Real core pore structure microfluidic chip-based crude oil solid deposition experimental device and experimental method
By using a microfluidic chip experimental device and method based on the pore structure of real rock cores, the problem of the inability to accurately simulate the microscopic pore structure of real rock cores in existing technologies has been solved. This enables intuitive observation and data accuracy of solid phase deposition under high temperature and high pressure conditions, and provides scientific research methods and early warning information.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- PETROCHINA CO LTD
- Filing Date
- 2024-12-03
- Publication Date
- 2026-06-05
AI Technical Summary
Existing crude oil solid phase deposition experimental methods cannot accurately simulate the micropore structure of real rock cores under high temperature and high pressure conditions, resulting in unintuitive experimental results and inaccurate data, making it impossible to effectively evaluate solid phase deposition phenomena and deposition conditions.
Using a microfluidic chip based on the pore structure of real rock cores, combined with a microscope and temperature controller, and through a constant speed and pressure pump and a vacuum pump system, the flow of crude oil and solid phase deposition under formation conditions are simulated, and the key critical pressure and temperature of solid phase deposition are directly observed and measured.
It realizes a scientific research method for solid phase deposition, provides an intuitive research method, and enables the observation of solid phase deposition phenomena in the pore structure of real rock cores, providing early warning information and prevention and control basis for oil and gas reservoir development.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of experimental technology for solid phase deposition of crude oil in formations, and is an experimental device and method for solid phase deposition of crude oil based on a microfluidic chip with a real core pore structure. Background Technology
[0002] Crude oil in reservoirs has a complex composition. During reservoir seepage and extraction, changes in formation temperature and pressure, or contact between substances such as paraffin, bitumen, and clay particles in the crude oil and the formation pore walls and well casing walls, can lead to particle precipitation. This solid-phase precipitation during reservoir development affects crude oil flow and reservoir development efficiency. Furthermore, during gas injection development, the injected gas alters the thermodynamic properties of the original hydrocarbon system, causing certain heavy components to change from liquid to solid, thus impacting normal oil production. To assess whether solid-phase deposition will occur during crude oil flow and gas injection, and to determine the conditions and severity of deposition, solid-phase deposition point testing in gas injection expansion experiments and solid-phase deposition volume testing during multi-stage contact between injected gas and crude oil can be used. These testing methods can guide appropriate preventative measures and provide important guidance for enhanced oil recovery strategies in the later stages of target reservoir development.
[0003] Currently, indoor experimental methods for testing solid-phase deposition under high temperature and high pressure conditions mainly include the light transmission method, the ultrasonic method, and the pressure difference method. The traditional ultrasonic method has relatively strict instrument requirements, while the pressure difference method requires the selection of filters with different pore sizes according to different samples, making the experimental process complex and the investment cost of experimental equipment high.
[0004] Microfluidic devices have become an important analytical tool for research and visualization processes in the oil and gas industry. However, most current chips are fabricated based on artificially designed regular-shaped flow channels and structures. The microscopic pore structure of oil and gas reservoir rocks in different regions is very complex. Chips with regular-shaped flow channels cannot accurately simulate the true scale and complexity of micropores in rock cores and cannot fully reflect the microscopic pore structure characteristics of real rock cores.
[0005] Traditional methods for solid deposition of crude oil in formations generally rely on external parameters or phenomena such as pressure and light transmittance to determine solid precipitation. These methods cannot directly test and observe the flow of crude oil in the pore space of the actual core, the characteristics of solid particle precipitation, and changes in state. Furthermore, they cannot directly test the key critical pressure and temperature conditions for solid deposition under different pore structures. Summary of the Invention
[0006] This invention provides an experimental apparatus and method for crude oil solid phase deposition based on a microfluidic chip with a real core pore structure, which overcomes the shortcomings of the prior art and can effectively solve the problems of the experimental process being not intuitive and the experimental results being incomplete and inaccurate in existing crude oil solid phase deposition experiments.
[0007] One of the technical solutions of this invention is achieved through the following measures: an experimental device for crude oil solid phase deposition based on a microfluidic chip with a real core pore structure, comprising a real core simulation device, a first constant-speed and constant-pressure pump, a second constant-speed and constant-pressure pump, a first intermediate container, a second intermediate container, and a third intermediate container. A microscopic imaging device is disposed above the real core simulation device, a temperature controller is disposed on the front side of the real core simulation device, and flow guide holes are disposed on the left and right sides of the real core simulation device. A first displacement pipeline is fixedly connected between the air outlet of the first constant-speed and constant-pressure pump and the air inlet at the bottom of the first intermediate container, and a third displacement pipeline is fixedly installed on the first displacement pipeline. A three-way valve is provided. A second displacement pipeline is fixedly connected between the right end outlet of the first three-way valve and the bottom inlet of the second intermediate container. A first delivery pipeline is fixedly connected between the top outlet of the first intermediate container and the left guide hole of the real core simulation device. A first six-way valve is fixedly installed on the first delivery pipeline. A second delivery pipeline is fixedly connected between the top outlet of the second intermediate container and the left inlet channel of the first six-way valve. A third displacement pipeline is fixedly connected between the outlet of the second constant speed and constant pressure pump and the bottom inlet of the third intermediate container. A third delivery pipeline is fixedly connected between the top outlet of the third intermediate container and the right guide hole of the real core simulation device.
[0008] The following are further optimizations and / or improvements to one of the above-mentioned technical solutions: The aforementioned real core simulation device includes a base, a sealing cap, and a microfluidic chip. The base is rectangular in shape, with a rectangular groove on the top surface. Three or more jet holes are located at the bottom of the groove. A flow channel runs horizontally through the base between the bottom of the groove and the bottom of the base. Flow holes are located at both the left and right ends of the flow channel. The flow channel and the jet holes are fixedly connected by the flow channel. The outlet of the first delivery pipeline is fixedly connected to the flow hole at the left end of the flow channel, and the outlet of the third delivery pipeline is fixedly connected to the flow hole at the right end of the flow channel. The microfluidic chip is a real core pore structure chip synthesized from silicon wafers and glass. The microfluidic chip is rectangular in shape and can be placed inside the groove.
[0009] The sealing cover is a rectangular plate with the same dimensions as the top surface of the base. A transparent viewing window with the same dimensions as the opening of the groove is provided in the middle of the sealing cover. A microscopic camera is provided above the viewing window. The sealing cover and the base are fixed and sealed together by bolts.
[0010] The aforementioned base has a first air guide hole, a second air guide hole, a third air guide hole, and a fourth air guide hole arranged sequentially at intervals on both the front and rear sides. An air inlet pipe is fixedly connected between the air outlet of the temperature controller and the first air guide hole on the front side of the base. A return air pipe is fixedly connected between the second air guide hole on the front side of the base and the air inlet of the temperature controller. A first connecting pipe is fixedly connected between the third air guide hole and the fourth air guide hole on the front side of the base. A second connecting pipe is fixedly connected between the first air guide hole and the second air guide hole on the rear side of the base. A third connecting pipe is fixedly connected between the third air guide hole and the fourth air guide hole on the rear side of the base. An airflow channel is fixedly connected between the air inlet pipe outlet, the return air pipe inlet, the inlet and outlet of the first connecting pipe, the inlet and outlet of the second connecting pipe, the inlet and outlet of the third connecting pipe, and the guide channel.
[0011] Pistons are installed in the first, second, and third intermediate containers, and a stirrer is installed in the first intermediate container.
[0012] The first six-way valve is fixedly connected to a first vacuum pipeline at its second outlet. A first vacuum pump is fixedly installed at the outlet of the first vacuum pipeline. A second six-way valve is fixedly installed on the third delivery pipeline. A second vacuum pipeline is fixedly connected to a second vacuum pipeline at its second outlet. A second vacuum pump is fixedly installed at the outlet of the second vacuum pipeline. A back pressure pipeline is fixedly connected to the right inlet of the second six-way valve. A second three-way valve is fixedly installed on the back pressure pipeline. A waste liquid collection pipeline is fixedly connected to the right outlet of the second three-way valve. A micro-metering tube is fixedly connected to the outlet of the waste liquid collection pipeline.
[0013] A first venting line is fixedly connected to the first vacuuming line, and a first venting valve is fixedly installed on the first venting line. A second venting line is fixedly connected to the second vacuuming line, and a second venting valve is fixedly installed on the second venting line. A first pressure gauge is fixedly installed on the first delivery line between the right channel port of the first six-way valve and the left end of the guide channel. A second pressure gauge is fixedly installed on the third delivery line between the right end of the guide channel and the left channel port of the second six-way valve.
[0014] The second technical solution of the present invention is achieved through the following measures: an experimental method for implementing a crude oil solid phase deposition experimental device based on a microfluidic chip with a real core pore structure, characterized by the following steps: The first step is to place the microfluidic chip into the groove of the base and fix the sealing cap to the top of the base with bolts to ensure the airtightness of the real core simulation device; The second step involves simultaneously pumping a vacuum into the microfluidic chip using both the first and second vacuum pumps, reducing the pore pressure of the microfluidic chip to a negative pressure P0. The third step involves the second constant-speed and constant-pressure pump saturating all the pores of the microfluidic chip with simulated oil in the third intermediate container. The fourth step involves the first constant-speed and constant-pressure pump replacing the simulated oil in all the pores of the microfluidic chip with crude oil in the first intermediate container, and saturating all the pores of the microfluidic chip with crude oil. In the fifth step, the temperature controller maintains the temperature of the microfluidic chip at the formation temperature. Then, the first constant-speed and constant-pressure pump drives the crude oil liquid in the first intermediate container to be input into the microfluidic chip, so that the pressure of the crude oil liquid in the pores of the microfluidic chip increases and is constant at the formation pressure. The temperature controller gradually reduces the temperature of the microfluidic chip until the crude oil liquid in the pores of the microfluidic chip undergoes a phase change. The microscopic imaging device collects the critical point of phase change of the crude oil liquid in the pores of the microfluidic chip, and obtains the critical temperature value corresponding to the critical point of phase change of the crude oil liquid in the pores of the microfluidic chip.
[0015] The following are further optimizations and / or improvements to the second technical solution of the above invention: The fourth step described above, after saturating all pores of the microfluidic chip with crude oil, also includes: First, a temperature controller maintains the microfluidic chip temperature at the formation temperature; then, a back pressure pump pressurizes the microfluidic chip with an injection pressure P1; next, a first constant-speed, constant-pressure pump pressurizes the first intermediate container step by step with a displacement pressure P2, so that the crude oil in the first intermediate container is input into the microfluidic chip at a constant pressure and speed until a phase change occurs in the crude oil in the pores of the microfluidic chip; finally, a microscope imaging device acquires the critical point of phase change of the crude oil in the pores of the microfluidic chip, obtaining the critical injection pressure value of the crude oil corresponding to the critical point of phase change of the crude oil in the pores of the microfluidic chip. Among them, the gas injection pressure P1 is higher than the formation crude oil bubble point pressure value and lower than the chip holder sealing safety pressure value, and the displacement pressure P2 is higher than the gas injection pressure P1 and lower than the chip holder sealing safety pressure value.
[0016] The fourth step described above, after saturating all pores of the microfluidic chip with crude oil, also includes: First, a temperature controller maintains the microfluidic chip temperature at the formation temperature; then, a back pressure pump pressurizes the microfluidic chip at injection pressure P3; next, a first constant-speed, constant-pressure pump pressurizes the second intermediate container step by step at displacement pressure P4, so that the displacement fluid in the second intermediate container is input into the microfluidic chip at a constant pressure and speed until the crude oil in the microfluidic chip pores undergoes a phase change; finally, a microscope imaging device acquires the critical point of phase change of the crude oil in the microfluidic chip pores, obtaining the critical pressure value of the displacement fluid injection corresponding to the critical point of phase change of crude oil in the microfluidic chip. Among them, the gas injection pressure P3 is higher than the formation crude oil bubble point pressure value and lower than the chip holder sealing safety pressure value, and the displacement pressure P4 is higher than the gas injection pressure P3 and lower than the chip holder sealing safety pressure value.
[0017] This invention enables the direct and clear observation of solid phase deposition phenomena of formation crude oil during flow and injection development in a microfluidic chip with real core pore structure, under the influence of reservoir temperature, pressure and injected fluid. It provides a scientific and intuitive research method for studying solid phase particle deposition during the development of different types of oil and gas reservoirs, and at the same time provides early warning information and prevention basis for preventing the negative impact of solid phase particle deposition on the development effect of oil and gas reservoirs. Attached Figure Description
[0018] Appendix Figure 1 This is a schematic diagram of the process flow structure of the present invention.
[0019] Appendix Figure 2 This is a schematic diagram of the main structure of the real core simulation device in this invention.
[0020] Appendix Figure 3 This is a top view of the sealing cap structure in this invention.
[0021] Appendix Figure 4 This is a top view of the base and temperature controller in this invention.
[0022] Appendix Figure 5 This is a schematic diagram of the design and fabrication process of the microfluidic chip in this invention.
[0023] The codes in the attached diagram are as follows: 1 for microfluidic chip, 2 for real core simulation device, 3 for first constant speed and pressure pump, 4 for second constant speed and pressure pump, 5 for first intermediate container, 6 for second intermediate container, 7 for third intermediate container, 8 for first vacuum pump, 9 for second vacuum pump, 10 for back pressure pump, 11 for piston, 12 for stirrer, 13 for first displacement line, 14 for first three-way valve, 15 for second displacement line, 16 for first delivery line, 17 for first six-way valve, 18 for second delivery line, 19 for first vacuum line, 20 for third displacement line, 21 for third delivery line, 22 for second six-way valve, 23 for second vacuum line, 24 for back pressure line, 25 for base, and 26 for seal. The following components are included: cover, groove (27), jet hole (28), guide channel (29), jet channel (30), viewing window (31), microscope camera (32), bolt (33), temperature controller (34), air inlet line (35), air return line (36), first connecting pipe (37), second connecting pipe (38), third connecting pipe (39), airflow channel (40), second three-way valve (41), waste liquid collection line (42), micro-metering tube (43), first vent line (44), first vent valve (45), second vent line (46), second vent valve (47), first pressure gauge (48), second pressure gauge (49), guide hole (50), first air guide hole (51), second air guide hole (52), third air guide hole (53), and fourth air guide hole (54). Detailed Implementation
[0024] The present invention is not limited to the following embodiments, and the specific implementation can be determined according to the technical solution of the present invention and the actual situation.
[0025] Unless otherwise specified, all equipment and devices used in this invention are existing, publicly known, and commonly used equipment and devices in the field.
[0026] In this invention, for ease of description, the relative positional relationships of each component are described according to the layout of the accompanying drawings. For example, the positional relationships of front, back, top, bottom, left, right, etc., are determined according to the layout direction of the accompanying drawings.
[0027] The present invention will be further described below with reference to embodiments: Example 1: As shown in the attached document Figure 1 As shown, the crude oil solid phase deposition experimental device based on a microfluidic chip with a real core pore structure includes a real core simulation device 2, a first constant-speed and constant-pressure pump 3, a second constant-speed and constant-pressure pump 4, a first intermediate container 5, a second intermediate container 6, and a third intermediate container 7. A microscopic imaging device 32 is installed above the real core simulation device 2, and a temperature controller 34 is installed on the front side of the real core simulation device 2. Flow guide holes 50 are provided on both the left and right sides of the real core simulation device 2. A first displacement pipeline 13 is fixedly connected between the air outlet of the first constant-speed and constant-pressure pump 3 and the air inlet at the bottom of the first intermediate container 5. A first three-way valve 14 is fixedly installed on the first displacement pipeline 13. The first three-way valve 14 is located on the right side of the first three-way valve 14. A second displacement pipeline 15 is fixedly connected between the end air outlet and the bottom air inlet of the second intermediate container 6. A first delivery pipeline 16 is fixedly connected between the top outlet of the first intermediate container 5 and the left guide hole 50 of the real core simulation device 2. A first six-way valve 17 is fixedly installed on the first delivery pipeline 16. A second delivery pipeline 18 is fixedly connected between the top outlet of the second intermediate container 6 and the left inlet channel of the first six-way valve 17. A third displacement pipeline 20 is fixedly connected between the air outlet of the second constant speed and constant pressure pump 4 and the bottom air inlet of the third intermediate container 7. A third delivery pipeline 21 is fixedly connected between the top air outlet of the third intermediate container 7 and the right guide hole 50 of the real core simulation device 2.
[0028] Example 2: As an optimization of the above examples, as shown in the appendix. Figure 2As shown, the real core simulation device 2 includes a base 25, a sealing cover 26, and a microfluidic chip 1. The base 25 is rectangular, and a rectangular groove 27 is provided on the top surface of the base 25. Three or more jet holes 28 are provided at the bottom of the groove 27. A flow channel 29 is provided on the base 25 between the bottom of the groove 27 and the bottom of the base 25. A flow hole 50 is provided at the left and right ends of the flow channel 29. A jet channel 30 is fixedly connected between the flow channel 29 and the jet holes 28. The outlet of the first delivery line 16 is fixedly connected to the flow hole at the left end of the flow channel 29, and the outlet of the third delivery line 21 is fixedly connected to the flow hole at the right end of the flow channel 29. The microfluidic chip 1 is a real core pore structure chip made of silicon wafer and glass. The microfluidic chip 1 is rectangular and can be placed in the groove 27.
[0029] As needed, such as Figure 5 As shown, the fabrication steps of microfluidic chip 1 include: First, selecting representative cores that can reflect the porosity and permeability of reservoir rocks, performing high-resolution CT scans on the cores to obtain core CT scan grayscale data; Second, selecting a series of two-dimensional core slice images with representative pore structures, and constructing a core pore structure unit image set using a binary segmentation algorithm; Third, stitching together all pores and skeletons of the core according to the specific morphology and relative positions of pores and skeletons in the core pore structure unit images to obtain a full-frame pore structure image that meets the size requirements of microfluidic chip 1. The fourth step involves using drawing tools to set fluid injection or extraction ports at the corners of the full-page pore structure map, obtaining a draft map of the microfluidic chip 1 that reflects the actual core pore structure. The fifth step involves fabricating the microfluidic chip from silicon chips. Deep reactive ion etching is performed on the silicon to obtain a silicon wafer with microflow channels. The shape of these flow channels is the same as the previously described pore structure draft map, and the depth of the flow channels is controllable (100 micrometers to 10 nanometers). The sixth step involves anodic bonding of the silicon wafer to glass to obtain a silicon-glass microfluidic chip that reflects the actual core pore structure.
[0030] This silicon-glass microfluidic chip 1 enables in-situ observation and effective testing of the thermodynamic phase behavior and flow behavior of fluids at the micrometer and nanometer scales. It offers advantages such as real-time visualization, low confinement scale, minimal sample consumption, and short measurement time. Furthermore, microfluidic chip technology can simulate various reservoir media, such as shale or sandstone, and achieve precise control of fluid flow. Its visualization capabilities allow researchers to gain a deeper understanding of the fluid dynamics at the rock pore scale.
[0031] Example 3: As an optimization of the above examples, as shown in the appendix Figure 2 , 3As shown, the sealing cover 26 is a rectangular plate with the same size as the top surface of the base 25. A transparent viewing window 31 with the same size as the opening surface of the groove 27 is provided in the middle of the sealing cover 26. A microscopic camera device 32 is provided above the viewing window 31. The sealing cover 26 and the base 25 are fixedly and sealed together by bolts 33.
[0032] As required, the microscopic imaging device 32 is a pE-300 light source. The microscopic imaging device 32 includes a computer and an electron microscope. The electron microscope is placed above the viewing window 31 and is used to directly observe the simulated formation oil flow state in the microfluidic chip 1 and whether there is solid particle deposition during the gas injection and extraction process. Based on the actual oil and gas reservoir pore structure and temperature and pressure conditions, it can also directly observe the formation oil flow state and whether there is solid particle deposition during the gas injection and extraction process, and determine the critical temperature or critical pressure value for solid particle deposition in formation crude oil.
[0033] like Figure 2 , 4 As shown, the experimental medium is ejected from the jet hole 28 at the bottom of the groove 27 and can be injected into or extracted from all the pores of the microfluidic chip 1 through all the ports of the microfluidic chip 1.
[0034] Example 4: As an optimization of the above embodiments, as shown in the appendix Figure 2 , 4 As shown, the base 25 has a first air guide hole 51, a second air guide hole 52, a third air guide hole 53, and a fourth air guide hole 54 arranged sequentially on the front and rear sides. An air inlet pipe 35 is fixedly connected between the air outlet of the temperature controller 34 and the first air guide hole on the front side of the base 25. A return air pipe 36 is fixedly connected between the second air guide hole on the front side of the base 25 and the air inlet of the temperature controller 34. A first connecting pipe 37 is fixedly connected between the third air guide hole and the fourth air guide hole on the front side of the base 25. A second connecting pipe 38 is fixedly connected between the first air guide hole and the second air guide hole on the rear side of the base 25. A third connecting pipe 39 is fixedly connected between the third air guide hole and the fourth air guide hole on the rear side of the base 25. An airflow channel 40 is fixedly connected between the outlet of the air inlet pipe 35, the inlet of the return air pipe 36, the inlet and outlet of the first connecting pipe 37, the inlet and outlet of the second connecting pipe 38, and the inlet and outlet of the third connecting pipe 39 and the guide channel 29, respectively.
[0035] As required, the temperature controller 34 is model THY-2015B. A temperature sensor is installed in the groove 27 of the base 25. The temperature sensor is electrically connected to the temperature controller 34. The temperature controller 34 can set and adjust the temperature to control the ambient temperature of the microfluidic chip 1 in the groove 27.
[0036] Example 5: As an optimization of the above embodiments, as shown in the appendix Figure 1As shown, pistons 11 are installed in the first intermediate container 5, the second intermediate container 6, and the third intermediate container 7, and a stirrer 12 is installed in the first intermediate container 5.
[0037] As needed, the first intermediate container 5 is filled with formation crude oil. During operation, to improve experimental results, the stirrer 12 can agitate the formation crude oil in the first intermediate container 5. The second intermediate container 6 is filled with one or a mixture of two or more of carbon dioxide, natural gas, and water. The third intermediate container 7 is filled with a simulated oil solution prepared from a mixture of surface degassed oil and kerosene, with the same viscosity as the formation crude oil. The first, second, and third intermediate containers 5, 6, and 7 above the piston 11 all contain experimental fluid media, while the first, second, and third intermediate containers 5, 6, and 7 below the piston 11 all contain compressed displacement gas.
[0038] Example 6: As an optimization of the above embodiments, as shown in the appendix Figure 1 As shown, the second outlet channel of the first six-way valve 17 is fixedly connected to the first vacuum line 19, and the outlet of the first vacuum line 19 is fixedly installed with the first vacuum pump 8. The third delivery line 21 is fixedly installed with the second six-way valve 22, and the second outlet channel of the second six-way valve 22 is fixedly connected to the second vacuum line 23. The outlet of the second vacuum line 23 is fixedly installed with the second vacuum pump 9. The right inlet channel of the second six-way valve 22 is fixedly connected to the back pressure line 24, and the back pressure line 24 is fixedly installed with the second three-way valve 41. The right outlet of the second three-way valve 41 is fixedly connected to the waste liquid collection line 42, and the outlet of the waste liquid collection line 42 is fixedly connected to the micro-metering tube 43.
[0039] If needed, the micrometer tube 43 can be used to collect waste liquid during the experiment.
[0040] Example 7: As an optimization of the above embodiments, as shown in the appendix Figure 1 As shown, a first venting line 44 is fixedly connected to the first vacuum line 19, and a first venting valve 45 is fixedly installed on the first venting line 44. A second venting line 46 is fixedly connected to the second vacuum line 23, and a second venting valve 47 is fixedly installed on the second venting line 46. A first pressure gauge 48 is fixedly installed on the first delivery line 16 between the right channel port of the first six-way valve 17 and the left end of the guide channel 29. A second pressure gauge 49 is fixedly installed on the third delivery line 21 between the right end of the guide channel 29 and the left channel port of the second six-way valve 22.
[0041] As needed, after the vacuum pumps 8 and 9 complete the vacuuming process of the microfluidic chip 1, the excess compressed gas in the first vacuum line 19 and the second vacuum line 23 can be vented out through the first vent line 44 and the second vent line 46. The first pressure gauge 48 and the second pressure gauge 49 can be used to display the pressure of the experimental medium entering and exiting at both ends of the flow channel 29, and can also be used to display the pore pressure of the microfluidic chip 1.
[0042] Depending on the needs, the pipelines and equipment of this crude oil solid phase deposition experimental device based on a microfluidic chip with a real core pore structure can also be equipped with conventional valves, thermometers, and pressure gauges that are known and commonly used in the field, according to production requirements.
[0043] Example 8: As attached Figure 1 , 2 As shown in Figures 3 and 4, an experimental method for crude oil solid-phase deposition based on a microfluidic chip with real core pore structure is carried out according to the following steps: The first step is to place the microfluidic chip 1 into the groove 27 of the base 25 and fix the sealing cap 26 to the top of the base 25 with bolts 33 to ensure the airtightness of the real core simulation device 2. The second step involves the first vacuum pump 8 and the second vacuum pump 9 simultaneously drawing a vacuum into the microfluidic chip 1, thereby reducing the negative pressure in the pores of the microfluidic chip 1 to a negative pressure P0. As needed, the first vacuum pump 8 and the second vacuum pump 9 can simultaneously evacuate the microfluidic chip 1 for 2 hours or more. The negative pressure P0 of the microfluidic chip 1 can also be increased as much as possible according to actual needs.
[0044] The third step is to saturate all the pores of the microfluidic chip 1 with the simulated oil in the third intermediate container 7 using the second constant speed and constant pressure pump 4. As needed, the simulated oil flow state inside the pores of the microfluidic chip 1 can be observed and recorded by the micro-camera device 32, and the state of all pores of the microfluidic chip 1 saturated with experimental medium can also be observed and recorded by the micro-camera device 32. Once all pores of the microfluidic chip 1 are saturated with simulated oil, the excess simulated oil in the device pipeline can be collected through the micro-metering tube 43, provided that the pressure of the simulated oil in the microfluidic chip 1 is at or above the bubble point pressure of the formation crude oil.
[0045] The fourth step is that the first constant speed and constant pressure pump 3 replaces the crude oil in the first intermediate container 5 with the simulated oil in all the pores of the microfluidic chip 1, and saturates all the pores of the microfluidic chip 1 with crude oil. As needed, the stirrer 12 automatically stirs the crude oil in the first intermediate container 5 to improve the homogenization of the crude oil and further improve the experimental effect of saturating all pores of the microfluidic chip 1 with crude oil.
[0046] In the fifth step, the temperature controller 34 maintains the temperature of the microfluidic chip 1 at the formation temperature. Then, the first constant speed and constant pressure pump 3 drives the crude oil liquid in the first intermediate container 5 to be input into the microfluidic chip 1, so that the pressure of the crude oil liquid in the pores of the microfluidic chip 1 is increased and kept constant at the formation pressure. The temperature controller 34 gradually reduces the temperature of the microfluidic chip 1 until the crude oil liquid in the pores of the microfluidic chip 1 undergoes a phase change. The microscopic imaging device 32 collects the critical point of phase change of the crude oil liquid in the pores of the microfluidic chip 1, and obtains the critical temperature value corresponding to the critical point of phase change of the crude oil liquid in the pores of the microfluidic chip 1.
[0047] As needed, the temperature controller 34 maintains the temperature of the microfluidic chip 1 at the formation temperature for 30 minutes or more, and the temperature controller 34 reduces the temperature of the microfluidic chip 1 by 1℃ / 20min. The microscopic imaging device 32 captures the critical point of phase change of crude oil in the pores of microfluidic chip 1 when solid particles precipitate out of the crude oil in the pores of microfluidic chip 1.
[0048] Example 9: As an optimization of the above embodiments, as shown in the appendix Figure 1 , 2 As shown in Figures 3 and 4, the experimental method for crude oil solid-phase deposition based on a microfluidic chip with a real core pore structure is characterized by the following steps: After saturating all pores of the microfluidic chip 1 with crude oil, the method further includes: First, a temperature controller 34 keeps the temperature of the microfluidic chip 1 constant at the formation temperature; then, a back pressure pump 10 pressurizes the microfluidic chip 1 with an injection pressure P1; then, a first constant-speed and constant-pressure pump 3 pressurizes the first intermediate container 5 step by step with a displacement pressure P2, so that the crude oil in the first intermediate container 5 is input into the microfluidic chip 1 at a constant pressure and speed until a phase change occurs in the pores of the microfluidic chip 1; finally, a microscope imaging device 32 collects the critical point of phase change of the crude oil in the pores of the microfluidic chip 1, and obtains the critical pressure value of crude oil injection corresponding to the critical point of phase change of the crude oil in the pores of the microfluidic chip 1. Among them, the gas injection pressure P1 is higher than the formation crude oil bubble point pressure value and lower than the sealing safety pressure value of the chip holder 2, and the displacement pressure P2 is higher than the gas injection pressure P1 and lower than the sealing safety pressure value of the chip holder 2.
[0049] As needed, the temperature controller 34 maintains the temperature of the microfluidic chip 1 at the formation temperature for 30 minutes or more, and the first constant speed and constant pressure pump 3 pressurizes the first intermediate container 5 step by step at a pressure higher than the injection pressure P10.1MPa. The microscopic imaging device 32 captures the critical point of phase change of crude oil in the pores of microfluidic chip 1 when solid particles precipitate out of the crude oil in the pores of microfluidic chip 1.
[0050] Example 10: As an optimization of the above embodiments, as shown in the appendix Figure 1 , 2As shown in Figures 3 and 4, the experimental method for crude oil solid-phase deposition using a microfluidic chip with a real core pore structure is characterized by the following fourth step: after saturating all pores of the microfluidic chip 1 with crude oil, the method further includes: first, a temperature controller 34 keeps the temperature of the microfluidic chip 1 constant at the formation temperature; then, a back pressure pump 10 pressurizes the microfluidic chip 1 with an injection pressure P3; then, a first constant-speed constant-pressure pump 3 pressurizes the second intermediate container 6 stepwise with a displacement pressure P4, so that the displacement fluid in the second intermediate container 6 is input into the microfluidic chip 1 at a constant pressure and speed until the crude oil in the pores of the microfluidic chip 1 undergoes a phase change; finally, a microscope imaging device 32 collects the critical point of phase change of the crude oil in the pores of the microfluidic chip 1, and obtains the critical pressure value of the displacement fluid injection corresponding to the critical point of phase change of the crude oil in the microfluidic chip 1. Among them, the gas injection pressure P3 is higher than the formation crude oil bubble point pressure value and lower than the sealing safety pressure value of the chip holder 2, and the displacement pressure P4 is higher than the gas injection pressure P3 and lower than the sealing safety pressure value of the chip holder 2.
[0051] As needed, the temperature controller 34 maintains the temperature of the microfluidic chip 1 at the formation temperature for 30 minutes or more, and the first constant speed and constant pressure pump 3 pressurizes the second intermediate container 6 step by step at a pressure higher than the injection pressure P30.1MPa. The microscopic imaging device 32 captures the critical point of phase change of crude oil in the pores of microfluidic chip 1 when solid particles precipitate out of the crude oil in the pores of microfluidic chip 1.
[0052] In summary, this invention can accurately reflect the microscopic pore structure characteristics of rocks and better represent the true characteristics of reservoir rocks. Using a microfluidic chip with a realistic core pore structure, and under the influence of reservoir temperature, pressure, and injected fluid, the solid-phase deposition phenomenon of formation crude oil during flow and injection development can be observed intuitively and clearly. This provides a scientific and intuitive research method for studying solid-phase particle deposition during the development of different types of oil and gas reservoirs, and also provides early warning information and prevention measures to prevent the negative impact of solid-phase particle deposition on oil and gas reservoir development.
[0053] The above technical features constitute various embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.
Claims
1. An experimental device for crude oil solid-phase deposition based on a microfluidic chip with real core pore structure, characterized in that... The system includes a real core simulation device, a first constant-speed and constant-pressure pump, a second constant-speed and constant-pressure pump, a first intermediate container, a second intermediate container, and a third intermediate container. A microscope camera is mounted above the real core simulation device, and a temperature controller is located at the front of the device. Flow guide holes are located on both the left and right sides of the device. A first displacement pipeline is fixedly connected between the outlet of the first constant-speed and constant-pressure pump and the air inlet at the bottom of the first intermediate container. A first three-way valve is fixedly installed on the first displacement pipeline. The air outlet at the right end of the first three-way valve is connected to the air inlet at the bottom of the second intermediate container. A second displacement pipeline is fixedly connected between the air inlets and outlets. A first delivery pipeline is fixedly connected between the top outlet of the first intermediate container and the left guide hole of the real core simulation device. A first six-way valve is fixedly installed on the first delivery pipeline. A second delivery pipeline is fixedly connected between the top outlet of the second intermediate container and the left inlet channel of the first six-way valve. A third displacement pipeline is fixedly connected between the air outlet of the second constant speed and constant pressure pump and the bottom air inlet of the third intermediate container. A third delivery pipeline is fixedly connected between the top outlet of the third intermediate container and the right guide hole of the real core simulation device.
2. The crude oil solid phase deposition experimental device based on a microfluidic chip with real core pore structure according to claim 1, characterized in that... The realistic core simulation device includes a base, a sealing cap, and a microfluidic chip. The base is rectangular in shape, with a rectangular groove on the top surface. The bottom of the groove has three or more jet holes. A flow channel runs horizontally through the base between the bottom of the groove and the bottom of the base. Flow holes are located at both the left and right ends of the flow channel. The flow channel and the jet holes are fixedly connected by the flow channel. The outlet of the first delivery pipeline is fixedly connected to the flow hole at the left end of the flow channel, and the outlet of the third delivery pipeline is fixedly connected to the flow hole at the right end of the flow channel. The microfluidic chip is a realistic core pore structure chip synthesized from silicon wafers and glass. The microfluidic chip is rectangular and can be placed inside the groove.
3. The crude oil solid phase deposition experimental device based on a microfluidic chip with real core pore structure according to claim 2, characterized in that... The sealing cover is a rectangular plate with the same dimensions as the top surface of the base. A transparent viewing window with the same dimensions as the opening of the groove is set in the middle of the sealing cover. A microscopic camera is set above the viewing window. The sealing cover and the base are fixed and sealed together by bolts.
4. The crude oil solid phase deposition experimental device based on a microfluidic chip with real core pore structure as described in claim 2 or 3, characterized in that... The base has a first air guide hole, a second air guide hole, a third air guide hole, and a fourth air guide hole arranged sequentially at intervals on both the front and rear sides. An air inlet pipe is fixedly connected between the air outlet of the temperature controller and the first air guide hole on the front side of the base. A return air pipe is fixedly connected between the second air guide hole on the front side of the base and the air inlet of the temperature controller. A first connecting pipe is fixedly connected between the third air guide hole and the fourth air guide hole on the front side of the base. A second connecting pipe is fixedly connected between the first air guide hole and the second air guide hole on the rear side of the base. A third connecting pipe is fixedly connected between the third air guide hole and the fourth air guide hole on the rear side of the base. An airflow channel is fixedly connected between the air inlet pipe outlet, the return air pipe inlet, the inlet and outlet of the first connecting pipe, the inlet and outlet of the second connecting pipe, the inlet and outlet of the third connecting pipe, and the guide channel.
5. The crude oil solid phase deposition experimental device based on a microfluidic chip with real core pore structure according to claim 1, 2, 3, or 4, characterized in that... Pistons are installed in the first intermediate container, the second intermediate container, and the third intermediate container, and a stirrer is installed in the first intermediate container.
6. The crude oil solid phase deposition experimental apparatus based on a microfluidic chip with real core pore structure according to any one of claims 1 to 5, characterized in that... The first six-way valve has its second outlet channel fixedly connected to a first vacuum line. A first vacuum pump is fixedly installed at the outlet of the first vacuum line. A second six-way valve is fixedly installed on the third delivery line. The second outlet channel of the second six-way valve has its second outlet channel fixedly connected to a second vacuum line. A second vacuum pump is fixedly installed at the outlet of the second vacuum line. The right inlet channel of the second six-way valve has its back pressure line fixedly connected to a back pressure line. A second three-way valve is fixedly installed on the back pressure line. The right outlet of the second three-way valve has its waste liquid collection line fixedly connected to a waste liquid collection line. The outlet of the waste liquid collection line has its micro-metering tube fixedly connected to a micro-metering tube.
7. The crude oil solid phase deposition experimental device based on a microfluidic chip with real core pore structure according to claim 6, characterized in that... A first vent line is fixedly connected to the first vacuum line, and a first vent valve is fixedly installed on the first vent line. A second vent line is fixedly connected to the second vacuum line, and a second vent valve is fixedly installed on the second vent line. A first pressure gauge is fixedly installed on the first delivery line between the right channel port of the first six-way valve and the left end of the guide channel. A second pressure gauge is fixedly installed on the third delivery line between the right end of the guide channel and the left channel port of the second six-way valve.
8. A method for crude oil solid phase deposition experiments based on a microfluidic chip with a real core pore structure according to any one of claims 2 to 7, characterized in that... include: The first step is to place the microfluidic chip into the groove of the base and fix the sealing cap to the top of the base with bolts to ensure the airtightness of the real core simulation device; The second step involves simultaneously pumping a vacuum into the microfluidic chip using both the first and second vacuum pumps, reducing the pore pressure of the microfluidic chip to a negative pressure P0. The third step involves the second constant-speed and constant-pressure pump saturating all the pores of the microfluidic chip with simulated oil in the third intermediate container. The fourth step involves the first constant-speed and constant-pressure pump replacing the simulated oil in all the pores of the microfluidic chip with crude oil in the first intermediate container, and saturating all the pores of the microfluidic chip with crude oil. In the fifth step, the temperature controller maintains the temperature of the microfluidic chip at the formation temperature. Then, the first constant-speed and constant-pressure pump drives the crude oil liquid in the first intermediate container to be input into the microfluidic chip, so that the pressure of the crude oil liquid in the pores of the microfluidic chip increases and is constant at the formation pressure. The temperature controller gradually reduces the temperature of the microfluidic chip until the crude oil liquid in the pores of the microfluidic chip undergoes a phase change. The microscopic imaging device collects the critical point of phase change of the crude oil liquid in the pores of the microfluidic chip, and obtains the critical temperature value corresponding to the critical point of phase change of the crude oil liquid in the pores of the microfluidic chip.
9. The experimental method for crude oil solid phase deposition based on a microfluidic chip with real core pore structure according to claim 8, characterized in that... The fourth step, after saturating all pores of the microfluidic chip with crude oil, includes: first, a temperature controller maintains the microfluidic chip temperature at the formation temperature; then, a back pressure pump pressurizes the microfluidic chip at an injection pressure P1; next, a first constant-speed, constant-pressure pump pressurizes the first intermediate container step by step at a displacement pressure P2, ensuring that the crude oil in the first intermediate container is input into the microfluidic chip at a constant pressure and speed until a phase change occurs in the crude oil within the microfluidic chip pores; finally, a microscope imaging device captures the critical point of phase change in the crude oil within the microfluidic chip pores, obtaining the critical injection pressure value of the crude oil corresponding to the critical point of phase change in the crude oil within the microfluidic chip pores. Among them, the gas injection pressure P1 is higher than the formation crude oil bubble point pressure value and lower than the chip holder sealing safety pressure value, and the displacement pressure P2 is higher than the gas injection pressure P1 and lower than the chip holder sealing safety pressure value.
10. The experimental method for crude oil solid phase deposition based on a microfluidic chip with real core pore structure according to claim 8 or 9, characterized in that... The fourth step, after saturating all pores of the microfluidic chip with crude oil, includes: first, a temperature controller maintains the microfluidic chip temperature at the formation temperature; then, a back pressure pump pressurizes the microfluidic chip at injection pressure P3; next, a first constant-speed, constant-pressure pump pressurizes the second intermediate container stepwise at displacement pressure P4, ensuring that the displacement fluid in the second intermediate container is input into the microfluidic chip at a constant pressure and speed until a phase change occurs in the crude oil within the microfluidic chip pores; finally, a microscope imaging device captures the critical point of phase change in the crude oil within the microfluidic chip pores, obtaining the critical pressure value for displacement fluid injection corresponding to the critical point of phase change in the crude oil within the microfluidic chip. Among them, the gas injection pressure P3 is higher than the formation crude oil bubble point pressure value and lower than the chip holder sealing safety pressure value, and the displacement pressure P4 is higher than the gas injection pressure P3 and lower than the chip holder sealing safety pressure value.