Method and device for determining gas saturation of coal rock gas

Abstract

The invention discloses a method and a device for determining the gas saturation of coal rock gas. The method comprises the steps that the total gas content of target well coal rock is determined based on a gas sample of the target well coal rock, and the maximum adsorption gas capacity of the target well coal rock is determined based on the coal rock sample of the target well coal rock; determining the maximum free gas capacity of the target well coal rock based on the pressure data, the temperature data and the coal rock porosity of the target well coal rock; and determining the gas saturation of the target well coal rock based on the maximum free gas capacity, the total gas content and the maximum adsorption gas capacity. The technical problem that a coal rock gas saturation calculation method in the prior art cannot accurately express the gas bearing capacity and the actual gas bearing abundance of coal rock is solved.

Description

Technical Field

[0001] The present invention relates to the field of exploration technology, and in particular to a method and device for determining the gas saturation of coal rock gas. Background Art

[0002] Gas saturation is a key parameter for characterizing the gas content of coal. Accurately expressing gas saturation is crucial for zone optimization, geological sweet spot evaluation, and reserve estimation. Traditional coalbed methane (CBM) is generally buried at shallow depths and primarily consists of adsorbed gas. Free and dissolved gas content is very low and often negligible. Therefore, the gas saturation calculation for traditional CBM is based on the ratio of the measured desorbed gas volume to the adsorbed gas capacity at formation temperature and pressure.

[0003] However, with the emergence of coal-rock gas (CRM) and breakthroughs in its exploration, the aforementioned saturation calculation method is no longer suitable for characterizing the enrichment of natural gas in coal. Because coal is subject to intense geostress and has low compressive strength, it is prone to the formation of numerous fracture-type macropores that connect cleats and micropores, resulting in a high concentration of free gas. Under high-temperature and high-pressure reservoir conditions, this free gas is typically in a supercritical state of compression, possessing a high density and contributing significantly to coal-rock gas production. Field pressure coring measurements reveal that natural gas contains significant amounts of free gas in addition to adsorbed gas.

[0004] Given the same adsorption capacity of coal, the significantly increased free gas content can cause the gas content measured during actual wellsite pressure coring to exceed the maximum adsorption gas capacity, ultimately leading to calculated adsorption gas saturation exceeding 100%. Such results neither conform to the conventional understanding of saturation nor accurately represent the gas-bearing capacity and actual gas abundance of the coal. Therefore, developing a method to accurately evaluate the gas saturation of coal with high free gas content is crucial for optimizing coal-gas zones and identifying sweet spots. Summary of the Invention

[0005] The present invention provides a method and device for determining the gas saturation of coal rock gas, so as to solve the technical problem that the existing coal rock gas saturation calculation method cannot accurately express the gas-bearing capacity and actual gas abundance of coal rock.

[0006] According to one aspect of the present invention, a method for determining gas saturation of coal rock gas is provided, the method comprising:

[0007] determining the total gas content of the target well coal rock based on the gas sample of the target well coal rock, and determining the maximum adsorbed gas capacity of the target well coal rock based on the coal rock sample of the target well coal rock;

[0008] Determine the maximum free gas capacity of the target well coal rock based on the pressure data, temperature data and coal rock porosity of the target well coal rock;

[0009] The gas saturation of the target well coal rock is determined based on the maximum free gas capacity, total gas content and maximum adsorbed gas capacity.

[0010] According to another aspect of the present invention, a device for determining gas saturation of coal gas is provided, the device comprising:

[0011] a gas quantity determination module, configured to determine the total gas content of the target well coal rock based on the gas sample of the target well coal rock, and to determine the maximum adsorbed gas capacity of the target well coal rock based on the coal rock sample of the target well coal rock;

[0012] A maximum free gas capacity determination module is used to determine the maximum free gas capacity of the target well coal rock based on the pressure data, temperature data and coal rock porosity of the target well coal rock;

[0013] The gas saturation determination module is used to determine the gas saturation of the target well coal rock based on the maximum free gas capacity, total gas content and maximum adsorbed gas capacity.

[0014] According to another aspect of the present invention, an electronic device is provided, the electronic device comprising:

[0015] at least one processor; and

[0016] a memory communicatively connected to at least one processor; wherein,

[0017] The memory stores a computer program that can be executed by at least one processor. The computer program is executed by at least one processor so that the at least one processor can execute the method for determining the gas saturation of coal rock gas according to any embodiment of the present invention.

[0018] According to another aspect of the present invention, a computer-readable storage medium is provided, which stores computer instructions, and the computer instructions are used to enable a processor to implement the method for determining the gas saturation of coal rock gas according to any embodiment of the present invention when executed.

[0019] The technical solution of the embodiments of the present invention first determines the total gas content of the target well coal rock based on gas samples from the target well coal rock, and also determines the maximum adsorbed gas capacity of the target well coal rock based on the target well coal rock sample. This enables the total gas content and maximum adsorbed gas capacity of the target well coal rock to be obtained based on the target well coal rock sample data. The maximum free gas capacity of the target well coal rock is then determined based on the target well coal rock pressure data, temperature data, and coal rock porosity, providing a data basis for considering the maximum free gas capacity when calculating gas saturation. Finally, the gas saturation of the target well coal rock is determined based on the maximum free gas capacity, total gas content, and maximum adsorbed gas capacity. This solves the technical problem that existing coal rock gas saturation calculation methods cannot accurately represent the coal rock's gas-bearing capacity and actual gas abundance. This method achieves the beneficial effect of accurately evaluating the gas saturation of coal rock wells, thereby providing a powerful reference for coal rock gas zone optimization and sweet spot evaluation.

[0020] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 This is a flow chart of a method for determining gas saturation of coal gas provided in accordance with the first embodiment of the present invention;

[0023] Figure 2 This is a flow chart of a method for determining gas saturation of coal gas provided in accordance with the second embodiment of the present invention;

[0024] Figure 3 This is a schematic structural diagram of a device for determining gas saturation of coal rock gas provided in accordance with a third embodiment of the present invention;

[0025] Figure 4 FIG. 1 is a schematic structural diagram of an electronic device 10 that can be used to implement an embodiment of the present invention. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0027] It should be noted that the terms "first," "second," and "target" and the like in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the numbers used in this way are interchangeable where appropriate so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to these processes, methods, products, or apparatus.

[0028] Example 1

[0029] Figure 1 A flow chart of a method for determining coal gas saturation is provided for the first embodiment of the present invention. This embodiment is applicable to determining coal gas saturation. The method can be executed by a coal gas saturation determination device. The coal gas saturation determination device can be implemented in the form of hardware and / or software. The coal gas saturation determination device can be configured in an electronic device. Figure 1 As shown, the method includes:

[0030] S110 , determining the total gas content of the target well coal rock based on the gas sample of the target well coal rock, and determining the maximum adsorption gas capacity of the target well coal rock based on the coal rock sample of the target well coal rock.

[0031] In this embodiment, the target well coal rock can be a coal rock gas well containing free gas for gas saturation calculation. The gas sample of the target well coal rock can be various gases contained in the coal rock core obtained by performing a closed pressure test on the target well coal rock. The total gas content of the target well coal rock is determined based on the gas sample of the target well coal rock, which can be the total gas content per unit mass of the coal rock obtained by analyzing and measuring the various gas components in the gas sample of the target well coal rock. The unit of the total gas content of the target well coal rock can be m 3 / t. The target well coal rock sample may be a coal rock sample collected during drilling exploration of the target well coal rock. The maximum adsorption gas capacity of the target well coal rock determined based on the target well coal rock sample may be the maximum adsorption gas capacity of the target well coal rock obtained by analyzing the coal rock sample using methods such as gas adsorption, thermogravimetric analysis, and adsorption isotherm extrapolation. The maximum adsorption gas capacity may refer to the maximum amount of natural gas that can be adsorbed per unit mass (or unit volume) of coal rock under specific conditions. The unit of the maximum adsorption gas capacity of the target well coal rock may be m3 / t.

[0032] Optionally, the total gas content of the target well coal rock is determined based on the gas sample of the target well coal rock, including: obtaining the gas sample of the target well coal rock, testing the gas sample based on a preset coalbed methane content determination method, and determining the pressure-releasing gas content, natural desorption gas content, residual gas content and lost gas content of the target well coal rock; and determining the total gas content of the target well coal rock based on the sum of the natural desorption gas content, residual gas content and lost gas content.

[0033] In this embodiment, the preset coalbed methane content determination method can refer to the national standard GB / T19559-2021, "Method for Determining Coalbed Methane Content," to accurately measure the content of various gases. The pressure-released gas content of the target well coal rock can be determined by measuring the pressure-released gas content in a gas sample based on the "Method for Determining Coalbed Methane Content." The pressure-released gas can be released from a sealed collection container or pipeline under certain conditions to maintain the pressure within the container or pipeline within a certain range. The naturally desorbed gas content of the target well coal rock can be determined by measuring the naturally desorbed gas content in a gas sample based on the "Method for Determining Coalbed Methane Content." Naturally desorbed gas can be spontaneously released from coal rock at room temperature and atmospheric pressure. The residual gas content of the target well coal rock can be determined by measuring the residual gas content in a gas sample based on the "Method for Determining Coalbed Methane Content." Residual gas can be gas that cannot be released in a sealed container. The lost gas content of the target well coal rock can be determined by measuring the amount of gas lost due to various factors during the collection and processing of the gas sample based on the "Method for Determining Coalbed Methane Content." The total gas content of the target well coal rock is determined based on the sum of the natural desorption gas content, the residual gas content and the lost gas content. The natural desorption gas content, the residual gas content and the lost gas content can be added together and the result is used as the total gas content of the target well coal rock.

[0034] Optionally, determining the maximum adsorption gas capacity of the target well coal rock based on the coal rock sample of the target well coal rock includes: obtaining the coal rock sample of the target well coal rock, and determining the maximum adsorption gas capacity of the target well coal rock based on a high-pressure isothermal adsorption test on the coal rock sample.

[0035] In this embodiment, the high-pressure isothermal adsorption test can be a test method for determining the maximum gas adsorption capacity of the target well coal rock by measuring the gas adsorption capacity of the coal rock sample under different pressure and temperature conditions. During the high-pressure isothermal adsorption test on the coal rock sample, the adsorption capacity of the coal rock can be determined by measuring the amount of gas adsorbed into the coal rock sample.

[0036] S120. Determine the maximum free gas capacity of the target well coal rock based on the pressure data, temperature data, and coal rock porosity of the target well coal rock.

[0037] In this embodiment, the target well coal rock pressure data may be formation pressure data. The temperature data may be formation temperature data. The coal rock porosity may be the proportion of pore space in the target well coal rock. Coal rock porosity directly affects the reservoir properties of the coal rock and has a significant impact on the storage and release of resources such as coalbed methane. Coal rock porosity can be obtained based on void volume fraction determination, water saturation, and adsorption methods. It can also be calculated based on geophysical methods, such as acoustic logging and nuclear magnetic resonance logging data. The maximum free gas capacity of the target well coal rock is determined based on the target well coal rock pressure data, temperature data, and coal rock porosity. The actual natural gas thermophysical properties of the target well coal rock can be calculated based on the target well coal rock pressure and temperature data, thereby determining the natural gas volume coefficient of the target well coal rock. The maximum free gas capacity of the target well coal rock is then calculated according to a corresponding calculation formula based on the natural gas volume coefficient and coal rock porosity information.

[0038] Optionally, the maximum free gas capacity of the target well coal rock is determined based on the pressure data, temperature data and coal rock porosity of the target well coal rock, including: determining the target gas deviation factor of the target well coal rock based on the pressure data and temperature data of the target well coal rock, and determining the natural gas volume coefficient of the target well coal rock based on the target gas deviation factor; obtaining the coal rock porosity of the target well coal rock, and determining the maximum free gas capacity of the target well coal rock based on the coal rock porosity and the natural gas volume coefficient.

[0039] In this embodiment, the target gas deviation factor can be a correction factor introduced by the difference between the behavior of the gas in the target well coal rock under the actual temperature and pressure conditions of the target well coal rock and the ideal gas behavior. Specifically, the target gas deviation factor can be the ratio of the actual gas volume in the target well coal rock to the ideal gas volume. Exemplarily, the target gas deviation factor can be calculated based on the GERG-2008 equation for calculating natural gas thermophysical property parameters recommended by the international standard ISO 20765-2. The natural gas volume coefficient can be the ratio of the coal rock gas volume under the actual formation conditions of the target well coal rock to the coal rock gas volume under standard conditions.

[0040] To obtain the target well's coal rock porosity, the total porosity φ of the coal rock can be determined based on the standard testing method provided in the Chinese Petroleum and Natural Gas Industry Standard SY / T6385-2016, "Determination of Porosity and Permeability of Rocks Under Overburden Pressure." The maximum free gas capacity of the target well's coal rock can be determined based on the coal rock porosity and the natural gas volume coefficient. A corrected natural gas volume parameter can be determined based on the natural gas volume coefficient and the target gas deviation factor. The maximum free gas capacity of the target well's coal rock can then be determined by multiplying the corrected natural gas volume parameter by the coal rock porosity.

[0041] S130. Determine the gas saturation of the target well coal rock based on the maximum free gas capacity, the total gas content, and the maximum adsorbed gas capacity.

[0042] In this embodiment, the theoretical maximum gas content of the target well coal rock can be determined based on the maximum free gas capacity and the maximum adsorbed gas capacity. Then, the gas saturation of the target well coal rock can be determined based on the relationship between the total gas content and the theoretical maximum gas content.

[0043] Optionally, the gas saturation of the target well coal rock is determined based on the maximum free gas capacity, the total gas content and the maximum adsorbed gas capacity, including: determining the maximum theoretical gas content based on the maximum free gas capacity and the maximum adsorbed gas capacity; and determining the gas saturation of the target well coal rock based on the ratio of the total gas content to the maximum theoretical gas content.

[0044] In this embodiment, the maximum theoretical gas content can be determined based on the sum of the maximum free gas capacity and the maximum adsorbed gas capacity, and then the gas saturation of the target well coal rock can be determined based on the ratio of the total gas content to the maximum theoretical gas content.

[0045] The technical solution of the embodiment of the present invention first obtains a gas sample from the target well coal rock and tests the gas sample based on a preset coalbed methane content determination method to determine the pressure-released gas content, naturally desorbed gas content, residual gas content, and lost gas content of the target well coal rock. The total gas content of the target well coal rock is determined based on the sum of the naturally desorbed gas content, residual gas content, and lost gas content. Next, a coal rock sample is obtained from the target well coal rock and the maximum adsorbed gas capacity of the target well coal rock is determined by performing a high-pressure isothermal adsorption test on the coal rock sample. This achieves the acquisition of the total gas content and maximum adsorbed gas capacity of the target well coal rock based on the target well coal rock sample data. The maximum free gas capacity of the target well coal rock is then determined based on the target well coal rock pressure data, temperature data, and coal rock porosity, providing a data basis for considering the maximum free gas capacity when calculating gas saturation. Finally, the maximum theoretical gas content is determined based on the maximum free gas capacity and the maximum adsorbed gas capacity. The gas saturation of the target well coal rock is determined based on the ratio of the total gas content to the maximum theoretical gas content. This method solves the technical problem that existing coal-rock gas saturation calculation methods cannot accurately express the gas-bearing capacity and actual gas abundance of coal. It achieves the beneficial effect of accurately evaluating the gas saturation of coal-rock wells, thereby providing a strong reference basis for coal-rock gas zone optimization and sweet spot evaluation.

[0046] Example 2

[0047] Figure 2 This is a flow chart of a method for determining gas saturation of coal rock gas provided in the second embodiment of the present invention. This embodiment is based on the above embodiments and specifically describes the calculation method of the maximum adsorbed gas capacity, natural gas volume coefficient and maximum free gas capacity of the target well coal rock. For the specific implementation method, please refer to the description of this embodiment. Among them, the technical features that are the same or similar to the above embodiments are not repeated here. Figure 2 As shown, the method includes:

[0048] S210 : Determine the total gas content of the target well coal rock based on the gas sample of the target well coal rock.

[0049] S220: Obtain a coal rock sample from the target well coal rock, and determine the maximum adsorption gas capacity of the target well coal rock based on a high-pressure isothermal adsorption test on the coal rock sample.

[0050] Optionally, the maximum adsorbed gas capacity of the target well coal rock is determined based on a high-pressure isothermal adsorption test on the coal rock sample, including: testing the coal rock sample based on the high-pressure isothermal adsorption test to obtain a target reservoir pressure and a target amount of adsorbed natural gas; determining an air-dried Langmuir volume corresponding to the target well coal rock based on the target reservoir pressure, the target amount of adsorbed natural gas, and a preset isothermal adsorption equation; determining the maximum adsorbed gas capacity of the target well coal rock based on the air-dried Langmuir volume; wherein the isothermal adsorption equation is as follows:

[0051]

[0052] Among them, V L is the Langmuir volume of air-dried coal rock, P L is the Langmuir pressure of air-dried base coal rock, P is the target reservoir pressure, and V is the target adsorbed natural gas volume.

[0053] In this embodiment, the coal rock sample is tested based on the high-pressure isothermal adsorption test to obtain the target reservoir pressure and the target adsorbed natural gas volume. The coal rock sample can be tested with reference to GB / T 19560-2008 "High-pressure Isothermal Adsorption Test Method for Coal". The target reservoir pressure and the target adsorbed natural gas volume can be obtained based on the reservoir pressure P and the adsorbed natural gas volume V of the target well coal rock obtained by the high-pressure isothermal adsorption test. The air-dried Langmuir volume corresponding to the target well coal rock is determined based on the target reservoir pressure, the target adsorbed natural gas volume and the preset isothermal adsorption equation. The intercept V can be obtained by fitting the straight line according to the isothermal adsorption equation in the above-mentioned embodiments in the plane coordinate system (V / P, V) based on the (V, P) data obtained by the high-pressure isothermal adsorption test. L and slope P L That is, the Langmuir volume (V L ) and Langmuir pressure (P L For coal reservoirs with deep burial depth and high formation pressure, the Langmuir volume (V L ) is the maximum adsorption gas capacity of the target well coal rock. Therefore, the maximum adsorption gas capacity of the target well coal rock can be determined based on the Langmuir volume of the air-dried basis coal rock.

[0054] S230 , determining a target gas deviation factor of the target well coal rock based on the pressure data and temperature data of the target well coal rock, and determining a natural gas volume coefficient of the target well coal rock based on the target gas deviation factor.

[0055] Optionally, determining the target gas deviation factor of the target well coal rock based on the pressure data and temperature data of the target well coal rock includes: determining the natural gas thermophysical parameters of the target well coal rock based on the pressure data and temperature data of the target well coal rock; and determining the target gas deviation factor of the target well coal rock based on the natural gas thermophysical parameters.

[0056] In this embodiment, the natural gas thermophysical property parameters of the target well coal rock can be determined based on the GERG-2008 equation, a method for calculating the natural gas thermophysical property parameters recommended by the international standard ISO 20765-2, using the pressure data and temperature data of the target well coal rock. Then, the target gas deviation factor of the target well coal rock can be determined based on the natural gas thermophysical property parameters.

[0057] Optionally, the natural gas volume coefficient of the target well coal rock is determined based on the target gas deviation factor, including: determining the target coal rock gas volume based on the target gas deviation factor, pressure data and temperature data of the target well coal rock; determining the standard coal rock gas volume based on the standard gas deviation factor, standard pressure and standard temperature; determining the natural gas volume coefficient of the target well coal rock based on the ratio of the target coal rock gas volume to the standard coal rock gas volume.

[0058] In this embodiment, the target coal rock gas volume V can be determined based on the target gas deviation factor, the pressure data and the temperature data of the target well coal rock. f Determine the standard coal gas volume V based on the standard gas deviation factor, standard pressure and standard temperature SC Based on the ratio of the target coal rock gas volume to the standard coal rock gas volume, the natural gas volume coefficient of the target well coal rock can be determined based on the following calculation formula:

[0059]

[0060] Among them, B g is the natural gas volume coefficient of the target well coal rock, V f is the volume of natural gas under coal formation conditions in the target well, V sc is the volume of natural gas under standard conditions, Z is the target gas deviation factor, T is the temperature data of the target well coal rock, P is the pressure data of the target well coal rock, and Z sc is the natural gas deviation factor in standard state, T sc is the standard temperature, P sc is the pressure in standard state. Among them, the standard state natural gas deviation factor Z sc It can take the value of 1, the temperature of the standard state T sc The domestic standard temperature can be 20℃, i.e. 293.15K, and the standard pressure P sc It can be one atmosphere, that is, 101.325 kPa. Therefore, the natural gas volume coefficient B of the target well coal rock is g The calculation result can be as follows:

[0061]

[0062] S240: Obtain the coal rock porosity of the target well coal rock, and determine the maximum free gas capacity of the target well coal rock based on the coal rock porosity and the natural gas volume coefficient.

[0063] Optionally, the maximum free gas capacity of the target well coal rock is determined based on the coal rock porosity and the natural gas volume coefficient, including: obtaining the coal rock apparent density of the target well coal rock, and determining the maximum free gas capacity of the target well coal rock based on the coal rock porosity, the natural gas volume coefficient and the coal rock apparent density.

[0064] In this embodiment, the apparent density of the coal rock can be the mass per unit volume obtained by measuring the coal rock sample in the target well. The apparent density of the coal rock in the target well is obtained, and the maximum free gas capacity of the target well coal rock is determined based on the coal rock porosity, natural gas volume coefficient, and the apparent density of the coal rock. Specifically, the following formula can be used:

[0065]

[0066] Among them, Q f is the maximum free gas capacity of the target well coal rock, φ is the total porosity of the coal rock, B g is the natural gas volume coefficient of the target well coal rock, ρ s It is the apparent density of coal rock.

[0067] S250. Determine the gas saturation of the target well coal rock based on the maximum free gas capacity, the total gas content, and the maximum adsorbed gas capacity.

[0068] In a preferred embodiment of the present invention, a specific example of calculating the gas saturation of a coal gas sample from a well in a certain basin in my country is used for illustration. According to the on-site pressure-maintained closed coring of a certain well, the coal sample depth is 2631.02 meters, the formation pressure is 25.78 MPa, the formation temperature is 85.16°C, and the total gas content of the on-site coring test is 30.27 m3 / t. According to the indoor test, the coal rock porosity is 6.91%; the Langmuir volume of the coal rock in the indoor high-pressure isothermal test is 19.52 m3 / t, and the Langmuir volume pressure is 2.88 MPa. The deviation factor of the coal gas calculated using the GERG-2008 equation is 0.9526, and the coal gas volume coefficient is 4.5758x10 -3 , the maximum volume of free gas is 10.943m 3 / t, total natural gas volume 30.463m 3 / t, and the final calculated coal rock gas saturation is 99.37%. If the traditional gas saturation calculation method is used to calculate the ratio of the measured desorbed gas volume to the adsorbed gas capacity under formation temperature and pressure conditions, the adsorbed gas saturation is 172.393%, exceeding 100%. Therefore, compared with traditional calculation methods, the gas saturation of the target well coal rock in this application can more accurately reflect the gas potential of the target well coal rock.

[0069] The technical solution of the embodiment of the present invention first determines the total gas content of the target well coal rock based on a gas sample from the target well coal rock. Then, a coal rock sample is obtained from the target well coal rock and the maximum adsorbed gas capacity of the target well coal rock is determined based on a high-pressure isothermal adsorption test. A target gas deviation factor is then determined based on the pressure and temperature data of the target well coal rock, and the natural gas volume coefficient of the target well coal rock is determined based on the target gas deviation factor. Furthermore, the coal rock porosity of the target well coal rock is obtained, and the maximum free gas capacity of the target well coal rock is determined based on the coal rock porosity and the natural gas volume coefficient. Finally, the gas saturation of the target well coal rock is determined based on the maximum free gas capacity, total gas content, and maximum adsorbed gas capacity. This solves the technical problem that existing coal rock gas saturation calculation methods cannot accurately represent the gas-bearing capacity and actual gas abundance of the coal rock. This method achieves the beneficial effect of accurately evaluating the gas saturation of coal rock wells, thereby providing a powerful reference for coal rock gas zone optimization and sweet spot evaluation.

[0070] Example 3

[0071] Figure 3 This is a schematic diagram of the structure of a device for determining gas saturation of coal gas provided in the third embodiment of the present invention. Figure 3 As shown, the device includes: a gas quantity determination module 310, a maximum ionizer capacity determination module 320 and a gas saturation determination module 330.

[0072] The gas amount determination module 310 is configured to determine the total gas content of the target well coal rock based on the gas sample of the target well coal rock, and to determine the maximum adsorbed gas capacity of the target well coal rock based on the coal rock sample of the target well coal rock;

[0073] A maximum free gas capacity determination module 320 is configured to determine the maximum free gas capacity of the target well coal rock based on the pressure data, temperature data, and porosity of the target well coal rock;

[0074] The gas saturation determination module 330 is used to determine the gas saturation of the target well coal rock based on the maximum free gas capacity, the total gas content and the maximum adsorbed gas capacity.

[0075] The technical solution of the embodiments of the present invention first determines the total gas content of the target well coal rock based on gas samples from the target well coal rock, and also determines the maximum adsorbed gas capacity of the target well coal rock based on the target well coal rock sample. This enables the total gas content and maximum adsorbed gas capacity of the target well coal rock to be obtained based on the target well coal rock sample data. The maximum free gas capacity of the target well coal rock is then determined based on the target well coal rock pressure data, temperature data, and coal rock porosity, providing a data basis for considering the maximum free gas capacity when calculating gas saturation. Finally, the gas saturation of the target well coal rock is determined based on the maximum free gas capacity, total gas content, and maximum adsorbed gas capacity. This solves the technical problem that existing coal rock gas saturation calculation methods cannot accurately represent the coal rock's gas-bearing capacity and actual gas abundance. This method achieves the beneficial effect of accurately evaluating the gas saturation of coal rock wells, thereby providing a powerful reference for coal rock gas zone optimization and sweet spot evaluation.

[0076] On the basis of the above technical solution, optionally, the gas quantity determination module 310 includes a total gas content determination unit.

[0077] Among them, the total gas content determination unit is used to obtain gas samples from the target well coal rock, test the gas samples based on the preset coalbed methane content determination method, and determine the pressure-maintaining release gas content, natural desorption gas content, residual gas content and loss gas content of the target well coal rock; and determine the total gas content of the target well coal rock based on the sum of the natural desorption gas content, residual gas content and loss gas content.

[0078] On the basis of the above technical solution, optionally, the gas quantity determination module 310 includes a maximum adsorbed gas capacity determination unit.

[0079] Among them, the maximum adsorption gas capacity determination unit is used to obtain coal rock samples of the target well coal rock, and determine the maximum adsorption gas capacity of the target well coal rock based on a high-pressure isothermal adsorption test on the coal rock sample.

[0080] On the basis of the above technical solution, an optional maximum adsorbed gas capacity determination unit is specifically used to test the coal rock sample based on a high-pressure isothermal adsorption test to obtain the target reservoir pressure and the target adsorbed natural gas volume; determine the air-dried Langmuir volume corresponding to the target well coal rock based on the target reservoir pressure, the target adsorbed natural gas volume and a preset isothermal adsorption equation; determine the maximum adsorbed gas capacity of the target well coal rock based on the air-dried Langmuir volume; wherein the isothermal adsorption equation is as follows,

[0081]

[0082] Among them, V L is the Langmuir volume of air-dried coal rock, P Lis the Langmuir pressure of air-dried base coal rock, P is the target reservoir pressure, and V is the target adsorbed natural gas volume.

[0083] On the basis of the above technical solution, further, the maximum free gas capacity determination module 320 is specifically used to determine the target gas deviation factor of the target well coal rock based on the pressure data and temperature data of the target well coal rock, and determine the natural gas volume coefficient of the target well coal rock based on the target gas deviation factor; obtain the coal rock porosity of the target well coal rock, and determine the maximum free gas capacity of the target well coal rock based on the coal rock porosity and the natural gas volume coefficient.

[0084] Based on the above technical solution, optionally, the maximum ionizer capacity determination module 320 includes a target gas deviation factor determination unit.

[0085] Among them, the target gas deviation factor determination unit is used to determine the natural gas thermophysical parameters of the target well coal rock based on the pressure data and temperature data of the target well coal rock; and determine the target gas deviation factor of the target well coal rock based on the natural gas thermophysical parameters.

[0086] Based on the above technical solution, optionally, the maximum scavenger capacity determination module 320 includes a natural gas volume coefficient determination unit.

[0087] Among them, the natural gas volume coefficient determination unit is used to determine the target coal rock gas volume based on the target gas deviation factor, the pressure data and temperature data of the target well coal rock; determine the standard coal rock gas volume based on the standard gas deviation factor, standard pressure and standard temperature; and determine the natural gas volume coefficient of the target well coal rock based on the ratio of the target coal rock gas volume to the standard coal rock gas volume.

[0088] On the basis of the above technical solution, further, the maximum free gas capacity determination module 320 is specifically used to obtain the apparent density of the coal rock of the target well, and determine the maximum free gas capacity of the coal rock of the target well based on the coal rock porosity, natural gas volume coefficient and coal rock apparent density.

[0089] Based on the above technical solution, optionally, the gas saturation determination module 330 is used to determine the maximum theoretical gas content based on the maximum free gas capacity and the maximum adsorbed gas capacity; and to determine the gas saturation of the target well coal rock based on the ratio of the total gas content to the maximum theoretical gas content.

[0090] The coal-rock gas gas saturation determination device provided in an embodiment of the present invention can execute the coal-rock gas gas saturation determination method provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the execution method.

[0091] Example 4

[0092] Figure 4A schematic diagram of the structure of an electronic device 10 that can be used to implement an embodiment of the present invention is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices (such as helmets, glasses, watches, etc.) and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present invention described and / or claimed herein.

[0093] like Figure 4 As shown, the electronic device 10 includes at least one processor 11 and a memory, such as a read-only memory (ROM) 12, a random access memory (RAM) 13, etc., which is communicatively connected to the at least one processor 11. The memory stores a computer program that can be executed by the at least one processor. The processor 11 can perform various appropriate actions and processes according to the computer program stored in the read-only memory (ROM) 12 or the computer program loaded from the storage unit 18 into the random access memory (RAM) 13. Various programs and data required for the operation of the electronic device 10 can also be stored in the RAM 13. The processor 11, ROM 12, and RAM 13 are connected to each other via a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0094] Multiple components in the electronic device 10 are connected to the I / O interface 15, including an input unit 16, such as a keyboard, a mouse, etc.; an output unit 17, such as various types of displays, speakers, etc.; a storage unit 18, such as a magnetic disk, an optical disk, etc.; and a communication unit 19, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 19 allows the electronic device 10 to exchange information / data with other devices via a computer network such as the Internet and / or various telecommunication networks.

[0095] The processor 11 can be any general-purpose and / or specialized processing component with processing and computing capabilities. Some examples of the processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various specialized artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. The processor 11 executes the various methods and processes described above, such as the method for determining coal gas saturation.

[0096] In some embodiments, the method for determining coal gas saturation may be implemented as a computer program, which is tangibly contained in a computer-readable storage medium, such as a storage unit 18. In some embodiments, part or all of the computer program may be loaded and / or installed on the electronic device 10 via the ROM 12 and / or the communication unit 19. When the computer program is loaded into the RAM 13 and executed by the processor 11, one or more steps of the method for determining coal gas saturation described above may be performed. Alternatively, in other embodiments, the processor 11 may be configured to execute the method for determining coal gas saturation by any other appropriate means (e.g., by means of firmware).

[0097] Various embodiments of the systems and techniques described herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), system-on-chip systems (SOCs), programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments can include being implemented in one or more computer programs that are executable and / or interpreted on a programmable system that includes at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0098] Computer programs for implementing the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when the computer program is executed by the processor, the functions / operations specified in the flowcharts and / or block diagrams are implemented. The computer program may be executed entirely on the machine, partially on the machine, as a stand-alone software package, partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0099] In the context of the present invention, computer-readable storage media can be tangible media that can contain or store a computer program for use with an instruction execution system, device or equipment or used in combination with an instruction execution system, device or equipment. Computer-readable storage media can include but are not limited to electronic, magnetic, optical, electromagnetic, infrared or semiconductor systems, devices or equipment, or any suitable combination of the foregoing. Alternatively, computer-readable storage media can be machine-readable signal media. More specific examples of machine-readable storage media can include electrical connections based on one or more lines, portable computer disks, hard disks, random access memories (RAM), read-only memories (ROM), erasable programmable read-only memories (EPROM or flash memory), optical fibers, portable compact disk read-only memories (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0100] To provide interaction with a user, the systems and techniques described herein can be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user can provide input to the electronic device. Other types of devices can also be used to provide interaction with the user; for example, the feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including acoustic input, voice input, or tactile input).

[0101] The systems and techniques described herein can be implemented in a computing system that includes back-end components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes front-end components (e.g., a user computer with a graphical user interface or web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such back-end components, middleware components, or front-end components. The components of the system can be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0102] A computing system may include clients and servers. The clients and servers are typically remote from each other and typically interact via a communication network. This client-server relationship arises through computer programs running on the respective computers, creating a client-server relationship. The server may be a cloud server, also known as a cloud computing server or cloud host. This server is a hosting product within the cloud computing service ecosystem that addresses the management difficulties and limited scalability of traditional physical hosting and VPS services.

[0103] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in the present invention can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution of the present invention can be achieved. This is not limited herein.

[0104] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A method for determining gas saturation of coal rock gas, characterized in that: include: Determining the total gas content of the target well coal rock based on the gas sample of the target well coal rock, and determining the maximum adsorbed gas capacity of the target well coal rock based on the coal rock sample of the target well coal rock; Determine the maximum free gas capacity of the target well coal rock based on the pressure data, temperature data and coal rock porosity of the target well coal rock; The gas saturation of the target well coal rock is determined based on the maximum free gas capacity, the total gas content, and the maximum adsorbed gas capacity.

2. The method according to claim 1, characterized in that The determining of the total gas content of the target well coal rock based on the gas sample of the target well coal rock includes: Obtaining a gas sample from the target well coal rock, testing the gas sample based on a preset coalbed methane content determination method, and determining the pressure-releasing gas content, naturally desorbed gas content, residual gas content, and lost gas content of the target well coal rock; The total gas content of the target well coal rock is determined based on the sum of the naturally desorbed gas content, the residual gas content and the lost gas content.

3. The method according to claim 1, characterized in that The determining the maximum adsorbed gas capacity of the target well coal rock based on the coal rock sample of the target well coal rock includes: A coal rock sample of the target well coal rock is obtained, and a maximum adsorption gas capacity of the target well coal rock is determined based on a high-pressure isothermal adsorption test on the coal rock sample.

4. The method according to claim 3, characterized in that The determining of the maximum adsorption gas capacity of the target well coal rock based on a high-pressure isothermal adsorption test on the coal rock sample comprises: Testing the coal rock sample based on a high-pressure isothermal adsorption test to obtain a target reservoir pressure and a target amount of adsorbed natural gas; Determining the air-dried Langmuir volume of the target well coal rock based on the target reservoir pressure, the target adsorbed natural gas volume, and a preset isothermal adsorption equation; determining the maximum adsorbed gas capacity of the target well coal rock based on the air-dried Langmuir volume of the coal rock; Wherein, the isothermal adsorption equation is as follows: Among them, V L is the Langmuir volume of air-dried coal rock, P L is the Langmuir pressure of air-dried base coal rock, P is the target reservoir pressure, and V is the target adsorbed natural gas volume.

5. The method according to claim 1, wherein The determining of the maximum free gas capacity of the target well coal rock based on the pressure data, temperature data and coal rock porosity of the target well coal rock includes: Determining a target gas deviation factor of the target well coal rock based on the pressure data and temperature data of the target well coal rock, and determining a natural gas volume coefficient of the target well coal rock based on the target gas deviation factor; The coal rock porosity of the target well coal rock is obtained, and the maximum free gas capacity of the target well coal rock is determined based on the coal rock porosity and the natural gas volume coefficient.

6. The method according to claim 5, characterized in that The determining of the target gas deviation factor of the target well coal rock based on the pressure data and temperature data of the target well coal rock includes: Determining the natural gas thermophysical property parameters of the target well coal rock based on the pressure data of the target well coal rock and the temperature data; The target gas deviation factor of the target well coal rock is determined based on the natural gas thermophysical property parameters.

7. The method according to claim 5, characterized in that The determining of the natural gas volume coefficient of the target well coal rock based on the target gas deviation factor includes: Determining a target coal rock gas volume based on the target gas deviation factor, the pressure data of the target well coal rock, and the temperature data; Determine the standard coal gas volume based on the standard gas deviation factor, standard pressure and standard temperature; The natural gas volume coefficient of the target well coal rock is determined based on the ratio of the target coal rock gas volume to the standard coal rock gas volume.

8. The method according to claim 5, characterized in that The determining of the maximum free gas capacity of the target well coal rock based on the coal rock porosity and the natural gas volume coefficient includes: Obtain the apparent density of the target well coal rock, and determine the maximum free gas capacity of the target well coal rock based on the coal rock porosity, the natural gas volume coefficient, and the coal rock apparent density.

9. The method according to claim 1, characterized in that The determining of the gas saturation of the target well coal rock based on the maximum free gas capacity, the total gas content, and the maximum adsorbed gas capacity includes: determining a maximum theoretical gas content based on the maximum free gas capacity and the maximum adsorbed gas capacity; The gas saturation of the target well coal rock is determined based on the ratio of the total gas content to the maximum theoretical gas content.

10. A device for determining rock gas saturation, characterized in that: include: a gas quantity determination module, configured to determine the total gas content of the target well coal rock based on the gas sample of the target well coal rock, and to determine the maximum adsorbed gas capacity of the target well coal rock based on the coal rock sample of the target well coal rock; a maximum free gas capacity determination module, configured to determine the maximum free gas capacity of the target well coal rock based on the pressure data, temperature data and coal rock porosity of the target well coal rock; A gas saturation determination module is used to determine the gas saturation of the target well coal rock based on the maximum free gas capacity, the total gas content and the maximum adsorbed gas capacity.

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