A method, system and electronic device for calculating the proportion of contribution of a hydrocarbon source rock to a gas reservoir

Abstract

The application discloses a kind of calculation method, system and electronic equipment of the contribution proportion of hydrocarbon source rock to gas reservoir, is related to natural gas exploration field, the method includes: the chemical kinetics model is applied to the calibration of methane in multiple gas samples, obtains the methane conversion rate of each horizon;According to methane conversion rate, methane carbon isotope is calibrated, and the methane carbon isotope value evolution curve of each horizon is obtained;According to methane carbon isotope value evolution curve, the hydrocarbon generation conversion rate of methane carbon isotope value of each horizon since different geological periods is calculated;According to hydrocarbon generation conversion rate, the methane carbon isotope probability density distribution frequency of corresponding each horizon is calculated;The methane carbon isotope probability density distribution frequency of multiple different horizons mixed gas reservoir is obtained;According to the methane carbon isotope probability density distribution frequency of mixed gas reservoir and the methane carbon isotope probability density distribution frequency of each horizon, the contribution proportion of each horizon gas reservoir in mixed gas reservoir is determined.The application improves natural gas exploration efficiency.

Description

Technical Field

[0001] This invention relates to the field of natural gas exploration, and in particular to a method, system, and electronic equipment for calculating the contribution ratio of source rocks to gas reservoirs. Background Technology

[0002] Gas reservoirs are typically supplied by multiple source rocks, resulting in multi-source methane contamination. Determining the quantitative contribution of different source rocks to mixed-source natural gas remains a challenging problem in natural gas exploration research both domestically and internationally. The hydrocarbon generation process is described in both "The Theory and Application of Hydrocarbon Formation Kinetics of Organic Matter" by Lu Shuangfang (Petroleum Industry Press) and the doctoral dissertation "Study and Application of Hydrogen Isotope Fractionation Kinetics in Natural Gas Generation" by Li Jijun, a doctoral student at Daqing Petroleum Institute. During hydrocarbon generation, the organic matter... 12 CH4 and 13 Differences in CH4 yield cause methane carbon isotope fractionation, the degree of which is related to the maturity of the source material. Therefore, the methane carbon isotopes in a gas reservoir can be used to infer the gas source situation. Summary of the Invention

[0003] The purpose of this invention is to provide a method, system, and electronic equipment for calculating the contribution ratio of source rocks to gas reservoirs, which can provide a basis for exploration well deployment and improve the efficiency of natural gas exploration.

[0004] To achieve the above objectives, the present invention provides the following solution:

[0005] A method for calculating the contribution ratio of source rocks to gas reservoirs, the calculation method comprising:

[0006] The methane in multiple gas samples was calibrated using a chemical kinetic model to obtain the methane conversion rate of each layer; the multiple gas samples were obtained by pyrolysis hydrocarbon generation experiments on kerogen from multiple source rock samples from different layers.

[0007] Based on the methane conversion rates of multiple layers, the methane carbon isotopes were calibrated to obtain the methane carbon isotope value evolution curves for each layer.

[0008] Based on the evolution curves of methane carbon isotope values ​​in each stratum, the hydrocarbon conversion rate of methane carbon isotope values ​​in each stratum from different geological periods to the present is calculated.

[0009] Based on the hydrocarbon conversion rate of methane carbon isotope values ​​from different geological periods in each stratum to the present, calculate the frequency of the probability density distribution of methane carbon isotopes in each stratum.

[0010] Obtain the frequency distribution of methane carbon isotope probability density in multiple mixed gas reservoirs at different stratigraphic levels;

[0011] Based on the probability density distribution frequency of methane carbon isotopes in the mixed gas reservoir and the probability density distribution frequency of methane carbon isotopes in each stratum, the contribution ratio of each stratum in the mixed gas reservoir is determined.

[0012] Optionally, the chemical kinetic model is a parallel first-order reaction model.

[0013] Optionally, the Cramer model can be applied to calibrate the methane carbon isotopes and obtain the evolution curves of methane carbon isotope values ​​at each layer.

[0014] Optionally, based on the hydrocarbon conversion rate of the methane carbon isotope values ​​from different geological periods to the present, the corresponding methane carbon isotope probability density distribution frequency for each stratum is calculated, specifically including:

[0015] Based on the hydrocarbon conversion rate of the methane carbon isotope values ​​from different geological periods in each stratum to the present, calculate the corresponding methane carbon isotope values ​​for each stratum.

[0016] Based on the methane carbon isotope values ​​of each layer, the ksdensity function is applied to calculate the frequency of the probability density distribution of methane carbon isotopes for each corresponding layer.

[0017] Optionally, the carbon isotope value calculation formula is applied to calculate the corresponding methane carbon isotope values ​​for each layer; the carbon isotope value calculation formula is as follows:

[0018] Carbon isotope value = (total potential ratio × r) 13 C / r 12 C / 1123.72-1)×1000;

[0019] Among them, the total potential ratio is 13 C and 12 The ratio of C to hydrocarbon generation potential; r 13 C is 13 Conversion rate of C; r 12 C is 12 Conversion rate of C.

[0020] A calculation system for the contribution ratio of source rocks to gas reservoirs, applying the aforementioned calculation method for the contribution ratio of source rocks to gas reservoirs, the calculation system comprising:

[0021] The methane conversion rate determination module is used to calibrate the methane in multiple gas samples using a chemical kinetic model to obtain the methane conversion rate of each layer; the multiple gas samples are obtained by pyrolysis hydrocarbon generation experiments on kerogen from multiple source rock samples from different layers.

[0022] The calibration module is used to calibrate the methane carbon isotopes based on the methane conversion rates of multiple layers, and obtain the methane carbon isotope value evolution curves for each layer.

[0023] The first calculation module is used to calculate the hydrocarbon conversion rate of methane carbon isotope values ​​from different geological periods to the present, based on the evolution curve of methane carbon isotope values ​​of each stratum.

[0024] The second calculation module is used to calculate the probability density distribution frequency of methane carbon isotopes in each layer based on the hydrocarbon conversion rate of the methane carbon isotope values ​​from different geological periods to the present.

[0025] The acquisition module is used to acquire the frequency of methane carbon isotope probability density distribution in multiple mixed gas reservoirs at different stratigraphic levels.

[0026] The contribution ratio determination module is used to determine the contribution ratio of each layer of gas reservoir in the mixed gas reservoir based on the probability density distribution frequency of methane carbon isotopes in the mixed gas reservoir and the probability density distribution frequency of methane carbon isotopes in each layer.

[0027] An electronic device includes a memory and a processor, the memory storing a computer program, and the processor running the computer program to enable the electronic device to perform the above-described method for calculating the contribution ratio of source rocks to gas reservoirs.

[0028] Optionally, the memory is a readable storage medium.

[0029] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0030] This invention establishes a methane carbon isotope fractionation model using a chemical kinetic model, calculates the methane carbon isotope distribution in each formation, and fits the measured isotope distribution of the gas reservoir by mixing them in different proportions to determine the optimal contribution ratio of each formation to natural gas. Applying methane carbon isotope calculations to determine the contribution ratio of source rocks to the gas reservoir significantly improves the scientific rigor and reliability of quantitative studies on the contribution ratio of mixed-source natural gas, providing a basis for exploration well deployment and improving natural gas exploration efficiency. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a flowchart illustrating the method for calculating the contribution ratio of source rocks to gas reservoirs according to the present invention.

[0033] Figure 2 This is a conversion rate-temperature curve of methane at layer A in this invention;

[0034] Figure 3 This is a reaction fraction-activation energy curve of methane at layer A in this invention;

[0035] Figure 4 This is a conversion-temperature curve of methane at layer B in this invention;

[0036] Figure 5 This is a reaction fraction-activation energy curve of methane at layer B in this invention;

[0037] Figure 6 This is the evolution curve of methane carbon isotope values ​​at layer A of the present invention;

[0038] Figure 7 In layer A of the present invention 12 C and 13 Reaction fraction-activation energy curve of C;

[0039] Figure 8 This is the evolution curve of the carbon isotope value of methane at layer B in this invention;

[0040] Figure 9 In layer B of the present invention 12 C and 13 Reaction fraction-activation energy curve of C;

[0041] Figure 10 This is a thermal history diagram of the burial site of the present invention;

[0042] Figure 11 This is a schematic diagram of the probability density distribution frequency of methane carbon isotopes according to the present invention;

[0043] Figure 12 This is a schematic diagram comparing the natural gas doping results at layer A and layer B in this invention. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] The purpose of this invention is to provide a method, system, and electronic equipment for calculating the contribution ratio of source rocks to gas reservoirs, which can provide a basis for exploration well deployment and improve the efficiency of natural gas exploration.

[0046] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0047] Example 1

[0048] like Figure 1 As shown, this invention provides a method for calculating the contribution ratio of source rocks to gas reservoirs, the calculation method comprising:

[0049] Step S1: Apply a chemical kinetic model to calibrate the methane in multiple gas samples to obtain the methane conversion rate of each layer; the multiple gas samples are obtained by pyrolysis hydrocarbon generation experiments of kerogen from multiple source rock samples from different layers.

[0050] In practical applications, carbon isotope test data of methane in gas reservoirs are collected. In this invention, source rock samples with low maturity from stratigraphic layers A and B that contribute to the gas reservoir are collected. The samples are purified into kerogen, and then soluble organic matter is removed by extraction to prepare kerogen samples.

[0051] Pyrolysis hydrocarbon generation experiments were conducted on kerogen samples from layers A and B. The experiments employed a gold tube-autoclave sealed system. 100 mg of prepared kerogen sample was sealed into a gold tube under argon protection. The gold tube was then placed inside the autoclave, which was interconnected. Pressure was regulated by controlling the high-pressure pump using a pressure sensor, achieving a pressure error of less than 2 MPa. The autoclave was heated using a programmed temperature ramp, with heating rates of 20 °C / h and 2 °C / h, respectively, from 300 °C to 600 °C, with each test temperature 24 °C apart. When the gold tube containing the sample reached the designated temperature, the autoclave was removed and cooled. The generated gas was collected in a vacuum and analyzed by chromatography-mass spectrometry and carbon isotope analysis of hydrocarbon gases (C1-C3).

[0052] When calibrating methane, the process of organic matter forming gas can be described by a chemical kinetic model. This invention selects a parallel first-order reaction model. The parallel first-order reaction model is an existing model.

[0053] Suppose that the hydrocarbon formation process of kerogen (KEO) consists of a series (NO) parallel first-order reactions, and the activation energy of each reaction is EOG. i Pre-exponential factor AOG i Let the initial potential of kerogen for each reaction be XOG. i0 Let i = 1, 2...NO. At time t, the hydrocarbon generation of the i-th reaction is XOG. i Let R be the molar gas constant and T be the thermodynamic temperature, then we have:

[0054]

[0055]

[0056] At this point, the total gas production from all first-order reactions is:

[0057]

[0058] in:

[0059] NOG – The number of parallel first-order reactions in the oil cracking to gas process.

[0060] AOG i —Pre-exponential factor.

[0061] EOG i — The magnitude of the activation energy of the i-th reaction.

[0062] XOG i —The gas production rate of the i-th reaction up to time t.

[0063] XOG i0 —The original potential of the i-th reaction.

[0064] KOG i —The reaction rate constant of the i-th reaction.

[0065] The oil-to-gas ratio measured after continuous heating under certain isothermal experimental conditions for a certain time t is defined as XOG1. lj Accordingly, set the EOG under the same conditions. i AOG i XOG i0 XOG calculated based on the model lj Objective function can be constructed as follows:

[0066]

[0067] in:

[0068] LOG — Number of experimental groups.

[0069] JOG – Number of sampling points on an experimental curve.

[0070] Where Q() is the error, XOG lj The oil-to-gas conversion rate calculated using the model in formula (1). XOG1 lj The measured oil-to-gas conversion rate is...

[0071] AOG in the formula i and XOG i0 It should also satisfy:

[0072]

[0073] That is, the calibration problem of the model is transformed into the problem of finding the minimum point of the non-negative objective function that satisfies the constraint condition, i.e., formula (3), and the dynamic problem is transformed into a mathematical calculation problem.

[0074] Based on the data from the metal tube thermal simulation hydrocarbon generation experiment, the methane yields of samples from the two layers were normalized and then calibrated using a chemical kinetic model. The calibration results are as follows: Figures 2-5 As shown. Among them, Figure 3 and Figure 5 The letter A in the exponential function is the pre-exponential factor.

[0075] Specifically, the chemical kinetic model is a parallel first-order reaction model.

[0076] Step S2: Based on the methane conversion rate of multiple layers, the methane carbon isotopes are calibrated to obtain the methane carbon isotope value evolution curves for each layer.

[0077] Specifically, the Cramer model was applied to calibrate the carbon isotopes of methane, and the evolution curves of the carbon isotope values ​​of methane at each layer were obtained.

[0078] In practical applications, methane carbon isotopes are labeled. According to the Cramer model, methane formation is considered as the result of n first-order reactions. For each reaction, the carbon isotopes of methane are... 13 C and containing 12 The formation rate coefficients of C gas are different:

[0079]

[0080] Where A is the pre-exponential factor, Ea is the magnitude of the activation energy of the reaction, R is the molar gas constant, T is the thermodynamic temperature, and ΔEa is the difference in activation energy.

[0081] The instantaneous model built upon this is:

[0082]

[0083] The cumulative effect model is as follows:

[0084]

[0085] Where, k i 12 c is the rate coefficient for methane formation; r i 12 c(t) represents the i-th reaction at time t. 12 CH4 formation rate; c i 12 c(t) represents the i-th reaction at time t. 12 CH4 cumulative production; For the i-th reaction 12The hydrocarbon generation potential of CH4 is equal to the product of the corresponding reaction fraction and the total hydrocarbon generation potential.

[0086] A hydrocarbon generation kinetic model was applied to calibrate a methane carbon isotope fractionation model, and the relevant parameters and fitting results were obtained as follows: Figures 6-9 As shown. Among them, Figure 7 and Figure 9 The letter A in the equation represents the pre-exponential factor. In this invention, δ 13 C(‰) is the carbon isotope value of methane.

[0087] Step S3: Based on the evolution curves of methane carbon isotope values ​​in each stratum, calculate the hydrocarbon conversion rate of methane carbon isotope values ​​from different geological periods to the present in each stratum.

[0088] In practical applications, virtual wells are established in areas without existing wells, and the depth of these virtual wells should extend vertically through the geological strata to be studied. PetroMod basin simulation software is used to analyze the evolutionary history of the target stratum in a single well. Based on the doctoral dissertation of Dr. He Chunmin from the Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, entitled "Geochemical Characteristics of Source Rocks, Hydrocarbon Generation Evolution, and Gas Source Tracing in the Deepwater Area of ​​the Qiongdongnan Basin," a virtual well burial history is established. On this basis, the simulated Ro value of the single well is compared with the Ro value obtained from analytical testing to ensure that the simulated geological process closely approximates the actual situation. Further refinement of data such as stratigraphic thickness, geochemical characteristics of source rocks, geothermal heat flow, and surface temperature is used to simulate the hydrocarbon generation capacity of the target stratum, qualitatively and quantitatively characterizing its evolutionary history. Figure 10 As shown. This step is to obtain the geothermal gradient and stratum thickness. Combining experimental values ​​with actual geological conditions is essential to better represent the underground situation.

[0089] By calibrating the results of thermal simulation experiments on hydrocarbon source rocks of stratigraphic layers A and B, it was determined that... 12 C and 13 C-reaction activation energy and reaction fraction, and based on the thermal history reconstruction of the study area, formula (3) was used to calculate the source rocks of different strata and periods for the two samples respectively. 12 C and 13 Hydrocarbon conversion rate of C.

[0090] Step S4: Based on the hydrocarbon conversion rate of the methane carbon isotope values ​​from different geological periods to the present, calculate the probability density distribution frequency of the methane carbon isotope in each layer.

[0091] S4 specifically includes:

[0092] Step S41: Calculate the corresponding methane carbon isotope values ​​for each stratum based on the hydrocarbon conversion rate of the methane carbon isotope values ​​from different geological periods to the present.

[0093] Step S42: Based on the methane carbon isotope values ​​of each layer, apply the ksdensity function to calculate the corresponding methane carbon isotope probability density distribution frequency for each layer.

[0094] Step S5: Obtain the probability density distribution frequency of methane carbon isotopes in multiple mixed gas reservoirs at different strata.

[0095] Specifically, the carbon isotope value calculation formula is applied to calculate the corresponding methane carbon isotope values ​​for each layer; the carbon isotope value calculation formula is as follows:

[0096] Carbon isotope value = (total potential ratio × r) 13 C / r 12 C / 1123.72-1)×1000(4)

[0097] The total potential ratio is the ratio of the hydrocarbon generation potential of 13C to that of 12C; r 13 C is 13 Conversion rate of C; r 12 C is 12 Conversion rate of C.

[0098] In practical applications, the total potential ratio (Rzqb) is the ratio of the hydrocarbon generation potential of 13C to that of 12C. The formula is zqb=(δ13C / 1000+1)×1123.72, where δ13C is the final cumulative isotope value determined by the evolution trend of isotope values. The corresponding conversion rate is determined according to the stratum depth. Based on formula (4), the methane carbon isotope values ​​generated from different geological periods to the present can be calculated. Furthermore, the distribution of methane carbon isotopes generated in two sets of strata is determined using the ksdensity function in MATLAB. For example... Figure 11 As shown.

[0099] Step S6: Determine the contribution ratio of each layer of gas reservoir in the mixed gas reservoir based on the probability density distribution frequency of methane carbon isotopes in the mixed gas reservoir and the probability density distribution frequency of methane carbon isotopes in each layer.

[0100] In practical applications, the distribution frequencies of methane carbon isotope experimental data from gas reservoir layers A and B are statistically analyzed. Using MATLAB software, the calculated methane carbon isotope distributions of the two layers are mixed in different proportions to fit the measured isotope distributions of the gas reservoir, thus determining the optimal proportion of natural gas contribution from each layer. For example... Figure 12 As shown, when the contribution of natural gas is calculated as 65% for layer A and 35% for layer B, it closely matches the main peak of carbon isotopes in the gas reservoir.

[0101] Specifically, assuming the proportion of stratigraphic A is k (k ranges from 1 to 9), then the proportion of stratigraphic B is 10-k. Calculate the methane carbon isotope values ​​of equal amounts of stratigraphic A and B, mix k times the calculated methane carbon isotope value of stratigraphic A with 10-k times the calculated methane carbon isotope value of stratigraphic B, and then use the ksdensity function to calculate the probability density distribution.

[0102] This invention provides a basis for deploying exploration wells. Specifically, by calculating the contribution ratio of two source rocks to natural gas using the method of this invention, it can be determined which source rock contributes more. The next gas reservoir can then be located based on the location of the source rock with the greater contribution. If the contribution is small or non-existent, then the location of this source rock will not be used as a basis for deploying exploration wells, thus guiding exploration. If the contribution ratios of the two source rocks are roughly equal, then both source rocks need to be considered.

[0103] Example 2

[0104] To implement the method corresponding to Embodiment 1 above and achieve the corresponding functions and technical effects, a calculation system for the contribution ratio of source rocks to gas reservoirs is provided below. The calculation system includes:

[0105] The methane conversion rate determination module is used to calibrate the methane in multiple gas samples using a chemical kinetic model to obtain the methane conversion rate of each layer; the multiple gas samples are obtained by pyrolysis hydrocarbon generation experiments on kerogen from multiple source rock samples from different layers.

[0106] The calibration module is used to calibrate the methane carbon isotopes based on the methane conversion rates of multiple layers, and obtain the evolution curves of the methane carbon isotope values ​​of each layer.

[0107] The first calculation module is used to calculate the hydrocarbon conversion rate of methane carbon isotope values ​​from different geological periods to the present, based on the methane carbon isotope value evolution curves of each stratum.

[0108] The second calculation module is used to calculate the probability density distribution frequency of methane carbon isotopes in each stratum based on the hydrocarbon conversion rate of the methane carbon isotope values ​​from different geological periods to the present.

[0109] The acquisition module is used to acquire the probability density distribution frequency of methane carbon isotopes in multiple mixed gas reservoirs at different strata.

[0110] The contribution ratio determination module is used to determine the contribution ratio of each layer of gas reservoir in the mixed gas reservoir based on the probability density distribution frequency of methane carbon isotopes in the mixed gas reservoir and the probability density distribution frequency of methane carbon isotopes in each layer.

[0111] Example 3

[0112] This invention provides an electronic device, including a memory and a processor. The memory stores a computer program, and the processor runs the computer program to enable the electronic device to execute the method for calculating the contribution ratio of source rocks to gas reservoirs according to Embodiment 1.

[0113] Alternatively, the aforementioned electronic device may be a server.

[0114] In addition, this embodiment of the invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the method for calculating the contribution ratio of source rocks to gas reservoirs as described in Embodiment 1.

[0115] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section.

[0116] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for calculating the contribution ratio of source rocks to gas reservoirs, characterized in that, The calculation method includes: The methane in multiple gas samples was calibrated using a chemical kinetic model to obtain the methane conversion rate of each layer; the multiple gas samples were obtained by pyrolysis hydrocarbon generation experiments on kerogen from multiple source rock samples from different layers. Based on the methane conversion rates of multiple layers, the methane carbon isotopes were calibrated to obtain the methane carbon isotope value evolution curves for each layer. Based on the evolution curves of methane carbon isotope values ​​in each stratum, the hydrocarbon conversion rate of methane carbon isotope values ​​in each stratum from different geological periods to the present is calculated. Based on the hydrocarbon conversion rate of methane carbon isotope values ​​from different geological periods in each stratum to the present, calculate the frequency of the probability density distribution of methane carbon isotopes in each stratum. Obtain the frequency distribution of methane carbon isotope probability density in multiple mixed gas reservoirs at different stratigraphic levels; Based on the probability density distribution frequency of methane carbon isotopes in the mixed gas reservoir and the probability density distribution frequency of methane carbon isotopes in each stratum, the contribution ratio of each stratum in the mixed gas reservoir is determined.

2. The method for calculating the contribution ratio of source rocks to gas reservoirs according to claim 1, characterized in that, The chemical kinetic model is a parallel first-order reaction model.

3. The method for calculating the contribution ratio of source rocks to gas reservoirs according to claim 1, characterized in that, The Cramer model was used to calibrate the carbon isotopes of methane, and the evolution curves of the carbon isotope values ​​of methane at each layer were obtained.

4. The method for calculating the contribution ratio of source rocks to gas reservoirs according to claim 1, characterized in that, Based on the hydrocarbon conversion rate of methane carbon isotope values ​​from different geological periods in each stratum to the present, the corresponding methane carbon isotope probability density distribution frequency for each stratum is calculated, specifically including: Based on the hydrocarbon conversion rate of the methane carbon isotope values ​​from different geological periods in each stratum to the present, calculate the corresponding methane carbon isotope values ​​for each stratum. Based on the methane carbon isotope values ​​of each layer, the ksdensity function is applied to calculate the frequency of the probability density distribution of methane carbon isotopes for each corresponding layer.

5. The method for calculating the contribution ratio of source rocks to gas reservoirs according to claim 4, characterized in that, The carbon isotope values ​​of methane at each layer are calculated using the carbon isotope value calculation formula; the carbon isotope value calculation formula is as follows: Carbon isotope value = (total potential ratio × r) 13 C / r 12 C / 1123.72-1)×1000; The total potential ratio is the ratio of the hydrocarbon generation potential of 13C to that of 12C; r 13 C is 13 Conversion rate of C; r 12 C is 12 Conversion rate of C.

6. A system for calculating the contribution ratio of source rocks to gas reservoirs, characterized in that, The computing system includes: The methane conversion rate determination module is used to calibrate the methane in multiple gas samples using a chemical kinetic model to obtain the methane conversion rate of each layer; the multiple gas samples are obtained by pyrolysis hydrocarbon generation experiments on kerogen from multiple source rock samples from different layers. The calibration module is used to calibrate the methane carbon isotopes based on the methane conversion rates of multiple layers, and obtain the methane carbon isotope value evolution curves for each layer. The first calculation module is used to calculate the hydrocarbon conversion rate of methane carbon isotope values ​​from different geological periods to the present, based on the evolution curve of methane carbon isotope values ​​of each stratum. The second calculation module is used to calculate the probability density distribution frequency of methane carbon isotopes in each layer based on the hydrocarbon conversion rate of the methane carbon isotope values ​​from different geological periods to the present. The acquisition module is used to acquire the frequency of methane carbon isotope probability density distribution in multiple mixed gas reservoirs at different stratigraphic levels. The contribution ratio determination module is used to determine the contribution ratio of each layer of gas reservoir in the mixed gas reservoir based on the probability density distribution frequency of methane carbon isotopes in the mixed gas reservoir and the probability density distribution frequency of methane carbon isotopes in each layer.

7. An electronic device, characterized in that, The device includes a memory and a processor, the memory being used to store a computer program, and the processor running the computer program to enable the electronic device to perform the method for calculating the contribution ratio of source rocks to gas reservoirs according to any one of claims 1 to 5.

8. An electronic device according to claim 7, characterized in that, The memory is a readable storage medium.

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