A measuring device and method for measuring seepage flow

Abstract

The application discloses a kind of measuring device, method of seepage flow, the measuring device includes: core, core holder, pressure sensor, differential pressure gauge, four-way, second valve, third valve and fourth valve;Core is used to be installed in core holder;The first end of four-way is used to be connected into the fluid to be measured, the second end is connected with the sensing end of pressure sensor, the third end is connected with the hole pressure import of core holder, the fourth end is connected with the first end of second valve;The hole pressure export of core holder is connected with the first end of fourth valve;The first end of differential pressure gauge is connected with the second end of second valve, the second end is connected with the first end of third valve;The second end of third valve is connected with the hole pressure export of core holder.In the scheme, based on Darcy's law in porous medium, the flow of the fluid to be measured is calculated by measuring the pressure difference between the two ends of the core, so that the measurement of seepage small flow is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of fluid measurement, and in particular to a device and method for measuring seepage flow. Background Art

[0002] As fluid measurement and metering systems develop towards miniaturization, there is a demand for large-scale measurement (including micro-flow measurement), and there is an increasing demand for accurate measurement of micro-flow to large-flow ranges.

[0003] Measuring micro-flows has always been a difficult problem in flow metering. In fields such as medical equipment, fluid component leak detection, micro-pore or capillary tube diameter measurement, and laboratories, it is often necessary to perform high-precision measurements of micro-flows of 1E-9L / h-10mL / h (1e-6mL / h to 10mL / h) of the test piece. Micro-flow measurements are generally performed under steady-state flow conditions. The principle is essentially the "stopwatch-measuring cup method", with a low degree of measurement automation and complex operation. Traditional flow meters such as throttling, positive displacement, and float are not suitable for measuring micro-flows in principle. For example, the volumetric flowmeter is the most accurate type of flow meter. Its principle is that the mechanical measuring element continuously divides the fluid into single known volume parts, and measures the total volume of the fluid according to the number of times the measuring chamber is repeatedly filled and discharged with the fluid in the volume part. For small flow rates, the small flow rate is too small relative to the divided known volume parts, and may not be measured by the mechanical measuring element within the measurement time period; similarly, for throttling flowmeters, the flow rate is deduced by measuring the pressure difference at both ends of the throttling device. For small flow rates, it is difficult to measure the pressure difference at both ends of the throttling device, and thus it is impossible to measure small flow rates. Summary of the Invention

[0004] In view of this, the present invention provides a seepage flow measurement device, which is based on Darcy's law in porous media and measures the pressure difference at both ends of the core to infer the flow of the fluid to be measured, thereby realizing the measurement of micro-seepage flow.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A seepage flow measurement device includes: a core, a core holder, a pressure sensor, a differential pressure gauge, a four-way valve, a second valve, a third valve, and a fourth valve;

[0007] The core is used to be installed in the core holder;

[0008] The first end of the four-way is used for passing into the fluid to be measured, the second end is connected with the sensing end of the pressure sensor, the third end is connected with the pore pressure inlet of the core holder, and the fourth end is connected with the first end of the second valve; the pore pressure outlet of the core holder is connected with the first end of the fourth valve; the first end of the differential pressure meter is connected with the second end of the second valve, and the second end is connected with the first end of the third valve; the second end of the third valve is connected with the pore pressure outlet of the core holder.

[0009] Preferably, the differential pressure meter is a high-precision differential pressure meter.

[0010] Preferably, it further comprises a first valve.

[0011] The first end of the first valve is connected with the fourth end of the four-way, and the second end is connected with the pore pressure outlet of the core holder.

[0012] Preferably, it further comprises a filter element.

[0013] The first end of the filter element is connected with the second end of the second valve, and the second end is connected with the first end of the high-precision differential pressure meter.

[0014] Preferably, the core is an artificial core.

[0015] Preferably, it further comprises a back pressure valve.

[0016] The first end of the back pressure valve is connected with the second end of the fourth valve.

[0017] Preferably, the core holder comprises a base, a cover, a heat shrink tube, a first gasket and a second gasket.

[0018] The first gasket and the second gasket are both provided with through micro-holes.

[0019] The cover is detachably connected with the base, and a confining pressure chamber is formed between the inner wall of the cover and the top of the base.

[0020] The heat shrink tube is arranged in the confining pressure chamber; the first gasket, the core and the second gasket are sequentially sealed and arranged in the heat shrink tube in the axial direction, and the two end faces of the core are respectively attached to the first gasket and the second gasket.

[0021] The base is provided with the pore pressure inlet connected with the micro-holes of the first gasket, the pore pressure outlet connected with the micro-holes of the second gasket, the confining pressure inlet connected with the confining pressure chamber, and the confining pressure outlet connected with the confining pressure chamber.

[0022] Preferably, the number of micro-holes of the first gasket and the second gasket is multiple, and the micro-holes are uniformly distributed.

[0023] Preferably, the top of the cover is provided with an exhaust hole communicated with the confining pressure chamber.

[0024] A method for measuring seepage flow, using the seepage flow measuring device as described above, comprising the following steps:

[0025] S1, the fluid to be measured into the four-way first end;

[0026] S2, close the second valve, the third valve and the fourth valve, observe the reading of the pressure sensor; wherein, when the reading of the pressure sensor reaches the maximum value, then enter step S3;

[0027] S3, open the second valve and the third valve, get the reading of the differential pressure gauge after stabilization;

[0028] S4, according to the reading of the differential pressure gauge to calculate the flow of the fluid to be measured.

[0029] From the above technical solution, the seepage flow measuring device provided by the application is based on Darcy's law in porous media, and the flow of the fluid to be measured is calculated by measuring the pressure difference between the two ends of the core, so that the measurement of seepage flow is realized. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0031] Figure 1 The schematic diagram of the seepage flow measuring device provided by the embodiment of the present application;

[0032] Figure 2 The structure top view of the core holder provided by the embodiment of the present application;

[0033] Figure 3 The A-A sectional view of Figure 2 ;

[0034] Figure 4 The B-B sectional view of Figure 2 .

[0035] Wherein, 1 is the first valve, 2 is the second valve, 3 is the third valve, 4 is the fourth valve, 5 is the back pressure valve, 6 is the core holder, 6.1 is the base, 6.2 is the cover, 6.3 is the heat shrink tube, 6.4 is the first gasket, 6.5 is the second gasket, 6.6 is the confining pressure chamber, 6.7 is the pore pressure inlet, 6.8 is the pore pressure outlet, 6.9 is the confining pressure inlet, 6.10 is the confining pressure outlet, 6.11 is the exhaust hole, 7 is the pressure sensor, 8 is the four-way, 9 is the core, 10 is the high-precision differential pressure gauge, 11 is the first filter element, 12 is the second filter element. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0037] The measuring device for seepage flow provided by the embodiments of the present application comprises a core 9, a core holder 6, a pressure sensor 7, a differential pressure gauge, a four-way 8, a second valve 2, a third valve 3 and a fourth valve 4. Figure 1 As shown in the figure, the core 9, the core holder 6, the pressure sensor 7, the differential pressure gauge, the four-way 8, the second valve 2, the third valve 3 and the fourth valve 4 are sequentially connected.

[0038] The core 7 is used for being installed in the core holder 6.

[0039] The first end of the four-way 8 is used for leading into the fluid to be measured, the second end is connected with the sensing end of the pressure sensor 7, the third end is connected with the pore pressure inlet 6.7 of the core holder 6, and the fourth end is connected with the first end of the second valve 2; the pore pressure outlet 6.8 of the core holder 6 is connected with the first end of the fourth valve 4; the first end of the differential pressure gauge is connected with the second end of the second valve 2, and the second end is connected with the first end of the third valve 3; the second end of the third valve 3 is connected with the pore pressure outlet of the core holder 6.

[0040] It should be noted that the core 9 comprises a natural core or an artificial core, and both are cylindrical cores; the core holder 6 is used for installing the core 9, so that the fluid to be measured can flow through the pores of the core 9; the pressure sensor 7 is used for monitoring the pressure of the fluid to be measured; the second valve 2 and the third valve 3 are used for controlling whether the differential pressure gauge is connected into the measuring device; the fourth valve 4 is used for controlling the opening and closing of the downstream channel of the core 9, wherein the upstream of the core 9 refers to one end of the core 9 into which the fluid flows, and the downstream refers to one end of the core 9 from which the fluid flows out.

[0041] In addition, under the precondition that the fourth valve 4 is closed, the fluid to be measured flows to the downstream through the core 9, and if the downstream pressure increases to a maximum value and then remains unchanged (measured by the pressure sensor 7), it is indicated that the fluid to be measured has flowed to the downstream through the core 9. At this time, the core 9 can be considered to be saturated with the fluid to be measured, and it is indicated that the differential pressure meter can be used to measure the pressure difference between the two ends of the core 9. In addition, the working principle (measurement process) of the measuring device is as follows: the fluid to be measured is introduced into the first end of the four-way valve 8, the second valve 2, the third valve 3 and the fourth valve 4 are closed, and the reading of the pressure sensor 7 is observed. When the reading of the pressure sensor 7 increases to a maximum value and then remains unchanged, the second valve 2 and the third valve 3 are opened at the same time, and the reading of the differential pressure meter is read. Finally, the flow rate of the fluid to be measured is calculated according to the reading of the differential pressure meter. Of course, the working process of the measuring device will be described in detail below.

[0042] That is, the present scheme is based on Darcy's law in porous media, and the flow rate of the fluid to be measured is calculated by measuring the pressure difference between the two ends of the core 9, so as to realize the measurement of the seepage flow rate. Of course, there is a strict mathematical relationship between the flow rate and the pressure difference. In particular, by changing the characteristics of the artificial core, the measurement range and accuracy of the micro flow rate are controlled, so as to help realize the measurement of the seepage flow rate and the cross-range flow rate. The details will be described below.

[0043] As can be seen from the above technical scheme, the seepage flow rate measuring device provided by the embodiment of the present application is based on Darcy's law in porous media, and the flow rate of the fluid to be measured is calculated by measuring the pressure difference between the two ends of the core, so as to realize the measurement of the seepage flow rate.

[0044] In the present scheme, in order to improve the detection accuracy of the differential pressure meter and better ensure the measurement accuracy of the micro flow rate, as a preferred embodiment, the differential pressure meter is a high-precision differential pressure meter 10.

[0045] Further, since the measurement range of the high-precision differential pressure meter 10 is very small, generally only a few hundred kPa, it is easy to be damaged due to exceeding the measurement range. In this regard, as shown in Figure 1 The seepage flow rate measuring device provided by the embodiment of the present application further comprises a first valve 1;

[0046] The first end of the first valve 1 is connected with the fourth end of the four-way valve 8, and the second end is connected with the pore pressure outlet of the core holder 6. The working principle (measurement process) of the scheme after adding the first valve 1 is as follows: the fluid to be measured is introduced into the first end of the four-way valve 8, the first valve 1, the second valve 2, the third valve 3 and the fourth valve 4 are closed, and the reading of the pressure sensor 7 is observed. When the reading of the pressure sensor 7 increases to a maximum value and then remains unchanged, the first valve 1 is first opened, so that the pressures at both ends of the core 9 are the same, that is, the differential pressure at both ends of the core 9 is zero, then the first valve 1 is closed again, the second valve 2 and the third valve 3 are opened, and the reading of the high-precision differential pressure gauge 10 is read. The subsequent process is the same and will not be described here. That is, before the high-precision differential pressure gauge 10 is used to measure the differential pressure at both ends of the core 9, if it is expected that the differential pressure at both ends of the core 9 will exceed the measurement range of the high-precision differential pressure gauge 10, the first valve 1 can be opened first to balance the pressure at both ends of the high-precision differential pressure gauge 10, thereby protecting the high-precision differential pressure gauge 10. Of course, the first valve 1 will also be closed when the differential pressure of the core 9 is measured, so as to prevent the fluid to be measured from flowing to the downstream through the first valve 1.

[0047] Further, the seepage flow measuring device provided by the embodiment of the present application further comprises a filter element;

[0048] The first end of the filter element is connected with the second end of the second valve 2, and the second end is connected with the first end of the high-precision differential pressure gauge 10. That is, the scheme is provided with a filter element upstream of the high-precision differential pressure gauge 10 to prevent impurities in the fluid to be measured from contacting the diaphragm of the high-precision differential pressure gauge 10 and reducing the accuracy. Of course, on this basis, the scheme is also provided with a filter element downstream of the high-precision differential pressure gauge 10 to further protect the high-precision differential pressure gauge 10. As shown in Figure 1 , the first filter element 11 and the second filter element 12 are arranged upstream and downstream of the high-precision differential pressure gauge 10, respectively.

[0049] Specifically, the core 9 is an artificial core. The artificial core is a core after material modification and material parameter calibration, such as a stainless steel compacted core, a glass ball core and the like, and the permeability coefficient of the artificial core is stable, thereby facilitating more accurate calculation of the flow of the fluid to be measured. That is, the scheme reversely uses the permeability coefficient measurement method, and the core used is an artificial core with a stable permeability coefficient, and the flow of the fluid to be measured is calculated in sequence by measuring the differential pressure at both ends of the artificial core with a stable permeability coefficient.

[0050] In the scheme, as shown in Figure 1 , the seepage flow measuring device provided by the embodiment of the present application further comprises a back pressure valve 5;

[0051] The first end of the back-pressure valve 5 is connected to the second end of the fourth valve 4. In other words, in this solution, a back-pressure valve 5 is provided downstream of the fourth valve 4 to ensure pressure stability in the measuring device. Furthermore, when the measured differential pressure threatens to reach the limit of the measuring range of the high-precision differential pressure gauge 10, the back-pressure valve 5 can be adjusted to increase the pressure of the entire measuring device, thereby reducing the differential pressure across the core 9 and ensuring that the high-precision differential pressure gauge 10 is not damaged by overpressure.

[0052] Specifically, if Figure 3 As shown, the core holder 6 includes: a base 6.1, a cover 6.2, a heat shrink tube 6.3, a first gasket 6.4 and a second gasket 6.5;

[0053] The first gasket 6.4 and the second gasket 6.5 are both provided with through micro-holes;

[0054] The cover 6.2 and the base 6.1 are detachably connected, and a confined pressure chamber 6.6 is formed between the inner wall of the cover 6.2 and the top of the base 6.1; Figure 2 and Figure 3 As shown, the cover 6.2 is connected to the base 6.1 by a plurality of bolts; moreover, the detachable connection between the cover 6.2 and the base 6.1 facilitates the installation of the core 9;

[0055] The heat shrink tube 6.3 is disposed in the confining pressure chamber 6.6; the first gasket 6.4, the rock core 9, and the second gasket 6.5 are used to be sequentially sealed and installed in the heat shrink tube 6.3 along the axial direction, and the two end surfaces of the rock core 9 are respectively in contact with the first gasket 6.4 and the second gasket 6.5;

[0056] like Figure 2 to Figure 3 As shown, the base 6.1 has a pore pressure inlet 6.7 connected to the micropores of the first gasket 6.4, a pore pressure outlet 6.8 connected to the micropores of the second gasket 6.5, a confining pressure inlet 6.9 connected to the confining pressure chamber 6.6, and a confining pressure outlet 6.10 connected to the confining pressure chamber 6.6. In other words, this solution uses a heat shrink tube 6.3 to coaxially seal the core 9 and the two gaskets to isolate the confining pressure and pore pressure, ensuring that the two media do not contact each other while still achieving pressure transmission. Furthermore, the two gaskets are placed in contact with the two end faces of the core 9 to evenly apply the pore pressure to the end faces of the core 9. Of course, the outer diameters of the core 9 and the two gaskets are the same as the inner diameter of the heat shrink tube 6.3. In addition, it is not difficult to understand that the measured fluid enters the pores of the core 9 through the pore pressure inlet 6.7 and then flows to the downstream of the core 9 through the pore pressure outlet 6.8; the confining pressure chamber 6.6 is pressurized through the confining pressure inlet 6.9 and the confining pressure outlet 6.10 is depressurized.

[0057] In addition, it should be noted that in order to ensure that the core 9 and the two gaskets are sealed and installed in the heat shrink tube 6.3, Figure 2As shown in the figure, the core holder 6 further comprises a first plug and a second plug; wherein the first plug and the second plug are respectively detachably installed in the two ends of the heat shrink tube 6.3, and the first gasket 6.4 is located between the first plug and the first end surface of the core 9, and the second gasket 6.5 is located between the second plug and the second end surface of the core 9. In addition, as shown in the figure, Figure 3 and Figure 4 The pore pressure inlet 6.7 is connected with the micropores of the first gasket 6.4, the pore pressure outlet 6.8 is connected with the micropores of the second gasket 6.5, the confining pressure inlet 6.9 is connected with the confining pressure chamber 6.6, and the confining pressure outlet 6.10 is connected with the confining pressure chamber 6.6, all through small pipes.

[0058] Further, as shown in the figure, Figure 3 the number of micropores of the first gasket 6.4 and the second gasket 6.5 is multiple, and is uniformly distributed. Wherein, the multiple micropores of the first gasket 6.4 and the second gasket 6.5 are uniformly distributed along the radial direction and the circumferential direction, and, as shown in the figure, Figure 3 the pore pressure inlet 6.7 is connected with the micropore at the center of the first gasket 6.4, and the pore pressure outlet 6.8 is connected with the micropore at the center of the second gasket 6.5. This design is to better uniformly apply pore pressure to the end surface of the core 9.

[0059] Further, the confining pressure medium of the core holder 6 is generally water, and if there is air in the confining pressure chamber 6.6, it will affect the confining pressure. On the one hand, because air is highly compressible, it will cause large confining pressure fluctuations and long stabilization time. On the other hand, the components in the air (such as CO2) will slowly dissolve into the water under high pressure, causing the confining pressure to slowly decrease. In order to overcome the above problems, as shown in the figure, Figure 3 the top of the cover 6.2 is provided with an exhaust hole 6.11 connected with the confining pressure chamber 6.6, so that when the confining pressure is pressurized, the air in the confining pressure chamber 6.6 can be easily discharged.

[0060] The embodiment of the present application also provides a measuring method of seepage flow, which uses the measuring device of seepage flow as described above to measure, and comprises the following steps:

[0061] S1, the fluid to be measured is introduced into the first end of the four-way valve;

[0062] S2, the second valve, the third valve and the fourth valve are closed, and the reading of the pressure sensor is observed; wherein, when the reading of the pressure sensor reaches the maximum value and remains unchanged, step S3 is entered;

[0063] S3, the second valve and the third valve are opened, and the reading of the differential pressure gauge after stabilization is obtained;

[0064] S4, the flow of the fluid to be measured is calculated according to the reading of the differential pressure gauge.

[0065] It should be noted that, since the present scheme uses the above-mentioned measuring device for measuring seepage flow, it also has corresponding beneficial effects, which can be referred to the previous description, and will not be repeated here.

[0066] In order to better understand the use process of the measuring device of the present scheme, more specifically, the seepage flow measuring method provided by the embodiments of the present application comprises the following steps:

[0067] 1. Installing the artificial core in the core holder; wherein, according to the different flow to be measured, artificial cores with different permeability coefficients are selected;

[0068] 2. Connecting the fluid to be measured into the measuring device;

[0069] 3. Closing the first valve 1, the second valve 2, the third valve 3 and the fourth valve 4, observing the reading of the pressure sensor, when the reading of the pressure sensor reaches the maximum value and does not change, then entering the next step; wherein, closing the four valves is to let the fluid to be measured flow to the downstream through the artificial core only, and cannot reach the downstream from other channels; and the first valve 1 is specially set to protect the high-precision differential pressure meter 10; and in the experiment, when the upstream and downstream pressure difference is large, only the second valve 2 and the third valve 3 cannot ensure the safety of the high-precision differential pressure meter 10, because the valve has leakage, if one of the second valve 2 and the third valve 3 is broken, it will cause the high-precision differential pressure meter 10 to be damaged due to overload, generally by cooperating with the use of the first valve 1, when the three valves are opened, it can ensure that the pressure at both ends of the high-precision differential pressure meter 10 is balanced; in addition, under the premise that the fourth valve 4 is closed, the fluid flows to the downstream through the artificial core, when the downstream pressure increases to the maximum and does not change, that is, the reading of the pressure sensor reaches the maximum value and does not change, then it means that the fluid to be measured has flowed to the downstream through the artificial core, at this time, it can be considered that the artificial core has been saturated with the measured fluid, then it means that the pressure difference between both ends of the artificial core can be measured at this time;

[0070] 4. Opening the first valve 1 to make the pressure at both ends of the artificial core the same;

[0071] 5. Closing the first valve 1, and opening the second valve 2 and the third valve 3 at the same time, at this time, the fluid can only flow to the outlet through the artificial core;

[0072] 6. Recording the reading of the high-precision differential pressure meter 10, after the high-precision differential pressure meter 10 is stable, reading the reading of the high-precision differential pressure meter 10, this data is the data required for measuring the flow;

[0073] 7. Calculating the flow of the fluid to be measured according to the reading of the high-precision differential pressure meter 10.

[0074] It should be noted that if the measured differential pressure has the possibility of reaching the range limit of the high-precision differential pressure gauge 10 in the sixth step, the outlet back pressure valve can be adjusted to increase the pressure of the entire device and reduce the differential pressure at both ends of the core, thereby ensuring that the high-precision differential pressure gauge is not damaged due to overpressure.

[0075] In addition, the present scheme selects a suitable cylindrical artificial core. After the artificial core is determined, the cross-sectional area A (the bottom area of the cylinder or the water passing section), the permeability coefficient K, and the length (the seepage path length) L of the artificial core can be known. By measuring the pressure difference at both ends of the artificial core, the seepage flow rate per unit time can be calculated.

[0076] Specifically, the permeability coefficient K is also the permeability. The permeability refers to the ability of the rock to allow fluid to pass under a certain pressure difference. It is a parameter that characterizes the ability of the core itself to conduct liquid. Its size is related to factors such as porosity, the geometry of the pores in the liquid permeation direction, particle size, and arrangement direction, and is independent of the properties of the liquid moving in the medium.

[0077] In simple terms, the permeability is only related to its own properties. After the artificial core is processed (of course, the natural core also needs to be processed to a size suitable for being placed in the core holder), its permeability is fixed and cannot be changed, and is independent of the fluid passing through the artificial core and the pressure difference at both ends of the core.

[0078] According to Darcy's law:

[0079]

[0080] Q: the flow rate of the fluid through the artificial rock per unit time; A: the cross-sectional area of the liquid passing through the rock;

[0081] μ: the viscosity of the liquid; L: the length of the rock; P 上 : the upstream pressure of the core; P 下 : the downstream pressure of the core.

[0082] When the artificial core and the fluid are determined, K, A, μ, and L are determined, and the ratio of the flow rate Q to (P 上 -P 下 ) is a known fixed value. Therefore, by measuring the pressure difference (P 上 -P 下 ) between the upstream and downstream of the artificial core, the flow rate of the measured liquid can be calculated.

[0083] In addition, it is also necessary to point out that the smaller the permeability of the artificial core, the greater the pressure difference at both ends of the artificial core, and the smaller the seepage flow that can be measured; the greater the permeability of the artificial core, the smaller the pressure difference at both ends of the artificial core, and the greater the seepage flow that can be measured. When the permeability of the artificial core changes by a magnitude, the flow measurement by a magnitude can be realized. That is, by replacing different artificial cores, different magnitude flows can be measured.

[0084] For example, by using artificial cores of the same size, assuming that the artificial core is a cylindrical artificial core with a length of 50 cm and a diameter of 25 cm, the flow Q is proportional to the permeability coefficient K and the pressure difference, and the pressure difference is related to the permeability coefficient. Therefore, by changing the permeability coefficient K, the flow measurement by different magnitudes can be realized.

[0085] Still taking the above-mentioned artificial core as an example, the length is 50 cm and the diameter is 25 cm;

[0086] When the permeability coefficient K of the artificial core used is between 1 and 100 mD, the range of the flow rate that can be measured is about 0.01 cm 2 / s to 16 cm 2 / s;

[0087] When the permeability coefficient K of the artificial core used is between 100 and 1D, the range of the flow rate that can be measured is about 16 cm 2 / s to 160 cm 2 / s;

[0088] That is, by using actual data, the present scheme shows how to realize the flow measurement by a magnitude. The permeability coefficient changes from 1 mD to 1D, and the flow rate changes from 0.01 cm 2 / s to 160 cm 2 / s.

[0089] The embodiments in the present specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments. The same or similar parts between the embodiments can be referred to each other.

[0090] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method of measuring seepage flow, characterized by, The measurement device comprises a core (9), a core holder (6), a pressure sensor (7), a differential pressure gauge, a four-way valve (8), a second valve (2), a third valve (3) and a fourth valve (4). The core (9) is used for being installed in the core holder (6); wherein the core (9) is a cylindrical artificial core. The first end of the four-way valve (8) is used for being connected with the fluid to be measured, the second end is connected with the sensing end of the pressure sensor (7), the third end is connected with the pore pressure inlet (6.7) of the core holder (6), and the fourth end is connected with the first end of the second valve (2); the pore pressure outlet (6.8) of the core holder (6) is connected with the first end of the fourth valve (4); the first end of the differential pressure gauge is connected with the second end of the second valve (2), and the second end is connected with the first end of the third valve (3); the second end of the third valve (3) is connected with the pore pressure outlet of the core holder (6). The measurement method comprises the following steps: S1, the fluid to be measured is connected to the first end of the four-way valve; S2, the second valve, the third valve and the fourth valve are closed, and the reading of the pressure sensor is observed; wherein when the reading of the pressure sensor reaches the maximum value and remains unchanged, step S3 is entered; S3, the second valve and the third valve are opened, and the reading of the differential pressure gauge after being stabilized is obtained; S4, the flow of the fluid to be measured is calculated according to the reading of the differential pressure gauge; wherein the flow Q of the fluid to be measured through the artificial core per unit time is calculated according to the following Darcy law: ； where Q is the flow rate of the fluid through the artificial core per unit time; A is the cross-sectional area of the liquid through the artificial core; μ is the viscosity of the liquid; L is the length of the artificial core; P 上 is the upstream pressure of the artificial core, P 下 is the downstream pressure of the artificial core, P 上 -P 下 is the differential pressure gauge reading; and K is the permeability or permeability coefficient of the artificial core. The core holder (6) comprises a base (6.1), a cover (6.2), a heat shrink tube (6.3), a first gasket (6.4) and a second gasket (6.5). The first gasket (6.4) and the second gasket (6.5) are both provided with through micro-holes; The cover (6.2) is detachably connected with the base (6.1), and a confining pressure chamber (6.6) is formed between the inner wall of the cover (6.2) and the top of the base (6.1); The heat shrink tube (6.3) is arranged in the confining pressure chamber (6.6); the first gasket (6.4), the core (9) and the second gasket (6.5) are sequentially and axially sealed and arranged in the heat shrink tube (6.3), and the two end surfaces of the core (9) are respectively attached to the first gasket (6.4) and the second gasket (6.5); The base (6.1) is provided with the pore pressure inlet (6.7) connected with the micro-holes of the first gasket (6.4), the pore pressure outlet (6.8) connected with the micro-holes of the second gasket (6.5), the confining pressure inlet (6.9) connected with the confining pressure chamber (6.6) and the confining pressure outlet (6.10) connected with the confining pressure chamber (6.6); The number of the micro-holes of the first gasket (6.4) and the second gasket (6.5) is multiple, and is uniformly distributed.

2. The method of measuring the flow rate of a seepage flow according to claim 1, wherein, The differential pressure gauge is a high-precision differential pressure gauge (10).

3. The method of measuring the flow rate of a seepage flow according to claim 2, wherein, It further comprises a first valve (1). The first end of the first valve (1) is connected with the fourth end of the four-way valve (8), and the second end is connected with the pore pressure outlet of the core holder (6).

4. The method of measuring seepage flow rate according to claim 2, wherein, Further comprising a filter element; The first end of the filter element is connected with the second end of the second valve (2), and the second end is connected with the first end of the high-precision differential pressure gauge (10).

5. The method of measuring seepage flow rate according to claim 1, wherein, Further comprising a back pressure valve (5); The first end of the back pressure valve (5) is connected with the second end of the fourth valve (4).

6. The method of measuring the flow rate of a seepage flow according to claim 1, wherein, The top of the cover (6.2) is provided with an exhaust hole (6.11) communicated with the confining pressure chamber (6.6).

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