System and method for micro-nano scale flow measurement
By designing a micro-nano scale flow measurement system that incorporates multiple devices and formulas, the problem of measuring small flow pressure differences and flow velocities under high temperature and high pressure was solved, enabling accurate measurement and analysis of micro-nano scale flow laws and revealing the fluid flow characteristics of tight oil and gas and shale oil and gas reservoirs.
Patent Information
- Application Number
- CN202411056122.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-02
- Publication Date
- 2026-02-03
AI Technical Summary
Existing micro-nano scale flow measurement devices are difficult to accurately measure small flow pressure differences and flow velocities under high temperature and high pressure conditions, resulting in limited experimental accuracy and an inability to effectively reveal the non-Darcy flow patterns of fluids in tight oil and gas and shale oil and gas reservoirs.
A measurement system was designed, comprising a first constant pressure pump, a second constant pressure pump, a pressure measurement insulating tube, a flow measurement insulating tube, a micro-nano channel connector, a resistor, and a data acquisition system. The system achieves pressure and flow measurement under high temperature and high pressure by converting resistance values, and calculates the flow rate using the Hagen-Poiseuille formula.
It enables precise measurement of micro-nano scale flow under high temperature and high pressure, improves measurement accuracy, and can reveal the non-Darcy flow law of fluid in micro-nano pore throats. It is applicable to the flow characteristic analysis of tight oil and gas and shale oil and gas reservoirs.
Smart Images
Figure CN121453597A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of micro-nano scale flow measurement technology, and more specifically to a system and method for micro-nano scale flow measurement. Background Technology
[0002] To ensure energy security, unconventional oil and gas resources, such as tight oil and gas and shale oil and gas, are considered important future oil replacement resources due to their abundant reserves. Unlike conventional oil and gas reservoirs, the main storage space of unconventional oil and gas reservoirs such as tight oil and gas and shale oil and gas is micro- and nano-pore throats, characterized by poor reservoir properties and small pore throats. The fluids, constrained by the narrow seepage space, often exhibit seepage characteristics different from Darcy's law, resulting in complex flow patterns. Understanding the flow patterns of fluids in micro- and nano-pore throats is crucial for the efficient development of unconventional oil and gas reservoirs such as tight oil and gas and shale oil and gas.
[0003] Currently, research on non-Darcy flow patterns of reservoir fluids in unconventional oil and gas reservoirs such as tight oil and gas and shale oil and gas mainly relies on flow simulation methods such as molecular simulation, lattice Boltzmann method, and digital core analysis. Physical experiments have not been employed. The main reasons for this include: 1) Core flow experiments reflect the macroscopic flow patterns of fluids within numerous tiny pores and throats in the core. Due to numerous interfering factors, it is difficult to reveal the hydrodynamic nature of fluid transport within these pores and throats; 2) Although microscale flow experiments can be used to study the flow patterns of fluids in single micro-tubes, micro-grooves, and other micro-nano channels, these methods and devices are mostly derived from the field of microelectromechanical systems. The experimental equipment used is difficult to withstand high experimental temperatures and pressures, making it difficult to accurately reproduce the true seepage environment of the reservoir; 3) The seepage process of fluids in unconventional oil and gas reservoirs such as tight oil and gas and shale oil and gas often has characteristics such as small flow pressure gradients and low flow velocities. Existing micro-nano flow experimental devices cannot accurately measure minute flow pressure differences and velocities under high temperature and high pressure conditions, thus limiting experimental accuracy.
[0004] In summary, while flow simulation can reveal the flow laws of fluids to a certain extent, the simulation results cannot be separated from the verification of physical experiments. Micro- and nano-scale flow experiments are an indispensable research method for revealing the non-Darcy flow laws of fluids in micro- and nano-sized pore throats. Summary of the Invention
[0005] The purpose of this invention is to provide a system for measuring micro-nano scale flow, which can accurately measure the pressure and flow rate of micro-nano scale flow under high temperature and high pressure.
[0006] To achieve the above objectives, embodiments of the present invention provide a system for micro-nano scale flow measurement, the system comprising a first constant pressure pump, a second constant pressure pump, a first intermediate container, a second intermediate container, a pressure measuring insulating tube, a flow measuring insulating tube, a first measuring liquid collector, a second measuring liquid collector, a micro-nano channel connector, a resistor, a data acquisition system, and a control device. In this configuration, the first constant pressure pump is connected to the first end of the first intermediate container; the second end of the first intermediate container is connected to the first end of the micro-nano channel connector; the second end of the micro-nano channel connector is connected to the first end of the flow measurement insulating tube and the first end of the pressure measurement insulating tube; pressure gauges are connected to both ends of the micro-nano channel connector; the second end of the pressure measurement insulating tube is connected to the first measuring liquid collector and the first valve, and then to the first end of the micro-nano channel connector; the first end of the flow measurement insulating tube is connected to the second valve and the second measuring liquid collector, and then to the first end of the second intermediate container; the second end of the flow measurement insulating tube is connected to the second end of the second intermediate container; the first end of the second intermediate container is also connected to the second constant pressure pump; both ends of the pressure measurement insulating tube and the flow measurement insulating tube are connected to the resistor and the data acquisition system; and the data acquisition system is connected to the control device.
[0007] Optionally, the exterior of the micro-nano channel connector is a metal structure; the interior of the micro-nano channel connector is a high-pressure resistant micro-tube fixed by adhesive bonding, or the interior of the micro-nano channel connector is a micro-nano scale micro-groove etched by laser etching.
[0008] Optionally, the pressure measuring insulating tube is placed vertically, with the top of the pressure measuring insulating tube being the first end and the bottom of the pressure measuring insulating tube being the second end, and the interior of the pressure measuring insulating tube includes an alloy wire.
[0009] Optionally, the inner diameter of the pressure measuring insulating tube is selected according to the range of pressure difference to be measured; or the pressure measuring insulating tube includes multiple pressure measuring insulating tubes connected in parallel to expand the range of pressure measurement.
[0010] This invention also provides a method for measuring flow at the micro-nano scale. The method is implemented using the aforementioned system for measuring flow at the micro-nano scale. A high-conductivity measuring liquid is placed in a first intermediate container, and the micro-nano scale flow characteristics of the high-conductivity measuring liquid are measured. The method includes: adjusting the pressure of the system to the required pressure condition; after the system pressure stabilizes, opening a first valve and recording the resistance value R of the pressure measuring insulating tube. 11 The resistance value R of the insulating tube for flow measurement 12Adjust the first constant pressure pump to increase the pressure inside the first intermediate container. When the pressure at the first end of the micro-nano channel connector is higher than the pressure at the second end, the first constant pressure pump stops increasing the pressure. After the system pressure stabilizes, record the resistance value R of the pressure measuring insulating tube. 21 And start timing, when the resistance value of the flow measurement insulating tube reaches R 22 When the timer stops, Δt is obtained; ΔR1 = (R 21 -R 11 ), △R2=(R 22 -R 12 Input the preset conversion relationships between resistance and pressure values and between resistance and flow rate values, respectively, to obtain the flow rate Q of the high conductivity measuring liquid through the micro-nano channel connector and the pressure difference ΔP between the two ends of the micro-nano channel connector; calculate the theoretical flow rate Q1 using ΔP and Δt, compare Q1 with the flow rate Q to determine the deviation between the actual flow and the theoretical flow of the high conductivity measuring liquid in the micro-nano channel connector; and repeat the above steps to obtain the micro-nano scale flow characteristics of the high conductivity measuring liquid under different experimental conditions.
[0011] Optionally, before adjusting the pressure of the system for micro / nano-scale flow measurement to the pressure condition to be measured, the method for micro / nano-scale flow measurement further includes: calibrating the pressure measurement system of the system for micro / nano-scale flow measurement to obtain the preset conversion relationship between the resistance value and the pressure value; and calibrating the flow measurement system of the system for micro / nano-scale flow measurement to obtain the preset conversion relationship between the resistance value and the flow rate value.
[0012] Optionally, calibrating the pressure measurement system of the system for micro / nano-scale flow measurement to obtain the preset conversion relationship between resistance and pressure values includes: isolating the first measuring liquid collector, the pressure measuring insulating tube, and the first valve, and connecting the first valve to the third pressure gauge and the third constant pressure pump respectively; recording the resistance value R1 when no measuring liquid enters the pressure measuring insulating tube and the pressure value P1 of the third pressure gauge; and turning on the third constant pressure pump, pumping a certain amount of measuring liquid into the pressure measuring insulating tube within a time t1, recording the resistance value R2 and the pressure value P2 of the third pressure gauge, repeating the above steps, measuring the pressure values at multiple different resistance values, and obtaining the preset conversion relationship between resistance and pressure values by performing data fitting on the multiple different resistance values and corresponding pressure values.
[0013] Optionally, calibrating the flow measurement system of the system for micro / nano-scale flow measurement to obtain the preset conversion relationship between resistance and flow rate includes: isolating the second measuring liquid collector, the flow measurement insulating tube, and the second valve, and connecting the second measuring liquid collector to the fourth constant pressure pump, recording the resistance value R3 when no measuring liquid enters the flow measurement insulating tube; and turning on the fourth constant pressure pump, pumping a certain amount of measuring liquid into the flow measurement insulating tube within a time Δt, recording the resistance value R4, repeating the above steps, measuring the flow rate at multiple different resistance values, and obtaining the preset conversion relationship between resistance and flow rate by data fitting of the multiple different resistance values and their corresponding flow rates.
[0014] Optionally, the conversion relationship between the preset resistance value and the flow rate value can be represented by the following formula:
[0015]
[0016] Where Q represents the flow rate, ΔR represents the resistance difference, Δt represents the time interval, D represents the inner diameter of the insulating tube for flow measurement, and b is a fitting constant.
[0017] Optionally, the step of calculating the theoretical flow rate Q1 using ΔP and Δt includes: inputting ΔP and Δt into the Hagen-Poiseuille formula to calculate the theoretical flow rate Q1.
[0018] The system for micro / nano-scale flow measurement provided by the above technical solution includes a first constant-pressure pump, a second constant-pressure pump, a first intermediate container, a second intermediate container, a pressure measuring insulating tube, a flow measuring insulating tube, a first measuring liquid collector, a second measuring liquid collector, a micro / nano channel connector, a resistor, a data acquisition system, and a control device. The resistance wires in the pressure measuring insulating tube and the flow measuring insulating tube are connected to the resistor, for example, via signal lines. The resistor is connected to the data acquisition system, which monitors and records the pressure, differential pressure, flow rate, temperature, and other values of the test section in real time. Both the pressure measuring insulating tube and the flow measuring insulating tube are filled with, for example, a high-conductivity measuring liquid stopper. The resistor is used to measure the resistance values inside the pressure measuring insulating tube and the flow measuring insulating tube. The control device converts the resistance values measured by the resistor into pressure and flow rate values. The system for measuring micro-nano scale flow provided in this invention can accurately measure the pressure and flow rate of micro-nano scale flow under high temperature and high pressure; it can accurately measure the minute pressure difference and minute flow rate in micro-nano scale flow, which can improve measurement accuracy and reduce measurement time; this invention can also reveal the laws of fluid micro-nano flow, that is, the non-Darcy flow law of fluids in tight / shale reservoirs.
[0019] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description section. Attached Figure Description
[0020] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:
[0021] Figure 1 This is a schematic diagram of the system structure for micro / nano-scale flow measurement provided in an embodiment of the present invention; and
[0022] Figure 2 This is a schematic diagram of the method for flow measurement at the micro-nano scale provided in an embodiment of the present invention.
[0023] Explanation of reference numerals in the attached figures
[0024] 1-First constant pressure pump, 2-Valve, 3-First intermediate container, 4-Valve, 5-Pressure gauge
[0025] 6-First measuring fluid collector, 7-Pressure measuring insulating tube, 8-First valve,
[0026] 9-Micro-nano channel connector, 10-Pressure gauge, 11-Signal line, 12-Signal line, 13-Signal line
[0027] 14-Flow measurement insulating tube, 15-Rheometer, 16-Data acquisition system, 17-Valve,
[0028] 18-Second valve, 19-Second measuring liquid collector, 20-Second intermediate container, 21-Valve
[0029] 22 - Second constant pressure pump. Detailed Implementation
[0030] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.
[0031] Figure 1 This is a schematic diagram of the system structure for micro / nano-scale flow measurement provided in an embodiment of the present invention. Please refer to it. Figure 1 The system for micro-nano scale flow measurement includes a first constant pressure pump 1, a second constant pressure pump 22, a first intermediate container 3, a second intermediate container 20, a pressure measuring insulating tube 7, a flow measuring insulating tube 14, a first measuring liquid collector 6, a second measuring liquid collector 19, a micro-nano channel connector 9, a resistor 15, a data acquisition system 16, and a control device (not shown in the figure).
[0032] The first constant pressure pump 1 is connected to the first end of the first intermediate container 3, the second end of the first intermediate container 3 is connected to the first end of the micro-nano channel connector 9, the second end of the micro-nano channel connector 9 is connected to the first end of the flow measurement insulating tube 14 and the first end of the pressure measurement insulating tube 7; the two ends of the micro-nano channel connector 9 are respectively connected to pressure gauges (5, 10); the second end of the pressure measurement insulating tube 7 is connected to the first measuring liquid collector 6 and the first valve 8, and then to the first end of the micro-nano channel connector 9; the first end of the flow measurement insulating tube 14 is connected to the second valve 18 and the second measuring liquid collector 19, and then to the first end of the second intermediate container 20, the second end of the flow measurement insulating tube 14 is connected to the second end of the second intermediate container 20, and the first end of the second intermediate container 20 is also connected to the second constant pressure pump 22; both ends of the pressure measurement insulating tube 7 and the flow measurement insulating tube 14 are connected to the resistor 15 and the data acquisition system 16, and the data acquisition system 16 is connected to the control device.
[0033] In this embodiment of the invention, the resistance wires in the pressure measuring insulating tube 7 and the flow measuring insulating tube 14 are preferably connected to a resistance meter 15, for example, via signal lines (11, 12, 13). The resistance meter 15 is connected to a data acquisition system 16, which is used to monitor and record the pressure, differential pressure, flow rate, temperature, and other values of the test section in real time. Both the pressure measuring insulating tube 7 and the flow measuring insulating tube 14 are filled with, for example, a high-conductivity measuring liquid stopper. The resistance meter 15 is used to measure the resistance values inside the pressure measuring insulating tube 7 and the flow measuring insulating tube 14, and the control device is used to convert the resistance values measured by the resistance meter 15 into pressure and flow rate values.
[0034] Please refer to Figure 1For example, the first end (i.e., the bottom) of the first intermediate container 3 is connected to the first constant pressure pump 1, which maintains a constant pressure. During flow measurement using this system, the high-pressure fluid (e.g., a high-conductivity measuring fluid) in the first intermediate container 3, driven by the pressure of the first constant pressure pump 1, enters the micro-nano channel connector 9. After flowing through the micro-nano channel (located in the inherent structure of the micro-nano channel connector 9), the fluid enters the flow measurement insulating tube 14 for flow measurement. High-precision pressure gauges (5, 10) are connected to each end of the micro-nano channel connector 9. The two ends of the micro-nano channel connector 9 can be connected to the pressure measurement insulating tube 7 and the first measuring fluid collector 6 via pressure-resistant lines, respectively. Both ends of the pressure measurement insulating tube 7 and the flow measurement insulating tube 14 can be connected to the data acquisition system 16 via signal lines (11, 12, 13). The first end (i.e., the downstream) of the flow measurement insulating tube 14 is connected to the second measuring fluid collector 19 and the second intermediate container 20, which provides back pressure to the system. The pressure-resistant pipeline, micro-nano channel connector 9, and flow measurement insulating tube 14 can all be placed in a constant temperature chamber to meet the requirements of micro-nano flow measurement under high temperature conditions. The high-precision pressure gauges (5, 10) have a range of, for example, 25 MPa and an accuracy of, for example, 0.25 class.
[0035] Please refer to Figure 1 The system for measuring flow at the micro-nano scale may also include components such as valve 2, valve 4, valve 17, and valve 21.
[0036] In a preferred embodiment of the present invention, the external structure of the micro-nano channel connector 9 can be a metal structure. The internal structure of the micro-nano channel connector can be a high-pressure resistant micro-tube fixed by adhesive bonding, or the internal structure of the micro-nano channel connector can be a micro-nano scale micro-groove etched by laser etching.
[0037] In a preferred embodiment of the present invention, the pressure measuring insulating tube 7 is placed vertically, with the top of the pressure measuring insulating tube 7 being the first end and the bottom of the pressure measuring insulating tube 7 being the second end. The interior of the pressure measuring insulating tube 7 includes an alloy wire.
[0038] In a preferred embodiment of the present invention, the pressure measuring insulating tube 7 can be selected based on the range of pressure difference to be measured; or the pressure measuring insulating tube 7 may include multiple pressure measuring insulating tubes connected in parallel to expand the range of pressure measurement.
[0039] As an example, the pressure measuring insulating tube 7 is placed vertically, with its bottom connected to the first measuring liquid collector 6 and its top connected to the second end (i.e., the outlet end) of the micro-nano channel connector 9. The interior of the pressure measuring insulating tube 7 may be pre-loaded with alloy wire, and during differential pressure measurement, it is filled with a high-conductivity measuring liquid (e.g., mercury or a liquid alloy slug). The length of the pressure measuring insulating tube 7 is, for example, 2 m, and its inner diameter is, for example, 0.1–0.5 cm. In practice, the inner diameter of the pressure measuring insulating tube 7 can be selected according to the range of differential pressure to be measured, and multiple pressure measuring insulating tubes 7 can be connected in parallel to expand the measurement range. The maximum pressure that the pressure measuring insulating tube 7 can withstand is, for example, 50 MPa.
[0040] Continuing with the above example, the flow measurement insulating tube 14 is placed horizontally. Its first end (i.e., the inlet end) is connected to the micro-nano channel connector 9 and also to a second measuring liquid collector 19. Its second end (i.e., the outlet end) is connected to a second intermediate container 20. The flow measurement insulating tube 14 may be pre-filled with alloy wires, and during flow measurement, it is filled with a high-conductivity measuring liquid (e.g., mercury or a liquid alloy slug). The bottom of the second measuring liquid collector 19 is connected to a second constant-pressure pump 22. The second measuring liquid collector 19 contains a high-conductivity measuring liquid and can be used for liquid injection and recovery. The second intermediate container 20 contains, for example, N2, to provide stable pressure for the system. The first constant-pressure pump 1 and the second constant-pressure pump 22 are, for example, high-pressure injection pumps.
[0041] Accordingly, the system for micro / nano-scale flow measurement provided in this embodiment of the invention includes a first constant-pressure pump, a second constant-pressure pump, a first intermediate container, a second intermediate container, a pressure measuring insulating tube, a flow measuring insulating tube, a first measuring liquid collector, a second measuring liquid collector, a micro / nano channel connector, a resistor, a data acquisition system, and a control device. The resistance wires in the pressure measuring insulating tube and the flow measuring insulating tube are connected to the resistor, for example, via signal lines. The resistor is connected to the data acquisition system, which monitors and records in real time the pressure, differential pressure, flow rate, temperature, and other values of the test section. Both the pressure measuring insulating tube and the flow measuring insulating tube are filled with, for example, a high-conductivity measuring liquid stopper. The resistor is used to measure the resistance values within the pressure measuring insulating tube and the flow measuring insulating tube. The control device converts the resistance values measured by the resistor into pressure and flow rate values. The system for measuring micro-nano scale flow provided in this invention can accurately measure the pressure and flow rate of micro-nano scale flow under high temperature and high pressure; it can accurately measure the minute pressure difference and minute flow rate in micro-nano scale flow, which can improve measurement accuracy and reduce measurement time; this invention can also reveal the laws of fluid micro-nano flow, that is, the non-Darcy flow law of fluids in tight / shale reservoirs.
[0042] Figure 2This is a schematic flowchart of a method for measuring micro- and nano-scale flow according to an embodiment of the present invention. The method is implemented using the system described above for measuring micro- and nano-scale flow. A high-conductivity measuring liquid is placed in a first intermediate container, and the micro- and nano-scale flow characteristics of the high-conductivity measuring liquid are measured. Please refer to... Figure 2 The method for micro / nano-scale flow measurement may include the following steps:
[0043] Step S110: Adjust the pressure of the system for micro / nano-scale flow measurement to the pressure condition to be measured.
[0044] Preferably, before step S110, the method for measuring flow at the micro-nano scale may further include steps S101-S102: Step S101, calibrating the pressure measurement system of the system for measuring flow at the micro-nano scale to obtain the preset conversion relationship between the resistance value and the pressure value; Step S102, calibrating the flow measurement system of the system for measuring flow at the micro-nano scale to obtain the preset conversion relationship between the resistance value and the flow rate value.
[0045] Preferably, step S101 may include: isolating the first measuring liquid collector, the pressure measuring insulating tube, and the first valve, and connecting the first valve to the third pressure gauge and the third constant pressure pump respectively; recording the resistance value R1 when no measuring liquid enters the pressure measuring insulating tube and the pressure value P1 of the third pressure gauge; and turning on the third constant pressure pump, pumping a certain amount of measuring liquid into the pressure measuring insulating tube within a time t1, recording the resistance value R2 and the pressure value P2 of the third pressure gauge, repeating the above steps, measuring the pressure value under multiple different resistance values, and obtaining the preset conversion relationship between the resistance value and the pressure value by performing data fitting on the multiple different resistance values and the corresponding pressure values.
[0046] Please refer to Figure 1 For example, the first measuring liquid collector 6, the pressure measuring insulating tube 7, and the first valve 8 are isolated. The first valve 8 is connected to a third pressure gauge (e.g., a high-precision pressure gauge with a range of 0.25 MPa) and a third constant-pressure pump (e.g., a constant-speed flow pump), respectively. The resistance meter 15 is turned on, and the resistance value R1 and the pressure value P1 of the third pressure gauge are recorded when no measuring liquid enters the pressure measuring insulating tube 7. The third constant-pressure pump is turned on, and a certain amount of measuring liquid is pumped into the pressure measuring insulating tube 7 within a time t1. The resistance value R2 and the pressure value P2 of the third pressure gauge are recorded. The above steps are repeated to measure the pressure values at multiple different resistance values. By fitting the data of multiple different resistance values and their corresponding pressure values, a preset conversion relationship between resistance and pressure values can be obtained, as shown in the following formula:
[0047] ΔP=aΔR (1)
[0048] Where ΔP represents the voltage difference, ΔR represents the resistance difference, and a is the fitting constant.
[0049] Preferably, step S102 may include: isolating the second measuring liquid collector, the flow measuring insulating tube, and the second valve, and connecting the second measuring liquid collector to the fourth constant pressure pump, recording the resistance value R3 when no measuring liquid enters the flow measuring insulating tube; and turning on the fourth constant pressure pump, pumping a certain amount of measuring liquid into the flow measuring insulating tube within a time Δt, recording the resistance value R4, repeating the above steps, measuring the flow value at multiple different resistance values, and obtaining the preset conversion relationship between the resistance value and the flow value by performing data fitting on the multiple different resistance values and the corresponding flow values.
[0050] Please refer to Figure 1 For example, the second measuring liquid collector 19, the flow measuring insulating tube 14, and the second valve 18 are isolated. The second measuring liquid collector 19 is connected to the fourth constant pressure pump (e.g., a constant speed flow pump). The resistance meter 15 is turned on, and the resistance value R3 when no measuring liquid enters the flow measuring insulating tube 14 is recorded. The fourth constant pressure pump is turned on, and a certain amount of measuring liquid is pumped into the flow measuring insulating tube 14 within a time Δt, and the resistance value R4 is recorded. The above steps are repeated to measure the flow rate at multiple different resistance values. By fitting the data of multiple different resistance values and their corresponding flow rates, a preset conversion relationship between resistance values and flow rates can be obtained.
[0051] Preferably, the conversion relationship between the preset resistance value and the flow rate value can be expressed by the following formula:
[0052]
[0053] Where Q represents the flow rate, ΔR represents the resistance difference, Δt represents the time interval, D represents the inner diameter of the insulating tube for flow measurement, and b is a fitting constant.
[0054] After calibrating the pressure and flow measurement systems, the micro-nano scale flow characteristics of the high-conductivity measurement fluid were measured. Please refer to [reference needed]. Figure 1 For example, open valves (2, 4, 17, 21) to adjust the system pressure to the pressure condition to be measured. After the pressure is balanced, open the second valve 18, pressurize the system through the second constant pressure pump 22, inject a small section of high conductivity measuring liquid into a certain position in the flow measurement insulating tube 14, close the second valve 18, and increase the pressure in the first intermediate container 3 to the corresponding pressure value.
[0055] Step S120: After the pressure of the system stabilizes, open the first valve and record the resistance value R of the pressure measuring insulating tube. 11 The resistance value R of the insulating tube for flow measurement 12 .
[0056] Following the example above, after the system pressure stabilizes (i.e., the reading of pressure gauge 5 is the same as the reading of pressure gauge 10), the first valve 8 is opened. The data acquisition system 16 can automatically read and record the resistance value R of the pressure measuring insulating tube through the resistance meter 15. 11 The resistance value R of the insulating tube for flow measurement 12 .
[0057] Step S130: Adjust the first constant pressure pump to increase the pressure inside the first intermediate container. When the pressure at the first end of the micro-nano channel connector is higher than the pressure at the second end, the first constant pressure pump stops increasing the pressure.
[0058] Following the example above, the first constant pressure pump 1 is adjusted to increase the pressure inside the first intermediate container 3, and the pressure gauge 5 is observed. When the pressure value shown by the pressure gauge 5 is slightly higher than the pressure value shown by the pressure gauge 10, the first constant pressure pump 1 stops pressurizing.
[0059] Step S140: After the pressure of the system stabilizes, record the resistance value R of the pressure measuring insulating tube. 21 And start timing, when the resistance value of the flow measurement insulating tube reaches R 22 When the timer stops, we obtain Δt.
[0060] Following the example above, after the pressure stabilizes, record the resistance value R of the pressure measuring insulating tube 7. 21 And start timing, when the resistance value of the flow measurement insulating tube 14 reaches R 22 When the timer stops, we obtain Δt.
[0061] Step S150: Set △R1=(R 21 -R 11 ), △R2=(R 22 -R 12 Input the preset conversion relationship between resistance and pressure and the preset conversion relationship between resistance and flow rate, respectively, to obtain the flow rate Q of the high conductivity measuring liquid through the micro-nano channel connector and the pressure difference ΔP between the two ends of the micro-nano channel connector.
[0062] Continuing with the example above, let △R1=(R 21 -R 11 ), △R2=(R 22 -R 12By inputting Δt into equations (1) and (2) respectively, the flow rate Q of the high conductivity measuring liquid through the micro-nano channel connector 9 and the pressure difference ΔP between the two ends of the micro-nano channel connector 9 can be obtained.
[0063] Step S160: Calculate the theoretical flow rate Q1 using ΔP and Δt, compare Q1 with the flow rate Q, and determine the deviation between the actual flow and the theoretical flow of the high conductivity measuring liquid in the micro-nano channel connector.
[0064] Preferably, the step of calculating the theoretical flow rate Q1 using ΔP and Δt may include: inputting ΔP and Δt into the Hagen-Poiseuille formula to calculate the theoretical flow rate Q1.
[0065] Following the example above, by substituting ΔP and time Δt into the Hagen-Poiseuille formula, the theoretical flow rate Q1 is calculated. By comparing the theoretical flow rate Q1 with the actual measured flow rate Q, the deviation between the actual flow and the theoretical flow of the high conductivity measuring liquid in the micro-nano channel connector 9 can be determined.
[0066] Step S170: Repeat steps S110-S160 above to obtain the micro-nano scale flow characteristics of the high conductivity measuring liquid under different experimental conditions.
[0067] Accordingly, in this embodiment of the invention, after the system pressure stabilizes, the first valve is opened, and the resistance value R of the pressure measuring insulating tube is recorded. 11 The resistance value R of the insulating tube for flow measurement 12 Adjust the first constant pressure pump to increase the pressure inside the first intermediate container. When the pressure at the first end of the micro-nano channel connector is higher than the pressure at the second end, the first constant pressure pump stops pressurizing. After the pressure inside the first intermediate container stabilizes, record the resistance value R of the pressure measurement insulation tube. 21 And start timing, when the resistance value of the flow measurement insulation tube reaches R 22 When the timer stops, Δt is obtained; ΔR1 = (R 21 -R 11 ), △R2=(R 22 -R 12The method uses preset conversion relationships between resistance and pressure values and between resistance and flow rate values, respectively, to obtain the flow rate Q of the high conductivity measuring fluid through the micro-nano channel connector and the pressure difference ΔP across the connector. Using ΔP and Δt, the theoretical flow rate Q1 is calculated. Q1 is compared with the flow rate Q to determine the deviation between the actual and theoretical flow of the high conductivity measuring fluid in the micro-nano channel connector. Repeating these steps yields the micro-nano scale flow characteristics of the high conductivity measuring fluid under different experimental conditions. The method for measuring micro-nano scale flow provided by this invention is implemented through a system for measuring micro-nano scale flow, enabling precise measurement of the micro-nano scale flow characteristics of the high conductivity measuring fluid. It can accurately measure minute pressure differences and flow rates in micro-nano scale flow, improving measurement accuracy and reducing measurement time. This invention also reveals the laws governing fluid micro-nano flow, namely, the non-Darcy flow laws of fluids in tight / shale reservoirs.
[0068] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.
[0069] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.
[0070] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.
[0071] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.
[0072] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.
[0073] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.
[0074] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.
[0075] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.
[0076] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.
Claims
1. A system for measuring flow at the micro / nano scale, characterized in that, The system for micro / nano-scale flow measurement includes a first constant-pressure pump, a second constant-pressure pump, a first intermediate container, a second intermediate container, a pressure measurement insulating tube, a flow measurement insulating tube, a first measuring liquid collector, a second measuring liquid collector, a micro / nano channel connector, a resistor, a data acquisition system, and a control device. The first constant pressure pump is connected to the first end of the first intermediate container, the second end of the first intermediate container is connected to the first end of the micro-nano channel connector, and the second end of the micro-nano channel connector is connected to the first end of the flow measurement insulating tube and the first end of the pressure measurement insulating tube. Pressure gauges are connected to both ends of the micro-nano channel connector. The second end of the pressure measuring insulating tube is connected to the first measuring liquid collector and the first valve, and then to the first end of the micro-nano channel connector. The first end of the flow measurement insulating tube is connected to the second valve and the second measuring liquid collector, and then to the first end of the second intermediate container. The second end of the flow measurement insulating tube is connected to the second end of the second intermediate container. The first end of the second intermediate container is also connected to the second constant pressure pump. Both ends of the pressure measuring insulating tube and the flow measuring insulating tube are connected to the resistor and the data acquisition system, and the data acquisition system is connected to the control device.
2. The system for micro / nano-scale flow measurement according to claim 1, characterized in that, The external structure of the micro-nano channel connector is metal. The internal structure of the micro / nano channel connector is a high-pressure resistant micro-tube fixed by adhesive bonding, or The interior of the micro-nano channel connector is formed by laser etching of micro-nano scale microgrooves.
3. The system for micro / nano-scale flow measurement according to claim 1, characterized in that, The pressure measuring insulating tube is placed vertically, with the top of the pressure measuring insulating tube being the first end and the bottom of the pressure measuring insulating tube being the second end. The pressure measuring insulating tube contains an alloy wire inside.
4. The system for micro / nano-scale flow measurement according to claim 3, characterized in that, The pressure measuring insulating tube is selected based on the inner diameter size according to the measured pressure difference range; or The pressure measuring insulating tube includes multiple pressure measuring insulating tubes connected in parallel to expand the range of pressure measurement.
5. A method for measuring flow at the micro / nano scale, characterized in that, The method for measuring micro-nano scale flow is implemented using the system for measuring micro-nano scale flow as described in any one of claims 1-4, wherein a high-conductivity measuring liquid is loaded into a first intermediate container, and the micro-nano scale flow characteristics of the high-conductivity measuring liquid are measured. The method for measuring micro-nano scale flow includes: Adjust the pressure of the system used for micro / nano-scale flow measurement to the pressure condition to be measured; After the system pressure stabilizes, open the first valve and record the resistance value R of the pressure measuring insulating tube. 11 The resistance value R of the insulating tube for flow measurement 12 ; Adjust the first constant pressure pump to increase the pressure inside the first intermediate container. When the pressure at the first end of the micro-nano channel connector is higher than the pressure at the second end, the first constant pressure pump stops increasing the pressure. After the pressure of the system stabilizes, record the resistance value R of the pressure measuring insulating tube. 21 And start timing, when the resistance value of the flow measurement insulating tube reaches R 22 When the timer stops, Δt is obtained; Let △R1=(R 21 -R 11 ), △R2=(R 22 -R 12 Input the preset conversion relationship between resistance and pressure and the preset conversion relationship between resistance and flow rate, respectively, to obtain the flow rate Q of the high conductivity measuring liquid through the micro-nano channel connector and the pressure difference ΔP between the two ends of the micro-nano channel connector; The theoretical flow rate Q1 is calculated using ΔP and Δt. Q1 is then compared with the flow rate Q to determine the deviation between the actual and theoretical flow of the high-conductivity measuring liquid in the micro / nano channel connector. Repeat the above steps to obtain the micro-nano scale flow characteristics of the high conductivity measuring liquid under different experimental conditions.
6. The method for micro / nano-scale flow measurement according to claim 5, characterized in that, Before adjusting the pressure of the system for micro / nano-scale flow measurement to the pressure condition to be measured, the method for micro / nano-scale flow measurement further includes: The pressure measurement system of the system used for micro / nano-scale flow measurement is calibrated to obtain the preset conversion relationship between the resistance value and the pressure value; and The flow measurement system of the system used for micro-nano scale flow measurement is calibrated to obtain the preset conversion relationship between the resistance value and the flow rate value.
7. The method for micro / nano-scale flow measurement according to claim 6, characterized in that, The calibration of the pressure measurement system of the system used for micro / nano-scale flow measurement to obtain the preset conversion relationship between the resistance value and the pressure value includes: The first measuring liquid collector, the pressure measuring insulating tube, and the first valve are isolated, and the first valve is connected to the third pressure gauge and the third constant pressure pump, respectively. Record the resistance value R1 of the pressure measuring insulating tube when no measuring fluid enters it and the pressure value P1 of the third pressure gauge; and Turn on the third constant pressure pump and pump a certain amount of measuring liquid into the pressure measuring insulating tube within time t1. Record the resistance value R2 and the pressure value P2 of the third pressure gauge. Repeat the above steps to measure the pressure values at multiple different resistance values. By performing data fitting on the multiple different resistance values and their corresponding pressure values, the conversion relationship between the preset resistance value and the pressure value can be obtained.
8. The method for micro / nano-scale flow measurement according to claim 6, characterized in that, The calibration of the flow measurement system for the system used for micro / nano-scale flow measurement, to obtain the preset conversion relationship between the resistance value and the flow rate value, includes: Isolate the second measuring liquid collector, the flow measuring insulating tube, and the second valve, and connect the second measuring liquid collector to the fourth constant pressure pump. Record the resistance value R3 when no measuring liquid enters the flow measurement insulating tube; and Turn on the fourth constant pressure pump, and within a time interval Δt, pump a certain amount of measuring liquid into the flow measuring insulating tube, and record the resistance value R4. Repeat the above steps to measure the flow rate at multiple different resistance values. By performing data fitting on the multiple different resistance values and their corresponding flow rates, the conversion relationship between the preset resistance value and the flow rate value can be obtained.
9. The method for measuring flow at the micro / nano scale according to claim 8, characterized in that, The following formula represents the conversion relationship between the preset resistance value and the flow rate value: Where Q represents the flow rate, ΔR represents the resistance difference, Δt represents the time interval, D represents the inner diameter of the insulating tube for flow measurement, and b is a fitting constant.
10. The method for micro / nano-scale flow measurement according to claim 5, characterized in that, The calculation of the theoretical flow rate Q1 using ΔP and Δt includes: Input ΔP and Δt into Hagenpoeia's formula to calculate the theoretical flow rate Q1.