Rock core porosity determination method, determination device and system

Abstract

The invention provides a rock core porosity determination method, determination device and system, and the determination method comprises the following steps: preparing a dry rock core sample, and measuring the volume of the dry rock core sample; placing the core sample in a confining pressure environment, and measuring the total porosity of the core sample; under the confining pressure level the same as the measured total porosity, measuring the absorption amount of the rock core sample when the rock core sample absorbs the working liquid to be saturated under the vacuum condition, and calculating and measuring the inorganic porosity of the rock core sample according to the absorption amount; and calculating the organic porosity of the rock core sample according to the total porosity and the inorganic porosity. Based on the technical scheme provided by the invention, the organic and inorganic porosity of the rock core sample in the overburden pressure state can be accurately measured, and accurate reference and basis are provided for various researches based on the porosity.

Description

Technical Field

[0001] The present invention relates to the technical field of porosity measurement, and in particular to a core porosity measurement method, a measurement device and a system. Background Art

[0002] Existing methods for characterizing the pore volume of rock cores, such as shale, often employ fluids such as helium, alcohol, and kerosene as media, using a fluid saturation method to characterize porosity. These tests often utilize a single fluid, making it difficult to accurately characterize the inorganic and organic pore volumes. Furthermore, existing methods can only characterize the total porosity of shale under overburden pressure, lacking a measurement method that can characterize both types of pore volume under overburden pressure. Therefore, a feasible solution is needed to address the difficulty in accurately characterizing the organic and inorganic pore volumes of shales under stress conditions. Summary of the Invention

[0003] In order to solve the problem that the organic pore volume and inorganic pore volume of the core under overburden stress conditions cannot be accurately measured and characterized under existing technologies, the present invention proposes a core porosity measurement method, measurement device and measurement system.

[0004] In a first aspect, the present invention provides a method for measuring core porosity, which comprises the following steps:

[0005] Prepare dry core samples and measure their volumes;

[0006] placing the core sample in a confining pressure environment, and measuring the total porosity of the core sample;

[0007] At the same confining pressure level as that for measuring the total porosity, measuring the absorption amount of the core sample when absorbing the working fluid to saturation under vacuum conditions, and calculating and measuring the inorganic porosity of the core sample based on the absorption amount;

[0008] The organic porosity of the core sample is calculated according to the total porosity and the inorganic porosity.

[0009] In one embodiment, the following steps are also included:

[0010] When measuring the total porosity, a plurality of different confining pressure values ​​are set for the confining pressure environment, and the total porosity of the core sample under the corresponding confining pressure values ​​is measured in sequence;

[0011] When measuring the inorganic porosity, at a confining pressure level corresponding to the corresponding confining pressure value, the inorganic porosity of the core sample at different confining pressure values ​​is measured respectively, and the corresponding organic porosity is calculated;

[0012] A relationship between the inorganic porosity, the organic porosity, and a formation pressure numerically corresponding to the confining pressure value is determined.

[0013] In one embodiment, after each measurement of the inorganic porosity, the core sample is dried again before the next measurement of the inorganic porosity is performed.

[0014] In one embodiment, placing the core sample in a confining pressure environment and measuring the total porosity of the core sample comprises the following steps:

[0015] placing the core sample in a sample chamber surrounded by a triaxial clamp, and introducing a pressure medium into the space where the triaxial clamp is located to apply confining pressure to the core sample through the triaxial clamp;

[0016] After the sample chamber and the pipeline system connected to the sample chamber are evacuated, a working gas is injected into the pipeline system until the pressure is balanced, and the balanced pressure P1 is recorded;

[0017] Disconnect the sample chamber from the pipeline system, pressurize the working gas in the pipeline system until the pressure is balanced, and record the balanced pressure P2;

[0018] Connect the sample chamber to the pipeline system, wait for the pressure in the pipeline system to be balanced, and then record the balanced pressure P3;

[0019] The total pore volume of the core sample is calculated based on the gas state equation in combination with the equilibrium pressure P1, the equilibrium pressure P2, and the equilibrium pressure P3, and the total porosity is calculated based on the total pore volume.

[0020] In one embodiment, calculating the total porosity comprises the following steps:

[0021] Substitute the equilibrium pressure P1, equilibrium pressure P2, and equilibrium pressure P3 into the gas state equation:

[0022]

[0023] Arrange and simplify the equation to calculate the total pore volume V p :

[0024]

[0025] The total porosity φ is calculated based on the total pore volume t :

[0026]

[0027] In the above formula: z1, z2 and z3 are the compression coefficients of the working gas at pressures P1, P2 and P3 respectively; V S is the volume of the core sample; V1 is the volume of the pipeline system; and V2 is the volume of the remaining cavity after the core sample is placed in the sample chamber.

[0028] In one embodiment, calculating and determining the inorganic porosity of the core sample according to the absorption amount comprises the following steps:

[0029] Under the corresponding confining pressure value, the sample chamber and the pipeline system connected to the sample chamber are placed in a vacuum state;

[0030] connecting the sample chamber to a dropper containing a working liquid through the pipeline system, so that the core sample in the sample chamber absorbs the working liquid until it is saturated;

[0031] Recording the absorption amount using the scale of the dropper, and using the value of the absorption amount as the inorganic pore volume of the core sample;

[0032] According to the calculation formula φ m =V m / V S , calculate the inorganic porosity; where, φ m is the inorganic porosity, V m is the inorganic pore volume, V S is the volume of the core sample.

[0033] In one embodiment, the organic porosity is calculated according to the following formula:

[0034] V k =V p -V m ;

[0035] φ k =φ t -φ m ;

[0036] Where V p is the total pore volume, V m is the inorganic pore volume, V k is the volume of organic pores, φ t is the total porosity, φ m is the inorganic porosity, φ k is organic porosity.

[0037] In one embodiment, the working gas is any one of helium, nitrogen, carbon dioxide, methane and argon.

[0038] In one embodiment, the working liquid is vacuumed deionized water or a simulated formation water solution prepared according to the formation where the core sample is located.

[0039] In a second aspect, the present invention provides a core porosity measurement device, which applies the above-mentioned measurement method and includes a pipeline system and a vacuum pump, a gas source, a sample chamber, and a dropper connected to the pipeline system, wherein the pipeline system is provided with a pressure sensor;

[0040] The pipeline system includes a standard chamber connected to a booster pump; the sample chamber is arranged in a confined pressure chamber, which is connected to a confined pressure pump and is provided with a pressure sensor.

[0041] In a third aspect, the present invention proposes a core porosity measurement system, which includes the above-mentioned measurement device and a constant temperature device, wherein the constant temperature device is used to provide a constant temperature environment for the measurement device.

[0042] The above technical features can be combined in various suitable ways or replaced by equivalent technical features, as long as the purpose of the present invention can be achieved.

[0043] The core porosity measurement method, device, and system provided by the present invention have at least the following advantages compared to the prior art:

[0044] The present invention provides a core porosity measurement method, measurement device and system. Based on the method and device of the present invention, the organic and inorganic porosity of core samples under overburden pressure can be accurately measured, providing an accurate reference and basis for various porosity-based studies. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The present invention will be described in more detail below based on embodiments and with reference to the accompanying drawings, wherein:

[0046] Figure 1 A schematic flow chart of the assay method of the present invention is shown;

[0047] Figure 2 shows a schematic structural diagram of the measuring device of the present invention;

[0048] Figure 3 A schematic diagram showing the absorption of working fluid by the core sample under a confining pressure of 2 MPa is shown;

[0049] Figure 4 A schematic diagram showing the absorption of working fluid by the core sample under a confining pressure of 6 MPa is shown;

[0050] Figure 5 A schematic diagram showing the absorption of working fluid by the core sample under a confining pressure of 10 MPa is shown;

[0051] Figure 6 A schematic diagram showing the relationship between porosity and confining pressure of core samples is shown.

[0052] In the drawings, like reference numerals are used for like parts, but the drawings are not necessarily true to scale.

[0053] Reference numerals:

[0054] 1-burette, 2-vacuum pump, 3-gas source, 4-standard chamber, 5-boost pump, 6-confining pressure chamber, 7-sample chamber, 8-confining pressure pump. DETAILED DESCRIPTION

[0055] The present invention will be further described below with reference to the accompanying drawings.

[0056] Example 1

[0057] An embodiment of the present invention provides a method for measuring core porosity, which includes the following steps:

[0058] S100: Prepare a dry core sample and measure its volume.

[0059] To ensure the accuracy of the measurement data, the prepared core sample must first be dried in a drying oven until its weight no longer changes. The dried core sample is then measured, primarily for volume. Since the drilled core sample is cylindrical, volume measurement only requires measuring the diameter and height of the core sample, from which the volume can be calculated. Of course, for core samples of other shapes and structures, the corresponding dimensions can be measured to calculate their volume.

[0060] In addition, when measuring the volume, the weight of the core sample can also be weighed as needed to provide a basis for the analysis of other properties of the core sample.

[0061] S200: placing the core sample in a confining pressure environment and measuring the total porosity of the core sample.

[0062] Specifically, the confining pressure environment is used to provide the core sample with a pressure that simulates the formation pressure that the core would experience under actual overburden. This pressure can be provided by injecting gas or liquid into the space containing the core sample, utilizing the pressure of the gas or liquid. Alternatively, mechanical extrusion can be used, depending on the specific design and needs.

[0063] S210: placing the core sample in a sample chamber surrounded by the triaxial clamp, and introducing a pressure medium into the space where the triaxial clamp is located to apply confining pressure to the core sample through the triaxial clamp.

[0064] Specifically, the three-axis clamp is used to place the core sample and enclose a relatively independent sample chamber. The space where the three-axis clamp is located as a whole is the confining pressure chamber, as shown in the attached figure. Figure 2 As shown, the confining pressure chamber can be filled with pressure medium to apply pressure to the triaxial holder to provide confining pressure to the core sample.

[0065] S220: After the sample chamber and the pipeline system connected to the sample chamber are evacuated, a working gas is injected into the pipeline system until the pressure is balanced, and the balanced pressure P1 is recorded.

[0066] Specifically, the working gas fills the sample chamber and the pipeline system connected to the sample chamber. After the overall pressure of the sample chamber and the pipeline system is balanced, the equilibrium pressure P1 is detected and recorded using a pressure sensor on the pipeline system. The specific type of working gas can be selected as needed, for example, any one of helium, nitrogen, carbon dioxide, methane, and argon can be selected.

[0067] S230: Disconnect the sample chamber from the pipeline system, pressurize the working gas in the pipeline system until the pressure is balanced, and record the balanced pressure P2.

[0068] Specifically, disconnecting the sample chamber from the pipeline system means that the sample chamber is relatively sealed, and the pressure therein is not affected by external factors. Pressurizing the pipeline system at this time does not change the pressure in the sample chamber. Disconnecting the sample chamber from the pipeline system can be achieved by closing the corresponding valves. After the pipeline system is pressurized to equilibrium, the equilibrium pressure P2 is detected and recorded using a pressure sensor on the pipeline system.

[0069] S240: Connect the sample chamber to the pipeline system, wait for the pressure in the pipeline system to be balanced, and then record the balanced pressure P3.

[0070] Specifically, the corresponding valve is opened. At this time, since the pressure of the pressurized pipeline system is greater than the pressure of the sample chamber, the working gas in the pipeline system will enter the sample chamber under the action of the pressure difference. After a certain period of time, the pressure of the pipeline system and the sample chamber gradually balance, and then the pressure sensor on the pipeline system is used to detect and record the balanced pressure P3.

[0071] S250: Calculate the total pore volume of the core sample based on the gas state equation in combination with the equilibrium pressure P1, the equilibrium pressure P2, and the equilibrium pressure P3, and calculate the total porosity based on the total pore volume.

[0072] S251: Substitute the equilibrium pressure P1, equilibrium pressure P2, and equilibrium pressure P3 into the gas state equation:

[0073]

[0074] S252: Arrange and simplify the equation to calculate the total pore volume Vp :

[0075]

[0076] S253: Calculate the total porosity φ based on the total pore volume t :

[0077]

[0078] In the above formula: z1, z2 and z3 are the compression coefficients of the working gas at pressures P1, P2 and P3 respectively; V S is the volume of the core sample; V1 is the volume of the pipeline system; V2 is the volume of the remaining cavity after the core sample is placed in the sample chamber.

[0079] Specifically, according to the gas state equation PV=nRT, the above relationship (1) can be obtained based on the relationship between the amount of gas substances in the above steps. By sorting and simplifying the relationship (1), the total pore volume V of the core sample can be obtained. p The expression is equation (2). According to the definition of porosity, the total porosity φ of the core sample can be calculated by equation (3): t .

[0080] It should be noted that V1 in the above formula is the total volume of the pipeline system (the capacity of the internal space) in principle. The pipeline system includes the following Figure 1 The standard chamber shown (mainly used to connect the booster pump to boost the gas, and its volume accounts for the main part of the total volume of the pipeline system) and the pipes connecting the various chambers, so if the volume of the standard chamber accounts for a large enough proportion of the total volume of the pipeline system, then the volume of the pipeline part can be ignored under the premise of considering the measurement accuracy, and the volume of the pipeline system can be as shown in the attached figure Figure 1 It is expressed as the volume V1 of the standard chamber.

[0081] S300: Under the same confining pressure level as that used for determining the total porosity, measure the absorption of the core sample when it absorbs the working fluid to saturation under vacuum conditions, and calculate the inorganic porosity of the core sample based on the absorption amount.

[0082] Specifically, considering the impact of confining pressure on porosity, the corresponding confining pressure level when measuring inorganic porosity should be consistent with the confining pressure level used to measure total porosity. For inorganic porosity measurement, the present invention uses liquid absorption. Because the organic matter corresponding to organic porosity is highly hydrophobic, the corresponding aqueous liquid is essentially completely absorbed into the inorganic pores of the core sample, allowing the absorption amount to reflect the inorganic porosity of the core sample.

[0083] Of course, since the organic matter corresponding to the organic porosity has strong hydrophobicity, the inorganic porosity of the core sample is determined, and the corresponding working liquid naturally needs to be an aqueous liquid. In this embodiment, vacuumed deionized water or a simulated formation water solution pre-configured according to the formation where the core sample is located can be used.

[0084] S310: Under a corresponding confining pressure value, the sample chamber and a pipeline system connected to the sample chamber are placed in a vacuum state.

[0085] Specifically, the determination of inorganic porosity is usually carried out after the determination of total porosity. During the determination of total porosity, the sample chamber where the core sample is located will be ventilated. Therefore, when measuring inorganic porosity, it is necessary to first re-vacuum the sample chamber and the pipeline system connected to the sample chamber.

[0086] S320: The sample chamber is connected to a dropper containing a working liquid through a pipeline system, so that the core sample in the sample chamber absorbs the working liquid until it is saturated.

[0087] Specifically, a dropper is connected to the sample chamber. The working liquid in the dropper enters the sample chamber and is absorbed by the core sample. The absorbed working liquid is then absorbed into the inorganic pores of the core sample. This entire absorption process takes time, so the amount of working liquid in the dropper needs to be continuously monitored. When the reading on the dropper scale stops changing, the core sample is saturated with the working liquid.

[0088] S330: Record the absorption amount using the scale of the dropper, and use the absorption amount as the inorganic pore volume of the core sample.

[0089] Specifically, when the core sample absorbs the working fluid to saturation, it proves that the working fluid has filled the core sample's inorganic pores. The change in the working fluid in the dropper is therefore the core sample's absorption. Of course, depending on accuracy requirements, it's also necessary to consider that some working fluid is stored in the pipeline system. Therefore, the pipeline volume can be measured beforehand by injecting the same amount of working fluid into the pipeline. The actual absorption is equal to the decrease in working fluid in the dropper minus the pipeline volume. Therefore, the absorption is the core sample's inorganic pore volume.

[0090] S340: According to the calculation formula φ m =V m / V S , calculate the inorganic porosity; where, φ m is the inorganic porosity, V m is the inorganic pore volume, V S is the volume of the core sample.

[0091] S400: Calculate the organic porosity of the core sample based on the total porosity and the inorganic porosity.

[0092] S410: Calculate the organic porosity according to the following formula:

[0093] V k =V p -V m ;

[0094] φ k =φ t -φ m ;

[0095] Where V p is the total pore volume, V m is the inorganic pore volume, V k is the volume of organic pores, φ t is the total porosity, φ m is the inorganic porosity, φ k is organic porosity.

[0096] Example 2

[0097] An embodiment of the present invention provides a method for measuring core porosity, which includes the following steps:

[0098] S100: Prepare a dry core sample and measure its volume.

[0099] To ensure the accuracy of the measurement data, the prepared core sample must first be dried in a drying oven until its weight no longer changes. The dried core sample is then measured, primarily for volume. Since the drilled core sample is cylindrical, volume measurement only requires measuring the diameter and height of the core sample, from which the volume can be calculated. Of course, for core samples of other shapes and structures, the corresponding dimensions can be measured to calculate their volume.

[0100] In addition, when measuring the volume, the weight of the core sample can also be weighed as needed to provide a basis for the analysis of other properties of the core sample.

[0101] S200: placing the core sample in a confining pressure environment and measuring the total porosity of the core sample.

[0102] Specifically, the confining pressure environment is used to provide the core sample with a pressure that simulates the formation pressure that the core would experience under actual overburden. This pressure can be provided by injecting gas or liquid into the space containing the core sample, utilizing the pressure of the gas or liquid. Alternatively, mechanical extrusion can be used, depending on the specific design and needs.

[0103] S210: placing the core sample in a sample chamber surrounded by the triaxial clamp, and introducing a pressure medium into the space where the triaxial clamp is located to apply confining pressure to the core sample through the triaxial clamp.

[0104] Specifically, the three-axis clamp is used to place the core sample and enclose a relatively independent sample chamber. The space where the three-axis clamp is located as a whole is the confining pressure chamber, as shown in the attached figure. Figure 2 As shown, the confining pressure chamber can be filled with pressure medium to apply pressure to the triaxial holder to provide confining pressure to the core sample.

[0105] S220: After the sample chamber and the pipeline system connected to the sample chamber are evacuated, a working gas is injected into the pipeline system until the pressure is balanced, and the balanced pressure P1 is recorded.

[0106] Specifically, the working gas fills the sample chamber and the pipeline system connected to the sample chamber. After the overall pressure of the sample chamber and the pipeline system is balanced, the equilibrium pressure P1 is detected and recorded using a pressure sensor on the pipeline system. The specific type of working gas can be selected as needed, for example, any one of helium, nitrogen, carbon dioxide, methane, and argon can be selected.

[0107] S230: Disconnect the sample chamber from the pipeline system, pressurize the working gas in the pipeline system until the pressure is balanced, and record the balanced pressure P2.

[0108] Specifically, disconnecting the sample chamber from the pipeline system means that the sample chamber is relatively sealed, and the pressure therein is not affected by external factors. Pressurizing the pipeline system at this time does not change the pressure in the sample chamber. Disconnecting the sample chamber from the pipeline system can be achieved by closing the corresponding valves. After the pipeline system is pressurized to equilibrium, the equilibrium pressure P2 is detected and recorded using a pressure sensor on the pipeline system.

[0109] S240: Connect the sample chamber to the pipeline system, wait for the pressure in the pipeline system to be balanced, and then record the balanced pressure P3.

[0110] Specifically, the corresponding valve is opened. At this time, since the pressure of the pressurized pipeline system is greater than the pressure of the sample chamber, the working gas in the pipeline system will enter the sample chamber under the action of the pressure difference. After a certain period of time, the pressure of the pipeline system and the sample chamber gradually balance, and then the pressure sensor on the pipeline system is used to detect and record the balanced pressure P3.

[0111] S250: Calculate the total pore volume of the core sample based on the gas state equation in combination with the equilibrium pressure P1, the equilibrium pressure P2, and the equilibrium pressure P3, and calculate the total porosity based on the total pore volume.

[0112] S251: Substitute the equilibrium pressure P1, equilibrium pressure P2, and equilibrium pressure P3 into the gas state equation:

[0113]

[0114] S252: Arrange and simplify the equation to calculate the total pore volume V p :

[0115]

[0116] S253: Calculate the total porosity φ based on the total pore volume t :

[0117]

[0118] In the above formula: z1, z2 and z3 are the compression coefficients of the working gas at pressures P1, P2 and P3 respectively; V S is the volume of the core sample; V1 is the volume of the pipeline system; V2 is the volume of the remaining cavity after the core sample is placed in the sample chamber.

[0119] Specifically, according to the gas state equation PV=nRT, the above relationship (1) can be obtained based on the relationship between the amount of gas substances in the above steps. By sorting and simplifying the relationship (1), the total pore volume V of the core sample can be obtained. p The expression is equation (2). According to the definition of porosity, the total porosity φ of the core sample can be calculated by equation (3): t .

[0120] It should be noted that V1 in the above formula is the total volume of the pipeline system (the capacity of the internal space) in principle. The pipeline system includes the following Figure 1 The standard chamber shown (mainly used to connect the booster pump to boost the gas, and its volume accounts for the main part of the total volume of the pipeline system) and the pipes connecting the various chambers, so if the volume of the standard chamber accounts for a large enough proportion of the total volume of the pipeline system, then the volume of the pipeline part can be ignored under the premise of considering the measurement accuracy, and the volume of the pipeline system can be as shown in the attached figure Figure 1 It is expressed as the volume V1 of the standard chamber.

[0121] S260: setting a plurality of different confining pressure values ​​for the confining pressure environment, and sequentially measuring the total porosity of the core sample under the corresponding confining pressure values.

[0122] Specifically, a plurality of different confining pressure values ​​are set in advance as needed, and multiple rounds of measurement are repeated in ascending order of the confining pressure values, with each round of measurement being performed according to steps S210 to S253.

[0123] S300: Under the same confining pressure level as that used for determining the total porosity, measure the absorption of the core sample when it absorbs the working fluid to saturation under vacuum conditions, and calculate the inorganic porosity of the core sample based on the absorption amount.

[0124] Specifically, considering the impact of confining pressure on porosity, the corresponding confining pressure level when measuring inorganic porosity should be consistent with the confining pressure level used to measure total porosity. For inorganic porosity measurement, the present invention uses liquid absorption. Because the organic matter corresponding to organic porosity is highly hydrophobic, the corresponding aqueous liquid is essentially completely absorbed into the inorganic pores of the core sample, allowing the absorption amount to reflect the inorganic porosity of the core sample.

[0125] Of course, since the organic matter corresponding to the organic porosity has strong hydrophobicity, the inorganic porosity of the core sample is determined, and the corresponding working liquid naturally needs to be an aqueous liquid. In this embodiment, vacuumed deionized water or a simulated formation water solution pre-configured according to the formation where the core sample is located can be used.

[0126] S310: Under a corresponding confining pressure value, the sample chamber and a pipeline system connected to the sample chamber are placed in a vacuum state.

[0127] Specifically, the determination of inorganic porosity is usually carried out after the determination of total porosity. During the determination of total porosity, the sample chamber where the core sample is located will be ventilated. Therefore, when measuring inorganic porosity, it is necessary to first re-vacuum the sample chamber and the pipeline system connected to the sample chamber.

[0128] S320: The sample chamber is connected to a dropper containing a working liquid through a pipeline system, so that the core sample in the sample chamber absorbs the working liquid until it is saturated.

[0129] Specifically, a dropper is connected to the sample chamber. The working liquid in the dropper enters the sample chamber and is absorbed by the core sample. The absorbed working liquid is then absorbed into the inorganic pores of the core sample. This entire absorption process takes time, so the amount of working liquid in the dropper needs to be continuously monitored. When the reading on the dropper scale stops changing, the core sample is saturated with the working liquid.

[0130] S330: Record the absorption amount using the scale of the dropper, and use the absorption amount as the inorganic pore volume of the core sample.

[0131] Specifically, when the core sample absorbs the working fluid to saturation, it proves that the working fluid has filled the core sample's inorganic pores. The change in the working fluid in the dropper is therefore the core sample's absorption. Of course, depending on accuracy requirements, it's also necessary to consider that some working fluid is stored in the pipeline system. Therefore, the pipeline volume can be measured beforehand by injecting the same amount of working fluid into the pipeline. The actual absorption is equal to the decrease in working fluid in the dropper minus the pipeline volume. Therefore, the absorption is the core sample's inorganic pore volume.

[0132] S340: According to the calculation formula φ m =V m / V S , calculate the inorganic porosity; where, φ m is the inorganic porosity, V m is the inorganic pore volume, V S is the volume of the core sample.

[0133] S350: At confining pressure levels corresponding to the corresponding confining pressure values, the inorganic porosity of the core sample at different confining pressure values ​​is measured respectively, and the corresponding organic porosity is calculated; after each inorganic porosity measurement, the core sample is dried again before the next inorganic porosity measurement is performed.

[0134] Specifically, multiple rounds of total porosity measurements are performed, followed by multiple rounds of inorganic porosity measurements. Each round of inorganic porosity corresponds to the previous round of total porosity measurements, i.e., is at a confining pressure level that matches the confining pressure value during the corresponding total porosity measurement.

[0135] S400: Calculating the organic porosity of the core sample under different confining pressures according to the multiple total porosity and inorganic porosity measurement results.

[0136] S410: Calculate the organic porosity according to the following formula:

[0137] V k =V p -V m ;

[0138] φ k =φ t -φ m ;

[0139] Where V p is the total pore volume, V m is the inorganic pore volume, V k is the volume of organic pores, φ t is the total porosity, φ m is the inorganic porosity, φ k is organic porosity.

[0140] S500: Determine the relationship between the inorganic porosity, the organic porosity, and the formation pressure corresponding to the confining pressure value in numerical value by fitting the multiple measurement results.

[0141] Example 3

[0142] An embodiment of the present invention provides a method for measuring core porosity, which includes the following steps:

[0143] S100: Prepare a dry core sample and measure its volume.

[0144] To ensure the accuracy of the measurement data, the prepared core sample must first be dried in a drying oven until its weight no longer changes. The dried core sample is then measured, primarily for volume. Since the drilled core sample is cylindrical, volume measurement only requires measuring the diameter and height of the core sample, from which the volume can be calculated. Of course, for core samples of other shapes and structures, the corresponding dimensions can be measured to calculate their volume.

[0145] In addition, when measuring the volume, the weight of the core sample can also be weighed as needed to provide a basis for the analysis of other properties of the core sample.

[0146] In this example, the shale core sample was placed in a drying oven and dried until the weight no longer changed. The core sample was weighed to be 59.19 g, and its diameter was measured to be 2.45 cm and its height was 4.90 cm. The volume V of the core sample was calculated. S 23.10cm 3 .

[0147] S200: placing the core sample in a confining pressure environment and measuring the total porosity of the core sample.

[0148] Specifically, the confining pressure environment is used to provide the core sample with a pressure that simulates the formation pressure that the core would experience under actual overburden. This pressure can be provided by injecting gas or liquid into the space containing the core sample, utilizing the pressure of the gas or liquid. Alternatively, mechanical extrusion can be used, depending on the specific design and needs.

[0149] S210: placing the core sample in a sample chamber surrounded by the triaxial clamp, and introducing a pressure medium into the space where the triaxial clamp is located to apply confining pressure to the core sample through the triaxial clamp.

[0150] Specifically, the three-axis clamp is used to place the core sample and enclose a relatively independent sample chamber. The space where the three-axis clamp is located as a whole is the confining pressure chamber, as shown in the attached figure. Figure 2As shown, the confining pressure chamber can be filled with pressure medium to apply pressure to the triaxial holder to provide confining pressure to the core sample.

[0151] In this embodiment, referring to the accompanying drawings Figure 2 In the measurement apparatus shown, a core sample is placed in the sample chamber formed by a triaxial gripper. Valve 7 is opened, and a confining pressure pump applies a confining pressure of 2 MPa to the core sample (monitored by pressure sensor 2). Valve 7 is then closed. Valves 2 and 4 are closed, and valves 1, 3, 5, and 6 are opened. A vacuum pump is used to extract the gas from the core sample and the pipeline system until the pressure in the pipeline system drops to -0.101 MPa. During this process, the entire measurement apparatus is maintained at a constant temperature of 26°C.

[0152] S220: After the sample chamber and the pipeline system connected to the sample chamber are evacuated, a working gas is injected into the pipeline system until the pressure is balanced, and the balanced pressure P1 is recorded.

[0153] Specifically, the working gas fills the sample chamber and the pipeline system connected to the sample chamber. After the overall pressure of the sample chamber and the pipeline system is balanced, the equilibrium pressure P1 is detected and recorded using a pressure sensor on the pipeline system. The specific type of working gas can be selected as needed, for example, any one of helium, nitrogen, carbon dioxide, methane, and argon can be selected.

[0154] In this example, valve 1 is closed and valve 2 is opened, allowing helium from the gas source to fill the sample chamber, the standard chamber of the pipeline system, the booster pump, and the pipelines of the pipeline system. Valve 2 is closed, and after the reading of pressure sensor 1 of the pipeline system stops changing, the equilibrium pressure P1 = 0.105 MPa is recorded.

[0155] S230: Disconnect the sample chamber from the pipeline system, pressurize the working gas in the pipeline system until the pressure is balanced, and record the balanced pressure P2.

[0156] Specifically, disconnecting the sample chamber from the pipeline system means that the sample chamber is relatively sealed, and the pressure therein is not affected by external factors. Pressurizing the pipeline system at this time does not change the pressure in the sample chamber. Disconnecting the sample chamber from the pipeline system can be achieved by closing the corresponding valves. After the pipeline system is pressurized to equilibrium, the equilibrium pressure P2 is detected and recorded using a pressure sensor on the pipeline system.

[0157] In this embodiment, the valve 5 is closed, and the helium in the pipeline system and the standard chamber is pressurized by the booster pump, and the equilibrium pressure P2 = 0.159 MPa is recorded by the pressure sensor 1 of the pipeline system.

[0158] S240: Connect the sample chamber to the pipeline system, wait for the pressure in the pipeline system to be balanced, and then record the balanced pressure P3.

[0159] Specifically, the corresponding valve is opened. At this time, since the pressure of the pressurized pipeline system is greater than the pressure of the sample chamber, the working gas in the pipeline system will enter the sample chamber under the action of the pressure difference. After a certain period of time, the pressure of the pipeline system and the sample chamber gradually balance, and then the pressure sensor on the pipeline system is used to detect and record the balanced pressure P3.

[0160] In this embodiment, valve 6 is closed and valve 5 is opened. Since the helium pressure in the standard chamber is greater than the helium pressure in the sample chamber, the pressure P2 begins to decrease. After the reading of the pressure sensor 1 of the pipeline system remains unchanged, the equilibrium pressure P3 = 0.135 MPa is recorded.

[0161] S250: Calculate the total pore volume of the core sample based on the gas state equation in combination with the equilibrium pressure P1, the equilibrium pressure P2, and the equilibrium pressure P3, and calculate the total porosity based on the total pore volume.

[0162] S251: Substitute the equilibrium pressure P1, equilibrium pressure P2, and equilibrium pressure P3 into the gas state equation:

[0163]

[0164] S252: Arrange and simplify the equation to calculate the total pore volume V p :

[0165]

[0166] S253: Calculate the total porosity φ based on the total pore volume t :

[0167]

[0168] In the above formula: z1, z2 and z3 are the compression coefficients of the working gas at pressures P1, P2 and P3 respectively; V S is the volume of the core sample; V1 is the volume of the pipeline system; V2 is the volume of the remaining cavity after the core sample is placed in the sample chamber.

[0169] Specifically, according to the gas state equation PV=nRT, the above relationship (1) can be obtained based on the relationship between the amount of gas substances in the above steps. By sorting and simplifying the relationship (1), the total pore volume V of the core sample can be obtained. p The expression is equation (2). According to the definition of porosity, the total porosity φ of the core sample can be calculated by equation (3): t .

[0170] It should be noted that V1 in the above formula is the total volume of the pipeline system (the capacity of the internal space) in principle. The pipeline system includes the following Figure 1 The standard chamber shown (mainly used to connect the booster pump to boost the gas, and its volume accounts for the main part of the total volume of the pipeline system) and the pipes connecting the various chambers, so if the volume of the standard chamber accounts for a large enough proportion of the total volume of the pipeline system, then the volume of the pipeline part can be ignored under the premise of considering the measurement accuracy, and the volume of the pipeline system can be as shown in the attached figure Figure 1 It is expressed as the volume V1 of the standard chamber.

[0171] In this embodiment, according to the gas state equation, the equilibrium pressures P1, P2, P3 and the helium compressibility coefficients z1, z2, z3 at the corresponding pressures are substituted into the equation, and the total porosity of the core sample under the overburden pressure of 2 MPa is calculated to be 8.23%.

[0172] S260: setting a plurality of different confining pressure values ​​for the confining pressure environment, and sequentially measuring the total porosity of the core sample under the corresponding confining pressure values.

[0173] Specifically, a plurality of different confining pressure values ​​are set in advance as needed, and multiple rounds of measurement are repeated in ascending order of the confining pressure values, with each round of measurement being performed according to steps S210 to S253.

[0174] In this embodiment, valve 7 is opened, and the confining pressure is raised to 6 MPa (monitored by pressure sensor 2) using a confining pressure pump. Valve 6 is opened, and steps S210 to S253 are repeated. The re-obtained equilibrium pressures P1 = 0.105 MPa, P2 = 0.162 MPa, and P3 = 0.137 MPa are calculated, and the total porosity of the core sample under the 6 MPa overburden pressure is calculated to be 6.01%.

[0175] Open valve 7 and use the confining pressure pump to increase the confining pressure to 10 MPa (monitored by pressure sensor 2). Open valve 6 and repeat steps S210 to S253. The re-obtained equilibrium pressures P1 = 0.105 MPa, P2 = 0.165 MPa, and P3 = 0.139 MPa. The total porosity of the core sample under the 10 MPa overburden pressure is calculated to be 5.13%.

[0176] S300: Under the same confining pressure level as that used for determining the total porosity, measure the absorption of the core sample when it absorbs the working fluid to saturation under vacuum conditions, and calculate the inorganic porosity of the core sample based on the absorption amount.

[0177] Specifically, considering the impact of confining pressure on porosity, the corresponding confining pressure level when measuring inorganic porosity should be consistent with the confining pressure level used to measure total porosity. For inorganic porosity measurement, the present invention uses liquid absorption. Because the organic matter corresponding to organic porosity is highly hydrophobic, the corresponding aqueous liquid is essentially completely absorbed into the inorganic pores of the core sample, allowing the absorption amount to reflect the inorganic porosity of the core sample.

[0178] Of course, since the organic matter corresponding to the organic porosity has strong hydrophobicity, the inorganic porosity of the core sample is determined, and the corresponding working liquid naturally needs to be an aqueous liquid. In this embodiment, vacuumed deionized water or a simulated formation water solution pre-configured according to the formation where the core sample is located can be used.

[0179] In this embodiment, several groups of confining pressures similar to those in the total porosity measurement process are set, and the inorganic pore volume of the shale core sample is measured by vacuum imbibition. The inorganic porosity and organic porosity under different overburden pressures are further calculated.

[0180] S310: Under a corresponding confining pressure value, the sample chamber and a pipeline system connected to the sample chamber are placed in a vacuum state.

[0181] Specifically, the determination of inorganic porosity is usually carried out after the determination of total porosity. During the determination of total porosity, the sample chamber where the core sample is located will be ventilated. Therefore, when measuring inorganic porosity, it is necessary to first re-vacuum the sample chamber and the pipeline system connected to the sample chamber.

[0182] S320: The sample chamber is connected to a dropper containing a working liquid through a pipeline system, so that the core sample in the sample chamber absorbs the working liquid until it is saturated.

[0183] Specifically, a dropper is connected to the sample chamber. The working liquid in the dropper enters the sample chamber and is absorbed by the core sample. The absorbed working liquid is then absorbed into the inorganic pores of the core sample. This entire absorption process takes time, so the amount of working liquid in the dropper needs to be continuously monitored. When the reading on the dropper scale stops changing, the core sample is saturated with the working liquid.

[0184] S330: Record the absorption amount using the scale of the dropper, and use the absorption amount as the inorganic pore volume of the core sample.

[0185] Specifically, when the core sample absorbs the working fluid to saturation, it proves that the working fluid has filled the core sample's inorganic pores. The change in the working fluid in the dropper is therefore the core sample's absorption. Of course, depending on accuracy requirements, it's also necessary to consider that some working fluid is stored in the pipeline system. Therefore, the pipeline volume can be measured beforehand by injecting the same amount of working fluid into the pipeline. The actual absorption is equal to the decrease in working fluid in the dropper minus the pipeline volume. Therefore, the absorption is the core sample's inorganic pore volume.

[0186] S340: According to the calculation formula φ m =V m / V S , calculate the inorganic porosity; where, φ m is the inorganic porosity, V m is the inorganic pore volume, V S is the volume of the core sample.

[0187] S350: At confining pressure levels corresponding to the corresponding confining pressure values, the inorganic porosity of the core sample at different confining pressure values ​​is measured respectively, and the corresponding organic porosity is calculated; after each inorganic porosity measurement, the core sample is dried again before the next inorganic porosity measurement is performed.

[0188] Specifically, multiple rounds of total porosity measurements are performed, followed by multiple rounds of inorganic porosity measurements. Each round of inorganic porosity corresponds to the previous round of total porosity measurements, i.e., is at a confining pressure level that matches the confining pressure value during the corresponding total porosity measurement.

[0189] S400: Calculating the organic porosity of the core sample under different confining pressures according to the multiple total porosity and inorganic porosity measurement results.

[0190] S410: Calculate the organic porosity according to the following formula:

[0191] V k =V p -V m ;

[0192] φ k =φ t -φ m ;

[0193] Where V p is the total pore volume, V m is the inorganic pore volume, V k is the volume of organic pores, φ t is the total porosity, φ m is the inorganic porosity, φ k is organic porosity.

[0194] In this example, valves 1, 5, and 7 were opened, valves 3 and 6 were closed, and the confining pressure was first reduced to 2 MPa. Then, the device was evacuated using a vacuum pump. A graduated dropper was filled with deionized water that had been evacuated. Valve 4 was opened, and the dropper reading and time were recorded until the reading stopped changing. The diagram of the change in water absorption of the core sample under 2 MPa overpressure over time is shown in the attached figure. Figure 3 As shown in Figure 2, the inorganic pore volume of the core sample under 2 MPa overburden pressure is 0.67 cm 3 , the organic pore volume is 1.23 cm 3 , and then calculated that the inorganic porosity is 2.92% and the organic porosity is 5.31%.

[0195] The core sample was taken out and dried until the mass no longer changed. The core sample was then placed back into the sample chamber and vacuumed after applying a confining pressure of 6 MPa. A graduated dropper was filled with deionized water that had been vacuumed, and valve 4 was opened. The dropper reading and time were recorded until the reading no longer changed. The diagram of the change in water absorption of the core sample under a 6 MPa confining pressure over time is shown in the attached figure. Figure 4 As shown in Figure 2, the inorganic pore volume of the core sample under 6 MPa overburden pressure is 0.58 cm 3 , the organic pore volume is 0.81 cm 3 , the inorganic porosity under 6MPa covering pressure is calculated to be 2.51%, and the organic porosity is calculated to be 3.50%.

[0196] The core sample was taken out and dried until the mass no longer changed. The core sample was then placed back into the sample chamber, and a confining pressure of 10 MPa was applied and vacuum was applied. The graduated dropper was filled with deionized water that had been vacuumed. Valve 4 was opened and the dropper reading and time were recorded until the reading no longer changed. The diagram of the change in water absorption of the core sample under a 10 MPa overpressure over time is shown in the attached figure. Figure 5 As shown in Figure 2, the inorganic pore volume of the core sample under 10 MPa overburden pressure is 0.51 cm 3 , the organic pore volume is 0.68 cm 3 , the inorganic porosity under 10 MPa overburden pressure was calculated to be 2.20%, and the organic porosity was calculated to be 2.93%.

[0197] S500: Determine the relationship between the inorganic porosity, the organic porosity, and the formation pressure corresponding to the confining pressure value in numerical value by fitting the multiple measurement results.

[0198] Specifically, the relationship diagram after fitting is shown in the attached figure Figure 6As shown in the figure, organic porosity is more sensitive to formation pressure than inorganic porosity, and the change in total porosity under different formation pressures is mainly affected by organic porosity. This can provide a reference and basis for studying the impact of formation pressure on oil and gas reservoirs.

[0199] Example 4

[0200] An embodiment of the present invention provides a core porosity measuring device, which includes a pipeline system and a vacuum pump 2, a gas source 3, a sample chamber 7 and a dropper 1 connected to the pipeline system. The pipeline system is provided with a pressure sensor.

[0201] The pipeline system includes a standard chamber 4 , which is connected to a booster pump 5 ; a sample chamber 7 is arranged in a confined pressure chamber 6 , which is connected to a confined pressure pump 8 and is provided with a pressure sensor.

[0202] Specifically, in this embodiment, the dropper 1 has a capacity of 10 ml and an accuracy of 0.05 ml, and is used to measure the water absorption volume of the core sample; the vacuum pump 2 is used to evacuate the entire device to a vacuum state; the gas source 3 is used to introduce working gas into the device when the corresponding valve is opened; the standard chamber 4 is used to store pressurized gas to pressurize the pipeline system; Figure 2 The black portion on the right side of the middle sample chamber 7 is not rigidly plugged, and is mainly used to seal the sample chamber 7 and isolate the core sample from the pipeline set on this side of the triaxial clamp.

[0203] The measuring device and the measuring method of the present invention are applicable to a variety of core samples, such as shale cores, biomass sandstone cores, coal cores and other core samples with a certain organic matter content.

[0204] Furthermore, the core porosity measuring device of this embodiment applies the following measuring method:

[0205] S100: Prepare a dry core sample and measure its volume.

[0206] S200: placing the core sample in a confining pressure environment and measuring the total porosity of the core sample.

[0207] S210: placing the core sample in a sample chamber surrounded by the triaxial clamp, and introducing a pressure medium into the space where the triaxial clamp is located to apply confining pressure to the core sample through the triaxial clamp.

[0208] S220: After the sample chamber and the pipeline system connected to the sample chamber are evacuated, a working gas is injected into the pipeline system until the pressure is balanced, and the balanced pressure P1 is recorded.

[0209] S230: Disconnect the sample chamber from the pipeline system, pressurize the working gas in the pipeline system until the pressure is balanced, and record the balanced pressure P2.

[0210] S240: Connect the sample chamber to the pipeline system, wait for the pressure in the pipeline system to be balanced, and then record the balanced pressure P3.

[0211] S250: Calculate the total pore volume of the core sample based on the gas state equation in combination with the equilibrium pressure P1, the equilibrium pressure P2, and the equilibrium pressure P3, and calculate the total porosity based on the total pore volume.

[0212] S251: Substitute the equilibrium pressure P1, equilibrium pressure P2, and equilibrium pressure P3 into the gas state equation:

[0213]

[0214] S252: Arrange and simplify the equation to calculate the total pore volume V p :

[0215]

[0216] S253: Calculate the total porosity φ based on the total pore volume t :

[0217]

[0218] In the above formula: z1, z2 and z3 are the compression coefficients of the working gas at pressures P1, P2 and P3 respectively; V S is the volume of the core sample; V1 is the volume of the pipeline system; V2 is the volume of the remaining cavity after the core sample is placed in the sample chamber.

[0219] S260: setting a plurality of different confining pressure values ​​for the confining pressure environment, and sequentially measuring the total porosity of the core sample under the corresponding confining pressure values.

[0220] S300: Under the same confining pressure level as that used for determining the total porosity, measure the absorption of the core sample when it absorbs the working fluid to saturation under vacuum conditions, and calculate the inorganic porosity of the core sample based on the absorption amount.

[0221] S310: Under a corresponding confining pressure value, the sample chamber and a pipeline system connected to the sample chamber are placed in a vacuum state.

[0222] S320: The sample chamber is connected to a dropper containing a working liquid through a pipeline system, so that the core sample in the sample chamber absorbs the working liquid until it is saturated.

[0223] S330: Record the absorption amount using the scale of the dropper, and use the absorption amount as the inorganic pore volume of the core sample.

[0224] S340: According to the calculation formula φ m =Vm / V S , calculate the inorganic porosity; where, φ m is the inorganic porosity, V m is the inorganic pore volume, V S is the volume of the core sample.

[0225] S350: At confining pressure levels corresponding to the corresponding confining pressure values, the inorganic porosity of the core sample at different confining pressure values ​​is measured respectively, and the corresponding organic porosity is calculated; after each inorganic porosity measurement, the core sample is dried again before the next inorganic porosity measurement is performed.

[0226] S400: Calculating the organic porosity of the core sample under different confining pressures according to the multiple total porosity and inorganic porosity measurement results.

[0227] S410: Calculate the organic porosity according to the following formula:

[0228] V k =V p -V m ;

[0229] φ k =φ t -φ m ;

[0230] Where V p is the total pore volume, V m is the inorganic pore volume, V k is the volume of organic pores, φ t is the total porosity, φ m is the inorganic porosity, φ k is organic porosity.

[0231] S500: Determine the relationship between the inorganic porosity, the organic porosity, and the formation pressure corresponding to the confining pressure value in numerical value by fitting the multiple measurement results.

[0232] Example 5

[0233] An embodiment of the present invention provides a core porosity measurement system, which is characterized by comprising the measurement device of the above embodiment and a constant temperature device, wherein the constant temperature device is used to provide a constant temperature environment for the measurement device.

[0234] Specifically, the specific temperature of the constant temperature environment can be designed according to the temperature of the formation where the core sample is located and the needs of the solution. In the embodiment of the present invention, the temperature value of the constant temperature environment is 26°C.

[0235] In the description of the present invention, it should be understood that the terms "upper", "lower", "bottom", "top", "front", "back", "inside", "outside", "left", "right", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention.

[0236] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of the invention. It should be understood that many modifications may be made to the illustrative embodiments, and that other arrangements may be devised, without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in ways other than those described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be employed in conjunction with other described embodiments.

Claims

1. A method for measuring core porosity, characterized in that: The following steps are involved: Prepare dry core samples and measure their volumes; placing the core sample in a confining pressure environment, and measuring the total porosity of the core sample; At the same confining pressure level as that for measuring the total porosity, measuring the absorption amount of the core sample when absorbing the working fluid to saturation under vacuum conditions, and calculating and measuring the inorganic porosity of the core sample based on the absorption amount; The organic porosity of the core sample is calculated according to the total porosity and the inorganic porosity.

2. The method for measuring core porosity according to claim 1, wherein: The following steps are also included: When measuring the total porosity, a plurality of different confining pressure values ​​are set for the confining pressure environment, and the total porosity of the core sample under the corresponding confining pressure values ​​is measured in sequence; When measuring the inorganic porosity, at a confining pressure level corresponding to the corresponding confining pressure value, the inorganic porosity of the core sample at different confining pressure values ​​is measured respectively, and the corresponding organic porosity is calculated; A relationship between the inorganic porosity, the organic porosity, and a formation pressure numerically corresponding to the confining pressure value is determined.

3. The core porosity measurement method according to claim 2, characterized in that: After each measurement of the inorganic porosity, the core sample is dried again before the next measurement of the inorganic porosity is performed.

4. The method for measuring core porosity according to claim 1, wherein: Placing the core sample in a confining pressure environment and measuring the total porosity of the core sample comprises the following steps: placing the core sample in a sample chamber surrounded by a triaxial clamp, and introducing a pressure medium into the space where the triaxial clamp is located to apply confining pressure to the core sample through the triaxial clamp; After the sample chamber and the pipeline system connected to the sample chamber are evacuated, a working gas is injected into the pipeline system until the pressure is balanced, and the balanced pressure P1 is recorded; Disconnect the sample chamber from the pipeline system, pressurize the working gas in the pipeline system until the pressure is balanced, and record the balanced pressure P2; Connect the sample chamber to the pipeline system, wait for the pressure in the pipeline system to be balanced, and then record the balanced pressure P3; The total pore volume of the core sample is calculated based on the gas state equation in combination with the equilibrium pressure P1, the equilibrium pressure P2, and the equilibrium pressure P3, and the total porosity is calculated based on the total pore volume.

5. The method for measuring core porosity according to claim 4, wherein: Calculating the total porosity comprises the following steps: Substitute the equilibrium pressure P1, equilibrium pressure P2, and equilibrium pressure P3 into the gas state equation: Arrange and simplify the equation to calculate the total pore volume V p : The total porosity φ is calculated based on the total pore volume t : In the above formula: z1, z2 and z3 are the compression coefficients of the working gas at pressures P1, P2 and P3 respectively; V S is the volume of the core sample; V1 is the volume of the pipeline system; and V2 is the volume of the remaining cavity after the core sample is placed in the sample chamber.

6. The method for measuring core porosity according to any one of claims 1 to 5, characterized in that: Calculating and determining the inorganic porosity of the core sample according to the absorption amount comprises the following steps: Under the corresponding confining pressure value, the sample chamber and the pipeline system connected to the sample chamber are placed in a vacuum state; connecting the sample chamber to a dropper containing a working liquid through the pipeline system, so that the core sample in the sample chamber absorbs the working liquid until it is saturated; Recording the absorption amount using the scale of the dropper, and using the value of the absorption amount as the inorganic pore volume of the core sample; According to the calculation formula φ m =V m / V S , calculate the inorganic porosity; where, φ m is the inorganic porosity, V m is the inorganic pore volume, V S is the volume of the core sample.

7. The method for measuring core porosity according to claim 6, wherein: The organic porosity is calculated according to the following formula: V k =V p -V m ; f k =φ t -f m ; Where V p is the total pore volume, V m is the inorganic pore volume, V k is the volume of organic pores, φ t is the total porosity, φ m is the inorganic porosity, φ k is organic porosity.

8. The method for measuring core porosity according to claim 4, wherein: The working gas is any one of helium, nitrogen, carbon dioxide, methane and argon.

9. The method for measuring core porosity according to claim 1, wherein: The working liquid is vacuumed deionized water or a simulated formation water solution prepared according to the formation where the core sample is located.

10. A core porosity measurement device, using the measurement method according to any one of claims 1 to 9, characterized in that: It includes a pipeline system and a vacuum pump, a gas source, a sample chamber and a dropper connected to the pipeline system, wherein the pipeline system is provided with a pressure sensor; The pipeline system includes a standard chamber connected to a booster pump; the sample chamber is arranged in a confined pressure chamber, which is connected to a confined pressure pump and is provided with a pressure sensor.

11. A core porosity measurement system, characterized in that: It comprises the measuring device as claimed in claim 10 and a constant temperature device, wherein the constant temperature device is used to provide a constant temperature environment for the measuring device.

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