A simulation experiment device and method for gas drive of a heterogeneous oil reservoir

Abstract

The application relates to a gas drive simulation experiment device and method for a heterogeneous oil reservoir, wherein the device comprises a core clamping system, an injection system and a vacuum pumping system; the core clamping system comprises a first core loader, a second core loader, a first four-way joint, a first three-way joint, a second three-way joint and gas drive communication valves; two outlets of the first four-way joint are respectively connected with inlets of the first core loader and the second core loader; the first core loader and the second core loader are connected through a plurality of gas drive communication valves; outlets of the first core loader and the second core loader are respectively connected with inlets of the first three-way joint and the second three-way joint; the injection system comprises a gas storage intermediate container, a water storage intermediate container and an oil storage intermediate container; a gas-water-oil output header is connected with an inlet of the first four-way joint; the vacuum pumping system comprises a vacuum pump; gas inlets of the vacuum pump are respectively connected with outlets of the first three-way joint and the second three-way joint.

Description

Technical Field

[0001] This invention relates to the field of petroleum extraction technology, specifically to a gas drive simulation experimental device and method for heterogeneous oil reservoirs. Background Technology

[0002] my country has abundant low-permeability oil reservoirs, characterized by low porosity, low permeability, and heterogeneity. During the development of these reservoirs, water injection presents challenges such as high injection pressure, low injection volume, and difficulty in replenishing formation energy. Furthermore, issues like water lock and water sensitivity exist, leading to high development costs, low recovery rates, and unsatisfactory development results.

[0003] Studies have shown that gas injection development in low-permeability reservoirs has significant advantages, such as lower injection pressure, effectively improving injection capacity; avoiding water lock and water sensitivity phenomena; the injected gas can dissolve in crude oil under formation conditions, reducing crude oil viscosity and increasing expansibility, which is beneficial to improving crude oil fluidity; and if oil and gas miscibility is achieved below the formation, the oil recovery rate can be significantly improved. Therefore, gas injection has gradually become one of the new technologies for effectively developing low-permeability heterogeneous reservoirs. In particular, for reservoirs with thick oil layers and a certain dip angle, gas injection at the top of the structure or at high points can form a gravity-stabilized gas injection drive. This utilizes the gravity differentiation of oil and gas to effectively avoid the disadvantages of gas channeling and low displacement efficiency caused by viscous fingering and gravity over-expansion during horizontal gas injection, thereby achieving the goal of improving oil recovery.

[0004] The survey found that current experimental studies on gravity-stabilized gas drive in low-permeability reservoirs mainly use homogeneous physical models, while experimental methods and studies using heterogeneous physical models are relatively few. Even when heterogeneous models are used, they are simply parallel connections of individual homogeneous models. There is no connection or material exchange between the heterogeneous models, which does not conform to the physical property characteristics of interconnected pores between oil layers with different permeabilities in actual heterogeneous reservoirs. Moreover, these heterogeneous models do not reflect the three-dimensional structure of heterogeneous oil layers and are not suitable for experimental studies on gravity-stabilized gas drive. Furthermore, the heterogeneous cores used were produced using a monolithic pressing method, meaning that one part of a core was a low-permeability layer and the other part was a high-permeability layer. Although the low-permeability and high-permeability layers of such cores were connected, this monolithic pressing method could not accurately control the permeability of the low-permeability and high-permeability layers. The permeability of each permeability layer in the pressed core differed greatly from the target value, and the permeability of each layer could not be measured individually. Moreover, the heterogeneous cores produced by monolithic pressing could not simulate the oil reservoir properties of the low-permeability and high-permeability layers at different dip angles.

[0005] In summary, the experimental setups and methods currently reported for gravity-stabilized gas drive in low-permeability heterogeneous reservoirs either fail to reflect the connectivity between oil layers with different permeabilities, fail to simulate the characteristics of different dip angles of oil layers with different permeabilities, or fail to accurately obtain the permeability of each permeable layer. In short, the existing technology does not have a device or method capable of conducting gas drive simulation experiments on heterogeneous reservoirs. Summary of the Invention

[0006] To address the aforementioned problems, the purpose of this invention is to provide a gas drive simulation experimental apparatus and method for heterogeneous oil reservoirs, as there is currently no apparatus or method available in the art capable of conducting gas drive simulation experiments on heterogeneous oil reservoirs.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention discloses a gas drive simulation experimental apparatus for heterogeneous oil reservoirs, comprising:

[0009] The core clamping system includes a first core loader, a second core loader, a first four-way valve, a first three-way valve, a second three-way valve, and pneumatically driven connecting valves. The first four-way valve includes one inlet and three outlets. The first three-way valve and the second three-way valve each include one inlet and two outlets. Two outlets of the first four-way valve are respectively connected to the inlets of the first core loader and the second core loader. The first core loader and the second core loader are connected by several pneumatically driven connecting valves. The outlets of the first core loader and the second core loader are respectively connected to the inlets of the first three-way valve and the second three-way valve.

[0010] The injection system includes a gas storage intermediate container, a water storage intermediate container, and an oil storage intermediate container. The output ends of the gas storage intermediate container, the water storage intermediate container, and the oil storage intermediate container are connected to a gas-water-oil output manifold. The gas-water-oil output manifold is connected to the inlet of the first four-way valve.

[0011] A vacuum system includes a vacuum pump, the inlet of which is connected to the outlets of the first three-way valve and the second three-way valve, respectively.

[0012] The core clamping system is used to clamp the first core loader and the second core loader.

[0013] The injection system is used to inject oil, gas, and water into the first core loader and the second core loader to simulate the oil, gas, and water in a heterogeneous oil reservoir.

[0014] The vacuum system is used to evacuate the interior of the first and second core loaders.

[0015] Preferably, the lower surface of the first core loading device has a plurality of overflow holes distributed along the length of the first core loading device, and the upper surface of the second core loading device has a plurality of return holes distributed along the length of the second core loading device. The positions of the plurality of overflow holes and return holes correspond one-to-one. Each pair of overflow holes and their corresponding return holes are connected by a pipe. Each pair of overflow holes and return holes is provided with a pneumatic connecting valve on the pipe connecting the two pairs of overflow holes and return holes.

[0016] Preferably, the injection system further includes an injection pump, and pistons are provided in the gas storage intermediate container, water storage intermediate container and oil storage intermediate container;

[0017] The gas storage intermediate container, water storage intermediate container, and oil storage intermediate container are connected in parallel to form an intermediate container group. The inlet ends of the gas storage intermediate container, the water storage intermediate container, and the oil storage intermediate container are combined to form the inlet end of the intermediate container group. The inlet end of the intermediate container group is connected to the outlet of the injection pump.

[0018] The outlets of the gas storage intermediate container, the water storage intermediate container, and the oil storage intermediate container are combined to form the outlet of the intermediate container group, and the outlet of the intermediate container group is connected to the inlet of the gas-water-oil output main pipe.

[0019] Preferably, the vacuum system further includes a safety bottle, and the air inlet of the vacuum pump is connected to the outlets of the first three-way valve and the second three-way valve respectively through the safety bottle;

[0020] The air inlet of the vacuum pump is connected to the outlet of the safety bottle, and the inlet of the safety bottle is connected to the outlets of the first three-way valve and the second three-way valve, respectively.

[0021] Preferably, the first core loader and the second core loader are of the same length, the first core loader and the second core loader are located on the same plane perpendicular to the horizontal plane, and the first core loader is located above the second core loader.

[0022] Preferably, the core clamping system further includes a support mechanism, which comprises a first support frame, a second support frame, a first clamping device, a second clamping device, a third clamping device, and a fourth clamping device.

[0023] The first clamping device, the second clamping device, the third clamping device and the fourth clamping device all include a support frame clamping device, a clamping component and a loader clamping device, and the support frame clamping device and the loader clamping device of the same clamping device are connected by the clamping component;

[0024] The support frame clamps of the first clamp device and the third clamp device are respectively fixed to the first support frame by bolts. The support frame clamps of the second clamp device and the fourth clamp device are respectively fixed to the second support frame by bolts. The loader clamps of the first clamp device and the third clamp device are respectively fixed to the ends of the first core loader and the second core loader on the same side by bolts. The loader clamps of the second clamp device and the fourth clamp device are respectively fixed to the ends of the first core loader and the second core loader on the other side by bolts.

[0025] The first and second support frames are marked with scales. The vertical height of the first core loader on the first support frame can be changed by the first and second clamping devices, and the vertical height of the second core loader on the second support frame can be changed by the third and fourth clamping devices. This changes the angle between the first and second core loaders in the horizontal direction to simulate the dip angle of oil layers with different permeability in a heterogeneous reservoir environment.

[0026] Preferably, the clamping component includes a rotating block and a fixed block, one end of the rotating block is fixedly connected to the loader clamp, and the other end of the rotating block is connected to a ball;

[0027] One end of the fixing block is fixedly connected to the support frame clamp, and the other end of the fixing block is provided with a circular groove;

[0028] The sphere is disposed within the circular groove.

[0029] Preferably, it also includes a back pressure control system.

[0030] The back pressure control system includes a first back pressure branch and a second back pressure branch.

[0031] The first back pressure branch includes a first back pressure valve, a first hand-cranked pump, and a second pressure gauge.

[0032] The first back pressure valve includes an inlet and a back pressure port.

[0033] The last remaining outlet of the first three-way valve is connected to the inlet of the first back pressure valve, and the back pressure port of the first back pressure valve is connected to the inlet of the first hand-cranked pump.

[0034] A second pressure gauge is installed on the connecting pipe between the back pressure port of the first back pressure valve and the inlet of the first hand-cranked pump;

[0035] The second back pressure branch includes a second back pressure valve, a second hand-cranked pump, and a third pressure gauge.

[0036] The second back pressure valve includes an inlet and a back pressure port.

[0037] The last remaining outlet of the second three-way valve is connected to the inlet of the second back pressure valve, and the back pressure port of the second back pressure valve is connected to the inlet of the second hand-cranked pump.

[0038] A third pressure gauge is installed on the connecting pipe between the back pressure port of the second back pressure valve and the inlet of the second hand-cranked pump.

[0039] Preferably, it further includes a gas-liquid collection system, which includes a first gas-liquid collection branch and a second gas-liquid collection branch.

[0040] The first gas-liquid collection branch includes a first oil-water volume collector, a first gas-water displacement device, and a first water volume collector. The first back pressure valve also includes an outlet. The outlet of the first back pressure valve is connected to the inlet of the first oil-water volume collector. The outlet of the first oil-water volume collector is connected to the inlet of the first gas-water displacement device. The outlet of the first gas-water displacement device is connected to the inlet of the first water volume collector, thereby realizing the sequential connection of the first three-way valve, the first back pressure valve, the first oil-water volume collector, the first gas-water displacement device, and the first water volume collector.

[0041] The second gas-liquid collection branch includes a second oil-water volume collector, a second gas-water displacement device, and a second water volume collector. The second back pressure valve also includes an outlet. The outlet of the second back pressure valve is connected to the inlet of the second oil-water volume collector. The outlet of the second oil-water volume collector is connected to the inlet of the second gas-water displacement device. The outlet of the second gas-water displacement device is connected to the inlet of the second water volume collector, thereby realizing the sequential connection of the second three-way valve, the second back pressure valve, the second oil-water volume collector, the second gas-water displacement device, and the second water volume collector.

[0042] Secondly, the present invention also discloses a gas drive simulation experimental method for heterogeneous oil reservoirs, employing the aforementioned apparatus, comprising:

[0043] Step A: Use saturated water to measure the permeability of the first and second core loaders respectively;

[0044] Step B: Use saturated oil to determine the saturation of bound water in the first and second core loaders, respectively;

[0045] Step C: Perform hydrocarbon accumulation aging on the first core packer and the second core packer;

[0046] Step D: Gas drive is carried out using different gas injection methods to obtain gravity-stabilized gas drive recovery rates of heterogeneous reservoirs with first and second core loaders under different injection and production methods;

[0047] Step E: Change the angle between the first and second core loaders and the horizontal plane and the core permeability, and repeat Step D to obtain the gas drive recovery rate of heterogeneous reservoirs under different injection and production methods under different oil layer physical properties.

[0048] Compared with the prior art, the beneficial effects of the present invention are:

[0049] (I) This invention provides a gas drive simulation experimental device and method for heterogeneous oil reservoirs. A core clamping system is used to clamp a first core packer and a second core packer; an injection system is used to inject oil, gas, and water into the first core packer 11 and the second core packer to simulate the oil, gas, and water in heterogeneous oil reservoirs; and a vacuum system is used to evacuate the interiors of the first and second core packers. This invention solves the problem that existing technologies lack devices and methods for simulating gas drive experiments in heterogeneous oil reservoirs. The gas drive simulation experimental device for heterogeneous oil reservoirs disclosed in this invention can simulate the connectivity between oil layers with different permeabilities during gas drive in a gravity-stabilized environment, and can also simulate the characteristics of different dip angles of oil layers with different permeabilities. It effectively restores the actual oil layer properties and gravity-stabilized gas drive process, accurately evaluates the effects of different gravity-stabilized gas drive methods on improving the recovery rate of different low-permeability heterogeneous oil reservoirs, and provides guidance for oilfield applications.

[0050] (II) This invention discloses a gas drive simulation experimental device for heterogeneous oil reservoirs. The interconnected overflow and return holes can simulate the connectivity between oil layers with different permeabilities in low-permeability heterogeneous oil reservoirs. During the gas drive process, gas and liquid can exchange between oil layers with different permeabilities, which is more consistent with the actual gas drive process in the field. By changing and measuring the permeability of the first and second core loaders, oil layers with different permeabilities in low-permeability heterogeneous oil reservoirs can be simulated. By changing the angle formed by the first and second core loaders with the horizontal plane, the dip angle of oil layers with different permeabilities in low-permeability heterogeneous oil reservoirs can be simulated. By changing the valves at the inlet and outlet ends of the core loaders, different gas injection methods for reservoir development can be simulated. Attached Figure Description

[0051] Figure 1 This is a schematic diagram of the gas drive simulation experimental device for heterogeneous oil reservoirs provided in Embodiment 1 of the present invention;

[0052] Figure 2 This is a schematic diagram of the structure of the first clamping device, the second clamping device, the third clamping device, or the fourth clamping device provided in Embodiment 1 of the present invention;

[0053] Figure 3 This is a schematic diagram of the clamping component provided in Embodiment 1 of the present invention.

[0054] Explanation of reference numerals in the attached drawings: 11-First core loading device, 12-Second core loading device, 13-First four-way valve, 14-First three-way valve, 15-Second three-way valve, 16-Pneumatic connecting valve, 161-Overflow hole, 162-Return hole; 101-Ninth valve, 102-Tenth valve, 103-Eleventh valve, 104-Twelfth valve, 105-Thirteenth valve, 110-First pressure gauge;

[0055] 20-Injection pump, 21-Gas storage intermediate container, 22-Water storage intermediate container, 23-Oil storage intermediate container, 201-First valve, 202-Second valve, 203-Third valve, 204-Fourth valve, 205-Fifth valve, 206-Sixth valve;

[0056] 30 - Vacuum pump, 31 - Safety bottle, 301 - Seventh valve, 302 - Eighth valve;

[0057] 41-First support frame, 42-Second support frame, 43-Support frame clamp, 44-Loader clamp, 451-Rotating block, 452-Fixing block, 453-Spherical ball, 454-Circular groove, 401-First clamp device, 402-Second clamp device, 403-Third clamp device, 404-Fourth clamp device;

[0058] 51-First back pressure valve, 52-First hand-cranked pump, 501-Second pressure gauge, 502-Fourteenth valve, 503-Fifteenth valve;

[0059] 61-Second back pressure valve, 62-Second hand pump, 601-Third pressure gauge, 602-Sixteenth valve, 603-Seventeenth valve;

[0060] 71-First oil-water volume collector, 72-First gas-water displacement device, 73-First water volume collector

[0061] 81-Second oil-water volume collector, 82-Second gas-water exchanger, 83-Second water volume collector.

[0062] The "-" indicates "for". Detailed Implementation

[0063] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the invention and to fully convey the scope of the invention to those skilled in the art.

[0064] Example 1: A gas drive simulation experimental device for heterogeneous oil reservoirs

[0065] Example 1 provides a gas drive simulation experimental device for heterogeneous oil reservoirs. Its structure is described in detail below with reference to the accompanying drawings.

[0066] refer to Figure 1 The gas drive simulation experimental device for this heterogeneous reservoir includes a core clamping system, an injection system, a vacuum pumping system, a back pressure control system, and a gas-liquid collection system.

[0067] The core clamping system includes a first core loader 11, a second core loader 12, a first four-way connector 13, a first three-way connector 14, and a second three-way connector 15. The first four-way connector 13 includes one inlet and three outlets. The first three-way connector 14 and the second three-way connector 15 each include one inlet and two outlets. Two outlets of the first four-way connector 13 are respectively connected to the inlets of the first core loader 11 and the second core loader 12. The first core loader 11 and the second core loader 12 are connected by a plurality of pneumatically driven connecting valves 16. The outlets of the first core loader 11 and the second core loader 12 are respectively connected to the inlets of the first three-way connector 14 and the second three-way connector 15.

[0068] The injection system includes a gas storage intermediate container 21, a water storage intermediate container 22, and an oil storage intermediate container 23. The output ends of the gas storage intermediate container 21, the water storage intermediate container 22, and the oil storage intermediate container 23 are connected to a gas-water-oil output main pipe, which is connected to the inlet of the first four-way valve 13.

[0069] The vacuum system includes a vacuum pump 30, the inlet of which is connected to the outlets of the first three-way valve 14 and the second three-way valve 15, respectively.

[0070] Among them, the first core packer 11 and the second core packer 12 are respectively filled with quartz sand of 100-180 mesh, which are used to simulate the formation of the oil reservoir;

[0071] The intermediate water storage container 22 stores a 1% NaCl solution to simulate formation water;

[0072] The core clamping system is used to clamp the first core loader 11 and the second core loader 12.

[0073] The injection system is used to inject oil, gas and water into the first core loader 11 and the second core loader 12 to simulate the oil, gas and water of a heterogeneous oil reservoir.

[0074] The vacuum system is used to evacuate the interior of the first core loader 11 and the second core loader 12.

[0075] The first core loading device 11 has several overflow holes 161 distributed on its lower surface along its length, and the second core loading device 12 has several return holes 162 distributed on its upper surface along its length. The positions of the overflow holes 161 and the return holes 162 are respectively one-to-one. Each pair of overflow holes 161 and their corresponding return holes 162 are connected by a pipe. Each pair of overflow holes 161 and return holes 162 is provided with a pneumatic valve 16 on the pipe connecting them.

[0076] Due to the influence of flow drive and the inner diameter of the experimental tube, it is difficult for gas and liquid to flow in different directions within a single tube. The flow properties of gas and liquid differ significantly from the actual underground conditions. Therefore, it is necessary to set up several overflow holes 161 and return holes 162 to allow gas and liquid to be transferred between core packers with different permeability. The overflow holes 161 and return holes 162 are arranged axially to better simulate the flow of gas and liquid between core packers with different permeability in the gas drive direction.

[0077] During the gas drive process, due to the gravitational separation of gas and liquid, the gas will gradually flow to the upper part of the first core packer 11 and the second core packer 12, while the liquid will gradually flow to the lower part of the first core packer 11 and the second core packer 12. The overflow hole 161 and the return hole 162 provide a transmission channel for the flow of gas and liquid between core packers with different permeability, simulating the displacement front characteristics of gas in low-permeability heterogeneous reservoirs.

[0078] Furthermore, the injection system also includes an injection pump 20, and pistons are provided in the gas storage intermediate container 21, the water storage intermediate container 22 and the oil storage intermediate container 23;

[0079] The gas storage intermediate container 21, water storage intermediate container 22, and oil storage intermediate container 23 are connected in parallel to form an intermediate container group. The inlet ends of the gas storage intermediate container 21, water storage intermediate container 22, and oil storage intermediate container 23 are combined to form the inlet end of the intermediate container group. The inlet end of the intermediate container group is connected to the outlet of the injection pump 20.

[0080] The outlets of the gas storage intermediate container 21, the water storage intermediate container 22, and the oil storage intermediate container 23 are combined to form the outlet of the intermediate container group, and the outlet of the intermediate container group is connected to the inlet of the gas-water-oil output main pipe.

[0081] The gas storage intermediate container 21, water storage intermediate container 22, oil storage intermediate container 23 and the inlet end of the intermediate container group are respectively equipped with a first valve 201, a second valve 202 and a third valve 203; the gas storage intermediate container 21, water storage intermediate container 22, oil storage intermediate container 23 and the inlet of the gas-water-oil output main pipe are respectively equipped with a fourth valve 204, a fifth valve 205 and a sixth valve 206.

[0082] Furthermore, the vacuum system also includes a safety bottle 31, and the air inlet of the vacuum pump 30 is connected to the outlets of the first three-way valve 14 and the second three-way valve 15 respectively through the safety bottle 31;

[0083] The air inlet of the vacuum pump 30 is connected to the outlet of the safety bottle 31, and the inlet of the safety bottle 31 is connected to the outlets of the first three-way valve 14 and the second three-way valve 15, respectively.

[0084] The pipe connecting the first three-way valve 14 and the safety bottle 31 is equipped with a seventh valve 301, and the pipe connecting the second three-way valve 15 and the safety bottle 31 is equipped with an eighth valve 302.

[0085] In one specific implementation, the first core loader 11 and the second core loader 12 are of the same length, the first core loader 11 and the second core loader 12 are located on the same plane perpendicular to the horizontal plane, and the first core loader 11 is located above the second core loader 12.

[0086] To simulate the dip angle of oil layers with different permeabilities in heterogeneous reservoir environments, one specific implementation includes a core clamping system that further comprises a support mechanism. This support mechanism includes a first support frame 41, a second support frame 42, a first clamping device 401, a second clamping device 402, a third clamping device 403, and a fourth clamping device 404.

[0087] The first clamping device 401, the second clamping device 402, the third clamping device 403, and the fourth clamping device 404 all include a support frame clamping device 43, a clamping component, and a loader clamping device 44. The support frame clamping device 43 and the loader clamping device 44 of the same clamping device are connected by the clamping component, such as... Figure 2 As shown;

[0088] The support frame clamps 43 of the first clamp device 401 and the third clamp device 403 are respectively fixed to the first support frame 41 by bolts. The support frame clamps 43 of the second clamp device 402 and the fourth clamp device 404 are respectively fixed to the second support frame 42 by bolts. The loader clamps 44 of the first clamp device 401 and the third clamp device 403 are respectively fixed to the ends of the first core loader 11 and the second core loader 12 on the same side by bolts. The loader clamps 44 of the second clamp device 402 and the fourth clamp device 404 are respectively fixed to the ends of the first core loader 11 and the second core loader 12 on the other side by bolts.

[0089] The first support frame 41 and the second support frame 42 are marked with scales. The first core loading device 11 can be changed on the first support frame 41 by the first clamping device 401 and the second clamping device 402. The second core loading device 12 can be changed on the second support frame 42 by the third clamping device 403 and the fourth clamping device 404. In this way, the angle between the first core loading device 11 and the second core loading device 12 in the horizontal direction can be changed to simulate the dip angle of oil layers with different permeability in a heterogeneous oil reservoir environment.

[0090] Specifically, after the distance between the first support frame 41 and the second support frame 42 is fixed, the angle between the first core loading device 11 and the second core loading device 12 and the horizontal plane can be obtained by reading the scale of the support frame clamp 43 on the first support frame 41 and the second support frame 42 according to the trigonometric function relationship. This part of the knowledge is common knowledge in textbooks and will not be elaborated here.

[0091] Furthermore, the first clamp device 401 and the third clamp device 403 are connected by the first support frame 41 and are vertically supported on the ground, and the second clamp device 402 and the fourth clamp device 404 are connected by the second support frame 42 and are vertically supported on the ground. The bottom of the first support frame 41 and the bottom of the second support frame 42 are fixed on the same horizontal plane.

[0092] To facilitate fixing the first core loader 11 and the second core loader 12 at different angles, and to better simulate the different dip angles of oil layers with different permeability in low-permeability heterogeneous reservoirs, a specific embodiment is that the clamping component includes a rotating block 451 and a fixing block 452, such as... Figure 3 As shown.

[0093] One end of the rotating block 451 is fixedly connected to the loader clamp 44, and the other end of the rotating block 451 is connected to a ball 453;

[0094] One end of the fixing block 452 is fixedly connected to the support frame clamp 43, and the other end of the fixing block 452 is provided with a circular groove 454;

[0095] The sphere 453 is disposed within the circular groove 454.

[0096] In order to detect the pressure of the first four-way valve 13, the first four-way valve 13 is equipped with a first pressure gauge 110. The inlets of the first pressure gauge 110, the first core loading device 11, and the second core loading device 12 are respectively connected to the three outlets of the first four-way valve 13.

[0097] For ease of control, the core clamping system is equipped with multiple valves, specifically:

[0098] A ninth valve 101 is installed on the pipe between the outlet of the first core loading device 11 and the outlet of the first four-way valve 13, and a tenth valve 102 is installed on the pipe between the outlet of the second core loading device 12 and the outlet of the first four-way valve 13.

[0099] An eleventh valve 103 is provided on the pipeline between the outlet of the first pressure gauge 110 and the outlet of the first four-way valve 13;

[0100] A twelfth valve 104 is provided on the pipe between the outlet of the first core loading device 11 and the inlet of the first tee 14;

[0101] A thirteenth valve 105 is provided on the pipeline between the outlet of the second core packer 12 and the inlet of the second tee 15.

[0102] In one specific implementation, the back pressure control system includes a first back pressure branch and a second back pressure branch.

[0103] The first back pressure branch includes a first back pressure valve 51, a first hand-cranked pump 52, and a second pressure gauge 501.

[0104] The first back pressure valve 51 includes an inlet and a back pressure port. The last remaining outlet of the first three-way valve 14 is connected to the inlet of the first back pressure valve 51, and the back pressure port of the first back pressure valve 51 is connected to the inlet of the first hand pump 52.

[0105] A second pressure gauge 501 is installed on the connecting pipe between the back pressure port of the first back pressure valve 51 and the inlet of the first hand-cranked pump 52.

[0106] Furthermore, a fourteenth valve 502 is provided on the pipeline between the first tee 14 and the first back pressure valve 51, and a fifteenth valve 503 is also provided on the connecting pipeline between the first back pressure valve 51 and the first hand-cranked pump 52.

[0107] The second back pressure branch includes a second back pressure valve 61, a second hand-cranked pump 62, and a third pressure gauge 601.

[0108] The second back pressure valve 61 includes an inlet and a back pressure port. The last remaining outlet of the second three-way valve 15 is connected to the inlet of the second back pressure valve 61, and the back pressure port of the second back pressure valve 61 is connected to the inlet of the second hand pump 62.

[0109] A third pressure gauge 601 is installed on the connecting pipe between the back pressure port of the second back pressure valve 61 and the inlet of the second hand-cranked pump 62.

[0110] Furthermore, a sixteenth valve 602 is provided on the pipeline between the second three-way valve 15 and the second back pressure valve 61, and a seventeenth valve 603 is also provided on the connecting pipeline between the second back pressure valve 61 and the second hand-cranked pump 62.

[0111] In one specific implementation, the gas-liquid collection system includes a first gas-liquid collection branch and a second gas-liquid collection branch.

[0112] The first gas-liquid collection branch includes a first oil-water volume collector 71, a first gas-water displacement device 72, and a first water volume collector 73. The first back pressure valve 51 also includes an outlet. The outlet of the first back pressure valve 51 is connected to the inlet of the first oil-water volume collector 71, the outlet of the first oil-water volume collector 71 is connected to the inlet of the first gas-water displacement device 72, and the outlet of the first gas-water displacement device 72 is connected to the inlet of the first water volume collector 73, thereby realizing the sequential connection of the first three-way valve 14, the first back pressure valve 51, the first oil-water volume collector 71, the first gas-water displacement device 72, and the first water volume collector 73.

[0113] The second gas-liquid collection branch includes a second oil-water volume collector 81, a second gas-water displacement device 82, and a second water volume collector 83. The second back pressure valve 61 also includes an outlet. The outlet of the second back pressure valve 61 is connected to the inlet of the second oil-water volume collector 81, the outlet of the second oil-water volume collector 81 is connected to the inlet of the second gas-water displacement device 82, and the outlet of the second gas-water displacement device 82 is connected to the inlet of the second water volume collector 83. This achieves the sequential connection of the second three-way valve 15, the second back pressure valve 61, the second oil-water volume collector 81, the second gas-water displacement device 82, and the second water volume collector 83.

[0114] Before the injection pump 20 injects pure water, the upper part of the gas storage intermediate container 21 stores gas, the upper part of the water storage intermediate container 22 stores simulated formation water, and the upper part of the oil storage intermediate container 23 stores oil.

[0115] Mass transport process:

[0116] The injection pump 20 injects pure water into the gas storage intermediate container 21, the water storage intermediate container 22, and the oil storage intermediate container 23. The gas, simulated formation water, and oil stored in the upper part of the gas storage intermediate container 21, the water storage intermediate container 22, and the oil storage intermediate container 23 flow into the first four-way valve 13 through the output main pipe of the injection system, and flow into the first core loader 11 and / or the second core loader 12, respectively.

[0117] The gas drive process is simulated in the first core loader 11 and / or the second core loader 12;

[0118] After the first core loader 11 and / or the second core loader 12 complete the simulated gas drive process, the oil, gas, water and other substances flow into the first three-way valve 14 and the second three-way valve 15 respectively.

[0119] Among them, the first back pressure branch that flows into the back pressure control system through the first three-way valve 14 is finally collected by the first gas-liquid collection branch of the gas-liquid collection system.

[0120] The water flows into the second back pressure branch of the back pressure control system through the second three-way valve 15, and is finally collected by the second gas-liquid collection branch of the gas-liquid collection system.

[0121] Example 2: A gas drive simulation experimental method for heterogeneous oil reservoirs

[0122] Example 2 provides a gas drive simulation experiment method for heterogeneous oil reservoirs, using the gas drive simulation experiment apparatus for heterogeneous oil reservoirs from Example 1. The preparatory work before the experiment includes:

[0123] (1) The first valve 201, the second valve 202 and the third valve 203, the fourth valve 204, the fifth valve 205 and the sixth valve 206, the seventh valve 301 and the eighth valve 302, the ninth valve 101 and the tenth valve 102, the eleventh valve 103, the twelfth valve 104 and the thirteenth valve 105, the fourteenth valve 502 and the fifteenth valve 503, the sixteenth valve 602 and the seventeenth valve 603 are all in the closed state;

[0124] (2) The vertical height of the first core loading device 11 on the first support frame 41 is changed by the first clamping device 401 and the second clamping device 402, and the vertical height of the second core loading device 12 on the second support frame 42 is changed by the third clamping device 403 and the fourth clamping device 404, thereby changing the angle between the first core loading device 11 and the second core loading device 12 in the horizontal direction respectively. Finally, the core loading device 11 is fixed on the first support frame 41 and the second support frame 42, and the length and inner diameter of the first core loading device 11 and the second core loading device 12 are measured.

[0125] The experimental method includes the following steps:

[0126] Step A: The permeability of the first core packer 11 and the second core packer 12 was determined using saturated water, including the following specific steps:

[0127] Step A1: Determine the permeability of the first core packer 11, including the following specific steps:

[0128] First, a vacuum was drawn on the first core loading device 11;

[0129] Specifically, the twelfth valve 104 and the seventh valve 301 are opened to evacuate the first core packer 11 for 6 hours.

[0130] Then, start the injection pump 20 to inject the solution in the intermediate water storage container 22 into the first core loading device 11 until it is saturated;

[0131] Specifically, open the second valve 202, the fifth valve 205, and the ninth valve 101, start the injection pump 20 and maintain its working state for 6 hours, and inject the solution in the intermediate water storage container 22 into the first core loading device 11 at a flow rate of 0.01 ml / min until saturation.

[0132] Finally, the water flowing out of the first core packer 11 is collected by the first oil-water volume collector 71 until the pressure of the first pressure gauge 110 stabilizes. The pressure value of the first pressure gauge 110, the pumping volume of the injection pump 20, and the volume of water collected by the first oil-water volume collector 71 for the first time are recorded to obtain the permeability of the first core packer 11.

[0133] Specifically, the twelfth valve 104, the seventh valve 301, the second valve 202, and the fifth valve 205 are closed, while the ninth valve 101 remains open. The third valve 203, the sixth valve 206, the twelfth valve 104, and the fourteenth valve 502 are opened. Water collected by the first oil-water volume collector 71 is collected until the pressure of the first pressure gauge 110 stabilizes. The pressure value of the first pressure gauge 110, the pumping volume of the injection pump 20, and the first water volume collected by the first oil-water volume collector 71 are recorded to obtain the permeability of the first core packer 11.

[0134] Step A2: Using the same method as described above, determine the permeability of the second core packer 12, including the following specific steps:

[0135] First, a vacuum was drawn on the second core loading device 12;

[0136] Specifically, the thirteenth valve 105 and the eighth valve 302 are opened to evacuate the second core packer 12 for 6 hours.

[0137] Then, start the injection pump 20 to inject the solution in the intermediate water storage container 22 into the second core loading device 12 until saturation;

[0138] Specifically, open the second valve 202, the fifth valve 205, and the tenth valve 102, start the injection pump 20 and maintain its working state for 6 hours, and inject the solution in the intermediate water storage container 22 into the second core loading device 12 at a flow rate of 0.01 ml / min until saturation.

[0139] Finally, water flowing out of the second core packer 12 is collected by the second oil-water volume collector 81 until the pressure of the first pressure gauge 110 stabilizes. The pressure value of the first pressure gauge 110, the pumping volume of the injection pump 20, and the volume of water collected by the second oil-water volume collector 81 for the first time are recorded to obtain the permeability of the second core packer 12.

[0140] Specifically, the thirteenth valve 105, the eighth valve 302, the second valve 202, and the fifth valve 205 are closed, while the tenth valve 102 remains open. The third valve 203, the sixth valve 206, the thirteenth valve 105, and the sixteenth valve 602 are opened. Water collected by the second oil-water volume collector 81 is collected until the pressure of the first pressure gauge 110 stabilizes. The pressure value of the first pressure gauge 110, the pumping volume of the syringe pump 20, and the first water volume collected by the second oil-water volume collector 81 are recorded to obtain the permeability of the second oil-water volume collector 81.

[0141] Step B: Use saturated oil to determine the saturation of bound water in the first core packer 11 and the second core packer 12 respectively;

[0142] Step B1: Determine the saturation of bound water in the first core packer 11, including the following specific steps:

[0143] First, the rated pressure P1 is set to the first back pressure valve 51 by the first hand-cranked pump 52;

[0144] Specifically, the fifteenth valve 503 is opened, the first hand pump 52 is used to set the rated pressure P1 to the first back pressure valve 51, and the fifteenth valve 503 is closed.

[0145] Secondly, the crude oil in the intermediate oil storage container 23 is injected into the first core loading device 11 after being saturated with water by the injection pump 20 to carry out oil-water displacement until no water flows out of the first oil-water volume collector 71.

[0146] Specifically, the third valve 203, the sixth valve 206, the ninth valve 101, the twelfth valve 104, and the fourteenth valve 502 are opened, and the crude oil in the intermediate oil storage container 23 is injected into the first core loading device 11 after it has been saturated with water at a flow rate of 0.01 ml / min through the injection pump 20 to carry out oil-water displacement until no water flows out of the first oil-water volume collector 71.

[0147] Finally, based on the second sampling of water and oil volumes by the first oil-water volume collector 71, the bound water saturation of the first core packer 11 is obtained.

[0148] Step B2: Perform oil-water displacement on the second core packer 12 using the same method to obtain the bound water saturation of the second core packer 12, including the following specific steps:

[0149] First, the rated pressure P1 is set to the second back pressure valve 61 by the second hand pump 62;

[0150] Specifically, the seventeenth valve 603 is opened, the first hand pump 52 is used to set the rated pressure P1 to the first back pressure valve 51, and the seventeenth valve 603 is closed.

[0151] Secondly, the crude oil in the intermediate oil storage container 23 is injected into the second core loading device 12 after being saturated with water by the injection pump 20 to carry out oil-water displacement until no water flows out of the second oil-water volume collector 81.

[0152] Specifically, the third valve 203, the sixth valve 206, the tenth valve 102, the thirteenth valve 105, and the sixteenth valve 602 are opened. The crude oil in the intermediate oil storage container 23 is injected into the second core loading device 12 after it has been saturated with water at a flow rate of 0.01 ml / min through the injection pump 20 to carry out oil-water displacement until no water flows out of the second oil-water volume collector 81.

[0153] Finally, based on the second oil-water volume collector 81 collecting the water and oil volumes for the second time, the bound water saturation of the second core packer 12 is obtained.

[0154] Step C: Perform hydrocarbon accumulation aging on the first core packer 11 and the second core packer 12;

[0155] Specifically, the storage and aging process is carried out at 60℃ for 3 to 5 days.

[0156] Step D: Gas drive is carried out using different gas injection methods to obtain gravity-stabilized gas drive recovery rates of heterogeneous reservoirs under different injection and production methods for the first core loader 11 and the second core loader 12.

[0157] Among them, the gas drive using different gas injection methods includes the same injection and extraction gas drive method, the top injection and bottom extraction gas drive method, the top injection and top extraction gas drive method, the bottom injection and bottom extraction gas drive method, and the bottom injection and top extraction gas drive method.

[0158] Specifically, the gas-driven injection and production method is as follows: nitrogen gas is injected into the first core loading device 11 and the second core loading device 12 at a rate of 0.2 mL / min to conduct a gas-driven oil experiment until no oil flows out of the first oil-water volume collector 71 and the second oil-water volume collector 81. The change in the value of the first pressure gauge 110 during the displacement process is recorded. The volume of oil flowing out at different displacement times is measured by the first oil-water volume collector 71 and the second oil-water volume collector 81. The volume of water flowing out at different displacement times is measured by the first water volume collector 73 and the second water volume collector 83. The volume of water flowing out collected by the first water volume collector 73 is the volume of gas exiting from the outlet end of the first core loading device 11, and the volume of water flowing out collected by the second water volume collector 83 is the volume of gas exiting from the outlet end of the second core loading device 12.

[0159] The above-injection and below-production gas drive method is as follows: nitrogen gas is injected into the first core loading device 11 at a rate of 0.2 mL / min to conduct a gas-driven oil experiment until no oil flows out of the second oil-water volume collector 81. The changes in the first pressure gauge 110 during the displacement process are recorded. The volume of oil flowing out at different displacement times is measured by the second oil-water volume collector 81, and the volume of water flowing out at different displacement times is measured by the second water volume collector 83. The volume of water flowing out collected by the second water volume collector 83 is the volume of gas exiting from the outlet end of the second core loading device 12.

[0160] The above-injection and above-production gas drive method is as follows: nitrogen gas is injected into the first core loading device 11 at a rate of 0.2 mL / min to carry out gas-driven oil experiments until no oil flows out of the first oil-water volume collector 71. The changes of the first pressure gauge 110 during the displacement process are recorded. The volume of oil flowing out at different displacement times is measured by the first oil-water volume collector 71, and the volume of water flowing out at different displacement times is measured by the first water volume collector 73. The volume of water flowing out collected by the first water volume collector 73 is the volume of gas exiting from the outlet end of the first core loading device 11.

[0161] The gas-driven injection method is as follows: nitrogen gas is injected into the second core loading device 12 at a rate of 0.2 mL / min to conduct a gas-driven oil experiment until no oil flows out of the second oil-water volume collector 81. The changes in the first pressure gauge 110 during the displacement process are recorded. The volume of oil flowing out at different displacement times is measured by the second oil-water volume collector 81, and the volume of water flowing out at different displacement times is measured by the second water volume collector 83. The volume of water flowing out collected by the second water volume collector 83 is the volume of gas exiting from the outlet end of the second core loading device 12.

[0162] The gas-driven injection method is as follows: gas is injected into the first core loading device 11 at a constant speed or pressure difference to conduct a gas-driven oil experiment until no oil flows out of the first oil-water volume collector 71. The changes in the first pressure gauge 110 during the displacement process are recorded. The volume of oil flowing out at different displacement times is measured by the first oil-water volume collector 71, and the volume of water flowing out at different displacement times is measured by the first water volume collector 73. The volume of water flowing out collected by the first water volume collector 73 is the volume of gas exiting from the outlet end of the first core loading device 11.

[0163] The angle between the first core loading device 11 and the second core loading device 12 and the horizontal plane is changed by moving the relative positions of the support frame clamps in the first clamping device 401, the second clamping device 402, the third clamping device 403 and the fourth clamping device 404 on the first support frame and the second support frame.

[0164] Step E: Change the angle between the first core loader 11 and the second core loader 12 and the horizontal plane, and the core permeability. Repeat step D to obtain the gas drive recovery rate of heterogeneous reservoirs under different injection and production methods under different oil layer physical properties.

[0165] By moving the relative positions of the support rod clamps in the first clamping device 401, the second clamping device 402, the third clamping device 403, and the fourth clamping device 404 on the first and second support rods, the angle between the first core loading device 11 and the second core loading device 12 and the horizontal plane is changed, as well as the permeability of the core loading device is changed. Step D is repeated to obtain the gas drive recovery rate of heterogeneous reservoirs under different injection and production methods under different oil layer physical properties.

[0166] Experimental results show that among several gas drive methods, the top-injection-bottom-production gas drive method has the highest recovery rate. This development method exhibits a significant gravity-stabilized gas drive effect, consistent with the field development results. Furthermore, the larger the angle between the core loading device and the horizontal plane, the smaller the range of the ratio of permeability of the first core loading device to that of the second core loading device, and the higher the recovery rate, which conforms to the objective laws governing the effect of gravity-stabilized gas drive. The data obtained by the device of this invention are accurate, and the method is feasible.

[0167] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A gas drive simulation experimental device for heterogeneous oil reservoirs, characterized in that, include The core clamping system includes a first core loader (11), a second core loader (12), a first four-way valve (13), a first three-way valve (14), a second three-way valve (15), and a pneumatically driven connecting valve (16). The first four-way valve (13) includes one inlet and three outlets. The first three-way valve (14) and the second three-way valve (15) each include one inlet and two outlets. Two outlets of the first four-way valve (13) are respectively connected to the inlets of the first core loader (11) and the second core loader (12). The first core loader (11) and the second core loader (12) are connected by several pneumatically driven connecting valves (16). The outlets of the two core loading devices (12) are respectively connected to the inlets of the first tee (14) and the second tee (15); the lower surface of the first core loading device (11) has a number of overflow holes (161) distributed along the length of the first core loading device (11), and the upper surface of the second core loading device (12) has a number of return holes (162) distributed along the length of the second core loading device (12). The positions of the overflow holes (161) and the return holes (162) are respectively one-to-one. Each pair of overflow holes (161) and the corresponding return holes (162) are connected by a pipe. Each pair of overflow holes (161) and the return holes (162) are connected by a gas-driven connecting valve (16). The core clamping system also includes a support mechanism, which comprises a first support frame (41), a second support frame (42), a first clamping device (401), a second clamping device (402), a third clamping device (403), and a fourth clamping device (404). Each of the first clamping device (401), the second clamping device (402), the third clamping device (403), and the fourth clamping device (404) includes a support frame clamping device (43), clamping components, and a loading device clamping device (44). The support frame clamp (43) and the loader clamp (44) of the same clamping device are connected by clamping components; the support frame clamps (43) of the first clamping device (401) and the third clamping device (403) are respectively fixed to the first support frame (41) by bolts, and the support frame clamps (43) of the second clamping device (402) and the fourth clamping device (404) are respectively fixed to the second support frame (42) by bolts, and the first clamping device (401) and the third clamping device (403) are respectively fixed to the second support frame (41) by bolts. The loading clamps (44) of the 03) are respectively fixed to the ends of the first core loading device (11) and the second core loading device (12) on the same side by bolts. The loading clamps (44) of the second clamp device (402) and the fourth clamp device (404) are respectively fixed to the ends of the first core loading device (11) and the second core loading device (12) on the other side by bolts. Among them, the first support frame (41) and the second support frame (42) are marked with scales. The device (401) and the second clamp device (402) can change the vertical height of the first core loader (11) on the first support frame (41). The third clamp device (403) and the fourth clamp device (404) can change the vertical height of the second core loader (12) on the second support frame (42), thereby changing the angle between the first core loader (11) and the second core loader (12) in the horizontal direction to simulate the dip angle of oil layers with different permeability in a heterogeneous reservoir environment. The injection system includes a gas storage intermediate container (21), a water storage intermediate container (22), an oil storage intermediate container (23), and an injection pump (20). The output ends of the gas storage intermediate container (21), the water storage intermediate container (22), and the oil storage intermediate container (23) are connected to a gas-water-oil output manifold, which is connected to the inlet of the first four-way valve (13). Each of the gas storage intermediate container (21), the water storage intermediate container (22), and the oil storage intermediate container (23) is equipped with a piston. The gas storage intermediate container (21), the water storage intermediate container (22), and the oil storage intermediate container (23) are connected to an injection pump (20). 2) The intermediate oil storage containers (23) are connected in parallel to form an intermediate container group. The inlet ends of the intermediate gas storage container (21), the intermediate water storage container (22), and the intermediate oil storage container (23) are combined to form the inlet end of the intermediate container group. The inlet end of the intermediate container group is connected to the outlet of the injection pump (20). The outlet ends of the intermediate gas storage container (21), the intermediate water storage container (22), and the intermediate oil storage container (23) are combined to form the outlet end of the intermediate container group. The outlet end of the intermediate container group is connected to the inlet of the gas-water-oil output main pipe. The vacuum system includes a vacuum pump (30) and a safety bottle (31). The inlet of the vacuum pump (30) is connected to the outlets of the first three-way valve (14) and the second three-way valve (15), respectively. The inlet of the vacuum pump (30) is connected to the outlets of the first three-way valve (14) and the second three-way valve (15) through the safety bottle (31). The inlet of the vacuum pump (30) is connected to the outlet of the safety bottle (31), and the inlet of the safety bottle (31) is connected to the outlets of the first three-way valve (14) and the second three-way valve (15), respectively. The clamping component includes a rotating block (451) and a fixed block (452). One end of the rotating block (451) is fixedly connected to the loader clamp (44), and the other end of the rotating block (451) is connected to a ball (453). One end of the fixed block (452) is fixedly connected to the support frame clamp (43), and the other end of the fixed block (452) is provided with a circular groove (454). The ball (453) is disposed in the circular groove (454). A back pressure control system is provided, comprising a first back pressure branch and a second back pressure branch. The first back pressure branch includes a first back pressure valve (51), a first hand-cranked pump (52), and a second pressure gauge (501). The first back pressure valve (51) includes an inlet and a back pressure port. The last remaining outlet of the first tee (14) is connected to the inlet of the first back pressure valve (51), and the back pressure port of the first back pressure valve (51) is connected to the inlet of the first hand-cranked pump (52). A connecting pipe is provided between the back pressure port of the first back pressure valve (51) and the inlet of the first hand-cranked pump (52). A second pressure gauge (501) is installed on the pipeline; the second back pressure branch includes a second back pressure valve (61), a second hand pump (62) and a third pressure gauge (601). The second back pressure valve (61) includes an inlet and a back pressure port. The last remaining outlet of the second tee (15) is connected to the inlet of the second back pressure valve (61), and the back pressure port of the second back pressure valve (61) is connected to the inlet of the second hand pump (62). A third pressure gauge (601) is installed on the connecting pipeline between the back pressure port of the second back pressure valve (61) and the inlet of the second hand pump (62). A gas-liquid collection system, comprising a first gas-liquid collection branch and a second gas-liquid collection branch, The first gas-liquid collection branch includes a first oil-water volume collector (71), a first gas-water exchanger (72), and a first water volume collector (73). The first back pressure valve (51) also includes an outlet. The outlet of the first back pressure valve (51) is connected to the inlet of the first oil-water volume collector (71). The outlet of the first oil-water volume collector (71) is connected to the inlet of the first gas-water exchanger (72). The outlet of the first gas-water exchanger (72) is connected to the inlet of the first water volume collector (73). This enables the first three-way valve (14), the first back pressure valve (51), the first oil-water volume collector (71), the first gas-water exchanger (72), and the first water volume collector (73) to be connected in sequence. The second gas-liquid collection branch includes a second oil-water volume collector (81), a second gas-water displacement device (82), and a second water volume collector (83). The second back pressure valve (61) also includes an outlet. The outlet of the second back pressure valve (61) is connected to the inlet of the second oil-water volume collector (81). The outlet of the second oil-water volume collector (81) is connected to the inlet of the second gas-water displacement device (82). The outlet of the second gas-water displacement device (82) is connected to the inlet of the second water volume collector (83). This achieves the sequential connection of the second three-way valve (15), the second back pressure valve (61), the second oil-water volume collector (81), the second gas-water displacement device (82), and the second water volume collector (83). The core clamping system is used to clamp the first core loader (11) and the second core loader (12). The injection system is used to inject oil, gas and water into the first core loader (11) and the second core loader (12) to simulate the oil, gas and water of a heterogeneous oil reservoir; The vacuum system is used to evacuate the interior of the first core loader (11) and the second core loader (12).

2. The gas drive simulation experimental apparatus for heterogeneous reservoirs according to claim 1, characterized in that, The first core loader (11) and the second core loader (12) are of the same length. The first core loader (11) and the second core loader (12) are located on the same plane perpendicular to the horizontal plane, and the first core loader (11) is located above the second core loader (12).

3. A gas drive simulation experimental method for heterogeneous oil reservoirs, using the apparatus described in any one of claims 1 to 2, characterized in that, include: Step A: The permeability of the first core packer (11) and the second core packer (12) was measured using saturated water. Step B: The saturation of bound water in the first core packer (11) and the second core packer (12) was determined using saturated oil. Step C: Perform hydrocarbon accumulation aging on the first core packer (11) and the second core packer (12); Step D: Gas drive is carried out using different gas injection methods to obtain the gravity-stabilized gas drive recovery rate of heterogeneous reservoirs with the first core packer (11) and the second core packer (12) under different injection and production methods; Step E: Change the angle between the first core loader (11) and the second core loader (12) and the horizontal plane and the core permeability, and repeat step D to obtain the gas drive recovery rate of heterogeneous reservoirs under different injection and production methods under different oil layer physical properties.

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