Simulation device and simulation method for liquid sulfur-gas-water multiphase flow and application thereof in high-temperature high-pressure high-sulfur gas reservoir

Abstract

This invention relates to the field of oil and gas exploration and development, and discloses a simulation device and method for liquid sulfur-gas-water multiphase flow, and its application in high-temperature, high-pressure, high-sulfur gas reservoirs. The simulation device includes an injection unit, a high-temperature, high-pressure visual reactor, and a data acquisition unit. The injection unit includes an intermediate container; the high-temperature, high-pressure visual reactor includes a microfluidic chip and is connected to the intermediate container via a three-way valve; the data acquisition unit includes a high-speed camera positioned directly above the high-temperature, high-pressure visual reactor and a computer connected to the camera. This method, through high-precision visualized microfluidics, can reproduce the multiphase flow behavior of liquid sulfur-gas-water three-phase coexistence under the constraints of actual porous media structures and in-situ high-temperature, high-pressure reservoir conditions, providing a theoretical basis for the efficient development of high-sulfur gas reservoirs.

Description

Technical Field

[0001] This invention relates to the field of oil and gas exploration and development, specifically to a simulation device and method for liquid sulfur-gas-water multiphase flow and its application in high-temperature, high-pressure, high-sulfur gas reservoirs. Background Technology

[0002] my country has abundant high-sulfur natural gas resources, mainly distributed in the Sichuan Basin, with a total amount exceeding 1×10⁻⁶. 12 m 3 High-sulfur gas reservoirs possess enormous development potential. Compared to conventional natural gas reservoirs, during development, as reservoir pressure decreases, the solubility of elemental sulfur in acidic gases declines, leading to precipitation. For deep or ultra-deep reservoirs, the reservoir temperature is generally higher than the melting point of sulfur (119℃). Therefore, elemental sulfur precipitates in liquid form, which, on the one hand, adsorbs and deposits in pores or throats, blocking gas flow channels and reducing reservoir permeability; on the other hand, it aggregates to form a mobile phase, creating two-phase flow with gas, further reducing the effective permeability of the gas phase, thus decreasing gas well productivity and affecting reservoir development. Furthermore, as reservoir development enters the middle and later stages, water intrusion leads to increased water content in the formation, resulting in three-phase flow of liquid sulfur, gas, and water, with a complex flow mechanism. The multiphase flow interactions in high-sulfur gas reservoirs control the natural gas extraction process during development. Whether liquid sulfur affects the production process under high temperature and pressure conditions remains a long-standing scientific question.

[0003] Currently, there are no reports on three-phase flow of gas-liquid sulfur-water in deep and ultra-deep high-sulfur gas reservoirs. Existing technologies have conducted limited experimental studies on two-phase flow of gas-liquid sulfur.

[0004] Gu Shaohua (Gu Shaohua, Shi Zhiliang, Hu Xiangyang, et al. Experiment on two-phase flow of gas-liquid sulfur in ultra-deep high-sulfur gas reservoirs[J]. Natural Gas Industry, 2018, 38(10):70-75) et al. conducted two-phase displacement experiments of gas-liquid sulfur under high temperature and high pressure conditions, and obtained the gas-liquid sulfur relative permeability curve based on the unsteady-state method to process the relative permeability experimental data.

[0005] Chen Qi (Study on the Influence of Liquid Sulfur Adsorption on Reservoirs in High-Sulfur Gas Reservoirs [D]. Southwest Petroleum University, 2019) selected cores with different porosities and permeabilities, changed stress conditions and carried out gas-liquid sulfur two-phase flow experiments, and used the unsteady-state method to obtain the gas-liquid sulfur relative permeability curves under different confining pressures.

[0006] He Linji (Study on gas-liquid sulfur seepage law in high-sulfur gas reservoirs [D]. Southwest Petroleum University, 2017) conducted experimental tests under different temperature and stress-sensitive conditions, and determined the relative permeability curves of gas-liquid sulfur two phases according to the unsteady-state method.

[0007] In summary, due to limitations in experimental conditions, there are currently few reported experimental studies related to liquid sulfur seepage, and they mainly focus on gas-liquid sulfur two-phase seepage experiments. No reports have been made on the multiphase flow behavior of liquid sulfur-gas-water coexistence under the actual spatial constraints of high-sulfur gas reservoirs, which greatly restricts the progress of research on efficient development and sulfur control in high-sulfur gas reservoirs.

[0008] Therefore, it is of great significance to study and develop a simulation method and device for multiphase flow of sulfur-gas-water in high-sulfur, high-temperature and high-pressure gas reservoirs. Summary of the Invention

[0009] The purpose of this invention is to provide a simulation device and method for multiphase flow of liquid sulfur-gas-water and its application in high-temperature, high-pressure, and high-sulfur gas reservoirs. This method, through high-precision and visualized microfluidic control, can overcome the difficulty of ensuring that the liquid sulfur flow maintains high temperature, high pressure, and safety throughout the entire process. It reproduces the multiphase flow behavior of liquid sulfur-gas-water three-phase coexistence under the constraints of actual porous media structures and in-situ reservoir high-temperature and high-pressure conditions, and can provide a theoretical basis for the efficient development of high-sulfur gas reservoirs.

[0010] To achieve the above objectives, the first aspect of the present invention provides a simulation device for liquid sulfur-gas-water multiphase flow, wherein the simulation device includes an injection unit, a high-temperature and high-pressure visual reactor 19, and a data acquisition unit.

[0011] The injection unit includes an intermediate container, which includes a sulfur intermediate container 5, a water intermediate container 6, and a gas intermediate container 7.

[0012] The high-temperature and high-pressure visual reactor 19 includes a microfluidic chip 18, and the high-temperature and high-pressure visual reactor 19 is connected to one end of the intermediate container through a three-way valve G17, so that the fluid in the intermediate container is injected into the microfluidic chip 18 through the connecting pipeline.

[0013] The data acquisition unit includes a high-speed camera 15 positioned directly above the high-temperature and high-pressure visual reactor 19 and a computer 24 connected to the high-speed camera 15, for real-time imaging and observation of fluid changes within the microfluidic chip 18.

[0014] A second aspect of the present invention provides a method for simulating liquid sulfur-gas-water multiphase flow, wherein the simulation method is performed in the aforementioned simulation apparatus, and wherein the simulation method includes:

[0015] The first simulation method:

[0016] (1) Fabrication of microfluidic chip 18:

[0017] 1) Prepare thin sections of the reservoir carbonate rock samples and extract the pore and fracture structure using microscopic imaging;

[0018] 2) Based on the described pore and fissure structure, microfluidic chip etching is performed to create a glass plate etching microscopic model;

[0019] 3) Another glass plate with injection holes and fluid extraction holes is bonded together by vacuum bonding to obtain a microfluidic chip 18 that represents the real reservoir pore structure;

[0020] (2) The liquid sulfur in the microfluidic chip 18 reaches saturation:

[0021] The microfluidic chip 18 is placed in a high-temperature and high-pressure visible reactor 19, and sulfur powder is filled into a sulfur intermediate container 5 and heated to melt into liquid sulfur. The liquid sulfur is then injected into the microfluidic chip 18 at high temperature until the liquid sulfur reaches saturation.

[0022] (3) Nitrogen cleaning pipeline:

[0023] The connection between the three-way valve 17 and the microfluidic chip 18 is closed, while the other branch is opened, allowing the three-way valve 17 to be directly connected to the back pressure valve 21. Nitrogen gas in the intermediate gas container 7 flows through the three-way valve 17, bypasses the microfluidic chip 18 along the branch, and directly flows through the back pressure valve 21 into the recovery device 22 to clean residual liquid sulfur in the pipeline until no liquid sulfur is generated in the recovery device 22. This is to prevent the liquid sulfur in the pipeline from affecting the sulfur saturation in the microfluidic chip 18 when the nitrogen gas displaces it.

[0024] (4) Gas-driven liquid sulfur simulation:

[0025] Adjust the three-way valve 17 to connect the three-way valve 17 with the microfluidic chip 18, inject nitrogen into the microfluidic chip 18, and obtain the simulated state of gas-liquid sulfur two-phase flow through the high-speed camera 15;

[0026] (5) Water cleaning pipeline:

[0027] The connection between the three-way valve 17 and the microfluidic chip 18 is closed, while the other branch is opened, allowing the three-way valve 17 to communicate directly with the back pressure valve 21. Water in the intermediate water container 6 flows through the three-way valve 17, bypasses the microfluidic chip 18 along the branch, and flows directly through the back pressure valve 21 into the recovery device 22 to clean residual gas in the pipeline until no obvious bubbles are generated in the recovery device 22. This is to prevent residual gas in the pipeline from affecting the gas-liquid sulfur saturation in the microfluidic chip 18 during water displacement.

[0028] (6) Simulation of three-phase liquid sulfur-gas-water under water-driven gas-liquid sulfur conditions:

[0029] Adjust the three-way valve 17 to connect the three-way valve 17 to the microfluidic chip 18, inject distilled water into the microfluidic chip 18, and obtain the simulated state of liquid sulfur-gas-water three-phase flow through the high-speed camera 15;

[0030] Alternatively, a second simulation method:

[0031] This is performed after steps (1) to (3) of the first simulation method:

[0032] (7) Simulation of three-phase flow of liquid sulfur-gas-water under alternating gas-water injection conditions:

[0033] After the aforementioned steps (1) to (3), the water intermediate container 6 and the gas intermediate container 7 are opened alternately to carry out gas-water alternating displacement until stability is achieved, and the simulated state of liquid sulfur-gas-water three-phase flow is obtained through the high-speed camera 15.

[0034] A third aspect of the present invention provides an application of the aforementioned simulation method in high-sulfur, high-temperature, and high-pressure gas reservoirs.

[0035] Through the above technical solution, the present invention has the following beneficial effects:

[0036] (1) This method is the first to realize the three-phase visualization simulation method containing liquid sulfur, and realizes the observation of the occurrence state of liquid sulfur under high temperature and high pressure conditions and the characterization of the interaction process with gas and water.

[0037] (2) This method is safe and feasible, with full heat and pressure preservation. The temperature range can reach 120-180℃ and the pressure range can reach 20-60MPa, replicating the actual high temperature and high pressure conditions of the reservoir.

[0038] (3) The sulfur recovery measuring cylinder and alkali solution at the outlet of this device ensure the smooth operation of the experiment and its safety and environmental protection.

[0039] (4) This device clarifies the tracking error between the internal environmental pressure and the injection pressure of the high-temperature and high-pressure reactor;

[0040] (5) The cleaning pipeline in this device can be cleaned during the heat preservation and pressure preservation experiment, and the steps do not affect each other, making the experiment more accurate. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the geometric morphology of the etched pore structure in Embodiment 1 of the present invention;

[0042] Figure 2 This is a schematic diagram of the etched microfluidic chip in Embodiment 1 of the present invention;

[0043] Figure 3 This is a schematic diagram of the liquid sulfur-gas-water three-phase microfluidic experimental device in Embodiment 1 of the present invention;

[0044] Figure 4 This is a schematic diagram of the high-temperature and high-pressure saturated liquid sulfur experiment in Example 1 of the present invention;

[0045] Figure 5 This is a schematic diagram of the saturated liquid sulfur result of the microfluidic chip in Embodiment 1 of the present invention;

[0046] Figure 6 This is a schematic diagram of the gas cleaning pipeline in Embodiment 1 of the present invention;

[0047] Figure 7 This is a schematic diagram of the gas-driven liquid sulfur simulation experiment in Embodiment 1 of the present invention;

[0048] Figure 8 This is a schematic diagram of the liquid sulfur-nitrogen two-phase flow in Embodiment 1 of the present invention;

[0049] Figure 9 This is a schematic diagram of the water cleaning pipeline in Embodiment 1 of the present invention;

[0050] Figure 10 This is a schematic diagram of the water-driven sulfur injection in Embodiment 1 of the present invention;

[0051] Figure 11 This is a schematic diagram of the formation water-driven gas-liquid sulfur three-phase occurrence in Embodiment 1 of the present invention;

[0052] Figure 12 This is a schematic diagram of the alternating water and air injection in Embodiment 1 of the present invention;

[0053] Figure 13 This is a schematic diagram of the liquid sulfur-gas-water three-phase occurrence in Embodiment 1 of the present invention;

[0054] Figure 14 This is a schematic flowchart of the simulation method used in Embodiment 1 of the present invention;

[0055] Figure 15 This is a schematic diagram of the geometric morphology of the etched pore structure in Embodiment 3 of the present invention.

[0056] Explanation of reference numerals in the attached figures

[0057] 1-ISCO constant speed and pressure pump; 2-Valve A; 3-Valve B;

[0058] 4-Valve C; 5-Sulfur intermediate container; 6-Water intermediate container;

[0059] 7-Gas intermediate container; 8-Valve D; 9-Valve E;

[0060] 10-Valve F; 11-Constant Temperature Heating Chamber A; 12-Circulating Pressure Tracking Pump;

[0061] 13-Pressure gauge A; 14-Pressure gauge B; 15-High-speed camera;

[0062] 16-Pressure gauge C; 17-Three-way valve G; 18-Microfluidic chip;

[0063] 19-High temperature and high pressure visual reactor; 20-LED light;

[0064] 21-Back pressure valve; 22-Liquid flow recovery device; 23-Constant temperature heating chamber B;

[0065] 24-Computer; 25-Pressure gauge D; 26-Exhaust gas treatment bottle;

[0066] 27 - Back pressure pump. Detailed Implementation

[0067] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0068] As mentioned above, the first aspect of the present invention provides a simulation device for liquid sulfur-gas-water multiphase flow, wherein the simulation device includes an injection unit, a high-temperature and high-pressure visual reactor 19, and a data acquisition unit.

[0069] The injection unit includes an intermediate container, which includes a sulfur intermediate container 5, a water intermediate container 6, and a gas intermediate container 7.

[0070] The high-temperature and high-pressure visual reactor 19 includes a microfluidic chip 18, and the high-temperature and high-pressure visual reactor 19 is connected to one end of the intermediate container through a three-way valve G17, so that the fluid in the intermediate container is injected into the microfluidic chip 18 through the connecting pipeline.

[0071] The data acquisition unit includes a high-speed camera 15 positioned directly above the high-temperature and high-pressure visual reactor 19 and a computer 24 connected to the high-speed camera 15, for real-time imaging and observation of fluid changes within the microfluidic chip 18.

[0072] The inventors of this invention discovered that by using an injection pump and three intermediate containers to achieve the displacement process of multiphase fluids, controlling the temperature, pressure and injection flow rate, and observing and acquiring the real-time dynamic three-phase flow characteristics in the microfluidic chip 18 through a high-speed camera 15, the micro-percolation characteristics of the liquid sulfur-gas-water three-phase micro-flow process can be obtained by analyzing parameters such as contact angle and occurrence morphology through image processing.

[0073] Furthermore, this invention, on the one hand, ensures high-temperature conditions throughout the entire process using a constant-temperature heating chamber and heating insulation belt, thus reproducing the actual flow state of liquid sulfur in the formation; on the other hand, it sets up a cleaning pipeline device during the experimental process, ensuring that the cleaning of the experimental pipeline is carried out under heat preservation and pressure, and that each step does not affect the others, making the experiment more accurate; the annular pressure tracking system ensures that a high-pressure environment can be achieved while preventing the microfluidic chip from being crushed; finally, a high-speed camera enables real-time monitoring of the entire process, reproducing the multiphase flow behavior of liquid sulfur-gas-water three-phase coexistence under the constraints of actual porous media structure and in-situ high-temperature and high-pressure reservoir conditions, providing a theoretical basis for the efficient development of high-sulfur gas reservoirs.

[0074] In addition, the device of the present invention is equipped with an exhaust gas treatment device at the tail end, which can ensure that the entire experimental process is safe and environmentally friendly.

[0075] According to the present invention, the injection unit further includes an ISCO constant speed and pressure pump 1, and the ISCO constant speed and pressure pump 1 is connected to the other end of the intermediate container to control the pressure and flow rate of the fluid in the intermediate container at a constant speed and pressure.

[0076] According to the present invention, valves D8, E9 and F10 are respectively provided at the bottom of the sulfur intermediate container 5, the water intermediate container 6 and the gas intermediate container 7, and valves D8, E9 and F10 are respectively connected to the ISCO constant speed and constant pressure pump 1.

[0077] According to the present invention, valves A2, B3, and C4 are respectively provided on the top of the sulfur intermediate container 5, the water intermediate container 6, and the gas intermediate container 7, and valves A2, B3, and C4 are connected to the three-way valve G17.

[0078] According to the present invention, the three-way valve G17 is built into the high-temperature and high-pressure visible reactor 19.

[0079] According to the present invention, the intermediate container and the connecting pipeline are placed in a constant temperature heater A11.

[0080] According to the present invention, the simulation device further includes a ring pressure unit connected to the ring pressure inlet end of the high temperature and high pressure visual reactor 19, the ring pressure unit providing ring pressure to the high temperature and high pressure visual reactor 19.

[0081] According to the present invention, the ring pressure unit includes a ring pressure tracking pump 12 and a pressure gauge, wherein the pressure gauge is disposed on the connecting pipeline between the ring pressure tracking pump 12 and the high temperature and high pressure visible reactor 19.

[0082] According to the present invention, the pressure gauge includes pressure gauge A13, pressure gauge B14 and pressure gauge C16.

[0083] According to the present invention, the simulation device further includes a back pressure valve 21 connected to the microfluidic chip 18; a back pressure pump 27 is provided at the other end of the back pressure valve 21, and a pressure gauge D 25 is provided on the pipeline connected to the back pressure valve 21 and the back pressure pump 27, the pressure gauge D 25 being used to collect and monitor the back pressure.

[0084] According to the present invention, the outlet of the back pressure valve 21 is provided with a fluid recovery device 22, which is used to measure the volume and / or mass of the fluid at the outlet end.

[0085] According to the present invention, the fluid recovery device 22 is connected to the tail gas recovery bottle 26 via a pipeline.

[0086] According to the present invention, the back pressure valve 21 and the fluid recovery device 22 are placed in a constant temperature heating chamber B23.

[0087] According to the present invention, the data acquisition unit further includes a high-brightness light source 20 disposed directly below the high-temperature and high-pressure visual reactor 19.

[0088] According to the present invention, the high-temperature and high-pressure visual reactor 19 further includes a chip holder, an electric heating system, a temperature sensor, a heat-conducting inner cavity, and a heat-insulating outer cavity.

[0089] According to the present invention, the microfluidic chip 18 is fixed in the thermally conductive cavity by the chip holder.

[0090] According to the present invention, the electric heating system is provided in the heat-conducting inner cavity and the heat-insulating outer cavity, and the electric heating system is connected to the computer 24 through the temperature sensor to monitor temperature changes in real time.

[0091] A second aspect of the present invention provides a method for simulating liquid sulfur-gas-water multiphase flow, wherein the simulation method is performed in the aforementioned simulation apparatus, and wherein the simulation method includes:

[0092] The first simulation method:

[0093] (1) Fabrication of microfluidic chip 18:

[0094] 1) Prepare thin sections from actual core samples of the reservoir and extract the pore and fracture structure using microscopic imaging;

[0095] 2) Based on the described pore and fissure structure, microfluidic chip etching is performed to create a glass plate etching microscopic model;

[0096] 3) Another glass plate with injection holes and fluid extraction holes is bonded together by vacuum bonding to obtain a microfluidic chip 18 that represents the real reservoir pore structure;

[0097] (2) The liquid sulfur in the microfluidic chip 18 reaches saturation:

[0098] The microfluidic chip 18 is placed in a high-temperature and high-pressure visible reactor 19, and sulfur powder is filled into a sulfur intermediate container 5 and heated to melt into liquid sulfur. The liquid sulfur is then injected into the microfluidic chip 18 at high temperature until the liquid sulfur reaches saturation.

[0099] (3) Nitrogen cleaning pipeline:

[0100] The connection between the three-way valve 17 and the microfluidic chip 18 is closed, while the other branch is opened, allowing the three-way valve 17 to be directly connected to the back pressure valve 21. Nitrogen gas in the intermediate gas container 7 flows through the three-way valve 17, bypasses the microfluidic chip 18 along the branch, and directly flows through the back pressure valve 21 into the recovery device 22 to clean residual liquid sulfur in the pipeline until no liquid sulfur is generated in the recovery device 22. This is to prevent the liquid sulfur in the pipeline from affecting the sulfur saturation in the microfluidic chip 18 when the nitrogen gas displaces it.

[0101] (4) Gas-driven liquid sulfur simulation:

[0102] After the aforementioned steps (1) to (3), adjust the three-way valve 17 to connect the three-way valve 17 with the microfluidic chip 18, inject nitrogen into the microfluidic chip 18, and obtain the simulated state of gas-liquid sulfur two-phase flow through the high-speed camera 15.

[0103] (5) Water cleaning pipeline:

[0104] After the aforementioned steps (1) to (4), the connection route between the three-way valve 17 and the microfluidic chip 18 is closed, while the other branch is opened, so that the three-way valve 17 is directly connected to the back pressure valve 21; the water in the intermediate water container 6 flows through the three-way valve 17, bypasses the microfluidic chip 18 along the branch, and flows directly through the back pressure valve 21 to the recovery device 22 to clean the residual gas in the pipeline until no obvious bubbles are generated in the recovery device 22; so as to avoid the residual gas in the pipeline from affecting the gas-liquid sulfur saturation in the microfluidic chip 18 when the water is displaced;

[0105] (6) Simulation of three-phase liquid sulfur-gas-water under water-driven gas-liquid sulfur conditions:

[0106] After the aforementioned steps (1) to (5), adjust the three-way valve 17 so that the three-way valve 17 is connected to the microfluidic chip 18, inject distilled water into the microfluidic chip 18, and obtain the simulated state of liquid sulfur-gas-water three-phase flow through the high-speed camera 15;

[0107] Alternatively, a second simulation method:

[0108] This is performed after steps (1) to (3) of the first simulation method:

[0109] (7) Simulation of three-phase flow of liquid sulfur-gas-water under alternating gas-water injection conditions:

[0110] After the aforementioned steps (1) to (3), the water intermediate container 6 and the gas intermediate container 7 are opened alternately to carry out gas-water alternating displacement until stability is achieved, and the simulated state of liquid sulfur-gas-water three-phase flow is obtained through the high-speed camera 15.

[0111] In this invention, it should be noted that the simulation method for liquid sulfur-gas-water multiphase flow of this invention includes two methods. One simulation method includes steps (1), (2), (3), (4), (5), and (6); the other simulation method includes steps (1), (2), (3), and (7). That is, each time a simulation experiment is performed, either steps (1) to (6) are selected for the simulation experiment, or steps (1) to (3) and step (7) are selected for the simulation experiment, and the simulated state of liquid sulfur-gas-water three-phase flow can be obtained.

[0112] According to the present invention, reservoir samples can be derived from actual carbonate rock downhole cores or natural outcrop cores. A natural outcrop refers to the portion of the rock strata exposed at the surface.

[0113] In addition, in this invention, the method for making it into a cast sheet includes processes such as vacuum infusion, high temperature and high pressure curing, sampling, grinding, and covering.

[0114] According to the present invention, in step (2), the method for the saturated liquid sulfur includes:

[0115] 1) Keep all valves closed, and maintain the three-way valve G17 connected to the microfluidic chip 18;

[0116] 2) Fill the sulfur intermediate container 5 with sulfur powder;

[0117] 3) Set the pressure of the back pressure valve 21 to 25-60MPa and monitor it in real time using pressure gauge 25 to maintain stable back pressure;

[0118] 4) Correlate the high-temperature and high-pressure visible vessel pressure controlled by pressure gauge A13 with the injection end pressure controlled by pressure gauge B14 to keep the pressure difference <0.2MPa at all times;

[0119] 5) Control the temperature of constant temperature heating chamber A11, high temperature and high pressure visual reaction vessel 19 and constant temperature heating chamber B23 to 120-180℃ and keep them at that temperature for 3-6 hours;

[0120] 6) Open valve 8 and valve 2 in sequence, start ISCO constant speed and constant pressure pump 1, inject in constant pressure mode, the pressure setting value is 1-2 MPa lower than the back pressure valve 21 pressure value in step 3); then switch to constant speed mode injection, the speed is set to 0.05-0.1 mL / min;

[0121] 7) Turn on the high-speed camera 15, start the recording mode, and observe the liquid sulfur saturation. When there are no obvious bubbles in the microfluidic chip 18, the liquid sulfur saturation ends. Then, turn off the ISCO constant speed and pressure pump 1 and close valves 8 and 2.

[0122] According to the present invention, in step (3), the method for purging the pipeline with nitrogen includes:

[0123] 1) Maintain all settings as in step (2);

[0124] 2) Adjust all valves to be in the closed state, adjust the connection route between the three-way valve G17 and the microfluidic chip 18 to be closed, and at the same time open the other branch, so that the three-way valve G17 is directly connected to the back pressure valve 21, bypassing the microfluidic chip 18;

[0125] 3) Open valves 10 and 4 in sequence, start ISCO constant speed and constant pressure pump 1, and inject at a constant speed of 0.1-0.5 mL / min.

[0126] 4) Stop cleaning when no obvious liquid sulfur is produced in the liquid sulfur recovery unit, turn off the ISCO constant speed and pressure pump 1 injection, and close valves 10 and 4.

[0127] According to the present invention, in step (4), the method for simulating gas-driven liquid sulfur includes:

[0128] 1) Maintain the state of all settings in step (3);

[0129] 2) Adjust all valves to the closed state, and adjust the three-way valve G17 to connect with the microfluidic chip 18;

[0130] 3) Open valves 10 and 4 in sequence, start ISCO constant speed and constant pressure pump 1, and inject at a constant speed in constant speed mode, with the speed set to 0.05-0.1 mL / min;

[0131] 4) When the sulfur saturation of the microfluidic chip 18 does not change, the gas-driven liquid sulfur simulation experiment is stopped by using image analysis. The injection of ISCO constant speed and pressure pump 1 is turned off, and valves 10 and 4 are closed to obtain the simulated state of gas-liquid sulfur two-phase flow.

[0132] According to the present invention, in step (5), the method for cleaning the pipeline with water includes:

[0133] (1) Maintain the state of all settings in step (4);

[0134] (2) Adjust all valves to be closed, adjust the connection route between the three-way valve G17 and the microfluidic chip 18 to be closed, and at the same time open the other branch, so that the three-way valve G17 and the back pressure valve 21 are directly connected, bypassing the microfluidic chip 18;

[0135] (3) Open valves 9 and 3 in sequence, start ISCO constant speed and constant pressure pump 1, and inject at a constant speed of 0.1-0.5 mL / min.

[0136] (4) Stop cleaning when no obvious bubbles are observed in the liquid sulfur recovery unit, turn off the ISCO constant speed and pressure pump 1, and close valves 9 and 3.

[0137] According to the present invention, in step (6), the method for simulating the three-phase flow of liquid sulfur-gas-water under water-driven gas-liquid sulfur conditions includes:

[0138] 1) Maintain the state of all settings in step (5);

[0139] 2) Adjust all valves to the closed state, and adjust the three-way valve G17 to connect with the microfluidic chip 18;

[0140] 3) Open valves 9 and 3 in sequence, start ISCO constant speed and pressure pump 1, and inject at a constant speed of 0.05-0.1 mL / min.

[0141] 4) When the microfluidic chip 18 is detected to have no change in fluid saturation using image analysis, stop the water-driven liquid sulfur experiment, turn off the ISCO constant speed and pressure pump 1, and close valves 9 and 3 to obtain the simulated state of liquid sulfur-gas-water three-phase flow under water-driven gas-liquid sulfur conditions.

[0142] According to the present invention, in step (7), the method for simulating the liquid sulfur-gas-water three-phase flow under the alternating gas-water injection condition includes:

[0143] 1) Maintain the state of all settings in step (3);

[0144] 2) Adjust all valves to the closed state, and adjust the three-way valve G17 to connect with the microfluidic chip 18;

[0145] 3) Open valves 10 and 4 in sequence, start ISCO constant speed and constant pressure pump 1, and inject at a constant speed in constant speed mode, with the speed set to 0.05-0.1 mL / min;

[0146] 4) After injecting for 50-100 minutes, pause the ISCO constant speed and pressure pump 1, close valve 10 and valve 4 in sequence, open valve 9 and valve 3 in sequence, start the ISCO constant speed and pressure pump 1, and inject at a constant speed in constant speed mode, with the speed set to 0.05-0.1 mL / min.

[0147] 5) After injecting for 50-100 minutes, pause the injection of ISCO constant speed and pressure pump 1, close valve 9 and valve 3 in sequence, open valve 10 and valve 4 in sequence, start ISCO constant speed and pressure pump 1, and inject at a constant speed in constant speed mode, with the speed set to 0.05-0.1 mL / min.

[0148] 6) Repeat steps (4) and (5) in sequence. When the sulfur saturation of the microfluidic chip 18 is detected to be unchanged by image analysis, stop the liquid sulfur-gas-water three-phase flow simulation experiment, turn off the ISCO constant speed and pressure pump 1, and close all valves.

[0149] According to the present invention, the simulation method further includes disassembling and replacing the simulation device with a microfluidic chip. Specifically, the method for disassembling and replacing the microfluidic chip includes:

[0150] (1) Keep all valves closed, keep the connection between the three-way valve G17 and the microfluidic chip 18 closed, open the other branch at the same time, keep the pump 12 running, and keep the tracking error between the pressure gauge 13 and the pressure gauge 14 less than 0.1 MPa;

[0151] (2) Turn off the heating device of the high-temperature and high-pressure visual reactor 19. Proceed to the next step when the temperature drops below 40°C.

[0152] (3) Reduce the pressure of back pressure valve 21 at a depressurization rate of 1MPa / 10min. After the pressure of back pressure valve is completely depressurized, disassemble and replace the microfluidic chip.

[0153] A third aspect of the present invention provides an application of the aforementioned simulation method in high-sulfur, high-temperature, and high-pressure gas reservoirs.

[0154] According to the present invention, the conditions of the high-sulfur, high-temperature and high-pressure gas reservoir include: a temperature of 120-200℃ and a pressure of 1-60MPa; preferably, the temperature is 120-180℃ and the pressure is 20-60MPa.

[0155] The present invention will be described in detail below through embodiments.

[0156] In the following embodiments:

[0157] The high-speed camera was purchased from Vision Research, USA, and its model is Phantom T1340.

[0158] Saturation parameters were measured using image analysis methods; the core thin sections were prepared from actual reservoir cores. Sulfur samples were prepared from commercially available high-purity sulfur powder purchased from Shanghai Husheng Laboratory Equipment Co., Ltd., with a purity >99.999%.

[0159] Example 1

[0160] according to Figure 14 The flowchart of the simulation method of the present invention shown herein specifically includes:

[0161] Step 1: Microfluidic chip fabrication:

[0162] (1) A thin section was prepared from a core sample of an actual reservoir in the Puguang gas field to obtain a planar diagram of the pore structure, as shown below. Figure 1 As shown, Figure 1 This is a schematic diagram of the geometric morphology of the etched pore structure in Embodiment 1. Figure 1 It can be seen that the carbonate reservoir has a complex pore structure, with pore throat sizes mainly distributed in the range of 10-400 μm;

[0163] (2) The microfluidic chip is 75mm×75mm×3mm in size, and the width of the inlet and outlet ends is 1mm;

[0164] (3) Select Borofloat-33 glass to make the model, such as Figure 2 As shown, Figure 2 This is a schematic diagram of the etched microfluidic chip in Example 1. The etched area of ​​the micromodel is 5.722mm × 2.182mm. The chip depth is based on the average size of the actual pore structure, which is 50μm. The throat size is distributed between 10-400μm, and the minimum throat size is 10μm.

[0165] The second step involves high-temperature, high-pressure saturated liquid sulfur.

[0166] (1) Install the microfluidic chip in the high-temperature, high-pressure visible reactor 19, keep all valves closed, and keep valve 17 connected to the microfluidic chip 18, using the following method: Figure 3 The simulation device shown Figure 3 This is a schematic diagram of the liquid sulfur-gas-water three-phase microfluidic experimental device of the present invention;

[0167] (2) Fill the intermediate container 5 with sulfur powder;

[0168] (3) Set the back pressure valve to 50MPa and monitor it in real time with pressure gauge 25 to keep the back pressure stable;

[0169] (4) Correlate the pressure 13 of the high-temperature and high-pressure visible reactor with the pressure 14 at the injection end, and keep the pressure difference <0.2MPa at all times;

[0170] (5) Heat the constant temperature box 11, the high temperature and high pressure visual reactor 19, and the constant temperature box 23 to 150°C and keep them at that temperature for 3 hours;

[0171] (6) Open valves 8 and 2 in sequence, start injection pump 1, and inject in constant pressure mode. The pressure setting value is 1 MPa lower than the back pressure valve 21 pressure value in step (3); then switch to constant speed mode injection, and set the speed to 0.05 mL / min. Figure 4 As shown, Figure 4 This is a schematic diagram of the high-temperature, high-pressure saturated liquid sulfur experiment in this embodiment;

[0172] (7) Turn on the camera 15, start the recording mode, and observe the liquid sulfur saturation. The liquid sulfur saturation is stopped when there are no obvious bubbles in the microfluidic chip 18. Figure 5 As shown, Figure 5 This is a schematic diagram of the saturated liquid sulfur result of the microfluidic chip in Example 1 of this embodiment. Figure 5 It can be seen that the liquid sulfur is golden yellow and fills the pore channels of the entire etched area. Pump 1 is shut off, and valves 8 and 2 are closed.

[0173] The third step is to purge the pipeline with nitrogen.

[0174] (1) Based on the second step, keep all settings in the state of the second step;

[0175] (2) Adjust all valves to be in the closed state, close the connection route between the three-way valve 17 and the microfluidic chip 18, and open the other branch at the same time so that the three-way valve 17 and the back pressure valve 21 are directly connected.

[0176] (3) Open valve 10 and valve 4 in sequence, start injection pump 1, and inject at a constant speed of 0.1 mL / min.

[0177] (4) Stop cleaning when no obvious sulfur is produced in the recovery unit 22, turn off pump 1, and close valves 10 and 4. Figure 6 As shown, Figure 6 This is a schematic diagram of the nitrogen cleaning pipeline in Example 1.

[0178] Step 4: Gas-driven liquid sulfur simulation

[0179] (1) Based on step three, keep all settings in the state of step three;

[0180] (2) Adjust all valves to be closed, and adjust the three-way valve 17 to be connected to the microfluidic chip 18;

[0181] (3) Open valves 10 and 4 in sequence, start injection pump 1, and inject at a constant speed of 0.05 mL / min. Figure 7 As shown, Figure 7 This is a schematic diagram of the gas-driven liquid sulfur simulation experiment in Example 1 of this embodiment;

[0182] (4) When image analysis is used to detect no change in the sulfur saturation of the microfluidic chip 18, the gas-driven liquid sulfur simulation experiment is stopped, the injection pump is turned off, and valves 10 and 4 are closed. The simulated state of the gas-liquid sulfur two-phase flow is as follows: Figure 8 As shown, Figure 8 This is a schematic diagram of the liquid sulfur-nitrogen two-phase flow in Example 1; from Figure 8 It can be seen that nitrogen drives the flow of liquid sulfur, and liquid sulfur and nitrogen coexist. Liquid sulfur tends to stagnate in the blind ends of pores, on the walls, and in some poorly connected throats.

[0183] Step 5: Water cleaning of pipelines

[0184] (1) Based on step four, keep all settings in the state of step four;

[0185] (2) Adjust all valves to be in the closed state, the connection route between the three-way valve 17 and the microfluidic chip 18 is closed, and the other branch is opened at the same time, so that the three-way valve 17 and the back pressure valve 21 are directly connected;

[0186] (3) Open valves 9 and 3 in sequence, start injection pump 1, and inject at a constant speed of 0.1 mL / min.

[0187] (4) Stop cleaning when no obvious sulfur is produced in the recovery unit 22, turn off pump 1, and close valves 9 and 3. Figure 9 As shown, Figure 9 This is a schematic diagram of the water cleaning pipeline in Embodiment 1.

[0188] Step 6: Simulation of three-phase liquid sulfur-gas-water under water-driven gas-liquid sulfur conditions

[0189] (1) Based on step 5, keep all settings in the state of step 5;

[0190] (2) Adjust all valves to be closed, and adjust the three-way valve 17 to be connected to the microfluidic chip 18;

[0191] (3) Open valves 9 and 3 in sequence, start injection pump 1, and inject at a constant speed of 0.05 mL / min. Figure 10 As shown, Figure 10 This is a schematic diagram of water-driven sulfur in Example 1;

[0192] (4) Using image analysis, when no change in the sulfur saturation of the microfluidic chip 18 is detected, the water-driven liquid sulfur experiment is stopped, the injection pump is turned off, and valves 9 and 3 are closed until only blue formation water is produced at the channel outlet. The final simulated state of the water-liquid sulfur-gas three-phase flow is as follows: Figure 11 As shown, Figure 11 This is a schematic diagram of the liquid sulfur-gas-water three-phase occurrence in this embodiment; from this... Figure 11 It can be seen that the injection of water drives the flow of nitrogen and liquid sulfur. Some liquid sulfur remains in the blind ends and pore walls, while a small amount of nitrogen remains in the pores.

[0193] In addition, after the simulation experiment in Example 1 was completed, the microfluidic chip was disassembled and replaced.

[0194] (1) Keep all valves closed, keep the connection route between the three-way valve 17 and the microfluidic chip 18 closed, and keep the other branch open, keep the pump 12 running, and keep the tracking error between the pressure gauge 13 and the pressure gauge 14 less than 0.1 MPa;

[0195] (2) Turn off the heating device of the high-temperature and high-pressure visual reactor 19. Proceed to the next step when the temperature drops below 40°C.

[0196] (3) Reduce the pressure of back pressure valve 21 at a depressurization rate of 1MPa / 10min. After the pressure of back pressure valve is completely depressurized, disassemble and replace the microfluidic chip.

[0197] Example 2

[0198] After performing the "microfluidic chip fabrication", "high temperature and high pressure saturated liquid sulfur" and "nitrogen cleaning pipeline" in the same way as the first, second and third steps in Example 1, the following seventh step is performed:

[0199] Step 7: Simulation of three-phase flow of liquid sulfur-gas-water under alternating gas-water injection conditions

[0200] (1) Keep all settings in the state of step three;

[0201] (2) Adjust all valves to be closed, and adjust the three-way valve 17 to be connected to the microfluidic chip 18;

[0202] (3) Open valves 10 and 4 in sequence, start injection pump 1, and inject at a constant speed of 0.1 mL / min. Figure 12 As shown, Figure 12 This is a schematic diagram of alternating water and air injection in Example 1 of this embodiment;

[0203] (4) After 50 minutes of injection, pause injection pump 1, close valve 10 and valve 4 in sequence, open valve 9 and valve 3 in sequence, start injection pump 1, and inject at a constant speed of 0.1 mL / min.

[0204] (5) After 50 minutes of injection, pause injection pump 1, close valves 9 and 3 in sequence, open valves 10 and 4 in sequence, start injection pump 1, and inject at a constant speed of 0.1 mL / min.

[0205] (6) Repeat steps (4) and (5) sequentially. When the sulfur saturation of the microfluidic chip 18 does not change, stop the gas-driven liquid sulfur simulation experiment, turn off the injection pump, close all valves, and obtain the liquid sulfur-gas-water three-phase morphology diagram, as shown in the figure. Figure 13 As shown, Figure 13 This is a schematic diagram of the liquid sulfur-gas-water three-phase occurrence prepared using the simulation method of Example 2. Figure 13 It can be seen that liquid sulfur is distributed at the blind ends of pores and on the wall, while water is distributed on the wall and in local pores. Both water and liquid sulfur have a significant impact on the gas channels.

[0206] In addition, after the simulation experiment in Example 2 was completed, the microfluidic chip was disassembled and replaced.

[0207] (1) Keep all valves closed, keep valve 17 disconnected from microfluidic chip 18, keep pump 12 running, and keep the tracking error of pressure gauge 13 and pressure gauge 14 less than 0.1 MPa;

[0208] (2) Turn off the heating device of the high-temperature and high-pressure visual reactor 19. Proceed to the next step when the temperature drops below 40°C.

[0209] (3) Reduce the pressure of back pressure valve 21 at a depressurization rate of 1MPa / 10min. After the pressure of back pressure valve is completely depressurized, disassemble and replace the microfluidic chip.

[0210] Example 3

[0211] The liquid sulfur-gas-water three-phase simulation was performed using the same simulation apparatus and method as in Example 1, with the following differences:

[0212] In the first step of microfluidic chip fabrication:

[0213] (1) Replace “1 actual reservoir core of Puguang Gas Field” with “2 other carbonate reservoir cores”; the structure of the other carbonate reservoir core 2 is significantly heterogeneous compared with that of Example 1, and the pore throat size is mainly distributed in the range of 10-800μm;

[0214] (2) The microfluidic chip is 75mm×75mm×3mm in size, and the width of the inlet and outlet ends is 1mm;

[0215] (3) Select Borofloat-33 glass to fabricate the model; the micro-model etching area is...

[0216] The chip depth is 4.404mm × 2.916mm, with the average size of the actual pore structure being 100μm. The throat size is distributed between 10-800μm.

[0217] in addition, Figure 15 This is a schematic diagram of the geometric morphology of the etched pore structure in Embodiment 3 of the present invention. Figure 15 It can be seen that its pore throat size distribution is more extensive and its heterogeneity is stronger.

[0218] In the second step, under high temperature and high pressure, saturated liquid sulfur:

[0219] in:

[0220] (5) Heat the constant temperature box 11, the high temperature and high pressure visual reactor 19, and the constant temperature box 23 to 150°C and keep them at that temperature for 3 hours;

[0221] (6) Open valve 8 and valve 2 in sequence, start injection pump 1, inject in constant pressure mode, pressure set to 50MPa; then adjust to constant speed mode injection, speed set to 0.05mL / min.

[0222] The results also allow for the simulation of three-phase flow of liquid sulfur, gas, and water. The three phases of liquid sulfur, gas, and water coexist in large pores, while local small channels are occupied by water or gas. Liquid sulfur is more abundant on the pore walls and at the blind ends of pores.

[0223] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A simulation device for liquid sulfur-gas-water multiphase flow, characterized in that, The simulation device includes an injection unit, a high-temperature and high-pressure visual reactor (19), and a data acquisition unit; The injection unit includes an intermediate container, which includes a sulfur intermediate container (5), a water intermediate container (6), and a gas intermediate container (7). The high-temperature and high-pressure visual reactor (19) includes a microfluidic chip (18), and the high-temperature and high-pressure visual reactor (19) is connected to one end of the intermediate container through a three-way valve G (17) so that the fluid of the intermediate container can be injected into the microfluidic chip (18) through the connecting pipeline. The data acquisition unit includes a high-speed camera (15) positioned directly above the high-temperature and high-pressure visual reactor (19) and a computer (24) connected to the high-speed camera (15) to observe the fluid changes inside the microfluidic chip (18) in real time. The injection unit further includes an ISCO constant speed and constant pressure pump (1), and the ISCO constant speed and constant pressure pump (1) is connected to the other end of the intermediate container to control the pressure and flow rate of the fluid in the intermediate container at a constant speed and constant pressure. Among them, the bottom of the sulfur intermediate container (5), the water intermediate container (6) and the gas intermediate container (7) are respectively provided with valves D (8), E (9) and F (10), and the valves D (8), E (9) and F (10) are respectively connected to the ISCO constant speed and constant pressure pump (1). Among them, the top of the sulfur intermediate container (5), the water intermediate container (6) and the gas intermediate container (7) are respectively provided with valve A (2), valve B (3) and valve C (4), and the valve A (2), valve B (3) and valve C (4) are connected to the three-way valve G (17); The three-way valve G (17) is built into the high-temperature and high-pressure visible reactor (19); The three-way valve G(17) has one inlet G1 and two outlets G2 and G3. When the valve is rotated, the inlet G1 is connected to the outlet G2, or the inlet G1 is connected to the outlet G3. There is no situation where the inlet G1 is connected to or disconnected from the outlets G2 and G3 at the same time. The intermediate container and the connecting pipeline are placed in a constant temperature heating box A (11); The simulation device further includes a ring pressure unit connected to the ring pressure inlet end of the high temperature and high pressure visual reactor (19), which provides ring pressure to the high temperature and high pressure visual reactor (19). The ring pressure unit includes a ring pressure tracking pump (12) and a pressure gauge, and the pressure gauge is installed on the connecting pipeline between the ring pressure tracking pump (12) and the high temperature and high pressure visual reactor (19). The pressure gauges include pressure gauge A (13), pressure gauge B (14) and pressure gauge C (16).

2. The simulation device according to claim 1, wherein, The simulation device also includes a back pressure valve (21) connected to the microfluidic chip (18). And / or, a back pressure pump (27) is provided at the other end of the back pressure valve (21), and a pressure gauge D (25) is provided on the pipeline connected to the back pressure valve (21) and the back pressure pump (27), and the pressure gauge D (25) is used to collect and monitor the back pressure.

3. The simulation device according to claim 2, wherein, The outlet of the back pressure valve (21) is provided with a fluid recovery device (22), which is used to measure the volume and / or mass of the fluid at the outlet.

4. The simulation device according to claim 3, wherein, The fluid recovery device (22) is connected to the tail gas recovery bottle (26) via a pipeline.

5. The simulation device according to claim 4, wherein, The back pressure valve (21) and the fluid recovery device (22) are placed inside the constant temperature heating box B (23).

6. The simulation apparatus according to claim 1, wherein, The data acquisition unit also includes a high-brightness light source (20) located directly below the high-temperature and high-pressure visual reactor (19). And / or, the high-temperature and high-pressure visual reactor (19) also includes a chip holder, an electric heating system, a temperature sensor, a heat-conducting inner cavity, and a heat-insulating outer cavity.

7. The simulation apparatus according to claim 6, wherein, The microfluidic chip (18) is fixed in the thermally conductive cavity by the chip holder.

8. The simulation apparatus according to claim 6, wherein, The electric heating system is provided in the heat-conducting inner cavity and the heat-insulating outer cavity. The electric heating system is connected to the computer (24) through the temperature sensor to monitor temperature changes in real time.

9. A method for simulating liquid sulfur-gas-water multiphase flow, wherein the simulation method is performed in the simulation apparatus described in any one of claims 1-8, characterized in that, The simulation method includes: The first simulation method: (1) Fabrication of microfluidic chips (18): 1) Prepare thin sections from actual core samples of the reservoir and extract the pore and fracture structure using microscopic imaging; 2) Based on the described pore and fissure structure, microfluidic chip etching is performed to create a glass plate etching micro-model; 3) Another glass plate with injection holes and fluid extraction holes is bonded together by vacuum bonding to obtain a microfluidic chip (18) representing the real reservoir pore structure. (2) The liquid sulfur in the microfluidic chip (18) reaches saturation: The microfluidic chip (18) is placed in a high-temperature and high-pressure visible reactor (19), and sulfur powder is filled into a sulfur intermediate container (5), heated and melted to liquid sulfur state, and the liquid sulfur is injected into the microfluidic chip (18) at high temperature until the liquid sulfur reaches saturation; (3) Nitrogen cleaning pipeline: The connection route between the three-way valve G (17) and the microfluidic chip (18) is closed, while the other branch is opened, so that the three-way valve G (17) is directly connected to the back pressure valve (21); the nitrogen in the gas intermediate container (7) flows through the three-way valve G (17), bypasses the microfluidic chip (18) along the branch, and flows directly through the back pressure valve (21) to the fluid recovery device (22) to clean the residual liquid sulfur in the pipeline until no liquid sulfur is generated in the fluid recovery device (22); so as to avoid the liquid sulfur in the pipeline from affecting the sulfur saturation in the microfluidic chip (18) when the nitrogen is displaced; (4) Gas-driven liquid sulfur simulation: Adjust the three-way valve G (17) to connect the three-way valve G (17) with the microfluidic chip (18), inject nitrogen into the microfluidic chip (18), and obtain the simulated state of gas-liquid sulfur two-phase flow through the high-speed camera (15); (5) Water cleaning pipeline: The connection route between the three-way valve G (17) and the microfluidic chip (18) is closed, while the other branch is opened, so that the three-way valve G (17) is directly connected to the back pressure valve (21); the water in the intermediate water container (6) flows through the three-way valve G (17), bypasses the microfluidic chip (18) along the branch, and flows directly through the back pressure valve (21) to the fluid recovery device (22) to clean the residual gas in the pipeline until no obvious bubbles are generated in the fluid recovery device (22); so as to avoid the residual gas in the pipeline from affecting the gas-liquid sulfur saturation in the microfluidic chip (18) when the water is displaced; (6) Simulation of three-phase liquid sulfur-gas-water under water-driven gas-liquid sulfur conditions: Adjust the three-way valve G (17) to connect the three-way valve G (17) to the microfluidic chip (18), inject distilled water into the microfluidic chip (18), and obtain the simulated state of liquid sulfur-gas-water three-phase flow through the high-speed camera (15); Alternatively, a second simulation method: This is performed after steps (1) to (3) of the first simulation method: (7) Simulation of three-phase flow of liquid sulfur-gas-water under alternating gas-water injection conditions: After the aforementioned steps (1) to (3), the water intermediate container (6) and the gas intermediate container (7) are opened alternately to carry out gas-water alternating displacement until stability is achieved, and the simulated state of liquid sulfur-gas-water three-phase flow is obtained through a high-speed camera (15).

10. The simulation method according to claim 9, wherein, In step (2), the method for achieving saturation of the liquid sulfur includes: 1) Keep all valves closed, and maintain the three-way valve G (17) connected to the microfluidic chip (18); 2) Fill the sulfur intermediate container (5) with sulfur powder; 3) Set the pressure of the back pressure valve (21) to 25-60MPa and monitor it in real time through pressure gauge D (25) to keep the back pressure stable; 4) Correlate the pressure of the high-temperature and high-pressure visible reactor controlled by pressure gauge A (13) with the pressure of the injection end controlled by pressure gauge B (14) to keep the pressure difference <0.2MPa. 5) The temperature of constant temperature heating box A (11), high temperature and high pressure visual reactor (19) and constant temperature heating box B (23) is controlled at 120-180℃ and kept at a constant temperature for 3-6 hours; 6) Open valves D (8) and A (2) in sequence, start the ISCO constant speed and constant pressure pump (1), inject in constant pressure mode, and set the pressure value to be 1-2 MPa lower than the back pressure valve (21) pressure value in step 3); then switch to constant speed mode injection, and set the speed to 0.05-0.1 mL / min; 7) Turn on the high-speed camera (15), start the recording mode, observe the liquid sulfur saturation, and end the liquid sulfur saturation when there are no obvious bubbles in the microfluidic chip (18). Then turn off the ISCO constant speed and pressure pump (1) injection and close valve D (8) and valve A (2).

11. The simulation method according to claim 9, wherein, In step (3), the method for purging the pipeline with nitrogen includes: 1) Maintain all settings as in step (2); 2) Adjust all valves to be closed, adjust the connection route between the three-way valve G (17) and the microfluidic chip (18) to be closed, and at the same time open the other branch, so that the three-way valve G (17) and the back pressure valve (21) are directly connected, bypassing the microfluidic chip (18). 3) Open valves F (10) and C (4) in sequence, start the ISCO constant speed and constant pressure pump (1), and inject at a constant speed of 0.1-0.5 mL / min. 4) Stop cleaning when no obvious liquid sulfur is produced in the fluid recovery device (22), turn off the ISCO constant speed and pressure pump (1) injection, and close valve F (10) and valve C (4).

12. The simulation method according to claim 9, wherein, In step (4), the gas-driven liquid sulfur simulation method includes: 1) Maintain the state of all settings in step (3); 2) Adjust all valves to be in the closed state, and adjust the three-way valve G (17) to be connected to the microfluidic chip (18); 3) Open valves F (10) and C (4) in sequence, start the ISCO constant speed and constant pressure pump (1), and inject at a constant speed of 0.05-0.1 mL / min. 4) When the sulfur saturation of the microfluidic chip (18) does not change, stop the gas-driven liquid sulfur simulation experiment by using image analysis, turn off the injection of the ISCO constant speed and pressure pump (1), and close valve F (10) and valve C (4) to obtain the simulated state of gas-liquid sulfur two-phase flow.

13. The simulation method according to claim 9, wherein, In step (5), the method for cleaning the pipeline with water includes: (1) Maintain the state of all settings in step (4); (2) Adjust all valves to be closed, adjust the connection route between the three-way valve G (17) and the microfluidic chip (18) to be closed, and open the other branch at the same time so that the three-way valve G (17) and the back pressure valve (21) are directly connected, bypassing the microfluidic chip (18). (3) Open valves E (9) and B (3) in sequence, start the ISCO constant speed and constant pressure pump (1), and inject in constant speed mode with a speed of 0.1-0.5 mL / min; (4) Stop cleaning when no obvious bubbles are produced in the fluid recovery device (22), turn off the ISCO constant speed and pressure pump (1) to inject, and close valve E (9) and valve B (3).

14. The simulation method according to claim 9, wherein, In step (6), the method for simulating the three-phase flow of liquid sulfur, gas, and water under water-driven gas-liquid sulfur conditions includes: 1) Maintain the state of all settings in step (5); 2) Adjust all valves to be in the closed state, and adjust the three-way valve G (17) to be connected to the microfluidic chip (18); 3) Open valves E (9) and B (3) in sequence, start the ISCO constant speed and constant pressure pump (1), and inject in constant speed mode with a speed of 0.05-0.1 mL / min; 4) When the sulfur saturation of the microfluidic chip (18) does not change, stop the water-driven liquid sulfur experiment by using image analysis, turn off the ISCO constant speed and pressure pump (1), and close valve E (9) and valve B (3) to obtain the simulated state of liquid sulfur-gas-water three-phase flow under water-driven gas-liquid sulfur conditions.

15. The simulation method according to claim 9, wherein, In step (7), the method for simulating the liquid sulfur-gas-water three-phase flow under the alternating gas-water injection condition includes: 1) Maintain the state of all settings in step (3); 2) Adjust all valves to be in the closed state, and adjust the three-way valve G (17) to be connected to the microfluidic chip (18); 3) Open valves F (10) and C (4) in sequence, start the ISCO constant speed and constant pressure pump (1), and inject at a constant speed of 0.05-0.1 mL / min. 4) After injecting for 50-100 minutes, pause the ISCO constant speed and pressure pump (1), close valve F (10) and valve C (4) in sequence, open valve E (9) and valve B (3) in sequence, start the ISCO constant speed and pressure pump (1), and inject in constant speed mode with a speed of 0.05-0.1 mL / min; 5) After injecting for 50-100 minutes, pause the ISCO constant speed and pressure pump (1), close valve E (9) and valve B (3) in sequence, open valve F (10) and valve C (4) in sequence, start the ISCO constant speed and pressure pump (1) and inject in constant speed mode, with the speed set to 0.05-0.1 mL / min; 6) Repeat steps (4) and (5) in sequence. When the sulfur saturation of the microfluidic chip (18) is detected to be unchanged by image analysis, stop the liquid sulfur-gas-water three-phase flow simulation experiment, turn off the ISCO constant speed and pressure pump (1), and close all valves.

16. An application of the simulation method described in any one of claims 9-15 in a high-sulfur, high-temperature, and high-pressure gas reservoir.

17. The application according to claim 16, wherein, The conditions for the high-sulfur, high-temperature, and high-pressure gas reservoir include: a temperature of 120-200℃ and a pressure of 1-60MPa.

18. The application according to claim 17, wherein, The conditions for the high-sulfur, high-temperature, and high-pressure gas reservoir include: a temperature of 120-180℃ and a pressure of 20-60MPa.

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