Rock porosity measurement method and device

Abstract

The present invention provides a rock porosity measurement method and device, relating to the field of geophysical technology. The method comprises: controlling a vacuum pump to evacuate a core cup until the vacuum level of the core cup is less than or equal to a first preset threshold; controlling a predetermined gas storage container to fill a reference chamber with a predetermined gas until the pressure in the reference chamber equals a preset initial absolute pressure; controlling a connecting valve between the core cup and the reference chamber to open, and after determining that the change in the reference chamber pressure within a preset time period is less than a second preset threshold, determining the equilibrium pressure after the core cup and the reference chamber are connected; obtaining the core cup volume, the reference chamber volume, and the total volume of the rock sample; determining the rock sample particle volume based on the core cup volume, the reference chamber volume, the preset initial absolute pressure, and the equilibrium pressure after the core cup and the reference chamber are connected; and determining the rock porosity based on the rock sample particle volume and the total volume of the rock sample. The present invention can improve the accuracy of rock porosity measurement.

Description

Technical Field

[0001] The present invention relates to the field of geophysical technology, and in particular to a rock porosity measurement method and device. Background Art

[0002] This section is intended to provide a background or context to the embodiments of the invention that are recited in the claims. No statement herein is admitted to be prior art by virtue of its inclusion in this section.

[0003] In recent years, with the rapid depletion of conventional oil and gas resources, the exploration and development of new oil and gas resources has become increasingly difficult. Global oil and gas exploration and development is shifting from traditional conventional exploration and development to a coordinated exploration and development of both conventional and unconventional resources. Unconventional oil and gas resources, such as shale oil, are abundant and widely distributed, presenting enormous exploration and development potential. Accurately calculating reservoir rock porosity is crucial for accurate reservoir evaluation and reconstruction, as well as for increasing oil and gas production. Existing laboratory porosimeter instruments measure gas porosity with low accuracy, making it difficult to accurately calibrate rock porosity, thus impacting the calculation of reservoir oil and gas reserves. Summary of the Invention

[0004] In an embodiment of the present invention, a rock porosity measurement method is proposed to improve the accuracy of rock porosity measurement and provide reliable data support for reservoir evaluation and oil and gas reserve calculation, including:

[0005] Controlling the vacuum pump to evacuate the core cup until the vacuum degree of the core cup is less than or equal to a first preset threshold;

[0006] Controlling the predetermined gas storage container to fill the reference chamber with the predetermined gas until the pressure in the reference chamber is equal to the preset initial absolute pressure;

[0007] Controlling the communication valve between the core cup and the reference chamber to open, and after determining that the change in the pressure of the reference chamber within the preset time period is less than a second preset threshold, determining the equilibrium pressure after the core cup and the reference chamber are connected;

[0008] Obtain the core cup volume, reference chamber volume, and total rock sample volume;

[0009] Determine the volume of the rock sample particles based on the core cup volume, the reference chamber volume, the preset initial absolute pressure, and the equilibrium pressure after the core cup and the reference chamber are connected;

[0010] The rock porosity is determined based on the particle volume and total volume of the rock sample.

[0011] In an embodiment of the present invention, a rock porosity measurement device is proposed to improve the accuracy of rock porosity measurement and provide reliable data support for reservoir evaluation and oil and gas reserve calculation, including:

[0012] A first control module is used to control the vacuum pump to evacuate the core cup until the vacuum degree of the core cup is less than or equal to a first preset threshold;

[0013] a second control module, configured to control the predetermined gas storage container to fill the reference chamber with the predetermined gas until the pressure in the reference chamber is equal to a preset initial absolute pressure;

[0014] a third control module, configured to control the opening of the communication valve between the core cup and the reference chamber, and after determining that the change in the pressure of the reference chamber within the preset time period is less than a second preset threshold, determine the equilibrium pressure after the core cup and the reference chamber are connected;

[0015] Data acquisition module, used to obtain the core cup volume, reference chamber volume, and total rock sample volume;

[0016] a volume determination module for determining the volume of rock sample particles based on the core cup volume, the reference chamber volume, a preset initial absolute pressure, and the equilibrium pressure after the core cup and the reference chamber are connected;

[0017] The porosity determination module is used to determine the rock porosity based on the particle volume and the total volume of the rock sample.

[0018] An embodiment of the present invention provides a computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, a rock porosity measurement method is implemented.

[0019] An embodiment of the present invention provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, a rock porosity measurement method is implemented.

[0020] An embodiment of the present invention provides a computer program product, which includes a computer program. When the computer program is executed by a processor, a rock porosity measurement method is implemented.

[0021] The rock porosity measurement method and device proposed in the embodiment of the present invention can solve the problem in the prior art that the measurement accuracy of gas porosity is low and cannot be used to accurately calibrate rock porosity, thereby affecting the calculation of oil and gas reserves in the reservoir; the embodiment of the present invention controls the vacuum pump to evacuate the core cup until the vacuum degree of the core cup is less than or equal to a first preset threshold; controls the predetermined gas storage container to fill the reference chamber with a predetermined gas until the pressure in the reference chamber is equal to a preset initial absolute pressure; controls the connecting valve between the core cup and the reference chamber to open, and after determining that the change in the reference chamber pressure within a preset time period is less than a second preset threshold, determines the equilibrium pressure after the core cup and the reference chamber are connected; obtains the core cup volume, the reference chamber volume, and the total volume of the rock sample; determines the rock sample particle volume based on the core cup volume, the reference chamber volume, the preset initial absolute pressure, and the equilibrium pressure after the core cup and the reference chamber are connected; and determines the rock porosity based on the rock sample particle volume and the total volume of the rock sample. The embodiments of the present invention can improve the accuracy of rock porosity measurement, provide reliable data support for reservoir evaluation and calculation of oil and gas reserves, and be conducive to increasing oil and gas production. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0023] Figure 1 1 is a schematic flow chart of a rock porosity measurement method according to an embodiment of the present invention;

[0024] Figure 2 This is an example diagram of the equipment composition of the rock porosity measurement method according to an embodiment of the present invention;

[0025] Figure 3 This is a specific example diagram of the rock porosity measurement method in an embodiment of the present invention;

[0026] Figure 4 This is a specific example diagram of the rock porosity measurement method in an embodiment of the present invention;

[0027] Figure 5 This is a specific example diagram of the rock porosity measurement method in an embodiment of the present invention;

[0028] Figure 6 This is a specific example diagram of the rock porosity measurement method in an embodiment of the present invention;

[0029] Figure 7 This is a specific example diagram of the rock porosity measurement method in an embodiment of the present invention;

[0030] Figure 8 This is a specific example diagram of the rock porosity measurement method in an embodiment of the present invention;

[0031] Figure 9 is a schematic diagram of a rock porosity measuring device according to an embodiment of the present invention;

[0032] Figure 10 Schematic diagram of a computer device according to an embodiment of the present invention.

[0033] Reference numerals:

[0034] 1-core cup, 2-tee connector, 3-connecting valve, 4-adjustable volume reference chamber, 5-temperature sensor, 6-absolute pressure sensor, 7-gas supply valve, 8-filter, 9-pressure reducing valve, 10-helium cylinder, 11-controller, 12-vacuum valve, 13-vacuum pump, 14-air release valve, 15-walk-in constant temperature box. DETAILED DESCRIPTION

[0035] To make the purpose, technical solutions and advantages of the embodiments of the present invention more clear, the embodiments of the present invention are further described in detail below with reference to the accompanying drawings. Here, the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0036] The term "and / or" herein simply describes an association relationship, indicating that three relationships can exist. For example, A and / or B can represent the existence of A alone, the simultaneous existence of A and B, and the existence of B alone. In addition, the term "at least one" herein refers to any combination of at least two of any one or more of a plurality of items. For example, "at least one of A, B, and C" can represent any one or more elements selected from the set consisting of A, B, and C.

[0037] In the description of this specification, the terms "include", "including", "have", "contain", etc. are all open terms, which mean including but not limited to. The descriptions with reference to the terms "one embodiment", "a specific embodiment", "some embodiments", "for example", etc. mean that the specific features, structures or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. The order of steps involved in each embodiment is used to schematically illustrate the implementation of the present application, and the order of steps therein is not limited and can be appropriately adjusted as needed.

[0038] The principles and spirit of the present invention are explained in detail below with reference to several representative embodiments of the present invention.

[0039] Figure 1 FIG. 1 is a flow chart of a rock porosity measurement method according to an embodiment of the present invention. Figure 1 As shown, the method includes:

[0040] Step 101: Control the vacuum pump to evacuate the core cup until the vacuum level of the core cup is less than or equal to a first preset threshold;

[0041] Step 102, controlling the predetermined gas storage container to fill the reference chamber with the predetermined gas until the pressure in the reference chamber is equal to the preset initial absolute pressure;

[0042] Step 103: Controlling the communication valve between the core cup and the reference chamber to open, and after determining that the change in the pressure of the reference chamber within the preset time period is less than a second preset threshold, determining the equilibrium pressure after the core cup and the reference chamber are connected;

[0043] Step 104, obtaining the core cup volume, reference chamber volume, and total rock sample volume;

[0044] Step 105, determining the volume of the rock sample particles based on the core cup volume, the reference chamber volume, the preset initial absolute pressure, and the equilibrium pressure after the core cup and the reference chamber are connected;

[0045] Step 106: Determine the rock porosity based on the rock sample particle volume and the total volume of the rock sample.

[0046] Depend on Figure 1 As can be seen from the illustrated process, the embodiment of the present invention controls the vacuum pump to evacuate the core cup until the vacuum degree of the core cup is less than or equal to a first preset threshold; controls the predetermined gas storage container to fill the reference chamber with a predetermined gas until the pressure in the reference chamber is equal to a preset initial absolute pressure; controls the connecting valve between the core cup and the reference chamber to open, and after determining that the change in the reference chamber pressure within a preset time period is less than a second preset threshold, determines the equilibrium pressure after the core cup and the reference chamber are connected; obtains the core cup volume, the reference chamber volume, and the total volume of the rock sample; determines the rock sample particle volume based on the core cup volume, the reference chamber volume, the preset initial absolute pressure, and the equilibrium pressure after the core cup and the reference chamber are connected; and determines the rock porosity based on the rock sample particle volume and the total volume of the rock sample. The embodiment of the present invention can improve the accuracy of rock porosity measurement, provide reliable data support for reservoir evaluation and oil and gas reserve calculation, and is conducive to increasing oil and gas production.

[0047] In order to explain the above rock porosity measurement method more clearly, each step is described in detail below.

[0048] In one embodiment of the present invention, a predetermined gas storage container is controlled to fill a reference chamber with a predetermined gas, wherein the predetermined gas is any one of helium, neon, argon, krypton, xenon, radon, and nitrogen. It should be noted that the predetermined gas must be physically and chemically stable, and the molecules of the predetermined gas must be sufficiently small.

[0049] Exemplarily, the predetermined gas of the present invention is helium, and the predetermined gas storage container is a helium cylinder.

[0050] Figure 2 2 is an example diagram of the equipment composition of the rock porosity measurement method in an embodiment of the present invention.

[0051] refer to Figure 2 In this example, the rock porosity measurement equipment includes: a core cup 1, a three-way connector 2, a connecting valve 3, an adjustable volume reference chamber 4, a temperature sensor 5, an absolute pressure sensor 6, an air supply valve 7, a filter 8, a pressure reducing valve 9, a helium cylinder 10, a controller 11, a vacuum valve 12, a vacuum pump 13, a vent valve 14, and a walk-in thermostatic chamber 15; wherein:

[0052] The core cup 1 consists of a pressure-bearing cylinder, a sealing cap, a temperature sensor 5, and a stainless steel high-pressure pipeline. The volume is kept constant during the pressurization and vacuuming process. Core cups 1 of different diameters can be selected according to the size of the rock sample.

[0053] The tee connector 2 includes a stainless steel connector, a pressure cap, a pressure ring and a stainless steel pipeline. The stainless steel pipeline is used to connect the various components of the tee connector 2 to avoid the influence of the pipeline volume change on the measurement results.

[0054] The connecting valve 3 is composed of a valve body, a valve needle, a sealing ring, a buffer chamber, and a limit handle, so that the connecting valve 3 has a fixed volume space in each open and closed state to avoid the influence of volume changes on the measurement results;

[0055] The adjustable volume reference chamber 4 includes: a pressure-bearing cylinder, a sealing plug, a sealing ring, a mechanical piston and a temperature sensor. The mechanical piston is used to adjust the volume of the reference chamber cavity to provide a stable and controllable initial pressure for rock porosity measurement;

[0056] The temperature sensor 5 is composed of a thermal resistor PT1000, a shielded wire, a sealed cavity and a connector, and can monitor the temperature in the reference chamber 4 and the core cup 1 in real time;

[0057] The absolute pressure sensor 6 is composed of a sensor, a shielded cable, a stainless steel pipeline, and a pressure cap. For example, a 4-20 mA current sensor with an accuracy of 0.01% can be used. The absolute pressure sensor 6 is used to measure the pressure of the reference chamber 4 and the equilibrium pressure after the reference chamber 4 is connected to the core cup 1.

[0058] The gas supply valve 7 is a high-pressure stop valve installed in the gas supply pipeline, which plays the role of opening and closing the gas supply process;

[0059] The filter 8 is composed of a pressure-bearing shell, a moisture-absorbing material, a filter screen, and a plug, which can ensure that the predetermined gas (helium) does not contain water vapor;

[0060] The pressure reducing valve 9 is a finished product;

[0061] The predetermined gas of the present invention is helium, and the predetermined gas storage container is a helium cylinder 10, which is a finished product; the gas supply valve 7, the filter 8, the pressure reducing valve 9 and the helium cylinder 10 constitute a gas supply system;

[0062] The controller 11 includes an acquisition control box, a computer, and measurement and control software. It controls the entire rock porosity measurement and constantly monitors and controls the pressure and temperature changes during the measurement process.

[0063] The vacuum valve 12 is a finished product;

[0064] The vacuum pump 13 is composed of a pump body, a vacuum pressure sensor and a control circuit, and provides a near-vacuum environment for the core cup 1;

[0065] The air release valve 14 is composed of a valve body and a muffler. When the measurement is completed, the pressure in the core cup 1 is released to facilitate the removal of the rock sample.

[0066] The walk-in constant temperature box 15 includes a cooling and heating system, a circulation control system, a harmful gas alarm system, a temperature and humidity measurement system, a lighting and power supply system. The above-mentioned porosity measurement device, personnel, operating table, and standard blocks are all placed in the walk-in constant temperature box 15 to ensure that the temperature change in the reference chamber 4 and the core cup 1 is less than 0.1°C at any time, for example.

[0067] In one embodiment of the present invention, a temperature variation of a walk-in incubator is controlled so as not to exceed a third preset threshold; wherein the core cup and the reference chamber are placed in the walk-in incubator. Specifically, when temperature-controlling the walk-in incubator, it is necessary to control the temperature variation of the walk-in incubator to, for example, not exceed 0.1°C, for example, to establish a stable, controllable constant temperature environment, and to control the temperature variation within a range of, for example, ±0.1°C.

[0068] In one embodiment of the present invention, with respect to step 101, controlling the vacuum pump to evacuate the core cup until the vacuum degree of the core cup is less than or equal to a first preset threshold value includes:

[0069] Control the vacuum valve to open; control the vacuum pump to evacuate the core cup until the vacuum degree of the core cup is less than or equal to a first preset threshold; wherein the sealing method of the core cup is side sealing.

[0070] Figure 32 is a specific example diagram of the rock porosity measurement method in an embodiment of the present invention.

[0071] In specific implementation, the vacuum pump is controlled to evacuate the core cup until the vacuum degree of the core cup is less than or equal to 1 mbar. In the embodiment of the present invention, reference is made to Figure 3 In part (a), since the sealing method of the old core cup adopts end face sealing, the old core cup structure will produce an absolute error of 0.2-1.5%. Therefore, the sealing method of the core cup is improved, referring to Figure 3 In part (b), the new core cup uses a side seal, which eliminates the volume changes associated with end-face sealing and ensures more stable and accurate measurements. This side seal eliminates and minimizes the effects of void volume changes, ensuring the core cup's cavity volume remains constant during vacuum and pressurization.

[0072] In one embodiment of the present invention, before controlling the predetermined gas storage container to fill the reference chamber with the predetermined gas until the pressure in the reference chamber equals the preset initial absolute pressure, the method further includes:

[0073] The preset initial absolute pressure of the reference chamber is set according to the permeability of the gas in the rock sample.

[0074] In one embodiment of the present invention, with respect to step 103, controlling the communication valve between the core cup and the reference chamber to open, and after determining that the change in the pressure of the reference chamber within the preset time period is less than a second preset threshold, determining the equilibrium pressure after the core cup and the reference chamber are connected includes:

[0075] The connecting valve between the core cup and the reference chamber is controlled to open. After determining that the change in the reference chamber pressure at the first moment and the reference chamber pressure at the second moment is less than a second preset threshold, the reference chamber pressure at the first moment is determined as the equilibrium pressure after the core cup and the reference chamber are connected; wherein the interval between the first moment and the second moment is the preset time length.

[0076] In a specific implementation, the connecting valve between the core cup and the reference chamber is controlled to open. After determining that the difference between the reference chamber pressure at the first moment and the reference chamber pressure at the second moment is less than a second preset threshold, for example, the second preset threshold is set to 0.015 kPa. The reference chamber pressure at the first moment is determined to be the equilibrium pressure after the core cup and the reference chamber are connected. The second moment may be 15 minutes before the first moment. Specifically, the injection of helium into the reference chamber and the evacuation of the core chamber are performed separately to prevent the mixing of helium and air during the equilibrium process after the connecting valve between the core cup and the reference chamber is opened.

[0077] In one embodiment of the present invention, before obtaining the volume of the reference chamber, the method further includes:

[0078] The volume of the reference chamber is adjusted to ensure that the ratio of the equilibrium pressure after the core cup is connected to the reference chamber to the preset initial absolute pressure of the reference chamber is within a preset ratio range; wherein the reference chamber is an adjustable volume reference chamber.

[0079] Obtain the total volume of the rock sample, including:

[0080] The total volume of rock samples was obtained using the Archimedean buoyancy method.

[0081] For example, the porosity of the rock sample is first estimated, and the volume of the reference chamber is adjusted according to the porosity of the rock sample to ensure that the equilibrium pressure after the core cup is connected to the reference chamber is 0.3-0.5 times the preset initial absolute pressure of the reference chamber; for regular rock samples, their total volume can be directly calculated, and for irregular rock samples, the total volume of the rock sample can be obtained using the Archimedean buoyancy method.

[0082] Figure 4 2 is a specific example diagram of the rock porosity measurement method in an embodiment of the present invention.

[0083] The existing technology uses a fixed volume reference chamber, reference Figure 4 In part (a), the fixed volume reference chamber cannot adjust the reference chamber volume, which may cause the core cup and the fixed volume reference chamber to be connected for a long time to balance the pressure, and also cause waste of helium; In the embodiment of the present invention, an adjustable volume reference chamber is creatively adopted. Figure 4 In part (b), the volume of the reference chamber can be adjusted according to the estimated porosity of the rock sample to ensure that the ratio of the equilibrium pressure after the core cup is connected to the reference chamber to the preset initial absolute pressure of the reference chamber is within the preset ratio range. At the same time, the waste of helium can be avoided and helium resources can be saved.

[0084] Figure 5 2 is a specific example diagram of the rock porosity measurement method in an embodiment of the present invention.

[0085] In one embodiment of the present invention, the monitoring curves of the pressure and temperature of the reference chamber and the core cup are referenced Figure 5 , real-time monitoring of the pressure drop process and temperature changes of the reference chamber and the core cup after they are connected, to improve the measurement accuracy of rock porosity.

[0086] In the prior art, the original Clapeyron formula can be used to calculate the volume of rock sample particles. The original Clapeyron formula is as follows:

[0087]

[0088] Wherein, P1 represents the preset initial absolute pressure of the reference chamber; P2 represents the equilibrium pressure after the core cup and the reference chamber are connected; P arepresents the initial absolute atmospheric pressure of the core cup; Z1 represents the gas deviation factor of helium at P1 and T1; Z2 represents the gas deviation factor of the mixed gas at P2 and T2; Z a Indicates that air is at P a and gas deviation factor at T1; T 1r Indicates the absolute temperature of the reference chamber at P1; T 1c represents the absolute temperature of the core cup at P1; T 2r represents the absolute temperature of the reference chamber after P2 stabilizes; T 2c represents the absolute temperature of the core cup after P2 stabilizes; V g Represents the volume of rock sample particles; V c Indicates the core cup volume; V r Indicates the volume of the reference chamber; V v Represents the volume change from closed to open in the connecting valve. The original Clapeyron formula makes too many assumptions. When the porosity of the rock sample being measured is less than 6%, the reference chamber pressure needs to be increased. If the reference chamber pressure exceeds 2 MPa, the measuring medium (helium) will not meet ideal gas conditions, resulting in a 6% relative error. In addition, when connecting the reference chamber and the core cup, a longer equilibration time is required to reach equilibrium pressure. If the temperature changes by 0.5°C during this period, an absolute error of 0.2-1% of porosity will be generated, reducing the accuracy of rock porosity measurements. Therefore, it is necessary to control the temperature change of the walk-in constant temperature chamber to, for example, no more than 0.1°C.

[0089] In one embodiment of the present invention, when evacuating the core cup, a vacuum state is ensured, the influence of the gas deviation factor is eliminated, and the pressure changes at different stages in the porosity measurement process are monitored in real time.

[0090] In one embodiment of the present invention, the core cup volume, the reference chamber volume, and the total volume of the rock sample are obtained; and the rock sample particle volume is determined based on the core cup volume, the reference chamber volume, the preset initial absolute pressure, and the equilibrium pressure after the core cup and the reference chamber are connected.

[0091] In specific implementation, the particle volume of the rock sample is determined according to the following formula:

[0092]

[0093] Among them, V g Represents the volume of rock sample particles; V c Indicates the core cup volume; V r Indicates the volume of the reference chamber; V v represents the volume change of the connecting valve from closed to open, and is set to 0 in the embodiment of the present invention; P1 represents the preset initial absolute pressure of the reference chamber; and P2 represents the equilibrium pressure after the core cup and the reference chamber are connected.

[0094] In one embodiment of the present invention, the rock porosity is determined based on the particle volume of the rock sample and the total volume of the rock sample.

[0095] In specific implementation, the rock porosity is determined according to the following formula:

[0096]

[0097] in, Indicates rock porosity; V 总 Represents the total volume of the rock sample; V g Represents the volume of rock sample particles.

[0098] Figure 6 2 is a specific example diagram of the rock porosity measurement method in an embodiment of the present invention.

[0099] In one embodiment of the present invention, referring to Figure 6 , rock porosity measurement methods include:

[0100] Step 601: A constant temperature and humidity measurement environment is established in a walk-in constant temperature chamber. A constant environment must be maintained during system calibration and measurement. In particular, the temperature variation must be controlled within, for example, ±0.1°C to eliminate the influence of temperature, which is the gas deviation factor in the original Clapeyron formula, i.e., T 1r : absolute temperature of the reference chamber at P1; T 1c : absolute temperature of the core cup at P1; T 2r : absolute temperature of the reference chamber after P2 stabilizes; T 2c : absolute temperature of the core cup after P2 stabilization;

[0101] Step 602: Determine the total volume V of the rock sample 总 ;

[0102] Step 603: Estimate the pore volume of the rock sample. Based on the estimated pore volume of the rock sample, adjust the mechanical piston of the reference chamber so that the reference chamber volume is equal to 2-3 times the pore volume of the rock sample. Determine the reference chamber volume and the preset initial absolute pressure P1 of the reference chamber monitored by the absolute pressure sensor. The reference chamber volume should not be too large, and a sufficient pressure drop is required when connected to the core cup.

[0103] Step 604: Select a corresponding core cup according to the volume of the rock sample. There are usually four core cups with different diameters to choose from. The standard core cup has a known volume, namely, the core cup volume V c ;

[0104] Step 605: Calibrate the measurement system using a standard block and save the calibrated scale parameters. The entire measurement system must be recalibrated before measuring each batch of rock samples. If any joint is twisted during the measurement process, the entire system must be recalibrated. The standard block is a non-porous standard object.

[0105] Step 606: Based on the total volume of the rock sample, select a suitable standard block and place it together with the core cup to minimize the blank volume in the core cup. Close the connecting valve and the vent valve, and open the vacuum valve. Set the vacuum pressure value based on the gas permeability of the rock sample, and start the vacuum pump to evacuate the core cup. When the vacuum reaches 1 mbar, close the vacuum valve and the vacuum pump to evacuate the core cup to eliminate the influence of the initial absolute atmospheric pressure of the core cup and the gas deviation factor; that is, P a : Initial absolute atmospheric pressure of the core cup; Z1: Gas deviation factor of helium at P1 and T1; Z2: Gas deviation factor of mixed gas at P2 and T2; Z a :Air in P a and the gas deviation factor at T1;

[0106] Step 607: Set a preset initial absolute pressure for the reference chamber based on the permeability of the gas in the rock sample. Low-permeability rock samples require a higher preset initial absolute pressure for the reference chamber, but the maximum preset initial absolute pressure should not exceed, for example, 1.5 MPa. Helium in the reference chamber is supplied from a helium cylinder and enters the reference chamber through a pressure reducing valve and a filter. The pressure in the reference chamber is controlled by a gas supply valve. When the pressure in the reference chamber reaches the preset initial absolute pressure, the gas supply valve is closed. The measurement and control system uses a temperature sensor and an absolute pressure sensor to determine whether the temperature and pressure of the reference chamber have stabilized. Once these conditions are stable, the next step is performed.

[0107] Step 608: Open the connecting valve and monitor the pressure change of the reference chamber in real time; the volume change V of the connecting valve from closed to open is v When the pressure in the reference chamber reaches 0, the high-pressure helium in the reference chamber is quickly filled into the core cup, and the pressure change in the reference chamber is monitored in real time by the absolute pressure sensor.

[0108] Step 609: After the reference chamber pressure stabilizes, calculate the rock porosity; draw a pressure change curve in real time; when the controller continuously detects that the change between the "current reference chamber pressure and the pressure point 15 minutes ago" at 10 points is less than 0.015 kPa, determine the equilibrium pressure P2 after the core cup and the reference chamber are connected; determine the rock sample particle volume based on the core cup volume, the reference chamber volume, the preset initial absolute pressure, and the equilibrium pressure after the core cup and the reference chamber are connected; and after determining the rock porosity based on the rock sample particle volume and the total volume of the rock sample, the measurement ends;

[0109] Step 610: close the connecting valve to retain the helium in the reference chamber in preparation for testing the next rock sample; open the vent valve, open the core cup, and take out the rock sample and the standard block.

[0110] Figure 7 2 is a specific example diagram of the rock porosity measurement method in an embodiment of the present invention.

[0111] Comparison of the rock porosity measurement method in the embodiment of the present invention with the rock porosity measured by industry standards Figure 7 The horizontal axis of the scatter plot represents the rock porosity measured using industry standards, while the vertical axis represents the rock porosity measured using an embodiment of the present invention. This demonstrates that the rock porosity measurement method of the present invention is more accurate. The repeatability error of the present invention is less than ±0.002%, which is smaller than the error of rock porosity measured using industry standards.

[0112] Figure 8 2 is a specific example diagram of the rock porosity measurement method in an embodiment of the present invention.

[0113] Comparison of the calibration results of rock gas porosity measured by the new method in the embodiment of the present invention and the industry standard on the well logging curve Figure 8 The figure shows the effective porosity from well logging, the rock porosity measured using the new method in this embodiment of the present invention, and the gas porosity measured using industry standards. This shows that the rock porosity measured using the new method in this embodiment of the present invention is closer to the effective porosity from well logging. This embodiment of the present invention effectively addresses the issue of existing gas porosity measurement methods being affected by various factors, such as ambient temperature, atmospheric pressure, and air in the rock sample. It improves the accuracy of rock porosity measurements and provides more reliable data support for reservoir evaluation and reconstruction.

[0114] The present invention is based on an improved Clapeyron formula. The core cup is evacuated under constant temperature conditions, and then the connecting valve between the reference chamber and the core cup is opened to allow helium to enter the core cup and measure the gas porosity of the rock. The present invention not only avoids the influence of mixed gases in the core cup on the measured value, but also facilitates the entry of helium into the small pores of the rock sample, making the test result closer to the effective porosity of the rock. The present invention also uses a walk-in constant temperature chamber and a temperature sensor with an accuracy of ±0.01°C to ensure that the temperature variation range during the measurement process is controlled within ±0.1°C, eliminating the influence of temperature variation on the measurement results. In addition, the present invention uses an absolute pressure sensor. Compared with relative pressure sensors, the present invention can ensure that the core cup reaches a true vacuum state and the initial absolute atmospheric pressure is zero when helium is injected into the reference chamber and the core cup is evacuated. The use of a constant volume connecting valve and a new core cup structure avoids the volume change of the core cup caused by end face sealing, making the measurement result more accurate. The measurement process of the present invention is controllable and the results are intuitive, avoiding the embarrassment of existing porosity meters that only provide numerical values ​​but cannot see the process.

[0115] It should be noted that although the operations of the method of the present invention are described in a specific order in the above embodiments and drawings, this does not require or imply that these operations must be performed in this specific order, or that all illustrated operations must be performed to achieve the desired results. Additionally or alternatively, certain steps may be omitted, multiple steps may be combined into one step, and / or one step may be broken down into multiple steps.

[0116] The implementation of the rock porosity measurement device can be referenced to the implementation of the above-mentioned method, and any repetitions will not be repeated here. The terms "module" or "unit" used below may refer to a combination of software and / or hardware that implements a predetermined function. Although the devices described in the following embodiments are preferably implemented using software, implementation using hardware, or a combination of software and hardware, is also possible and contemplated.

[0117] Based on the same inventive concept, the present invention also proposes a rock porosity measuring device, such as Figure 9 As shown, the device includes:

[0118] The first control module 901 is used to control the vacuum pump to evacuate the core cup until the vacuum degree of the core cup is less than or equal to a first preset threshold;

[0119] The second control module 902 is used to control the predetermined gas storage container to fill the reference chamber with the predetermined gas until the pressure in the reference chamber is equal to the preset initial absolute pressure;

[0120] The third control module 903 is used to control the opening of the communication valve between the core cup and the reference chamber, and after determining that the change in the pressure of the reference chamber within the preset time period is less than a second preset threshold, determine the equilibrium pressure after the core cup and the reference chamber are connected;

[0121] Data acquisition module 904, used to obtain the core cup volume, reference chamber volume, and total rock sample volume;

[0122] The volume determination module 905 is used to determine the volume of the rock sample particles based on the core cup volume, the reference chamber volume, the preset initial absolute pressure, and the equilibrium pressure after the core cup and the reference chamber are connected;

[0123] The porosity determination module 906 is used to determine the rock porosity based on the rock sample particle volume and the total volume of the rock sample.

[0124] In one embodiment of the present invention, the present invention further includes:

[0125] The fourth control module is used to control the temperature change of the walk-in constant temperature box to not exceed a third preset threshold value; wherein the core cup and the reference chamber are placed in the walk-in constant temperature box.

[0126] In one embodiment of the present invention, the first control module 901 is specifically configured to:

[0127] Control the vacuum valve to open;

[0128] The vacuum pump is controlled to evacuate the core cup until the vacuum degree of the core cup is less than or equal to a first preset threshold value; wherein the sealing method of the core cup is side sealing.

[0129] In one embodiment of the present invention, the present invention further includes:

[0130] The pressure setting module is used to control the predetermined gas storage container to fill the reference chamber with the predetermined gas until the pressure in the reference chamber is equal to the preset initial absolute pressure, and then set the preset initial absolute pressure of the reference chamber according to the permeability of the gas in the rock sample.

[0131] In one embodiment of the present invention, the third control module 903 is specifically configured to:

[0132] The connecting valve between the core cup and the reference chamber is controlled to open. After determining that the change in the reference chamber pressure at the first moment and the reference chamber pressure at the second moment is less than a second preset threshold, the reference chamber pressure at the first moment is determined as the equilibrium pressure after the core cup and the reference chamber are connected; wherein the interval between the first moment and the second moment is the preset time length.

[0133] In one embodiment of the present invention, the present invention further includes:

[0134] A volume adjustment module is used to adjust the volume of the reference chamber to ensure that the ratio of the equilibrium pressure after the core cup is connected to the reference chamber to the preset initial absolute pressure of the reference chamber is within a preset ratio range; wherein the reference chamber is an adjustable volume reference chamber;

[0135] The data acquisition module 904 is specifically used for:

[0136] The total volume of rock samples was obtained using the Archimedean buoyancy method.

[0137] In one embodiment of the present invention, the volume determination module 805 is specifically configured to:

[0138] The particle volume of the rock sample is determined by the following formula:

[0139]

[0140] Among them, V g Represents the volume of rock sample particles; V c Indicates the core cup volume; V r Indicates the volume of the reference chamber; V v It indicates the volume change from closing to opening of the connecting valve; P1 indicates the preset initial absolute pressure of the reference chamber; P2 indicates the equilibrium pressure after the core cup and the reference chamber are connected.

[0141] In one embodiment of the present invention, the porosity determination module 906 is specifically configured to:

[0142] The rock porosity is determined by the following formula:

[0143]

[0144] in, Indicates rock porosity; V 总 Represents the total volume of the rock sample; V g Represents the volume of rock sample particles.

[0145] In one embodiment of the present invention, the predetermined gas is any one of helium, neon, argon, krypton, xenon, radon, and nitrogen.

[0146] It should be noted that while the detailed description above mentions several modules of the rock porosity measurement device, this division is merely exemplary and not mandatory. In practice, depending on embodiments of the present invention, the features and functions of two or more modules described above may be embodied in a single module. Conversely, the features and functions of a single module described above may be further divided and embodied by multiple modules.

[0147] Based on the above invention concept, Figure 10 As shown, the present invention also proposes a computer device 1000, including a memory 1001, a processor 1002, and a computer program 1003 stored in the memory 1001 and executable on the processor 1002, wherein the processor 1002 implements the aforementioned rock porosity measurement method when executing the computer program 1003.

[0148] Based on the aforementioned inventive concept, the present invention proposes a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the aforementioned rock porosity measurement method is implemented.

[0149] Based on the aforementioned inventive concept, the present invention proposes a computer program product, which includes a computer program. When the computer program is executed by a processor, a rock porosity measurement method is implemented.

[0150] The rock porosity measurement method and device proposed in the embodiment of the present invention can solve the problem in the prior art that the measurement accuracy of gas porosity is low and cannot be used to accurately calibrate rock porosity, thereby affecting the calculation of oil and gas reserves in the reservoir; the embodiment of the present invention controls the vacuum pump to evacuate the core cup until the vacuum degree of the core cup is less than or equal to a first preset threshold; controls the predetermined gas storage container to fill the reference chamber with a predetermined gas until the pressure in the reference chamber is equal to a preset initial absolute pressure; controls the connecting valve between the core cup and the reference chamber to open, and after determining that the change in the reference chamber pressure within a preset time period is less than a second preset threshold, determines the equilibrium pressure after the core cup and the reference chamber are connected; obtains the core cup volume, the reference chamber volume, and the total volume of the rock sample; determines the rock sample particle volume based on the core cup volume, the reference chamber volume, the preset initial absolute pressure, and the equilibrium pressure after the core cup and the reference chamber are connected; and determines the rock porosity based on the rock sample particle volume and the total volume of the rock sample. The embodiments of the present invention can improve the accuracy of rock porosity measurement, provide reliable data support for reservoir evaluation and calculation of oil and gas reserves, and be conducive to increasing oil and gas production.

[0151] It will be understood by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0152] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0153] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0154] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0155] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A rock porosity measurement method, characterized in that: include: Controlling the vacuum pump to evacuate the core cup until the vacuum degree of the core cup is less than or equal to a first preset threshold; Controlling the predetermined gas storage container to fill the reference chamber with the predetermined gas until the pressure in the reference chamber is equal to the preset initial absolute pressure; Controlling the communication valve between the core cup and the reference chamber to open, and after determining that the change in the pressure of the reference chamber within the preset time period is less than a second preset threshold, determining the equilibrium pressure after the core cup and the reference chamber are connected; Obtain the core cup volume, reference chamber volume, and total rock sample volume; Determine the volume of the rock sample particles based on the core cup volume, the reference chamber volume, the preset initial absolute pressure, and the equilibrium pressure after the core cup and the reference chamber are connected; Determine the rock porosity based on the rock sample particle volume and the total volume of the rock sample; Controlling the temperature change of the walk-in constant temperature box to not exceed a third preset threshold value; wherein the core cup and the reference chamber are placed in the walk-in constant temperature box; Before controlling the predetermined gas storage container to fill the reference chamber with the predetermined gas until the pressure in the reference chamber is equal to the preset initial absolute pressure, the method further includes: According to the permeability of gas in the rock sample, the preset initial absolute pressure of the reference chamber is set; Before obtaining the reference chamber volume, also include: Adjust the volume of the reference chamber to ensure that the ratio of the equilibrium pressure after the core cup is connected to the reference chamber to the preset initial absolute pressure of the reference chamber is within a preset ratio range; wherein the reference chamber is an adjustable volume reference chamber; Obtain the total volume of the rock sample, including: The total volume of rock samples was obtained using the Archimedean buoyancy method; The particle volume of the rock sample is determined by the following formula: Among them, V g Represents the volume of rock sample particles; V c Indicates the core cup volume; V r Indicates the volume of the reference chamber; V v It indicates the volume change from closing to opening of the connecting valve; P1 indicates the preset initial absolute pressure of the reference chamber; P2 indicates the equilibrium pressure after the core cup and the reference chamber are connected.

2. The method according to claim 1, characterized in that Controlling the vacuum pump to evacuate the core cup until the vacuum degree of the core cup is less than or equal to a first preset threshold value includes: Control the vacuum valve to open; The vacuum pump is controlled to evacuate the core cup until the vacuum degree of the core cup is less than or equal to a first preset threshold value; wherein the sealing method of the core cup is side sealing.

3. The method according to claim 1, characterized in that Controlling the communication valve between the core cup and the reference chamber to open, and after determining that a change in the pressure of the reference chamber within a preset time period is less than a second preset threshold, determining the equilibrium pressure after the core cup and the reference chamber are connected, comprising: The connecting valve between the core cup and the reference chamber is controlled to open. After determining that the change in the reference chamber pressure at the first moment and the reference chamber pressure at the second moment is less than a second preset threshold, the reference chamber pressure at the first moment is determined as the equilibrium pressure after the core cup and the reference chamber are connected; wherein the interval between the first moment and the second moment is the preset time length.

4. The method according to claim 1, wherein The rock porosity is determined by the following formula: in, Indicates rock porosity; V 总 Represents the total volume of the rock sample; V g Represents the volume of rock sample particles.

5. The method according to claim 1, wherein The predetermined gas is any one of helium, neon, argon, krypton, xenon, radon, and nitrogen.

6. A rock porosity measuring device, characterized in that: include: A first control module is used to control the vacuum pump to evacuate the core cup until the vacuum degree of the core cup is less than or equal to a first preset threshold; a second control module, configured to control the predetermined gas storage container to fill the reference chamber with the predetermined gas until the pressure in the reference chamber is equal to a preset initial absolute pressure; a third control module, configured to control the opening of the communication valve between the core cup and the reference chamber, and after determining that the change in the pressure of the reference chamber within the preset time period is less than a second preset threshold, determine the equilibrium pressure after the core cup and the reference chamber are connected; Data acquisition module, used to obtain the core cup volume, reference chamber volume, and total rock sample volume; a volume determination module for determining the volume of rock sample particles based on the core cup volume, the reference chamber volume, a preset initial absolute pressure, and the equilibrium pressure after the core cup and the reference chamber are connected; A porosity determination module is used to determine the rock porosity based on the rock sample particle volume and the rock sample total volume; a fourth control module, configured to control a temperature change of the walk-in constant temperature box so as not to exceed a third preset threshold; wherein the core cup and the reference chamber are placed in the walk-in constant temperature box; a pressure setting module for controlling a predetermined gas storage container to fill the reference chamber with a predetermined gas until the pressure in the reference chamber equals the predetermined initial absolute pressure, and setting the predetermined initial absolute pressure of the reference chamber according to the permeability of the gas in the rock sample; A volume adjustment module is used to adjust the volume of the reference chamber to ensure that the ratio of the equilibrium pressure after the core cup is connected to the reference chamber to the preset initial absolute pressure of the reference chamber is within a preset ratio range; wherein the reference chamber is an adjustable volume reference chamber; The data acquisition module is specifically used for: The total volume of rock samples was obtained using the Archimedean buoyancy method; The volume determination module is specifically used to: The particle volume of the rock sample is determined by the following formula: Among them, V g Represents the volume of rock sample particles; V c Indicates the core cup volume; V r Indicates the volume of the reference chamber; V v It indicates the volume change from closing to opening of the connecting valve; P1 indicates the preset initial absolute pressure of the reference chamber; P2 indicates the equilibrium pressure after the core cup and the reference chamber are connected.

7. The device according to claim 6, characterized in that The first control module is specifically configured to: Control the vacuum valve to open; The vacuum pump is controlled to evacuate the core cup until the vacuum degree of the core cup is less than or equal to a first preset threshold value; wherein the sealing method of the core cup is side sealing.

8. The device according to claim 6, characterized in that The third control module is specifically configured to: The connecting valve between the core cup and the reference chamber is controlled to open. After determining that the change in the reference chamber pressure at the first moment and the reference chamber pressure at the second moment is less than a second preset threshold, the reference chamber pressure at the first moment is determined as the equilibrium pressure after the core cup and the reference chamber are connected; wherein the interval between the first moment and the second moment is the preset time length.

9. The device according to claim 6, characterized in that The porosity determination module is specifically used to: The rock porosity is determined by the following formula: in, Indicates rock porosity; V 总 Represents the total volume of the rock sample; V g Represents the volume of rock sample particles.

10. The device according to claim 6, characterized in that The predetermined gas is any one of helium, neon, argon, krypton, xenon, radon, and nitrogen.

11. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the method according to any one of claims 1 to 5 is implemented.

12. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method according to any one of claims 1 to 5 is implemented.

13. A computer program product, characterized in that The computer program product comprises a computer program, and when the computer program is executed by a processor, the method according to any one of claims 1 to 5 is implemented.

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