Carbon release estimation method for organic carbon in continental lake basin

Abstract

The invention discloses a carbon release estimation method for continental lake basin organic carbon, and relates to the technical field of carbon release data operation processing, and the method comprises the steps: obtaining geological data of a target region; respectively determining hydrocarbon source rock data and reservoir stratum data according to the geological data; according to the hydrocarbon source rock data and the reservoir stratum data, oil source comparison is carried out by adopting a chromatography-mass spectrogram comparison method, and the corresponding relation between the hydrocarbon source rock and the reservoir stratum is determined; simulating an oil-gas accumulation dynamic process, and determining hydrocarbon generation rate and hydrocarbon expulsion rate data; according to the hydrocarbon source rock data, the reservoir stratum data, the corresponding relation between the hydrocarbon source rock and the reservoir stratum and the hydrocarbon generation rate and hydrocarbon expulsion rate data, the carbon release amount of organic carbon in the target area is obtained through calculation. According to the method, the accuracy of estimating the carbon release amount of continental lake basin organic carbon can be effectively improved.

Description

Technical Field

[0001] The present application relates to the technical field of carbon release data calculation and processing, and in particular to a carbon release estimation method for organic carbon in a terrestrial lake basin. Background Art

[0002] Against the backdrop of global warming, the carbon cycle has become a hot topic in the field of earth science. As an important part of the carbon cycle, the storage and release of carbon in terrestrial ecosystems has a profound impact on the global climate. Continental lake basins are important carbon storage sites in terrestrial ecosystems, and the dynamic changes of organic carbon in lake basins are closely related to global climate change. By calculating the release of organic carbon in continental lake basins, we can reflect the changes in carbon dioxide during the geological history, make corresponding explanations for the changes in the climate environment during the geological history, and provide a reference for modern climate change.

[0003] At present, the existing methods for calculating the carbon release of organic carbon mainly include laboratory simulation method, numerical model method and field monitoring method. Among them, for laboratory simulation method, such as pyrolysis experiment, it is mainly to measure the carbon release at different temperatures by heating the sample. Although this laboratory simulation method has the advantages of fast and good repeatability, it may not conform to the actual geological conditions under high temperature conditions, resulting in inaccurate results of carbon release of organic carbon. For numerical model methods, such as geochemical models, it is mainly based on the geochemical reaction kinetics of organic carbon in sedimentary rocks to establish a mathematical model to simulate the release process of organic carbon. The uncertainty of the model parameters of this numerical model method is large, and a large amount of data support is required, otherwise the final carbon release result of organic carbon will be inaccurate. For field monitoring methods, such as gas flux measurement, the carbon release is determined by directly measuring the carbon dioxide flux released from the surface of sedimentary rocks. However, this field monitoring method is greatly affected by environmental factors, the data fluctuates greatly, and there is also a general inaccuracy in the carbon release results of organic carbon.

[0004] In summary, the existing methods for calculating the carbon release of organic carbon generally have the problem of low precision. Therefore, how to improve the accuracy of estimating the carbon release of organic carbon in terrestrial lake basins has become a technical problem that needs to be urgently solved in this field. Summary of the invention

[0005] The purpose of this application is to provide a method for estimating carbon release from organic carbon in continental lake basins, which can effectively improve the accuracy of estimating the carbon release amount of organic carbon in continental lake basins.

[0006] To achieve the above objectives, this application provides the following solutions:

[0007] The present application provides a method for estimating carbon release of organic carbon in a continental lake basin, and the method for estimating carbon release of organic carbon in a continental lake basin comprises the following steps:

[0008] Obtain the geological data of the target area;

[0009] According to the geological data, determine the source rock data and the reservoir data respectively; the source rock data and the reservoir data are respectively used to characterize the horizons and ranges of the source rock layer and the reservoir layer;

[0010] According to the source rock data and the reservoir data, use the chromatogram - mass spectrometry comparison method for oil - source correlation to determine the corresponding relationship between the source rock and the reservoir;

[0011] Simulate the dynamic process of hydrocarbon accumulation to determine the hydrocarbon generation rate and hydrocarbon expulsion rate data;

[0012] According to the source rock data, the reservoir data, the corresponding relationship between the source rock and the reservoir, and the hydrocarbon generation rate and hydrocarbon expulsion rate data, calculate the carbon release amount of organic carbon in the target area.

[0013] Optionally, according to the geological data, determining the source rock data and the reservoir data respectively specifically includes the following steps:

[0014] According to the geochemical data and logging curve data in the geological data, define the horizons and spatial distribution profiles of the source rock layer in the target area, and analyze the hydrocarbon generation and expulsion history of the source rock to obtain the source rock data;

[0015] According to the geochemical data in the geological data, divide and detect the reservoir in the target area to obtain the reservoir data.

[0016] Optionally, according to the source rock data and the reservoir data, using the chromatogram - mass spectrometry comparison method for oil - source correlation to determine the corresponding relationship between the source rock and the reservoir specifically includes the following steps:

[0017] According to the source rock data and the reservoir data, determine the chromatograms and mass spectra of various biomarker compounds in the crude oil in the target area;

[0018] According to the chromatograms and mass spectra of various biomarker compounds in the crude oil in the target area, use the chromatogram - mass spectrometry comparison method to analyze the chromatographic characteristics and mass spectrometric characteristics of various biomarker compounds in the crude oil, determine the influence of different source rock types and thermal evolution degrees on the crude oil composition, and respectively compare the retention times, mass spectrometric characteristics and relative abundances of various biomarker compounds, identify the types, maturities and generation processes of the source rocks in the source rocks, realize oil - source correlation, trace back the origin of the oil and gas, and determine the corresponding relationship between the source rock and the reservoir.

[0019] Optionally, simulate the hydrocarbon accumulation dynamics process to determine the hydrocarbon generation rate and hydrocarbon expulsion rate data, specifically including the following steps:

[0020] Use BasinMod software to simulate the hydrocarbon accumulation dynamics process to define the hydrocarbon generation and expulsion history, tectonic subsidence history, burial history, thermal evolution history, and hydrocarbon charging history, and determine the hydrocarbon distribution characteristics and patterns;

[0021] Based on the hydrocarbon distribution characteristics and patterns, restore the hydrocarbon generation and expulsion history to obtain the hydrocarbon generation rate and hydrocarbon expulsion rate data.

[0022] Optionally, calculate the carbon release amount of organic carbon in the target area according to the source rock data, the reservoir data, the corresponding relationship between the source rock and the reservoir, and the hydrocarbon generation rate and hydrocarbon expulsion rate data, specifically including the following steps:

[0023] Calculate the total hydrocarbon generation amount of the source rock and the geological reserves of the reservoir respectively according to the source rock data, the reservoir data, the corresponding relationship between the source rock and the reservoir, and the hydrocarbon generation rate and hydrocarbon expulsion rate data;

[0024] Calculate the total hydrocarbon release amount according to the total hydrocarbon generation amount of the source rock and the geological reserves of the reservoir;

[0025] Calculate the organic carbon content of the total hydrocarbons released into the environment according to the total hydrocarbon release amount and the source rock data;

[0026] Calculate the carbon release amount of organic carbon in the target area according to the total hydrocarbon release amount and the organic carbon content of the total hydrocarbons released into the environment.

[0027] Optionally, calculate the total hydrocarbon generation amount of the source rock using the following formula:

[0028] Q = S × H × ρ × TOC 残留 × K c × β × 10 -3 ;

[0029] K c = TOC 原始 / TOC 残留 ;

[0030] where Q is the total hydrocarbon generation amount of the source rock; S is the area of the source rock; H is the thickness of the source rock; ρ is the density of the source rock; TOC 残留 is the current organic carbon content; TOC 原始 is the initial organic carbon content; K c is the organic carbon recovery coefficient; β is the hydrocarbon production rate.

[0031] Optionally, the geological reserves of the reservoir include the geological reserves of crude oil and the geological reserves of natural gas.

[0032] The geological reserves of the crude oil and the geological reserves of the natural gas are calculated respectively by the following formulas:

[0033]

[0034] Wherein, N is the geological reserves of the crude oil; G is the geological reserves of the natural gas; A is the oil / gas-bearing area; h is the effective thickness of the oil / gas layer; is the effective porosity of the oil / gas layer; S oi is the original oil saturation of the oil layer; S gi is the original gas saturation of the gas layer; ρ o is the density of the surface degassed crude oil; B oi is the original crude oil volume factor; B gi is the original natural gas volume factor.

[0035] Optionally, the total amount of hydrocarbon released is calculated by the following formula:

[0036] T = Q - N(G);

[0037] Wherein, T is the total amount of hydrocarbon released; Q is the total hydrocarbon generation amount of the source rock; N is the geological reserves of the crude oil; G is the geological reserves of the natural gas.

[0038] Optionally, the organic carbon content of the total hydrocarbons released into the environment is calculated by the following formula:

[0039] TOC 释放 = T / (S × H × ρ × K c × β × 10 -3 );

[0040] Wherein, TOC 释放 is the organic carbon content of the total hydrocarbons released into the environment; T is the total amount of hydrocarbon released; S is the area of the source rock; H is the thickness of the source rock; ρ is the density of the source rock; K c is the organic carbon recovery coefficient; β is the hydrocarbon production rate.

[0041] Optionally, the carbon release amount of the organic carbon in the target area is calculated by the following formula:

[0042] C = TOC 释放 × T;

[0043] Wherein, T is the total amount of hydrocarbon released; TOC 释放 is the organic carbon content of the total hydrocarbons released into the environment; C is the total carbon release amount.

[0044] According to the specific embodiments provided by the present application, the present application has the following technical effects:

[0045] The present application provides a method for estimating the carbon release of organic carbon in continental lacustrine basins. First, hydrocarbon source rock data and reservoir data are determined based on geological data, and then oil-source correlation is carried out by using the chromatogram-mass spectrometry comparison method to determine the corresponding relationship between hydrocarbon source rocks and reservoirs. Then, by simulating the hydrocarbon accumulation dynamics process, the hydrocarbon generation rate and hydrocarbon expulsion rate data are determined. Finally, based on the hydrocarbon source rock data, reservoir data, the corresponding relationship between hydrocarbon source rocks and reservoirs, and the hydrocarbon generation rate and hydrocarbon expulsion rate data, the carbon release amount of organic carbon in the target area is calculated, which can systematically and comprehensively estimate the carbon release amount in the continental lacustrine basin area, comprehensively consider the processes of hydrocarbon generation, migration, storage and emission in the continental lacustrine basin area, effectively improve the accuracy of estimating the carbon release amount of organic carbon in continental lacustrine basins, solve the limitations and low accuracy problems of methods such as laboratory simulation method, numerical model method and field monitoring method, and is conducive to the development of carbon release analysis, ecological balance and environmental protection in the continental lacustrine basin area. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0047] Figure 1 It is an application environment diagram of a method for estimating the carbon release of organic carbon in a continental lacustrine basin in an embodiment of the present application.

[0048] Figure 2 It is a schematic flowchart of a method for estimating the carbon release of organic carbon in a continental lacustrine basin provided in an embodiment of the present application.

[0049] Figure 3 It is a schematic flowchart for judging whether carbon is released under formation uplift and denudation provided in an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0050] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, rather than all embodiments. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0051] To make the above objects, features and advantages of the present application more obvious and understandable, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0052] A method for estimating carbon release of organic carbon in continental lacustrine basins provided by an embodiment of the present application can be applied to, for example, Figure 1 the application environment shown. Among them, the terminal 102 communicates with the server 104 through the network. The data storage system can store the geological data that the server 104 needs to process. The data storage system can be set separately, integrated on the server 104, or placed on the cloud or other servers. The terminal 102 can send the geological data to be processed to the server 104. After the server 104 receives the geological data to be processed, for the geological data to be processed, the server 104 respectively determines the source rock data and the reservoir data according to the geological data; according to the source rock data and the reservoir data, the oil-source correlation is carried out by using the chromatogram-mass spectrometry comparison method to determine the corresponding relationship between the source rock and the reservoir; the hydrocarbon generation and expulsion kinetics process is simulated to determine the hydrocarbon generation rate and expulsion rate data; according to the source rock data, the reservoir data, the corresponding relationship between the source rock and the reservoir, and the hydrocarbon generation rate and expulsion rate data, the carbon release amount of organic carbon in the target area is calculated. The server 104 can feedback the obtained carbon release amount of organic carbon in the target area to the terminal 102. In addition, in some embodiments, the method for estimating carbon release of organic carbon in continental lacustrine basins can also be implemented independently by the server 104 or the terminal 102. For example, the terminal 102 can directly perform carbon release amount calculation processing on the geological data to be processed, or the server 104 can obtain the geological data to be processed from the data storage system and perform carbon release amount calculation processing on the geological data to be processed.

[0053] Among them, the terminal 102 can be, but is not limited to, various desktop computers, laptop computers, smart phones, tablet computers, Internet of Things devices, and portable wearable devices. The Internet of Things devices can be smart speakers, smart TVs, smart air conditioners, smart in-vehicle devices, etc. The portable wearable devices can be smart watches, smart bracelets, head-mounted devices, etc. The server 104 can be implemented by an independent server or a server cluster composed of multiple servers, and can also be a cloud server.

[0054] In an exemplary embodiment, as Figure 2 shown, a method for estimating carbon release of organic carbon in continental lacustrine basins is provided. This method is executed by a computer device, and can be specifically executed independently by a computer device such as a terminal or a server, or jointly executed by a terminal and a server. In the embodiment of the present application, taking this method applied to Figure 1 the server 104 in as an example for illustration, it includes the following steps S1 to S5. Among them:

[0055] Step S1: Obtain the geological data of the target area.

[0056] In this embodiment, geological data of the target area can be obtained by conducting geological monitoring on the target area. The geological data includes various types of data such as, but not limited to, geochemical data and logging curve data.

[0057] Step S2: Determine source rock data and reservoir data respectively according to the geological data.

[0058] In this embodiment, step S2 determines source rock data and reservoir data respectively according to the geological data, and specifically includes the following steps:

[0059] Step S21: Define the source rock horizons and their spatial distribution profiles in the target area according to the geochemical data and logging curve data in the geological data, and analyze the hydrocarbon generation and expulsion processes of the source rocks to obtain the source rock data.

[0060] Step S22: Divide and detect the reservoirs in the target area according to the geochemical data in the geological data to obtain the reservoir data.

[0061] In this embodiment, step S2 is mainly used to determine source rock data and reservoir data. The source rock data are mainly parameters related to the horizons and ranges of source rocks. Based on geochemical data and logging curve information, the horizons and spatial distribution profiles of source rocks are accurately defined, and their hydrocarbon generation and expulsion processes are deeply analyzed to determine the carbon release nodes, laying a solid foundation for calculating the total hydrocarbon generation amount of source rocks. Specifically, use data such as geochemistry to accurately anchor the horizons and lower limits of source rocks, and then clarify their distribution ranges and effective thicknesses; by tracing back the hydrocarbon generation and expulsion history, obtain the hydrocarbon generation and expulsion ratios at different sedimentary stages, so as to provide key parameter support for comprehensively grasping the hydrocarbon generation potential and dynamic processes of source rocks, and ensuring the accuracy and scientificity of subsequent calculations of the total hydrocarbon generation amount of source rocks.

[0062] In this embodiment, the specific process and indicators for accurately anchoring the horizons and lower limits of source rocks using geochemical data are as follows:

[0063] (1) Organic matter abundance index:

[0064] (1) Total organic carbon (TOC): By analyzing the TOC of rock samples at different horizons, a curve of TOC vs. depth or horizon can be plotted. The intervals where the TOC content significantly increases and reaches a certain threshold can often be initially determined as source rock horizons.

[0065] Chloroform bitumen "A": When combined with TOC analysis, if the content of chloroform bitumen "A" in a certain horizon is relatively high and has a good positive correlation with TOC, it can further confirm that this horizon is a source rock.

[0066] Hydrocarbon generation potential (Pg): Obtained through rock pyrolysis experiments, it represents the potential amount of hydrocarbons that can be generated in the source rock. The horizons corresponding to higher Pg values are usually the horizons where source rocks develop.

[0067] (2) Organic matter maturity indicators:

[0068] Vitrinite reflectance (Ro): According to the variation of Ro values with depth or horizon, the horizon and depth limit of the source rock entering the hydrocarbon generation stage can be determined.

[0069] Pyrolysis peak temperature (Tmax): The Tmax value is positively correlated with the organic matter maturity. The horizons with higher Tmax values may be the horizons where source rocks with higher maturity are located.

[0070] (3) Biomarker indicators:

[0071] n-alkane distribution: The n-alkane distribution characteristics are different for source rocks from different sources and sedimentary environments. For example, in source rocks mainly composed of aquatic organisms, n-alkanes often mainly have low carbon numbers; while in source rocks mainly composed of terrestrial higher plants, n-alkanes with high carbon numbers are relatively abundant. By analyzing the carbon number distribution, main peak carbon position, etc. of n-alkanes, the type and sedimentary environment of the source rock can be judged, and then the source rock horizon can be determined assistively.

[0072] Steranes and terpanes: Their composition and distribution have strong biological source specificities. For example, the relative content and isomerization degree of regular steranes can reflect the maturity and source of organic matter, and the gammacerane index can indicate the salinity of the sedimentary environment, etc. Using the characteristics of these indicators, source rocks of different horizons can be distinguished and their horizon attribution can be determined.

[0073] This embodiment uses the retrospection of the history of hydrocarbon generation and expulsion to obtain the hydrocarbon generation and expulsion rates at different depositional stages. Specifically, based on the diversity of sedimentary environments, different lithological compositions are formed, which in turn result in different organic matter abundances and occurrence forms, forming different hydrocarbon generation patterns. The source rocks in saline environments have the characteristics of efficient hydrocarbon generation and expulsion. According to the recovery results of ancient water salinity and the comprehensive analysis of ancient climate environments, the appropriate salinity range allows biological flourishing, and the level of ancient productivity is significantly improved, reaching a super-eutrophic level. Stable terrigenous organic matter input and high ancient productivity provide a material basis for the formation of source rocks, and intermittent reduction environments provide a guarantee for the formation of high-quality source rocks. Freshwater environments mainly generate light-medium mature oil with high wax content and a small amount of low-mature oil. High-quality source rocks have strong hydrocarbon generation capabilities and high hydrocarbon content at the same evolutionary stage, providing more material basis for hydrocarbon expulsion, and hydrocarbon generation and pressurization are an effective mechanism for the formation of abnormal pressure. In terms of lithology, high-quality source rocks have high plasticity, are prone to undercompaction, and are also conducive to the formation of abnormal flow pressure. At the same time, the lamination and organic network of high-quality source rocks are well developed, which is conducive to the formation of good migration channels and makes the conditions for hydrocarbon expulsion more sufficient. The hydrocarbon expulsion of source rocks is determined by the basin evolution and its own characteristics. If the same basin evolution conditions are experienced, the properties of the source rocks themselves become an important factor affecting hydrocarbon expulsion, so each set of source rocks also has different hydrocarbon expulsion patterns.

[0074] In this embodiment, reservoir division is achieved through core observation, thin section observation, resistivity logging, acoustic time difference logging, seismic phase analysis and geochemical logging, so as to obtain reservoir data.

[0075] In this embodiment, the source rock data mainly include various parameters related to the source rock, which are used to characterize the source rock layer and range. The source rock data mainly include the source rock area, source rock thickness, source rock density, current organic carbon content and initial organic carbon content, etc. The reservoir data mainly include various parameters related to the reservoir, such as oil / gas area, effective thickness of oil / gas layer, effective porosity of oil / gas layer, original oil saturation of oil layer, original gas saturation of gas layer, density of ground degassed crude oil, original crude oil volume coefficient and original natural gas volume coefficient, etc.

[0076] Step S3: performing oil source comparison based on the source rock data and the reservoir data by using a chromatography-mass spectrometry comparison method to determine the corresponding relationship between the source rock and the reservoir.

[0077] In this embodiment, step S3 uses a chromatography mass spectrometry comparison method to perform oil source comparison based on the source rock data and the reservoir data to determine the corresponding relationship between the source rock and the reservoir, and specifically includes the following steps:

[0078] Step S31: Determine the chromatograms and mass spectra of various biomarker compounds in the crude oil of the target area based on the source rock data and the reservoir data.

[0079] Step S32: According to the chromatograms and mass spectra of various biomarker compounds in the crude oil of the target area, use the chromatogram-mass spectrum comparison method to analyze the chromatographic characteristics and mass spectral characteristics of various biomarker compounds in the crude oil, determine the influence of different source rock types and thermal evolution degrees on the crude oil composition, and compare the retention times, mass spectral characteristics and relative abundances of various biomarker compounds respectively, identify the types, maturities and generation processes of the source rocks in the hydrocarbon source rocks, achieve oil-source correlation, trace the origin of oil and gas, and determine the corresponding relationship between the source rocks and the reservoirs.

[0080] In this embodiment, the chromatogram-mass spectrum comparison method is adopted. The chromatogram-mass spectrum comparison method is a method for comparing chromatograms and mass spectra to clarify the influence of different source rock types and thermal evolution degrees on the crude oil composition. Through the process of oil-source correlation, organic geochemical indicators such as biomarker compounds are analyzed, and different oil sources are accurately compared to ensure the accurate relationship between each source rock and the corresponding reservoir. Under this premise, two key geological phenomena can be clearly identified: one is "one source with multiple reservoirs", which means that the hydrocarbons generated by the same source rock are distributed and accumulated in multiple reservoirs; the other is "one reservoir with multiple sources", that is, the hydrocarbons in a reservoir come from multiple different source rocks.

[0081] In this embodiment, the analysis of organic geochemical indicators such as biomarker compounds specifically includes the following analysis steps:

[0082] 1) Geochemical indicators:

[0083] Carbon isotope: Organic matter from different sources has different carbon isotope compositions. Generally speaking, the carbon isotope of organic matter from marine sources is relatively heavier, while that from continental sources is relatively lighter. Comparing the carbon isotope values of crude oil and source rock, if the two are close, it may indicate the same origin.

[0084] n-alkanes: The carbon number distribution range, main peak carbon number and distribution pattern of n-alkanes can be used as the "fingerprint" for oil-source correlation. The n-alkanes in the organic matter of clastic rock series rich in terrigenous materials are mainly C27, C29, and C31, with odd-even predominance, while the n-alkanes from aquatic organisms are mainly C15 and C17, with no obvious odd-even predominance.

[0085] 2) Common biomarker compounds

[0086] Sterane compounds:

[0087] Download of source and structural feature documents: C27 steranes are mainly derived from lower planktonic plants such as algae, C28 mainly from diatoms and coccolithophores, and C29 from higher plants or algae. It has a specific tetracyclic steroid nucleus structure and is relatively stable during geological evolution.

[0088] 3) Application of oil-source correlation: Analyze the carbon number distribution, isomerization parameters, etc. of steranes in crude oil and possible source rocks. For example, if C27 steranes dominate in the crude oil and also have a relatively high content in a certain source rock, and other relevant parameters also match, it may indicate a genetic relationship between the crude oil and the source rock. In addition, isomerization parameters such as 20S / (20S + 20R) of steranes can also reflect the maturity of organic matter, and similar maturity is also an important basis for oil-source correlation.

[0089] 4) Analytical methods

[0090] Gas chromatography (GC): It can separate and analyze various organic compounds in petroleum, obtain the carbon number distribution curve of compounds such as n-alkanes, and judge the similarity of oil sources by comparing the shape of the curve, the position of the main peak carbon, etc.

[0091] Gas chromatography - mass spectrometry (GC-MS): It can more accurately identify and quantify biomarker compounds. It can analyze the specific types and relative contents of biomarker compounds such as steranes and terpanes, providing richer and more accurate data for oil-source correlation.

[0092] In this embodiment, among the series of sterane compounds, the relative abundances of C27, C28, and C29 regular steranes can indicate the input of the organic matter source of the hydrocarbon source rock. The principle of using the relative content of n-alkanes in the hydrocarbon source rock and crude oil for oil-source correlation is that due to differences in organic matter types, thermal evolution degrees, etc. in different hydrocarbon source rocks, the distribution characteristics of the n-alkanes generated in the crude oil are unique. By comparing the relative contents of n-alkanes in the crude oils of different oil reservoirs, the source of the crude oil can be inferred, the same or different hydrocarbon source rocks can be identified, and thus a strong basis can be provided for oil-source analysis and oil and gas exploration work.

[0093] In this embodiment, oil-source correlation is carried out using chromatograms and mass spectra. By deeply analyzing the chromatographic and mass spectral characteristics of biomarker compounds in crude oil, the effects of different hydrocarbon source rock types and thermal evolution degrees on the composition of crude oil are revealed. Crude oils from different oil sources have characteristic biomarker compound spectra (including chromatograms and mass spectra). By comparing the retention times, mass spectra, and relative abundances of various biomarker compounds in the crude oil samples, the types, maturities, and generation processes of the source rocks can be identified, thereby realizing oil-source correlation and tracing the origin of oil and gas.

[0094] Step S4: Simulate the hydrocarbon accumulation dynamics process to determine the hydrocarbon generation rate and hydrocarbon expulsion rate data.

[0095] In this embodiment, step S4 simulates the hydrocarbon accumulation dynamics process to determine the hydrocarbon generation rate and hydrocarbon expulsion rate data, specifically including the following steps:

[0096] Step S41: Use BasinMod software to simulate the hydrocarbon accumulation dynamics process to define the hydrocarbon generation and expulsion history, tectonic subsidence history, burial history, thermal evolution history, and hydrocarbon filling history, and determine the hydrocarbon distribution characteristics and patterns.

[0097] Step S42: Based on the hydrocarbon distribution characteristics and patterns, restore the hydrocarbon generation and expulsion history to obtain the hydrocarbon generation rate and hydrocarbon expulsion rate data.

[0098] In step S4 of this embodiment, it is mainly the simulation of hydrocarbon accumulation dynamics. Using BasinMod software to simulate the hydrocarbon accumulation dynamics process, accurately define the hydrocarbon generation and expulsion history, tectonic subsidence history, burial history, thermal evolution history, and hydrocarbon filling history, and then clarify the hydrocarbon distribution characteristics and patterns. Specifically, by restoring the hydrocarbon generation and expulsion history, the hydrocarbon generation rate and hydrocarbon expulsion rate data at different sedimentary stages can be accurately obtained. During the reconstruction of the tectonic subsidence history and burial history, it is judged whether there is stratigraphic uplift and erosion during a specific period. At the same time, through the restoration of the thermal evolution history and hydrocarbon filling history, it can be clearly determined whether the source rock meets the hydrocarbon generation conditions, and whether the hydrocarbon reservoir has been uplifted and eroded, providing a solid theoretical basis and scientific guidance for oil and gas exploration and development.

[0099] Step S5: Calculate the carbon release amount of organic carbon in the target area according to the source rock data, the reservoir data, the corresponding relationship between the source rock and the reservoir, and the hydrocarbon generation rate and hydrocarbon expulsion rate data.

[0100] In step S5 of this embodiment, it is mainly to calculate the carbon release amount. Based on the source rock data and reservoir data obtained in step S2, the corresponding relationship between the source rock and the reservoir obtained in step S3, and the hydrocarbon generation rate and hydrocarbon expulsion rate data obtained in step S4, calculate the carbon release amount of organic carbon in the target area.

[0101] After the source rock generates and expels hydrocarbons, the organic carbon migrates and enters the reservoir to form an oil and gas reservoir. For the case without stratigraphic uplift and erosion. The difference between the total hydrocarbon generation amount of the source rock and the geological reserves of the reservoir is the amount of hydrocarbons discharged into the environment during the migration process, and the carbon release amount can be obtained by back-calculation. The carbon released into the air is mainly the carbon lost into the air through faults during the migration of oil and gas. Therefore, the difference between the hydrocarbons in the source rock and the reservoir is the amount of hydrocarbons released.

[0102] In this embodiment, by restoring the burial history and tectonic subsidence history, the evolution process of the formation can be reconstructed, so as to identify the formations that have experienced uplift and erosion in the geological history. Combining the thermal evolution history with the hydrocarbon accumulation process, it is possible to further determine whether the source rock and reservoir have experienced erosion. If the source rock has generated hydrocarbons or the reservoir has experienced uplift and erosion, there will be carbon release, and there is no carbon release without uplift and erosion. The judgment process of whether there is carbon release under formation uplift and erosion is as Figure 3 shown. Among them, formation uplift and erosion mainly consider two aspects: the source rock and the reservoir. When judging whether the source rock has experienced erosion, when the source rock has generated hydrocarbons (thermal evolution), it is determined that there is carbon release, otherwise it is determined that there is no carbon release. When judging whether the reservoir has experienced erosion, when the reservoir has achieved hydrocarbon accumulation (experienced uplift and erosion), it is determined that there is carbon release, otherwise it is determined that there is no carbon release.

[0103] Based on the source rock data, reservoir data, the corresponding relationship between the source rock and the reservoir, and the hydrocarbon generation rate and hydrocarbon expulsion rate data in this embodiment, combined with parameters such as the volumetric method, organic carbon recovery coefficient, and hydrocarbon production rate, the total hydrocarbon generation amount of the source rock and the geological reserves of the reservoir can be calculated. Through the difference between the total hydrocarbon generation amount of the source rock and the geological reserves of the reservoir, the total hydrocarbon release amount can be obtained. Through further calculation, the carbon release amount of organic carbon in the target area, that is, the total carbon release amount, can be estimated.

[0104] Therefore, step S5 of this embodiment specifically includes the following steps:

[0105] Step S51: Calculate the total hydrocarbon generation amount of the source rock and the geological reserves of the reservoir respectively according to the source rock data, the reservoir data, the corresponding relationship between the source rock and the reservoir, and the hydrocarbon generation rate and hydrocarbon expulsion rate data. Among them, the geological reserves of the reservoir include the geological reserves of crude oil and natural gas, etc.

[0106] In this embodiment, the calculation formula for the total hydrocarbon generation amount of the source rock is:

[0107] Q = S × H × ρ × TOC 残留 × K c × β × 10 -3 (1).

[0108] K c = TOC 原始 / TOC 残留 (2).

[0109] Among them, Q is the total hydrocarbon generation amount of the source rock, with the unit of kg or m 3 ; S is the area of the source rock, with the unit of m 2 ; H is the thickness of the source rock, with the unit of m; ρ is the density of the source rock, with the unit of kg / m 3 ; TOC 残留is the current organic carbon content, which is a decimal; TOC 原始 is the initial organic carbon content, which is a decimal; K c is the organic carbon recovery coefficient, which can be obtained by calculating Ro and has no unit; β is the hydrocarbon generation rate, which is derived from the hydrocarbon generation rate and hydrocarbon expulsion rate data, and the unit is kg / tTOC or m 3 / tTOC.

[0110] In this embodiment, the hydrocarbon generation rate and hydrocarbon expulsion rate data are mainly used to determine the hydrocarbon generation rate, etc. The hydrocarbon generation rate refers to the rate of hydrocarbon generation in the source rock per unit time; while the hydrocarbon expulsion rate refers to the ratio of the hydrocarbon expulsion volume to the hydrocarbon generation volume of the source rock. Since the hydrocarbon expulsion rate is equal to the ratio of the hydrocarbon expulsion volume to the hydrocarbon generation volume, and the hydrocarbon generation rate refers to the hydrocarbon generation capacity of the source rock and is an important parameter for calculating the hydrocarbon generation volume. Therefore, the hydrocarbon generation rate is closely related to the hydrocarbon generation rate and hydrocarbon expulsion rate data. This embodiment can obtain the value of the hydrocarbon generation rate according to the hydrocarbon generation rate and hydrocarbon expulsion rate data, so as to calculate the total hydrocarbon generation volume of the source rock, etc.

[0111] In this embodiment, since the geological reserves of the reservoir include the geological reserves of crude oil and the geological reserves of natural gas, therefore, the calculation formulas for the geological reserves of crude oil and the geological reserves of natural gas in the reservoir geological reserves are respectively:

[0112]

[0113] Among them, N is the geological reserves of crude oil, and the unit is 10 4 t; G is the geological reserves of natural gas, and the unit is 10 8 m 3 ; A is the oil / gas-bearing area, and the unit is km 2 ; h is the effective thickness of the oil / gas layer, and the unit is m; is the effective porosity of the oil / gas layer, which is a decimal; S oi is the original oil saturation of the oil layer, which is a decimal; S gi is the original gas saturation of the gas layer, which is a decimal; ρ o is the density of surface degassed crude oil, and the unit is t / m 3 ; B oi is the original oil volume factor, which has no unit; B gi is the original natural gas volume factor, which has no unit.

[0114] Step S52, calculate the total hydrocarbon release amount according to the total hydrocarbon generation amount of the source rock and the geological reserves of the reservoir.

[0115] In this embodiment, the calculation formula for the total hydrocarbon release amount is:

[0116] T = Q - N(G) (5).

[0117] Among them, T is the total hydrocarbon release amount, and the unit is kg or m3 ; Q is the total hydrocarbon generation amount of the source rock, with the unit of kg or m 3 ; N is the geological reserve of crude oil, with the unit of 10 4 t; G is the geological reserve of natural gas, with the unit of 10 8 m 3 .

[0118] It should be noted that in this embodiment, since the total hydrocarbon release amount is calculated by taking the difference between the total hydrocarbon generation amount of the source rock and the geological reserve of the reservoir, and the geological reserve of the reservoir in the target area of this embodiment includes two types, namely the geological reserve of crude oil and the geological reserve of natural gas, that is, the geological reserves of crude oil and natural gas. Therefore, when calculating the total hydrocarbon release amount using formula (5), the difference between the total hydrocarbon generation amount of the source rock and the geological reserve of crude oil, and the difference between the total hydrocarbon generation amount of the source rock and the geological reserve of natural gas can be calculated respectively, and then the total hydrocarbon release amount can be obtained by integrating the two aspects. In addition, the geological reserve of the reservoir corresponding to one of the crude oil and natural gas in the reservoir and its total hydrocarbon release amount can be calculated according to actual needs.

[0119] Step S53: Calculate the organic carbon content of the total hydrocarbons released into the environment according to the total hydrocarbon release amount and the source rock data.

[0120] In this embodiment, the calculation formula for the organic carbon content of the total hydrocarbons released into the environment is:

[0121] TOC 释放 = T / (S × H × ρ × K c × β × 10 -3 ) (6).

[0122] Among them, TOC 释放 is the organic carbon content of the total hydrocarbons released into the environment, which is a decimal; T is the total hydrocarbon release amount, with the unit of kg or m 3 ; S is the area of the source rock, with the unit of m 2 ; H is the thickness of the source rock, with the unit of m; ρ is the density of the source rock, with the unit of kg / m 3 ; K c is the organic carbon recovery coefficient, which can be obtained by calculating Ro, without unit; β is the hydrocarbon production rate, with the unit of kg / tTOC or m 3 / tTOC.

[0123] Step S54: Calculate the carbon release amount of the organic carbon in the target area according to the total hydrocarbon release amount and the organic carbon content of the total hydrocarbons released into the environment.

[0124] In this embodiment, the calculation formula for the carbon release amount of the organic carbon in the target area (i.e., the total carbon release amount) is:

[0125] C = TOC 释放 × T (7).

[0126] wherein, T is the total amount of hydrocarbon release, with the unit of kg or m 3 ; TOC 释放 is the organic carbon content of the total hydrocarbons released into the environment, which is a decimal; C is the total amount of carbon release, with the unit of kg or m 3 .

[0127] In this embodiment, by determining the source rock horizons and ranges, oil-source correlation, hydrocarbon accumulation dynamics simulation, and the carbon release amount calculation formula, the carbon release amount in the continental lacustrine basin area can be systematically and comprehensively estimated, accurately located, focusing on the carbon release amount within a certain area, with high accuracy. Considering the processes of hydrocarbon generation, migration, accumulation, and emission in the continental lacustrine basin area, the accuracy of estimating the carbon release amount of organic carbon in the continental lacustrine basin can be effectively improved, which is beneficial to the development of carbon release analysis, ecological balance, and environmental protection in the continental lacustrine basin area.

[0128] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0129] Specific examples are used in this article to elaborate on the principles and implementation manners of this application. The description of the above embodiments is only used to help understand the method and its core idea of this application; at the same time, for those of ordinary skill in the art, based on the idea of this application, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to this application.

Claims

1. A method for estimating carbon release from organic carbon in continental lake basins, characterized in that: The carbon release estimation method of the terrestrial lake basin organic carbon includes: Obtain geological data of the target area; According to the geological data, source rock data and reservoir data are determined respectively; the source rock data and reservoir data are used to characterize the source rock layer position and range and the reservoir layer position and range respectively; According to the source rock data and the reservoir data, a chromatogram mass spectrometry comparison method is used to perform oil source comparison to determine the corresponding relationship between the source rock and the reservoir; Simulate the dynamic process of oil and gas accumulation to determine the data of hydrocarbon generation rate and hydrocarbon expulsion rate; The carbon release amount of organic carbon in the target area is calculated based on the source rock data, the reservoir data, the corresponding relationship between the source rock and the reservoir, and the hydrocarbon generation rate and hydrocarbon expulsion rate data.

2. The carbon release estimation method of organic carbon in continental lake basins according to claim 1, characterized in that: According to the geological data, source rock data and reservoir data are determined respectively, including: Based on the geochemical data and well logging data in the geological data, the source rock layers and their spatial distribution profiles in the target area are defined, and the hydrocarbon generation and expulsion history of the source rock is analyzed to obtain the source rock data; According to the geochemical data in the geological data, the reservoir in the target area is divided and detected to obtain the reservoir data.

3. The carbon release estimation method of organic carbon in continental lake basins according to claim 1, characterized in that: According to the source rock data and the reservoir data, the chromatogram mass spectrometry comparison method is used to perform oil source comparison to determine the corresponding relationship between the source rock and the reservoir, specifically including: Determine the chromatogram and mass spectrum of various biomarker compounds in the crude oil in the target area according to the source rock data and the reservoir data; According to the chromatograms and mass spectra of various biomarker compounds in the crude oil of the target area, the chromatogram-mass spectrometer comparison method is used to analyze the chromatographic characteristics and mass spectral characteristics of various biomarker compounds in the crude oil, determine the effects of different source rock types and thermal evolution degrees on the crude oil composition, and compare the retention time, mass spectral characteristics and relative abundance of various biomarker compounds to identify the type, maturity and generation process of the oil source rock in the source rock, realize oil-source comparison, trace the source of oil and gas, and determine the correspondence between the source rock and the reservoir.

4. The carbon release estimation method of organic carbon in continental lake basins according to claim 1, characterized in that: Simulate the dynamic process of oil and gas accumulation and determine the hydrocarbon generation rate and hydrocarbon expulsion rate data, including: BasinMod software is used to simulate the dynamic process of oil and gas accumulation to determine the history of hydrocarbon generation and expulsion, structural sedimentation history, burial history, thermal evolution history and oil and gas filling history, and to determine the characteristics and patterns of oil and gas distribution; Based on the oil and gas distribution characteristics and patterns, the hydrocarbon generation and expulsion history is restored to obtain the hydrocarbon generation rate and hydrocarbon expulsion rate data.

5. The carbon release estimation method of organic carbon in continental lake basins according to claim 1, characterized in that: The carbon release amount of organic carbon in the target area is calculated based on the source rock data, the reservoir data, the corresponding relationship between the source rock and the reservoir, and the hydrocarbon generation rate and hydrocarbon expulsion rate data, specifically including: According to the source rock data, the reservoir data, the corresponding relationship between the source rock and the reservoir, and the hydrocarbon generation rate and hydrocarbon expulsion rate data, respectively calculate the total hydrocarbon generation amount of the source rock and the geological reserves of the reservoir; Calculating the total amount of hydrocarbon release based on the total hydrocarbon generation of the source rock and the geological reserves of the reservoir; Calculating the organic carbon content of the total hydrocarbons released into the environment based on the total amount of hydrocarbons released and the source rock data; The carbon release amount of the organic carbon in the target area is calculated based on the total amount of hydrocarbons released and the organic carbon content of the total hydrocarbons released into the environment.

6. The carbon release estimation method of organic carbon in continental lake basins according to claim 5, characterized in that: The total hydrocarbon generation amount of the source rock is calculated using the following formula: Q=S×H×ρ×TOC 残留 ×K c ×β×10 -3 ; K c =TOC 原始 / TOC 残留 ; Among them, Q is the total hydrocarbon generation of source rock; S is the area of ​​source rock; H is the thickness of source rock; ρ is the density of source rock; TOC 残留 is the current organic carbon content; TOC 原始 is the initial organic carbon content; K c is the organic carbon recovery coefficient; β is the hydrocarbon production rate.

7. The carbon release estimation method of organic carbon in continental lake basins according to claim 6, characterized in that: The reservoir geological reserves include crude oil geological reserves and natural gas geological reserves; The following formulas are used to calculate the geological reserves of crude oil and natural gas respectively: Wherein, N is the geological reserves of crude oil; G is the geological reserves of natural gas; A is the oil / gas-bearing area; h is the effective thickness of the oil / gas layer; is the effective porosity of the oil / gas layer; S oi is the original oil saturation of the oil layer; S gi is the original gas saturation of the gas layer; ρ o B is the density of ground degassed crude oil; oi is the volume coefficient of the original crude oil; B gi is the original natural gas volume coefficient.

8. The carbon release estimation method of organic carbon in continental lake basins according to claim 7, characterized in that: The total amount of hydrocarbon release is calculated using the following formula: T = Q - N (G); Among them, T is the total amount of hydrocarbon released; Q is the total hydrocarbon generation of source rocks; N is the geological reserves of crude oil; and G is the geological reserves of natural gas.

9. The carbon release estimation method of organic carbon in continental lake basins according to claim 8, characterized in that: The organic carbon content of the total hydrocarbons released into the environment is calculated using the following formula: TOC 释放 =T / (S×H×ρ×K c ×β×10 -3 ); Among them, TOC 释放 is the organic carbon content of total hydrocarbons released into the environment; T is the total amount of hydrocarbons released; S is the area of ​​source rock; H is the thickness of source rock; ρ is the density of source rock; K c is the organic carbon recovery coefficient; β is the hydrocarbon production rate.

10. The carbon release estimation method of organic carbon in continental lake basins according to claim 9, characterized in that: The carbon release of organic carbon in the target area is calculated using the following formula: C=TOC 释放 ×T; Where T is the total amount of hydrocarbon released; TOC 释放 is the organic carbon content of total hydrocarbons released into the environment; C is the total amount of carbon released.

Images