Experimental device and method for simulating migration and elution of petroleum hydrocarbon in karst fissure

Abstract

The invention discloses an experimental device and method for simulating migration and elution of petroleum hydrocarbon in karst fissures. The experimental device comprises a seepage box, a pressurization assembly, an oil supply assembly, a water supply assembly and a separation sampling assembly. The seepage box is provided with a sample cavity for placing a sample; the pressurizing assembly can apply axial pressure and confining pressure to the sample cavity; the oil supply assembly can introduce oil pollutants with different temperatures and different flow velocities into the sample cavity; the water supply assembly can introduce water with different temperatures and different flow velocities into the sample cavity; a mixture flowing out of the lower side of the sample cavity can enter the separating and sampling assembly, and oil pollutants and water are separated and sampled. The device can be used for researching migration and elution processes of petroleum pollutants in medium micro cracks, solution gaps and wide cracks of a water-bearing layer of a karst system and pipelines, so as to promote migration and transformation mechanism research of the petroleum pollutants in the karst system and development of related disposal technologies. The invention further discloses an experimental method for simulating migration and elution of petroleum hydrocarbon in karst fissures.

Description

Technical Field

[0001] The present invention relates to the technical field of karst system research experiments, and particularly relates to an experimental device and method for simulating the migration and elution of petroleum hydrocarbons in karst fissures. Background Art

[0002] Karst groundwater is an important part of the hydrological cycle, which can not only provide drinking water, but also play an important role in agricultural irrigation and industrial production. However, in recent years, with the rapid development of social economy, pollutant leakage incidents related to the petroleum industry have occurred frequently in karst areas, resulting in a large amount of organic pollutants entering the karst groundwater system. Under the influence of factors such as lithology and structure, there are often microfissures, solution cavities, wide cracks and pipelines in karst aquifer media. Therefore, karst groundwater can respond quickly to rainfall and form rapid pipe flow, increasing the migration speed and distribution range of petroleum pollutants, bringing great risks to human health and the ecological environment. At the same time, the strong heterogeneity of the channel space of karst aquifer media also leads to a high degree of uncertainty in the migration and distribution of petroleum pollutants, further increasing the difficulty of dealing with petroleum pollution incidents in karst groundwater systems.

[0003] At present, the research methods for the migration and diffusion of petroleum pollutants in karst systems can be mainly divided into two categories: indoor experiments and numerical simulations, in order to reveal the migration and transformation laws of petroleum pollutants in karst systems and provide a theoretical basis for the remediation of polluted sites. In terms of numerical simulation research, the simulation technology for multiphase fluid flow in saturated and unsaturated zones has been relatively mature, and can be used to analyze the migration rate and distribution characteristics of non-aqueous phase organic pollutants in heterogeneous aquifer media under different rainfall conditions, and study the influence mechanisms of rainfall infiltration rate, pore and permeability conditions of aquifer media, etc. on the migration and transformation of petroleum pollutants. However, after petroleum pollutants enter the groundwater environment, the physical processes they experience include dissolution, convection, dispersion, diffusion and adsorption, etc., and the chemical processes include biological and abiotic degradation processes involving a series of redox reactions. At the same time, due to the high heterogeneity of karst aquifer media, it is difficult to accurately capture the flow law of karst groundwater. Therefore, the generalization and assumptions made by mathematical models for the above situations when depicting the system often lead to a large deviation between the numerical simulation results and the actual situation, and are mostly used for theoretical research on the migration and diffusion of petroleum pollutants in karst systems under relatively ideal scenarios. And improving the accuracy of numerical model simulation results requires obtaining more accurate empirical formulas and parameters based on indoor experimental research.

[0004] At present, relevant indoor experimental studies mainly focus on soil column leaching and sandbox simulation experiments, which can analyze the phase distribution and interfacial processes of petroleum pollutants in the water-soil-sediment system to reveal the influence mechanism of soil types and mineral compositions on the adsorption, desorption, degradation, etc. of pollutants. However, relevant experimental studies on the migration and elution of petroleum pollutants in the microfractures, solution gaps, wide cracks, and pipelines of the aquifer medium in the karst system are still extremely scarce. Summary of the Invention

[0005] The purpose of the present invention is to provide an experimental device and method for simulating the migration and elution of petroleum hydrocarbons in karst fractures to solve the problems existing in the above-mentioned prior art, which can be used to study the migration and elution processes of petroleum pollutants in the microfractures, solution gaps, wide cracks, and pipelines of the aquifer medium in the karst system, so as to promote the research on the migration and transformation mechanism of petroleum pollutants in the karst system and the development of related disposal technologies.

[0006] To achieve the above purpose, the present invention provides the following solutions:

[0007] The present invention provides an experimental device for simulating the migration and elution of petroleum hydrocarbons in karst fractures, including a seepage box, a pressurization assembly, an oil supply assembly, a water supply assembly, and a separation and sampling assembly; the seepage box has a sample chamber for placing samples; the pressurization assembly is connected to the seepage box and can apply axial pressure and confining pressure to the sample chamber; the oil supply assembly is communicated with the upper side of the sample chamber and can introduce oil pollutants with different temperatures and different flow rates into the sample chamber; the water supply assembly is communicated with the upper side of the sample chamber and can introduce water with different temperatures and different flow rates into the sample chamber; the separation and sampling assembly is communicated with the lower side of the sample chamber, and the mixture flowing out from the lower side of the sample chamber can enter the separation and sampling assembly for separation and sampling.

[0008] Preferably, an axial pressure chamber and a confining pressure chamber are respectively arranged on the upper side and the peripheral side of the sample chamber in the seepage box; the pressurization assembly can respectively communicate with the axial pressure chamber and the confining pressure chamber and introduce media into the axial pressure chamber and the confining pressure chamber to apply axial pressure and confining pressure to the sample chamber respectively.

[0009] Preferably, a heat preservation device is arranged outside the seepage box.

[0010] Preferably, the pressurization assembly includes an axial pressure pressurization mechanism and a confining pressure pressurization mechanism. The axial pressure pressurization mechanism is communicated with the axial pressure chamber through an axial pressure pipeline and can introduce fluid into the axial pressure chamber, and the confining pressure pressurization mechanism is communicated with the confining pressure chamber through a confining pressure pipeline and can introduce fluid into the confining pressure chamber.

[0011] Preferably, the oil supply assembly includes an oil storage tank, an oil supply pump, an oil temperature control mechanism, and a pollutant leakage member. The pollutant leakage member is laid on the upper side inside the sample. The oil storage tank is connected to the pollutant leakage member through an oil supply pipeline. The pollutant leakage member can leak oil pollutants into the sample. The oil supply pump and the oil temperature control mechanism are both arranged on the oil supply pipeline. The oil supply pump is used to control the flow rate, and the oil temperature control mechanism is used to control the temperature.

[0012] Preferably, the water supply assembly includes a water storage tank, a water supply pump, a water temperature control mechanism, and a precipitation infiltration member. The precipitation infiltration member is laid on the top of the sample and placed above the pollutant leakage member. The water storage tank is connected to the precipitation infiltration member through a water supply pipeline. The precipitation infiltration member can introduce water into the sample. The water supply pump and the water temperature control mechanism are both arranged on the water supply pipeline. The water supply pump is used to control the flow rate, and the water temperature control mechanism is used to control the temperature.

[0013] Preferably, the separation and sampling assembly includes a gas-liquid separator, a gas-phase sampling component, and a liquid-phase sampling component. The gas-liquid separator is connected to the lower side of the sample chamber through a discharge pipeline. The gas outlet of the gas-liquid separator is connected to the gas-phase sampling component through a gas outlet pipeline, and the liquid outlet of the gas-liquid separator is connected to the liquid-phase sampling component through a liquid outlet pipeline.

[0014] Preferably, on-off valves are provided on the oil supply pipeline, the water supply pipeline, the axial pressure pipeline, the confining pressure pipeline, the discharge pipeline, the gas outlet pipeline, and the liquid outlet pipeline. Pressure monitoring components are provided on the oil supply pipeline, the water supply pipeline, the axial pressure pipeline, the confining pressure pipeline, and the discharge pipeline. Temperature monitoring components are provided on the oil supply pipeline, the water supply pipeline, the discharge pipeline, and the seepage box. Flow monitoring components are provided on the oil supply pipeline, the water supply pipeline, the discharge pipeline, the gas outlet pipeline, and the liquid outlet pipeline.

[0015] Preferably, it further includes a control component, which is communicatively connected to the on-off valve, the pressure monitoring component, the temperature monitoring component, and the flow monitoring component, and can receive monitoring information. The control component can also be communicatively connected to the oil temperature control mechanism and the water temperature control mechanism, and can perform control.

[0016] The present invention also provides an experimental method for simulating the migration and elution of petroleum hydrocarbons in karst fractures. Based on the experimental device for simulating the migration and elution of petroleum hydrocarbons in karst fractures as described above, it includes the following steps:

[0017] Place the sample in the sample chamber, and the pressurizing assembly applies confining pressure and axial pressure to the sample chamber;

[0018] Pass water at a set temperature into the sample cavity through the water supply component until the fractures in the sample reach water saturation;

[0019] Pass oil pollutants at a set temperature and set flow rate into the sample cavity through the oil supply component, and simultaneously obtain the flow information of the fluid;

[0020] Pass water at a set temperature and set flow rate into the sample cavity through the water supply component to be able to elute the oil pollutants, and separate and sample the eluted mixture through the separation and sampling component.

[0021] The present invention has achieved the following technical effects compared with the prior art:

[0022] The experimental device for simulating the migration and elution of petroleum hydrocarbons in karst fractures provided by the present invention places a sample with fractures in the sample cavity of the seepage box, and then applies axial pressure and confining pressure to the sample through the pressurizing component to simulate the in-situ pressure state. The oil supply component can pass oil pollutants into the sample cavity, enabling the oil pollutants to migrate and transform in the sample. The water supply component can pass water into the sample cavity to elute the oil pollutants in the sample, and then separate and sample the eluted mixture through the separation and sampling component for subsequent analysis of the elution situation; by changing the load pressure of the axial pressure, the migration law of petroleum pollutants in karst fractures under different karst fracture aperture conditions can be studied; by changing the load pressure in the axial pressure and confining pressure, the migration and transformation process of petroleum pollutants in karst fractures under different formation pressure conditions can be studied; by changing the temperature of the oil pollutants and water, the migration and transformation law of petroleum pollutants in karst fractures under different temperature conditions can be studied; by changing the flow rate of water, the elution process of petroleum pollutants in karst fractures under different rainfall infiltration conditions can be studied; by changing the flow rate of oil pollutants, the influence of the oil leakage rate on the migration rate of petroleum pollutants in karst fractures can be studied.

[0023] The experimental method for simulating the migration and elution of petroleum hydrocarbons in karst fractures provided by the present invention places the sample in the sample cavity, and the pressurizing component applies confining pressure and axial pressure to the sample cavity to simulate the formation pressure state; pass water at a set temperature into the sample cavity through the water supply component until the fractures in the sample reach water saturation, which can simulate different formation temperatures; pass oil pollutants at a set temperature and set flow rate into the sample cavity through the oil supply component, and simultaneously obtain the internal structure information of the sample to observe the migration process of the oil pollutants; pass water at a set temperature and set flow rate into the sample cavity through the water supply component to be able to elute the oil pollutants, and separate and sample the eluted mixture through the separation and sampling component for subsequent analysis of the elution situation. Description of the Drawings

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for use in the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0025] Figure 1 Schematic diagram of the experimental device for simulating the migration and elution of petroleum hydrocarbons in karst fractures provided for Embodiment 1.

[0026] In the figure: 1 - seepage box; 11 - sample chamber; 12 - axial pressure chamber; 13 - confining pressure chamber; 14 - heat preservation device; 15 - piston plate; 16 - rubber sleeve; 2 - pressurization assembly; 21 - axial pressure pressurization mechanism; 22 - confining pressure pressurization mechanism; 23 - axial pressure pipeline; 24 - confining pressure pipeline; 25 - hand pump; 3 - oil supply assembly; 31 - oil storage tank; 32 - oil supply pump; 33 - oil temperature control mechanism; 34 - pollutant leakage part; 35 - oil supply pipeline; 4 - water supply assembly; 41 - water storage tank; 42 - water supply pump; 43 - water temperature control mechanism; 44 - precipitation infiltration part; 45 - water supply pipeline; 5 - separation and sampling assembly; 51 - gas-liquid separator; 52 - gas-phase sampling component; 53 - liquid-phase sampling component; 54 - discharge pipeline; 55 - gas outlet pipeline; 56 - liquid outlet pipeline; 6 - on-off valve; 7 - pressure monitoring part; 8 - temperature monitoring part; 9 - flow monitoring part; 10 - control component. Detailed implementation manners

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0028] The purpose of the present invention is to provide an experimental device and method for simulating the migration and elution of petroleum hydrocarbons in karst fractures to solve the problems existing in the above-mentioned prior art, and it can be used to study the migration, adsorption, desorption, degradation and elution processes of petroleum pollutants in microfractures, solution fissures, wide cracks and pipelines in the aquifer medium of the karst system, so as to promote the research on the migration and transformation mechanism of petroleum pollutants in the karst system and the development of related disposal technologies.

[0029] To make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0030] Embodiment 1

[0031] This embodiment provides an experimental device for simulating the migration and elution of petroleum hydrocarbons in karst fissures. Please refer to Figure 1 , which includes a seepage box 1, a pressurization assembly 2, an oil supply assembly 3, a water supply assembly 4, and a separation and sampling assembly 5. The seepage box 1 has a sample chamber 11 for placing samples. The pressurization assembly 2 is connected to the seepage box 1 and can apply axial pressure and confining pressure to the sample chamber 11. The oil supply assembly 3 is communicated with the upper side inside the sample chamber 11 and can introduce oil pollutants with different temperatures and different flow rates into the sample chamber 11. The water supply assembly 4 is communicated with the upper side inside the sample chamber 11 and can introduce water with different temperatures and different flow rates into the sample chamber 11. The separation and sampling assembly 5 is communicated with the lower side of the sample chamber 11, and the mixture flowing out from the lower side of the sample chamber 11 can enter the separation and sampling assembly 5 for separation and sampling.

[0032] Place the sample with fissures in the sample chamber 11 of the seepage box 1, and then apply axial pressure and confining pressure to the sample through the pressurization assembly 2 to simulate the in-situ pressure state. The oil supply assembly 3 can introduce oil pollutants into the sample chamber 11 to enable the migration and transformation of oil pollutants in the sample. The water supply assembly 4 can introduce moisture into the sample chamber 11 to elute the oil pollutants in the sample, and then separate and sample the eluted mixture through the separation and sampling assembly 5 for subsequent analysis of the elution situation. By changing the load pressure of the axial pressure, the migration law of petroleum pollutants in karst fissures under different karst fissure aperture conditions can be studied. By changing the load pressure in the axial pressure and confining pressure, the migration and transformation process of petroleum pollutants in karst fissures under different formation pressure conditions can be studied. By changing the temperatures of the oil pollutants and water, the migration and transformation law of petroleum pollutants in karst fissures under different temperature conditions can be studied. By changing the flow rate of water, the elution process of petroleum pollutants in karst fissures under different rainfall infiltration conditions can be studied. By changing the flow rate of oil pollutants, the influence of the oil leakage rate on the migration rate of petroleum pollutants in karst fissures can be studied.

[0033] In an optional solution of this embodiment, preferably, an axial pressure chamber 12 and a confining pressure chamber 13 are further included in the seepage box 1, which are respectively arranged on the upper side and the circumferential side of the sample chamber 11. The pressurization assembly 2 can be respectively communicated with the axial pressure chamber 12 and the confining pressure chamber 13 and introduce media into the axial pressure chamber 12 and the confining pressure chamber 13 to respectively apply axial pressure and confining pressure to the sample chamber 11. Specifically, the sample chamber 11 is surrounded by a piston plate 15 and a rubber sleeve 16. The piston plate 15 is hermetically arranged on the upper side of the annular rubber sleeve 16 and is hermetically and slidably connected to the inner wall of the seepage box 1. An axial pressure chamber 12 is formed between the piston plate 15 and the top wall of the seepage box 1, and a confining pressure chamber 13 is formed between the rubber sleeve 16 and the side wall of the seepage box 1. Fluid can be introduced into the axial pressure chamber 12 to squeeze the piston plate 15 so as to axially pressurize the sample in the sample chamber 11. Similarly, fluid can be introduced into the confining pressure chamber 13 to squeeze through the rubber sleeve 16 so as to circumferentially pressurize the sample in the sample chamber 11.

[0034] In an alternative embodiment of the present example, preferably, a heat preservation device 14 is provided outside the seepage box 1. Specifically, the heat preservation device 14 is set as a heat insulation layer to reduce heat exchange with the outside.

[0035] In an alternative embodiment of the present example, preferably, the pressure application assembly 2 includes an axial pressure application mechanism 21 and a confining pressure application mechanism 22. The axial pressure application mechanism 21 is connected to the axial pressure chamber 12 through an axial pressure pipeline 23 and can introduce fluid into the axial pressure chamber 12. The confining pressure application mechanism 22 is connected to the confining pressure chamber 13 through a confining pressure pipeline 24 and can introduce fluid into the confining pressure chamber 13. Specifically, both the axial pressure application mechanism 21 and the confining pressure application mechanism 22 are set as hand pumps 25. The two hand pumps 25 are respectively connected to the axial pressure chamber 12 and the confining pressure chamber 13 through the axial pressure pipeline 23 and the confining pressure pipeline 24. The two hand pumps 25 can adjust the axial pressure and the confining pressure respectively by pumping the water in the pump into the axial pressure chamber 12 and the confining pressure chamber 13.

[0036] In an alternative embodiment of the present example, preferably, the oil supply assembly 3 includes an oil storage tank 31, an oil supply pump 32, an oil temperature control mechanism 33 and a pollutant leakage member 34. The pollutant leakage member 34 is laid on the upper side inside the sample. The oil storage tank 31 is connected to the pollutant leakage member 34 through an oil supply pipeline 35. The pollutant leakage member 34 can leak oil pollutants into the sample. The oil supply pump 32 and the oil temperature control mechanism 33 are both arranged on the oil supply pipeline 35. The oil supply pump 32 is used to control the flow rate, and the oil temperature control mechanism 33 is used to control the temperature. Specifically, the oil temperature control mechanism 33 includes a condenser and a preheater connected in series to the oil supply pipeline 35, which can cool and heat the oil pollutants. The pollutant leakage member 34 can be set as multiple branch pipelines. The branch pipelines are laid inside the sample, and multiple leakage holes are arranged on the lower side of the branch pipelines. The oil pollutants are leaked at a specific horizontal plane through the multiple branch pipelines, and the influence on the flow of precipitation is reduced.

[0037] In an alternative embodiment of the present example, preferably, the water supply assembly 4 includes a water storage tank 41, a water supply pump 42, a water temperature control mechanism 43 and a precipitation infiltration member 44. The precipitation infiltration member 44 is laid on the top of the sample and placed above the pollutant leakage member 34. The water storage tank 41 is connected to the precipitation infiltration member 44 through a water supply pipeline 45. The precipitation infiltration member 44 can introduce water source into the sample. The water supply pump 42 and the water temperature control mechanism 43 are both arranged on the water supply pipeline 45. The water supply pump 42 is used to control the flow rate, and the water temperature control mechanism 43 is used to control the temperature. Specifically, the water temperature control mechanism 43 includes a condenser and a preheater connected in series to the water supply pipeline 45, which can cool and heat the water. The precipitation infiltration member 44 can be set as a flat plate, which is laid on the top of the sample, and multiple leakage holes are arranged on the lower side of the flat plate. The precipitation simulation is realized at the top through the flat plate.

[0038] In an alternative embodiment of the present example, more preferably, the separation and sampling assembly 5 includes a gas-liquid separator 51, a gas-phase sampling component 52, and a liquid-phase sampling component 53; the gas-liquid separator 51 is connected to the lower side of the sample chamber 11 through a discharge pipeline 54, the gas outlet of the gas-liquid separator 51 is connected to the gas-phase sampling component 52 through a gas outlet pipeline 55, and the liquid outlet of the gas-liquid separator 51 is connected to the liquid-phase sampling component 53 through a liquid outlet pipeline 56. The components discharged from the sample chamber 11 through the discharge pipeline 54 may include a liquid phase and a gas phase. The gas phase may contain water vapor and gas hydrocarbons, and the liquid phase is liquid water, liquid oil, and oil dissolved in the liquid water. Subsequently, the gas-phase and liquid-phase components can be detected and confirmed respectively through the gas-phase sampling component 52 and the liquid-phase sampling component 53 for elution analysis.

[0039] In an alternative embodiment of the present example, more preferably, on-off valves 6 such as stop valves are provided on the oil supply pipeline 35, the water supply pipeline 45, the axial pressure pipeline 23, the confining pressure pipeline 24, the discharge pipeline 54, the gas outlet pipeline 55, and the liquid outlet pipeline 56 to control the flow of fluids; pressure monitoring components 7 such as pressure sensors are provided on the oil supply pipeline 35, the water supply pipeline 45, the axial pressure pipeline 23, the confining pressure pipeline 24, and the discharge pipeline 54 for pressure monitoring and regulation; temperature monitoring components 8 such as temperature sensors are provided on the oil supply pipeline 35, the water supply pipeline 45, the discharge pipeline 54, and the seepage tank 1 for temperature monitoring and regulation; flow monitoring components 9 such as flow meters are provided on the oil supply pipeline 35, the water supply pipeline 45, the discharge pipeline 54, the gas outlet pipeline 55, and the liquid outlet pipeline 56. By obtaining flow information, it is convenient to perform data analysis on subsequent oil migration and elution; among them, the on-off valves 6 on the oil supply pipeline 35 and the water supply pipeline 45 are respectively close to the outlets of the oil storage tank 31 and the water storage tank 41.

[0040] In an alternative embodiment of the present example, more preferably, the experimental device for simulating the migration and elution of petroleum hydrocarbons in karst fractures provided in this example further includes a control component 10, which is communicatively connected to the on-off valve 6, the pressure monitoring component 7, the temperature monitoring component 8, and the flow monitoring component 9 and can receive monitoring information; the control component 10 can also be communicatively connected to the oil temperature control mechanism 33 and the water temperature control mechanism 43 and can perform control; specifically, the control component 10 includes a computer terminal and a PLC control cabinet connected in communication. The PLC control cabinet realizes system control, and the computer terminal can perform data acquisition and analysis. The control component 10 can also be communicatively connected to the oil supply pump 32 and the oil supply pump 32 to control the flow rate.

[0041] Embodiment II

[0042] This embodiment provides an experimental method for simulating the migration and elution of petroleum hydrocarbons in karst fractures, based on the experimental device for simulating the migration and elution of petroleum hydrocarbons in karst fractures as in Embodiment I, including the following steps:

[0043] Place the sample in the sample chamber 11, and the pressurizing assembly 2 applies confining pressure and axial pressure to the sample chamber 11; pass clear water at a set temperature into the sample chamber 11 through the water supply assembly 4 until the cracks in the sample reach water saturation; pass oil pollutants at a set temperature and set flow rate into the sample chamber 11 through the oil supply assembly 3, and simultaneously obtain the flow information of the fluid; pass water at a set temperature and set flow rate into the sample chamber 11 through the water supply assembly 4 to be able to elute the oil pollutants, and separate and sample the eluted oil-water mixture through the separation and sampling assembly 5.

[0044] Further, the detailed steps are as follows:

[0045] 1 Determine the experimental conditions, including the type of soil used, the fracture morphology of the carbonate rock sample, the experimental pressure and temperature, the rainfall infiltration rate, and the leakage rate of petroleum pollutants.

[0046] 2 Place the cylindrical carbonate rock sample with prefabricated fractures at the bottom of the sample chamber 11, place the soil sample on top of the cylindrical carbonate rock sample and make the upper surface of the soil sample flush with the top of the sample chamber 11, bury the pollutant leakage part 34 and the rainfall infiltration part 44 in the upper layer of the soil sample, then place the piston plate 15, and weigh the seepage box 1.

[0047] 3 Inject water into the axial pressure chamber 12 and the confining pressure chamber 13 respectively through the axial pressure pressurizing mechanism 21 and the confining pressure pressurizing mechanism 22 to generate load pressure, and stop the pressure loading after the pressure displayed by the pressure monitoring part reaches the experimental set confining pressure and axial pressure conditions.

[0048] 4 Open the on-off valve 6 at the outlet of the water storage tank 41, pump clear water into the rainfall infiltration part 44 through the water supply pump 42 and introduce it into the sample, open the condenser or preheater to make the fluid temperature reach the experimental set value, and stop pumping clear water after the pores and fractures of the soil sample and the carbonate rock sample reach the water saturation state, and record the flow rates of the clear water at the fluid inlet end and the outlet end of the sample chamber 11.

[0049] 5 Open the on-off valve 6 at the outlet of the oil storage tank 31, pump petroleum hydrocarbons into the pollutant leakage part 34 through the oil supply pump 32 and leak them into the sample, open the condenser or preheater to make the fluid temperature reach the experimental set value, and stop pumping after the pumped-in amount of petroleum hydrocarbons reaches the experimental set value; in addition, while pumping in petroleum hydrocarbons, turn on the nuclear magnetic resonance spectrometer and record the nuclear magnetic imaging characteristics of the fluid in the sample chamber 11 to obtain migration information.

[0050] 6 Open the on-off valve 6 at the outlet of the water storage tank 41, pump clear water into the rainfall infiltration part 44 through the water supply pump 42 and introduce it into the sample, simulate the elution effect of petroleum pollutants after rainfall infiltration into the soil and karst channels, and record the separated liquid phase and gas phase in the gas-liquid separator 51.

[0051] The experimental method provided in this embodiment can study the migration law of petroleum pollutants in karst fractures under different karst fracture aperture conditions by changing the load pressure of axial compression; the migration and transformation process of petroleum pollutants in karst fractures under different formation pressure conditions can be studied by changing the load pressure of axial compression and confining pressure; the migration and transformation law of petroleum pollutants in karst fractures under different temperature conditions can be studied by changing the temperature of oil pollutants and water; the elution process of petroleum pollutants in karst fractures under different rainfall infiltration conditions can be studied by changing the water flow rate; and the influence of oil leakage rate on the migration rate of petroleum pollutants in karst fractures can be studied by changing the flow rate of oil pollutants.

[0052] Specific examples are used in the present invention to illustrate the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, there will be changes in the specific implementation manner and application scope according to the idea of the present invention. In summary, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. An experimental device for simulating the migration and elution of petroleum hydrocarbons in karst fissures, characterized in that: Comprising: A seepage box (1) having a sample chamber (11) for placing a sample; A pressurizing assembly (2) connected to the seepage box (1) and capable of applying axial pressure and confining pressure to the sample chamber (11); An oil supply assembly (3) communicating with the upper side inside the sample chamber (11) and capable of introducing oil pollutants at different temperatures and different flow rates into the sample chamber (11); A water supply assembly (4) communicating with the upper side inside the sample chamber (11) and capable of introducing water at different temperatures and different flow rates into the sample chamber (11); A separation and sampling assembly (5) communicating with the lower side of the sample chamber (11), and the mixture flowing out from the lower side of the sample chamber (11) can enter the separation and sampling assembly (5) for separation and sampling.

2. The experimental device for simulating the migration and elution of petroleum hydrocarbons in karst fissures according to claim 1, wherein: An axial pressure chamber (12) and a confining pressure chamber (13) are further included inside the seepage box (1), which are respectively arranged on the upper side and the peripheral side of the sample chamber (11); the pressurizing assembly (2) can respectively communicate with the axial pressure chamber (12) and the confining pressure chamber (13) and introduce a medium into the axial pressure chamber (12) and the confining pressure chamber (13) to apply axial pressure and confining pressure to the sample chamber (11) respectively.

3. The experimental device for simulating the migration and elution of petroleum hydrocarbons in karst fissures according to claim 1, characterized in that: A heat preservation device (14) is arranged outside the seepage box (1).

4. The experimental device for simulating the migration and elution of petroleum hydrocarbons in karst fissures according to claim 2, wherein: The pressurizing assembly (2) includes an axial pressure pressurizing mechanism (21) and a confining pressure pressurizing mechanism (22). The axial pressure pressurizing mechanism (21) communicates with the axial pressure chamber (12) through an axial pressure pipeline (23) and can introduce a fluid into the axial pressure chamber (12). The confining pressure pressurizing mechanism (22) communicates with the confining pressure chamber (13) through a confining pressure pipeline (24) and can introduce a fluid into the confining pressure chamber (13).

5. The experimental device for simulating the migration and elution of petroleum hydrocarbons in karst fissures according to claim 4, characterized in that: The oil supply assembly (3) includes an oil storage tank (31), an oil supply pump (32), an oil temperature control mechanism (33) and a pollutant leakage member (34). The pollutant leakage member (34) is laid on the upper side inside the sample. The oil storage tank (31) is communicated with the pollutant leakage member (34) through an oil supply pipeline (35). The pollutant leakage member (34) can leak oil pollutants into the sample. The oil supply pump (32) and the oil temperature control mechanism (33) are both arranged on the oil supply pipeline (35). The oil supply pump (32) is used to control the flow rate, and the oil temperature control mechanism (33) is used to control the temperature.

6. The experimental device for simulating the migration and elution of petroleum hydrocarbons in karst fissures according to claim 5, wherein: The water supply assembly (4) includes a water storage tank (41), a water supply pump (42), a water temperature control mechanism (43) and a precipitation infiltration member (44). The precipitation infiltration member (44) is laid on the top of the sample and placed above the pollutant leakage member (34). The water storage tank (41) is communicated with the precipitation infiltration member (44) through a water supply pipeline (45). The precipitation infiltration member (44) can introduce a water source into the sample. The water supply pump (42) and the water temperature control mechanism (43) are both arranged on the water supply pipeline (45). The water supply pump (42) is used to control the flow rate, and the water temperature control mechanism (43) is used to control the temperature.

7. The experimental device for simulating the migration and elution of petroleum hydrocarbons in karst fissures according to claim 6, wherein: The separation and sampling assembly (5) includes a gas-liquid separator (51), a gas-phase sampling component (52), and a liquid-phase sampling component (53); the gas-liquid separator (51) is connected to the lower side of the sample chamber (11) through a discharge pipeline (54), the gas outlet of the gas-liquid separator (51) is connected to the gas-phase sampling component (52) through a gas outlet pipeline (55), and the liquid outlet of the gas-liquid separator (51) is connected to the liquid-phase sampling component (53) through a liquid outlet pipeline (56).

8. The experimental device for simulating the migration and elution of petroleum hydrocarbons in karst fissures according to claim 7, wherein: On-off valves (6) are provided on the oil supply pipeline (35), the water supply pipeline (45), the axial pressure pipeline (23), the confining pressure pipeline (24), the discharge pipeline (54), the gas outlet pipeline (55), and the liquid outlet pipeline (56); pressure monitoring components (7) are provided on the oil supply pipeline (35), the water supply pipeline (45), the axial pressure pipeline (23), the confining pressure pipeline (24), and the discharge pipeline (54); temperature monitoring components (8) are provided on the oil supply pipeline (35), the water supply pipeline (45), the discharge pipeline (54), and the seepage tank (1); flow monitoring components (9) are provided on the oil supply pipeline (35), the water supply pipeline (45), the discharge pipeline (54), the gas outlet pipeline (55), and the liquid outlet pipeline (56).

9. The experimental device for simulating the migration and elution of petroleum hydrocarbons in karst fissures according to claim 8, wherein: It further includes a control assembly (10), which is communicatively connected to the on-off valve (6), the pressure monitoring component (7), the temperature monitoring component (8), and the flow monitoring component (9), and can receive monitoring information; the control assembly (10) can also be communicatively connected to the oil temperature control mechanism (33) and the water temperature control mechanism (43), and can perform control.

10. An experimental method for simulating the migration and elution of petroleum hydrocarbons in karst fractures, characterized in that: Based on the experimental device for simulating the migration and elution of petroleum hydrocarbons in karst fractures as described in any one of claims 1-9, it includes the following steps: Place the sample in the sample chamber (11), and the pressurizing assembly (2) applies confining pressure and axial pressure to the sample chamber (11). Pass clear water at a set temperature into the sample chamber (11) through the water supply assembly (4) until the fractures in the sample reach water saturation. Pass oil pollutants at a set temperature and set flow rate into the sample chamber (11) through the oil supply assembly (3), and simultaneously obtain the flow information of the fluid. Pass water at a set temperature and set flow rate into the sample chamber (11) through the water supply assembly (4) to elute the oil pollutants, and separate and sample the eluted mixture through the separation and sampling assembly (5).

Images