A high-precision ultra-low permeability porosity measuring instrument and its measuring method

Abstract

The present invention provides an ultra-low permeability porosity measuring instrument for high-precision measurement and a measuring method thereof, which is applied in the field of porous material permeability detection. The pressure result detected by a dynamic balance tube is used to detect the pressure inside the material part through pressure balance, and then the porosity of the sample is calculated using a gas equation. At the same time, the detection device performs continuous detection, thereby reducing the influence of the systematic error caused by the experimental instrument itself on the experimental data and results, and increasing the accuracy of the experimental detection. In addition, by entering the detection data into a coordinate system, the discrete degree of the detection data can be clearly known through the coordinate system diagram using the average line, and then a suitable method can be selected to calculate the pore volume of the sample. The discrete degree of the detection data can be clearly known through the coordinate system diagram, and then a suitable method can be selected to calculate the pore volume of the sample, and the detection personnel can intuitively judge the accuracy of this experiment through the thickness of the precision line.

Description

Technical Field

[0001] The present application relates to the field of porous material permeability detection, and in particular to a high-precision ultra-low permeability porosity measuring instrument and a measuring method thereof. Background Art

[0002] Porosity refers to the ratio of the sum of the volumes of all pore spaces in a rock sample to the volume of the rock sample, which is called the total porosity of the rock and is expressed as a percentage. The larger the total porosity of the reservoir, the larger the pore space in the rock. From a practical point of view, only those pores that are interconnected are of practical significance, because they can not only store oil and gas, but also allow oil and gas to permeate through them. Therefore, in production practice, the concept of effective porosity is proposed. Effective porosity refers to the ratio of the sum of the volumes of those interconnected pores that allow fluid to flow under normal pressure conditions to the total volume of the rock sample, expressed as a percentage. Obviously, the effective porosity of the same rock is less than its total porosity.

[0003] In the field of oil exploration, low permeability is a special term, which refers to oil fields with low permeability, low abundance and low single-well production capacity of oil reservoirs. Low permeability oil and gas fields are of great significance in oil and gas development. The distribution of low permeability oil and gas resources is characterized by high oil and gas content, multiple oil and gas reservoir types, wide distribution area, and "gas above and oil below, mainly marine gas, and both terrestrial oil and gas".

[0004] However, low-permeability rocks and minerals have low porosity and the sample pore volume is much smaller than the sample cavity vacant volume. Slight measurement errors in the sample cavity vacant volume and the volume of gas free space in the sample cavity will significantly affect the measurement results and the accuracy of the measurement, which in turn will affect the oil exploration structure. Summary of the invention

[0005] The purpose of the present application is to increase the accuracy of detection and reduce the impact on the exploration structure of oil. Compared with the prior art, a high-precision ultra-low permeability porosity measuring instrument is provided, which includes a material pipe through a material part, a sealing cover is threadedly connected to the opening of the material pipe, a sealing ring is connected between the sealing cover and the material pipe, and the sealing ring is fixedly connected to the sealing cover. An I-shaped movable groove is excavated on the inner wall of the material pipe, and the I-shaped movable groove is located in the lower half of the material pipe. A material boat is slidably connected in the I-shaped movable groove. The loading boat includes a boat body, and a limiting slider matching the I-shaped movable groove is fixedly connected to the lower end of the boat body. A movable wedge is slidably connected in the I-shaped movable groove close to the sealing cover. The movable wedge contacts the loading boat. The material part is away from the sealing cover. A positioning hole is drilled at the end, the power balance part includes a power balance pipe, a sealing ring 2 is connected between the power balance pipe and the material pipe, the sealing ring 2 is fixedly connected to the power balance pipe, one end of the power balance pipe close to the material part is fixedly connected with a connecting pipe matching the positioning hole, and the material pipe and the power balance pipe are communicated through the connecting pipe, a sealing rubber pad matching the power balance pipe is slidably connected inside the power balance pipe,) one end of the power balance pipe away from the connecting pipe is fixedly connected with an air outlet, and the outer wall surface of the power balance pipe is engraved with scale patterns, especially, the reading of the scale patterns is the sum of the space of the material pipe and the power balance pipe on the left side of the sealing rubber pad when the ultra-low permeability porosity measuring instrument is working, and a connecting rubber hose is fixedly connected between the air outlet and the negative pressure air pump;

[0006] The pressure inside the material part is detected by using the pressure balance detected by the dynamic balance tube, and then the porosity of the sample is calculated using the gas equation. At the same time, the detection device performs continuous detection to reduce the influence of systematic errors caused by the experimental instrument itself on the experimental data and results, and increase the accuracy of experimental detection.

[0007] Furthermore, a movable ring groove is formed at one end of the sealing ring 2 away from the air outlet, an electromagnetic ring is fixedly connected to the bottom plate of the movable ring groove, a locking ring is slidably connected in the movable ring groove, the locking ring comprises a locking block and an adsorption ring, and the shape of the locking block matches that of the sealing ring 2, the locking block is located on the outside of the movable ring groove, and the adsorption ring is located on the inside of the movable ring groove. When measuring the porosity, the electromagnetic ring is energized, and the strong adsorption force between the electromagnetic ring and the adsorption ring is used to fix the locking ring as a whole, and the locking ring is used to fix the material part and the dynamic balance part to each other, so that it is not easy for gaps to appear in the connection between the material part and the dynamic balance part.

[0008] Furthermore, an air outlet is fixedly connected to one end of the reinforcement part away from the material part, and the air outlet is radiated from the center to the surrounding areas. The air outlet is used to protect the reinforcement part, so that the reinforcement part is not easily deformed excessively.

[0009] Furthermore, the movable wedge block includes an I-shaped blocking body and a bottom plate, the bottom plate is located at the lower side of the I-shaped blocking body, a compression spring is fixedly connected between the I-shaped blocking body and the bottom plate, a connecting rod is fixedly connected to the upper end of the bottom plate, and the end of the connecting rod away from the bottom plate passes through the I-shaped blocking body and extends to the upper side of the I-shaped blocking body. When the movable wedge block needs to be moved, the bottom plate can be lifted by the connecting rod to release the fixation of the movable wedge block, and when the movable wedge block is fixed, due to the action of the compression spring in a compressed state, the friction between the bottom plate and the I-shaped movable groove is increased, thereby increasing the fixing effect of the movable wedge block.

[0010] Furthermore, a wear-resistant tube is connected between the I-shaped blocking body and the connecting rod, and the wear-resistant tube is fixedly connected to the I-shaped blocking body, thereby reducing the friction between the I-shaped blocking body and the connecting rod, making the connection between the I-shaped blocking body and the connecting rod less prone to shaking.

[0011] Furthermore, one end of the connecting rod away from the bottom plate is fixedly connected with a finger rod, so as to facilitate lifting the connecting rod and the bottom plate.

[0012] A high-precision ultra-low permeability porosity measuring method mainly includes the following steps:

[0013] S1. Material loading, the volume of the object to be tested is detected and recorded as V 0 After the material tube is closed, the net space inside the material tube is recorded as V 101 The pore volume of the sample is denoted as V 孔 , then load the object to be tested into the loading boat, place it in the material part, and fix it with a movable wedge, then start the negative pressure air pump, and then seal the material pipe with a sealing cover. At this time, the material pipe and the power balance pipe are both at normal temperature and pressure, and the sealing pad is located on the leftmost side of the power balance pipe;

[0014] S2. Porosity measurement: Start the negative pressure air pump to reduce the pressure of the dynamic balance tube at a rate of 1 KPa / min. Record the real-time air pressure in the dynamic balance tube and the reading of the sealing pad position every three minutes, marked as (P 1 ,V 1 )、(P 2 ,V 2 )、(P 3 ,V 3 )……(P n ,V n ) until the change in the position readings of two adjacent sealing pads is less than 1% of the total volume of the dynamic balance tube, and then stop the test;

[0015] S3, porosity calculation, input the data measured in step S2 into the processing terminal, and calculate the porosity of the object to be detected according to the input data by the pre-input algorithm, wherein the porosity algorithm is:

[0016] (P 1 , V 1 ) data set as an example, where the ideal gas equation is pV=nRT, where n is the amount of gas, T is the temperature, and R is the molar gas constant. During the entire measurement process, n, R, and T can all be controlled as constants, that is, the product of the P and V values ​​in multiple sets of data is customized:

[0017] P 1 (V 1 -V 0 +V 孔 )=P 2 (V 2 -V 0 +V 孔 )=……=P n (V n -V 0 +V 孔 )=P 标 (V 101 -V 0 +V 孔 )

[0018] For (P 1 , V 1 ) data set, a total of N sets of equations can be established, and in all equations only V 孔 One unknown quantity, N sets of equations can obtain N V 孔 The values ​​that differed from the median by more than 5% were removed and the average was taken, which was recorded as (P 1 , V 1 ) data set, denoted as V 孔1 According to the above method, (P 2 ,V 2 )、(P 3 ,V 3 )……(P n ,V n ) data set, denoted as V 孔2 、V 孔3 ……V 孔n , which constitutes the data set of sample porosity (V 孔1 、V 孔2 、V 孔3 ……V 孔n ), remove the values ​​that differ from the median by more than 5%, take the average, and get the final sample pore volume: The final calculation formula for the sample porosity is:

[0019]

[0020] Obtain the final sample porosity.

[0021] Furthermore, in (P n , V n ) data set, if the number removed exceeds half of the number, it is considered that (P 1 , V 1 ) data group has a large error in the test data, so it is discarded (P 1 , V 1 ) data group, when calculating the final sample pore volume, if the number removed exceeds half of the number, the experiment is considered a failure. After checking the airtightness of the device, the installation experiment is repeated.

[0022] Furthermore, (P 1 , V 1 The pore volumes of N samples calculated in the data set are labeled P-V 孔 coordinate system, and calculate the average pore volume of all samples, in P-V 孔 Draw the average line in the coordinate system, remove the values ​​that differ from the median by more than 5%, and calculate the number of points above and below the average line. When the difference between the number of points above and below the average line is less than 15% of the total data, the effective digits are still used to directly take the average to obtain (P 1 , V 1 ) data set, and when the difference between the number of points above and below the average line is greater than 15% of the total data, the data consisting of significant figures are first averaged and then the variance is taken. When there are more points above the average line, (P 1 , V 1 ) data set is the sum of the mean and the variance. When there are more points on the lower side of the draw, (P 1 , V 1 ) The sample porosity of the data group is the mean minus the variance to obtain the sample pore volume. The discrete degree of the test data can be clearly known through the coordinate system diagram, and then the appropriate method can be selected to calculate the sample pore volume.

[0023] Furthermore, when calculating the pore volume of the sample, the P-V 孔 Draw a precision line in the coordinate system with the vertical coordinate value equal to the pore volume of the sample, and then gradually thicken the precision line until the precision line is connected to all valid digits. The tester can intuitively judge the accuracy of this experiment by the thickness of the precision line: the thicker the precision line, the worse the experimental accuracy. When the experimental accuracy is too low, the experiment is judged to have failed. After checking the airtightness of the device, reinstall the experiment.

[0024] Compared with the prior art, the advantages of this application are:

[0025] In this scheme, pressure balance is used to detect the pressure inside the material part using the pressure results detected by the dynamic balance tube. The porosity of the sample is then calculated using the gas equation. At the same time, the detection device performs continuous detection to reduce the impact of systematic errors caused by the experimental instrument itself on the experimental data and results, thereby increasing the accuracy of experimental detection.

[0026] In addition, by entering the test data into the coordinate system, the degree of discreteness of the test data can be clearly known through the coordinate system diagram using the average line, and then a suitable method can be selected to calculate the pore volume of the sample. When the difference in the number of points above and below the average line is less than 15% of the total data, the effective digits are directly used to take the average as the final value. When the difference in the number of points above and below the average line is greater than 15% of the total data, the data composed of effective digits are first averaged, then the variance is taken, and finally the final value is calculated. The degree of discreteness of the test data can be clearly known through the coordinate system diagram, and then a suitable method can be selected to calculate the pore volume of the sample. The test personnel can intuitively judge the accuracy of this experiment by the thickness of the accuracy line: the thicker the accuracy line, the worse the experimental accuracy. When the experimental accuracy is too low, the experiment is judged to have failed. After checking the airtightness of the device, the experiment is reinstalled. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The structure diagram of the ultra-low permeability porosity measuring instrument of this application is shown in FIG. Figure 1 ;

[0028] Figure 2 The structure diagram of the ultra-low permeability porosity measuring instrument of this application is shown in FIG. Figure 2 ;

[0029] Figure 3 A front cross-sectional view of the ultra-low permeability porosity measuring instrument of the present application;

[0030] Figure 4 A front cross-sectional view of the material portion of this application;

[0031] Figure 5 It is a front cross-sectional view of the power balance part of the present application;

[0032] Figure 6 for Figure 5 The structural diagram at A in the middle;

[0033] Figure 7 This is a schematic diagram of the structure of the sealing gasket of the present application;

[0034] Figure 8 A schematic diagram of the structure of the movable wedge of the present application;

[0035] Fig. 9 A front cross-sectional view of the movable wedge of the present application;

[0036] Fig.10 A schematic diagram of the rotation of the locking ring of the present application;

[0037] Fig.11 is the auxiliary coordinate system for averaging the pore volumes of the samples in this application;

[0038] Fig.12 It is an auxiliary coordinate system for determining the porosity measurement accuracy of samples in this application.

[0039] Description of the numbers in the figure:

[0040] 1 material part, 101 material pipe, 102 sealing cover, 103 sealing ring 1, 104 positioning hole, 2 power balance part, 201 power balance pipe, 202 sealing ring 2, 203 connecting pipe, 204 sealing rubber pad, 205 strengthening part, 206 air outlet, 207 movable ring groove, 208 electromagnetic ring, 3 negative pressure air pump, 4 type movable groove, 5 loading boat, 501 boat body, 502 limit slider, 6 movable wedge block, 601 type blocking body, 602 wear-resistant pipe, 603 bottom plate, 604 connecting rod, 605 finger rod, 606 compression spring, 7 locking ring, 701 locking block, 702 adsorption ring, 8 connecting hose. DETAILED DESCRIPTION

[0041] The embodiments will be combined with the drawings in the specification to clearly and completely describe the technical solution of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making any creative work shall fall within the scope of protection of the present application.

[0042] Embodiment 1:

[0043] The present invention provides a high-precision ultra-low permeability porosity measuring instrument, please refer to Figure 1-5, including a material part 1, a dynamic balance part 2 and a negative pressure air pump 3, the material part 1 includes a material pipe 101, a sealing cover 102 is threadedly connected at the opening of the material pipe 101, a sealing ring 103 is connected between the sealing cover 102 and the material pipe 101, and the sealing ring 103 is fixedly connected to the sealing cover 102, an I-shaped movable groove 4 is cut on the inner wall of the material pipe 101, the I-shaped movable groove 4 is located in the lower half of the material pipe 101, a loading boat 5 is slidably connected in the I-shaped movable groove 4, the loading boat 5 includes a boat body 501, a limiting slider 502 matching the I-shaped movable groove 4 is fixedly connected at the lower end of the boat body 501, a movable wedge 6 is slidably connected in the I-shaped movable groove 4 close to the sealing cover 102, and the movable wedge 6 contacts the loading boat 5, a positioning hole 104 is cut on the end of the material part 1 away from the sealing cover 102, and the dynamic balance part 2 includes a dynamic balance pipe 20 1. A sealing ring 202 is connected between the power balance tube 201 and the material tube 101. The sealing ring 202 is fixedly connected to the power balance tube 201. One end of the power balance tube 201 close to the material part 1 is fixedly connected with a connecting tube 203 matching the positioning hole 104, and the material tube 101 and the power balance tube 201 are communicated through the connecting tube 203. A sealing rubber pad 204 matching the power balance tube 201 is slidably connected inside the power balance tube 201. One end of the power balance tube 201 away from the connecting tube 203 is fixedly connected with an air outlet 206. The outer wall surface of the power balance tube 201 is engraved with scale patterns. In particular, the scale pattern reading is the sum of the spaces between the material tube 101 and the power balance tube 201 located on the left side of the sealing rubber pad 204 when the ultra-low permeability porosity measuring instrument is working. A connecting rubber hose 8 is fixedly connected between the air outlet 206 and the negative pressure air pump 3.

[0044] See also Figure 5-6 A movable ring groove 207 is formed at one end of the sealing ring 202 away from the air outlet 206, and an electromagnetic ring 208 is fixedly connected to the bottom plate of the movable ring groove 207. A locking ring 7 is slidably connected in the movable ring groove 207. The locking ring 7 includes a locking block 701 and an adsorption ring 702. The shape of the locking block 701 matches the sealing ring 202. The locking block 701 is located on the outside of the movable ring groove 207, and the adsorption ring 702 is located on the inside of the movable ring groove 207. When measuring the porosity, the electromagnetic ring 208 is energized, and the strong adsorption force between the electromagnetic ring 208 and the adsorption ring 702 is used to fix the locking ring 7 as a whole. The locking ring 7 is used to fix the material part 1 and the dynamic balance part 2 to each other, so that it is not easy to have a gap in the connection between the material part 1 and the dynamic balance part 2.

[0045] See also Figure 7 One end of the reinforcement part 205 away from the material part 1 is fixedly connected with an air outlet 206, and the air outlet 206 is radially extending from the center to the surrounding areas. The air outlet 206 is used to protect the reinforcement part 205, so that the reinforcement part 205 is not easily deformed excessively.

[0046] See also Figure 3 and Figure 8-9 The movable wedge block 6 includes an I-shaped blocking body 601 and a bottom plate 603. The bottom plate 603 is located at the lower side of the I-shaped blocking body 601. A compression spring 606 is fixedly connected between the I-shaped blocking body 601 and the bottom plate 603. The upper end of the bottom plate 603 is fixedly connected to a connecting rod 604. The end of the connecting rod 604 away from the bottom plate 603 passes through the I-shaped blocking body 601 and extends to the upper side of the I-shaped blocking body 601. When it is necessary to move the movable wedge block 6, the bottom plate 603 can be lifted by the connecting rod 604 to release the fixing of the movable wedge block 6. When the movable wedge block 6 is fixed, it is in compression. The compression spring 606 in the state increases the friction between the base plate 603 and the I-shaped movable groove 4, and increases the fixing effect of the movable wedge block 6; a wear-resistant tube 602 is connected between the I-shaped blocking body 601 and the connecting rod 604; the wear-resistant tube 602 is fixedly connected to the I-shaped blocking body 601, reducing the friction between the I-shaped blocking body 601 and the connecting rod 604, making the connection between the I-shaped blocking body 601 and the connecting rod 604 less prone to shaking; a finger rod 605 is fixedly connected to one end of the connecting rod 604 away from the base plate 603, which facilitates lifting the connecting rod 604 and the base plate 603.

[0047] A high-precision ultra-low permeability porosity measuring method mainly includes the following steps:

[0048] S1. Material loading, the volume of the object to be tested is detected and recorded as V 0 After the material pipe 101 is closed, the net space inside the material pipe 101 is denoted as V 101 (i.e. the volume after the material tube 101 is closed and the material boat 5 is removed), the pore volume of the sample is recorded as V 孔 , then load the object to be tested into the loading boat 5, and place it into the material part 1, and fix it with the movable wedge 6, then start the negative pressure air pump 3, and then seal the material pipe 101 with the sealing cover 102. At this time, the material pipe 101 and the power balance pipe 201 are both at normal temperature and pressure, and the sealing rubber pad 204 is located at the leftmost side of the power balance pipe 201;

[0049] S2, porosity measurement, start the negative pressure air pump 3, reduce the pressure of the dynamic balance tube 201, the pressure reduction rate is 1KPa / min, and record the real-time air pressure in the dynamic balance tube 201 and the reading of the position of the sealing rubber pad 204 every three minutes, which are marked as (P 1 ,V 1 )、(P 2 ,V 2 )、(P 3 ,V 3 )……(P n ,V n) until the change in the position readings of two adjacent sealing rubber pads 204 is less than 1% of the total volume of the power balance tube 201, and then the test is stopped;

[0050] S3, porosity calculation, input the data measured in step S2 into the processing terminal, and calculate the porosity of the object to be detected according to the input data by the pre-input algorithm, wherein the porosity algorithm is:

[0051] (P 1 , V 1 ) data set as an example, where the ideal gas equation is pV=nRT, where n is the amount of gas, T is the temperature, and R is the molar gas constant. During the entire measurement process, n, R, and T can all be controlled as constants, that is, the product of the P and V values ​​in multiple sets of data is customized:

[0052] P 1 (V 1 -V 0 +V 孔 )=P 2 (V 2 -V 0 +V 孔 )=……=P n (V n -V 0 +V 孔 )=P 标 (V 101 -V 0 +V 孔 )

[0053] For (P 1 , V 1 ) data set, a total of N sets of equations can be established, and in all equations only V 孔 One unknown quantity, N sets of equations can obtain N V 孔 The values ​​that differed from the median by more than 5% were removed and the average was taken, which was recorded as (P 1 , V 1 ) data set, denoted as V 孔1 , in particular, when the number removed exceeds half of the number, it is considered that (P 1 , V 1 ) data group has a large error in the test data, so it is discarded (P 1 , V 1 ) data group, according to the above method, we measured (P 2 ,V 2 )、(P 3 ,V 3 )……(P n ,V n ) data set, denoted as V孔2 、V 孔3 ……V 孔n , which constitutes the data set of sample porosity (V 孔1 、V 孔2 、V 孔3 ……V 孔n ), remove the values ​​that differ from the median by more than 5%, take the average, and get the final sample pore volume: When the number removed exceeds half of the number, the experiment is considered to have failed. After checking the airtightness of the device, the installation experiment is re-performed, and the final calculation formula for the sample porosity is:

[0054]

[0055] In particular, the pressure data can be detected and obtained by installing an air pressure sensor on the inner wall of the connecting tube 203 close to one end of the negative pressure air pump 3. This is a well-known technology for those skilled in the art and is therefore not disclosed in detail in this application.

[0056] In this scheme, pressure balance is used to detect the pressure inside the material part 1 using the pressure result detected by the dynamic balance tube 201, and then the porosity of the sample is calculated using the gas equation. At the same time, the detection device performs continuous detection to reduce the impact of systematic errors caused by the experimental instrument itself on the experimental data and results, thereby increasing the accuracy of experimental detection.

[0057] Embodiment 2:

[0058] The present invention provides a high-precision ultra-low permeability porosity measuring instrument measuring method, please refer to Fig.11 , will (P 1 , V 1 The pore volumes of N samples calculated in the data set are labeled P-V 孔 coordinate system, and calculate the average pore volume of all samples, in P-V 孔 Draw the average line in the coordinate system, remove the values ​​that differ from the median by more than 5%, and calculate the number of points above and below the average line. When the difference between the number of points above and below the average line is less than 15% of the total data, the effective digits are still used to directly take the average to obtain (P 1 , V 1 ) data set, and when the difference between the number of points above and below the average line is greater than 15% of the total data, the data consisting of significant figures are first averaged and then the variance is taken. When there are more points above the average line, (P 1 , V 1 ) data set is the sum of the mean and the variance. When there are more points on the lower side of the draw, (P 1 , V 1) The sample porosity of the data group is the mean minus the variance to obtain the sample pore volume. The discrete degree of the test data can be clearly known through the coordinate system diagram, and then the appropriate method can be selected to calculate the sample pore volume.

[0059] See also Fig.12 When calculating the pore volume of the sample, the P-V 孔 Draw a precision line in the coordinate system with the vertical coordinate value equal to the pore volume of the sample, and then gradually thicken the precision line until the precision line is connected to all valid digits. The tester can intuitively judge the accuracy of this experiment by the thickness of the precision line: the thicker the precision line, the worse the experimental accuracy. When the experimental accuracy is too low, the experiment is judged to have failed. After checking the airtightness of the device, reinstall the experiment.

[0060] The calculation and accuracy of the final sample pore volume of other data combinations can all be calculated using the above methods, and those skilled in the art can easily obtain them based on the contents disclosed in this application, so they are not described one by one in this application. Personnel in this field can enter the algorithm into the processing terminal in advance, and the test personnel only need to enter the test data during the test process, or directly input it into the processing terminal through the sensor, so as to directly calculate the porosity of the sample and judge the accuracy of this test through the coordinate graph.

[0061] The above is only the best implementation method adopted by this application in combination with current actual needs, but the protection scope of this application is not limited to this.

Claims

1. A high-precision ultra-low permeability porosity measuring instrument, comprising a material part (1), a dynamic balance part (2) and a negative pressure air pump (3), characterized in that: The material part (1) comprises a material pipe (101), a sealing cover (102) is threadedly connected to the opening of the material pipe (101), a sealing ring (103) is connected between the sealing cover (102) and the material pipe (101), and the sealing ring (103) is fixedly connected to the sealing cover (102), an inner wall of the material pipe (101) is cut with a work-shaped movable groove (4), the work-shaped movable groove (4) is located in the lower half of the material pipe (101), a material carrying boat (5) is slidably connected in the work-shaped movable groove (4), and the material carrying boat (5) comprises a boat body (501), and a limit slider matching the work-shaped movable groove (4) is fixedly connected to the lower end of the boat body (501). (502), a movable wedge (6) is slidably connected to the inner side of the I-shaped movable groove (4) close to the sealing cover (102), and the movable wedge (6) is in contact with the loading boat (5). The movable wedge (6) comprises an I-shaped blocking body (601) and a bottom plate (603), and the bottom plate (603) is located at the lower side of the I-shaped blocking body (601). A compression spring (606) is fixedly connected between the I-shaped blocking body (601) and the bottom plate (603), and a connecting rod (604) is fixedly connected to the upper end of the bottom plate (603), and the end of the connecting rod (604) away from the bottom plate (603) passes through the I-shaped blocking body (601) and extends to the upper side of the I-shaped blocking body (601); The material portion (1) has a positioning hole (104) drilled at one end thereof away from the sealing cover (102); the power balancing portion (2) comprises a power balancing tube (201); a sealing ring 2 (202) is connected between the power balancing tube (201) and the material tube (101); the sealing ring 2 (202) is fixedly connected to the power balancing tube (201); an end of the power balancing tube (201) close to the material portion (1) is fixedly connected to a connecting tube (203) matching the positioning hole (104); and the material tube (101) and the power balancing tube (201) are connected to each other. 01) are connected via a connecting pipe (203); a sealing rubber pad (204) matching the power balance pipe (201) is slidably connected inside the power balance pipe (201); an air outlet (206) is fixedly connected to one end of the power balance pipe (201) away from the connecting pipe (203); scale patterns are engraved on the outer wall surface of the power balance pipe (201); the material pipe (101) and the power balance pipe (201) are located on the left side of the sealing rubber pad (204); a connecting rubber hose (8) is fixedly connected between the air outlet (206) and the negative pressure air pump (3).

2. The high-precision ultra-low permeability porosity measuring instrument according to claim 1, characterized in that: A movable ring groove (207) is formed at one end of the sealing ring 2 (202) away from the air outlet (206); an electromagnetic ring (208) is fixedly connected to the groove bottom plate of the movable ring groove (207); a locking ring (7) is slidably connected inside the movable ring groove (207); the locking ring (7) comprises a locking block (701) and an adsorption ring (702); the shape of the locking block (701) matches that of the sealing ring 2 (202); the locking block (701) is located on the outer side of the movable ring groove (207), and the adsorption ring (702) is located on the inner side of the movable ring groove (207).

3. The high-precision ultra-low permeability porosity measuring instrument according to claim 1, characterized in that: One end of the sealing rubber pad (204) away from the material portion (1) is fixedly connected to a reinforcement portion (205), and the reinforcement portion (205) is radially extending from the center to the surrounding areas.

4. The high-precision ultra-low permeability porosity measuring instrument according to claim 1, characterized in that: A wear-resistant tube (602) is connected between the I-shaped blocking body (601) and the connecting rod (604), and the wear-resistant tube (602) is fixedly connected to the I-shaped blocking body (601).

5. The high-precision ultra-low permeability porosity measuring instrument according to claim 1, characterized in that: One end of the connecting rod (604) away from the bottom plate (603) is fixedly connected to a finger rod (605).

6. The high-precision ultra-low permeability porosity measuring instrument according to claim 1, characterized in that: The detection method mainly includes the following steps: S1. Material loading, the volume of the object to be detected is detected and recorded as V0. After the material pipe (101) is closed, the net space inside the material pipe (101) is recorded as V 101 The pore volume of the sample is denoted as V 孔 , then the object to be tested is loaded into the loading boat (5), and then placed in the material part (1), and fixed with a movable wedge (6), then the negative pressure air pump (3) is started, and then the material pipe (101) is sealed with a sealing cover (102), at which time the material pipe (101) and the power balance pipe (201) are both at normal temperature and pressure, and the sealing rubber pad (204) is located at the leftmost side of the power balance pipe (201); S2. Porosity measurement: start the negative pressure air pump (3) to reduce the pressure of the dynamic balance tube (201) at a rate of 1 KPa / min. Record the real-time air pressure in the dynamic balance tube (201) and the reading of the position of the sealing rubber pad (204) every three minutes, and mark them as (P1, V1), (P2, V2), (P3, V3) ... (P n ,V n ) until the change in the position readings of two adjacent sealing rubber pads (204) is less than 1% of the total volume of the power balance tube (201), and the test is stopped; S3, porosity calculation, input the data measured in step S2 into the processing terminal, and calculate the porosity of the object to be detected according to the input data by the pre-input algorithm, wherein the porosity algorithm is: Take the processing of the (P1, V1) data set as an example, where the ideal gas equation is pV=nRT, where n is the amount of gas, T is the temperature, and R is the molar gas constant. During the entire measurement process, n, R, and T are all controlled as constants, that is, the product of the P and V values ​​in multiple sets of data is customized: P1(V1-V0+V 孔 )=P2(V2-V0+V 孔 )=……=P n (V n -V0+V 孔 )=P 标 (V 101 -V0+V 孔 ) For the (P1, V1) data set, a total of N sets of equations can be established, and in all equations only V 孔 One unknown quantity, N sets of equations can obtain N V 孔 The values ​​that differ from the median by more than 5% are removed and the average is taken, which is recorded as the sample pore volume of the (P1, V1) data group, recorded as V 孔1 According to the above method, (P2, V2), (P3, V3)... (P n ,V n ) data set, denoted as V 孔2 、V 孔3 ……V 孔n , which constitutes the data set of sample porosity (V 孔1 、V 孔2 、V 孔3 ……V 孔n ), remove the values ​​that differ from the median by more than 5%, take the average, and get the final sample pore volume: The final calculation formula for the sample porosity is: Obtain the final sample porosity.

7. The high-precision ultra-low permeability porosity measuring instrument according to claim 6, characterized in that: In the calculation (P n , V n ) data group, when the removed numbers exceed half of the total numbers, it is considered that there is a large error in the detection data of the (P1, V1) data group. The (P1, V1) data group is discarded. When calculating the final sample pore volume, when the removed numbers exceed half of the total numbers, the experiment is judged to have failed. After checking the airtightness of the device, the installation experiment is carried out again.

8. The high-precision ultra-low permeability porosity measuring instrument according to claim 6, characterized in that: In the porosity determination step S2, the pore volumes of the N samples calculated in the (P1, V1) data set are marked as P-V 孔 coordinate system, and calculate the average pore volume of all samples, in P-V 孔 Draw the average line in the coordinate system, remove the values ​​that differ from the median by more than 5%, and then calculate the number of points above and below the average line. When the difference in the number of points above and below the average line is less than 15% of the total data, the effective digits are still directly used to take the average to obtain the sample pore volume of the (P1, V1) data group. When the difference in the number of points above and below the average line is greater than 15% of the total data, the data composed of effective digits are first averaged and then the variance is taken. When there are more points above the average, the sample porosity of the (P1, V1) data group is the sum of the average and the variance. When there are more points below the average, the sample porosity of the (P1, V1) data group is the average minus the variance to obtain the sample pore volume.

9. The high-precision ultra-low permeability porosity measuring instrument according to claim 8, characterized in that: In the porosity determination step S2, when calculating the pore volume of the sample, the porosity of the sample is calculated by the following formula: 孔 Draw a precision line in the coordinate system with the vertical coordinate value equal to the pore volume of the sample, and then gradually thicken the precision line until the precision line connects all significant digits.

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