Rock porosity measuring method and device

Abstract

The invention provides a rock porosity measuring method and device, and relates to the technical field of geophysics, and the method comprises the steps: controlling a vacuum pump to vacuumize a core cup until the vacuum degree of the core cup is smaller than or equal to a first preset threshold value; controlling the predetermined gas storage container to fill predetermined gas into the reference chamber until the pressure in the reference chamber is equal to the preset initial absolute pressure; a communication valve between the core cup and the reference chamber is controlled to be opened, and after it is determined that the variable quantity of the pressure of the reference chamber within the preset duration is smaller than a second preset threshold value, balance pressure after the core cup and the reference chamber are communicated is determined; acquiring the volume of a core cup, the volume of a reference chamber and the total volume of a rock sample; determining the particle volume of the rock sample according to the volume of the core cup, the volume of the reference chamber, the preset initial absolute pressure and the balance pressure after the core cup is communicated with the reference chamber; and determining the rock porosity according to the rock sample particle volume and the rock sample total volume. According to the invention, the precision of rock porosity measurement can be improved.

Description

Technical Field

[0001] The 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 recited in the claims. No admission is made that the description herein is prior art by inclusion in this section.

[0003] In recent years, with the rapid consumption of conventional oil and gas resources, the difficulty of exploring and developing new oil and gas resources has increased. The global oil and gas resource exploration and development is changing from the traditional conventional oil and gas resource exploration and development to the joint exploration and development of conventional and unconventional oil and gas resources. Unconventional oil and gas resources such as shale oil are abundant and widely distributed, showing huge exploration and development potential; and the correct calculation of reservoir rock porosity is of great significance for the correct evaluation and transformation of reservoirs, as well as for increasing oil and gas production. The gas porosity measured by the existing laboratory porosity meter is of low accuracy and cannot be used to accurately calibrate the rock porosity, thus affecting the calculation of oil and gas reserves in the reservoir. 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 calculation of oil and gas reserves, 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 connecting 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 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 rock sample particles based on the volume of the core cup, the volume of the reference chamber, 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 rock sample particle volume and the 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 calculation of oil and gas reserves, including:

[0012] A first control module, used for 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;

[0013] A second control 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;

[0014] A third control module is used to control the opening of the connecting 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 is less than a second preset threshold, determine the equilibrium pressure after the core cup and the reference chamber are connected;

[0015] A data acquisition module is 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 according to the volume of the core cup, the volume of the reference chamber, the preset initial absolute pressure, and the equilibrium pressure after the core cup is connected to the reference chamber;

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

[0018] In an embodiment of the present invention, a computer device is proposed, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements a rock porosity measurement method when executing the computer program.

[0019] In an embodiment of the present invention, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, a rock porosity measurement method is implemented.

[0020] A computer program product is provided in an embodiment of the present invention. The computer program product 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 that the measurement accuracy of gas porosity in the prior art 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 the first preset threshold value; 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 the 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 the preset time is less than the second preset threshold value, 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 according to 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; determines the rock porosity according to 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 help increase 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 drawings required for use in the description of the embodiments will be briefly introduced below. 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 creative work.

[0023] Figure 1 1 is a schematic diagram of a process for measuring rock porosity in an embodiment of the present invention;

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

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

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

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

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

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

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

[0031] Fig. 9 is a schematic diagram of a rock porosity measuring device in an embodiment of the present invention;

[0032] Fig.10 Schematic diagram of a computer device in an embodiment of the present invention.

[0033] Reference numerals:

[0034] 1-core cup, 2-three-way 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 thermostatic chamber. DETAILED DESCRIPTION

[0035] To make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the embodiments of the present invention are further described in detail below in conjunction with 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 only describes an association relationship, indicating that three relationships may exist. For example, A and / or B may represent the following three situations: A exists alone, A and B exist at the same time, and B exists alone. In addition, the term "at least one" herein represents any combination of at least two of any one or more of a plurality of. For example, including at least one of A, B, and C may represent including 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 representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures or characteristics described may 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 is not limited and can be appropriately adjusted as needed.

[0038] The principle 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, controlling a 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;

[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 connecting 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 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 rock sample particles according to the volume of the core cup, the volume of the reference chamber, the preset initial absolute pressure, and the equilibrium pressure after the core cup and the reference chamber are connected;

[0045] Step 106, determining the rock porosity based on the rock sample particle volume and the rock sample total volume.

[0046] Depend on Figure 1 It can be known from the process shown that 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 the first preset threshold value; 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 the 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 pressure of the reference chamber within the preset time is less than the second preset threshold value, determines the equilibrium pressure after the core cup and the reference chamber are connected; obtains the volume of the core cup, the volume of the reference chamber, and the total volume of the rock sample; determines the volume of the rock sample particles according to the volume of the core cup, the volume of the reference chamber, the preset initial absolute pressure, and the equilibrium pressure after the core cup and the reference chamber are connected; determines the rock porosity according to the volume of the rock sample particles 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 calculation of oil and gas reserves, 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, the predetermined gas storage container is controlled to fill the reference chamber with the 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 is a gas with stable physical and chemical properties, and the molecules of the predetermined gas need to be small enough.

[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 joint 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 venting valve 14, and a walk-in thermostatic box 15; wherein:

[0052] The core cup 1 is composed 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. The core cup 1 of different diameters can be selected according to the size of the rock sample;

[0053] The three-way 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 components of the three-way connector 2 to avoid the influence of the volume change of the pipeline on the measurement result.

[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 to open and close 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 a collection control box, a computer and measurement and control software, which controls the measurement of the entire rock porosity 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 thermostatic box 15 includes a refrigeration 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 thermostatic 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, the temperature variation of the walk-in thermostat is controlled not to exceed a third preset threshold value; wherein the core cup and the reference chamber are placed in the walk-in thermostat. Specifically, when the temperature of the walk-in thermostat is controlled, the temperature variation of the walk-in thermostat needs to be controlled not to exceed 0.1°C, for example, to construct a stable and controllable constant temperature environment, and control the temperature variation within a variation 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 the 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 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%, so the sealing method of the core cup is improved, referring to Figure 3 In part (b), the new core cup is sealed with a side seal, which avoids the change in the core cup volume caused by the end seal, making the measurement more stable and accurate. The side seal of the core cup can eliminate and reduce the influence of the blank volume change, and can ensure that the cavity volume of the core cup remains unchanged during the vacuum and pressurization process.

[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 is equal to the preset initial absolute pressure, the process 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, for step 103, controlling the connecting 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 is less than the 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, and 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 a preset duration.

[0076] In specific implementation, the connecting valve between the core cup and the reference chamber is controlled to open, and 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 the second preset threshold, for example, the second preset threshold is set to 0.015Kpa, and 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 second moment may be 15 minutes before the first moment. Specifically, the injection of helium into the reference chamber and the vacuuming of the core chamber are operated separately to avoid 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] Exemplarily, 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 prior art uses a fixed volume reference chamber, referring to Figure 4 In part (a), the fixed volume reference chamber cannot adjust the reference chamber volume, which may cause the core cup to be connected to the fixed volume reference chamber for a long time to balance the pressure, and also waste helium; in the embodiment of the present invention, an adjustable volume reference chamber is creatively used. 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 a preset ratio range, while avoiding the waste of helium and saving helium resources.

[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 of the reference chamber and the core cup after they are connected, as well as their respective temperature changes, improves 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 is connected to the reference chamber; 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 represents 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 is stabilized; T 2c represents the absolute temperature of the core cup after P2 is stabilized; 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 Indicates the volume change of the connecting valve from closed to open. The original Clapeyron formula assumes too many conditions. When the porosity of the rock sample to be measured is less than 6%, the reference chamber pressure needs to be increased. If the reference chamber pressure is greater than 2MPa, the measuring medium (helium) does not meet the ideal gas condition, which will cause a relative error of 6%. In addition, when connecting the reference chamber and the core cup, a longer equilibrium time is required to reach the equilibrium pressure. If the temperature changes by 0.5°C during this period, an absolute error of 0.2-1% porosity will be generated, which will reduce the accuracy of rock porosity measurement. Therefore, it is necessary to control the temperature change of the walk-in thermostat, for example, not exceeding 0.1°C.

[0089] In one embodiment of the present invention, when evacuating the core cup, a vacuum state is ensured to eliminate the influence of the gas deviation factor, thereby facilitating real-time monitoring of pressure changes at different stages in the process of measuring porosity.

[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; 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 It represents the volume change of the connecting valve from closed to open, and is taken as 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 is connected to the reference chamber.

[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, reference Figure 6 , rock porosity measurement methods include:

[0100] Step 601, a constant temperature and humidity measurement environment is established by a walk-in thermostat. A constant environment must be maintained during system calibration and measurement, especially the temperature change is controlled within ±0.1°C, eliminating the influence of temperature, that 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 is stabilized; 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, estimating the pore volume of the rock sample, adjusting the mechanical piston of the reference chamber according to the estimated pore volume of the rock sample so that the reference chamber volume is equal to 2-3 times the pore volume of the rock sample, determining the reference chamber volume and the preset initial absolute pressure P1 of the reference chamber monitored by the absolute pressure sensor; wherein, the reference chamber volume should not be too large, and there should be sufficient pressure drop when connected to the core cup;

[0103] Step 604, select a corresponding core cup according to the volume of the rock sample. Usually, there are four core cups with different diameters to choose from. Among them, the standard core cup has a known volume, that is, the core cup volume V c ;

[0104] Step 605, calibrate the measurement system with the standard block and save the calibrated scale parameters; wherein, the entire measurement system needs to be recalibrated before measuring each batch of rock samples, and the entire system must be recalibrated if any joint is screwed during the measurement process; wherein, the standard block is a standard object without pores;

[0105] Step 606, according to the total volume of the rock sample, select a suitable standard block and put it into the core cup together 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 according to the gas permeability of the rock sample, turn on the vacuum pump to evacuate the core cup, and when the vacuum degree 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, according to the permeability of the gas in the rock sample, set the preset initial absolute pressure of the reference chamber; low permeability rock samples require a higher preset initial absolute pressure of the reference chamber, but the maximum preset initial absolute pressure should not exceed, for example, 1.5MPa; the helium in the reference chamber is provided by a helium cylinder and enters the reference chamber through a pressure reducing valve and a filter, and the pressure in the reference chamber is controlled by the gas supply valve; when the pressure in the reference chamber reaches the preset initial absolute pressure, close the gas supply valve, and the measurement and control system determines whether the temperature and pressure of the reference chamber are stable through the temperature sensor and the absolute pressure sensor, and proceeds to the next step after stabilization;

[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 opened 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 pressure in the reference chamber is stable, calculate the rock porosity; draw a pressure change curve in real time, and when the controller continuously detects that the change between the "current pressure in the reference chamber 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 is connected to the reference chamber, and determine the rock sample particle volume according to the core cup volume, the reference chamber volume, the preset initial absolute pressure, and the equilibrium pressure after the core cup is connected to the reference chamber; after determining the rock porosity according to 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 to prepare 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] The rock porosity measurement method in the embodiment of the present invention is compared with the rock porosity results measured by the industry standard. Figure 7 The horizontal axis of the scatter plot is the rock porosity measured by the industry standard, and the vertical axis is the rock porosity measured by the embodiment of the present invention. It can be seen that the rock porosity measurement method in the embodiment of the present invention has higher accuracy. The repetition error of the present invention is less than ±0.002%, which is smaller than the rock porosity error measured by the industry standard.

[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 of well logging, the rock porosity measured by the new method in the embodiment of the present invention, and the gas porosity measured by the industry standard; it can be seen that the rock porosity measured by the new method in the embodiment of the present invention is closer to the effective porosity of well logging. The embodiment of the present invention effectively solves the problem that the existing gas porosity measurement method is affected by multiple factors such as ambient temperature, atmospheric pressure and air in the rock sample, improves the accuracy of rock porosity measurement, and provides more reliable data support for reservoir evaluation and reservoir transformation.

[0114] The present invention is based on the improved Clapeyron formula, and 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 to measure the gas porosity of the rock; the present invention not only avoids the influence of the mixed gas in the core cup on the measured value, but also facilitates the helium to enter the small pores of the rock sample, so that the detection result is closer to the effective porosity of the rock; the present invention also adopts a walk-in constant temperature box and a temperature sensor with an accuracy of ±0.01°C, ensuring that the temperature change range is controlled within ±0.1°C during the measurement process, eliminating the influence of temperature change on the measurement result; in addition, the present invention adopts an absolute pressure sensor, which can ensure that when helium is injected into the reference chamber and the core cup is evacuated, the core cup reaches a true vacuum state and the initial absolute atmospheric pressure is zero compared to the relative pressure sensor; a constant volume connecting valve and a new core cup structure are adopted to avoid the change in the core cup volume caused by the end face seal, so that the measurement result is more accurate; the measurement process of the present invention is controllable and the result is intuitive, avoiding the embarrassment that the existing porosity meter only provides numerical values ​​and 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 the accompanying drawings, this does not require or imply that the operations must be performed in the specific order, or that all the operations shown must be performed to achieve the desired results. Additionally or alternatively, some steps may be omitted, multiple steps may be combined into one step, and / or one step may be decomposed into multiple steps.

[0116] The implementation of the rock porosity measuring device can refer to the implementation of the above method, and the repeated parts will not be repeated. The term "module" or "unit" used below can be a combination of software and / or hardware that implements a predetermined function. Although the device described in the following embodiments is preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceivable.

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

[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 connecting 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 is less than the 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 rock sample particles according to the volume of the core cup, the volume of the reference chamber, 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 rock sample total volume.

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

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

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

[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, it 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 used for:

[0132] The connecting valve between the core cup and the reference chamber is controlled to open, and 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 a preset duration.

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

[0134] A volume adjustment module, 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 used for:

[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 of the connecting valve from closed to open; P1 indicates the preset initial absolute pressure of the reference chamber; P2 indicates the equilibrium pressure after the core cup is connected to the reference chamber.

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

[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, although several modules of the rock porosity measuring device are mentioned in the above detailed description, such division is merely exemplary and not mandatory. In fact, according to an embodiment of the present invention, the features and functions of two or more modules described above can be embodied in one module. Conversely, the features and functions of one module described above can be further divided into multiple modules for embodiment.

[0147] Based on the above invention concept, Fig.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, and 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 that the measurement accuracy of gas porosity in the prior art 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 the first preset threshold value; 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 the 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 the preset time is less than the second preset threshold value, 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 according to 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; determines the rock porosity according to 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 help increase oil and gas production.

[0151] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, 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 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 flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, 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 flowchart and / or block diagram. 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 capable of directing a computer or other programmable data processing device to operate 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 A 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 operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified 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 value; 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 connecting 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 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 rock sample particles based on the volume of the core cup, the volume of the reference chamber, the preset initial absolute pressure, and the equilibrium pressure after the core cup and the reference chamber are connected; The rock porosity is determined based on the rock sample particle volume and the total volume of the rock sample.

2. The method according to claim 1, characterized in that: Also includes: The temperature change of the walk-in thermostatic box is controlled not to exceed a third preset threshold value; wherein the core cup and the reference chamber are placed in the walk-in thermostatic box.

3. 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, including: 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.

4. The method according to claim 1, characterized in that: 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: The preset initial absolute pressure of the reference chamber is set according to the permeability of the gas in the rock sample.

5. The method according to claim 1, characterized in that Controlling the connecting 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 is less than a second preset threshold, determining the equilibrium pressure after the core cup and the reference chamber are connected, including: The connecting valve between the core cup and the reference chamber is controlled to open, and 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 a preset duration.

6. The method according to claim 1, characterized in that 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.

7. The method according to claim 1, characterized in that 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 of the connecting valve from closed to open; P1 indicates the preset initial absolute pressure of the reference chamber; P2 indicates the equilibrium pressure after the core cup is connected to the reference chamber.

8. The method according to claim 1, characterized in that 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.

9. The method according to claim 1, characterized in that: The predetermined gas is any one of helium, neon, argon, krypton, xenon, radon and nitrogen.

10. A rock porosity measuring device, characterized in that: include: A first control module, used for 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; A second control 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; A third control module is used to control the opening of the connecting 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 is less than a second preset threshold, determine the equilibrium pressure after the core cup and the reference chamber are connected; A data acquisition module is 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 according to the volume of the core cup, the volume of the reference chamber, the preset initial absolute pressure, and the equilibrium pressure after the core cup is connected to the reference chamber; The porosity determination module is used to determine the rock porosity based on the rock sample particle volume and the rock sample total volume.

11. The device according to claim 10, characterized in that Also includes: The fourth control module is used to control the temperature change of the walk-in thermostatic box to not exceed a third preset threshold value; wherein the core cup and the reference chamber are placed in the walk-in thermostatic box.

12. The device according to claim 10, characterized in that The first control module is specifically used for: 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.

13. The device according to claim 10, characterized in that Also includes: 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.

14. The device according to claim 10, characterized in that The third control module is specifically used for: The connecting valve between the core cup and the reference chamber is controlled to open, and 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 a preset duration.

15. The device according to claim 10, characterized in that Also includes: A volume adjustment module, 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.

16. The device according to claim 10, characterized in that The volume determination module is specifically used for: 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 of the connecting valve from closed to open; P1 indicates the preset initial absolute pressure of the reference chamber; P2 indicates the equilibrium pressure after the core cup is connected to the reference chamber.

17. The device according to claim 10, characterized in that The porosity determination module is specifically used for: 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.

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

19. A computer device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the method according to any one of claims 1 to 9 is implemented.

20. 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 9 is implemented.

21. 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 9 is implemented.

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