engaged with the adjacent guide groove on the first fixing shell.

4. A CO2-water core flooding experimental operation method according to claim 3, characterized in that: The invention also includes a pressurizing mechanism for strengthening the sealing between the elastic bag and the object to be measured, the pressurizing mechanism is arranged on the elastic bag, and the elastic bag is provided with evenly distributed grooves. The pressurizing mechanism includes evenly distributed annular sleeves, and the evenly distributed annular sleeves are all fixed in the elastic bag, and the annular sleeves are opposite to the adjacent grooves on the elastic bag. The annular sleeves and the elastic bag cooperate to form an annular cavity filled with hydraulic oil. The elastic bag is fixed with multiple evenly distributed groups of second fixed shells, each group of the second fixed shells includes multiple second fixed shells distributed equidistantly in the circumferential direction, and the number of the multiple groups of the second fixed shells is one less than the number of the evenly distributed grooves on the elastic bag. The multiple groups of the second fixed shells are respectively located in adjacent grooves on the elastic bag. The second fixed shell is slidably provided with a first sliding column that penetrates the elastic bag and is slidably connected to it. The second fixed shell is connected to a first conduit, the first conduit penetrates the adjacent annular sleeve and is fixed to it, and the first conduit is connected to the annular sleeve on its lower side.

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