A method for compensating and correcting the S1 light hydrocarbon content parameter of shale oil content

Abstract

This application relates to the field of oil and gas exploration and discloses a method for compensating and correcting light hydrocarbons in the oil-bearing parameter S1 of shale. The method includes: performing online pyrolysis on simulated shale samples and downhole shale samples of corresponding maturity from natural evolution profiles; quantitatively analyzing the hydrocarbon components of the pyrolysis products from the simulated and downhole shale samples; obtaining the proportion of light hydrocarbons in the total hydrocarbons of the simulated and downhole shale samples from the quantitative analysis results; and compensating and correcting the oil-bearing parameter S1 of the downhole shale samples for light hydrocarbons based on a comparison of the proportions of light hydrocarbons in the total hydrocarbons of the simulated and downhole shale samples. This significantly improves the accuracy of recovering light hydrocarbon losses in shale samples, effectively reduces experimental costs, shortens the time cycle, and facilitates large-scale application based on existing data.

Description

Technical Field

[0001] This invention relates to the field of oil and gas exploration, and in particular to a method for compensating and correcting the S1 light hydrocarbon content parameter of mudstone and shale. Background Technology

[0002] Shale oil, as an important component of unconventional energy, has attracted much attention due to its enormous resource potential. As a crucial step in oil and gas exploration, the evaluation of the oil-bearing potential of mudstone and shale is the foundation for predicting sweet spots and regions in shale oil production, and is also the core of assessing shale oil resource potential.

[0003] Rock pyrolysis has become a major research method for characterizing the oil-bearing potential of shale due to its advantages of simple operation, abundant information in the test results, and low cost. The commonly used parameter S1 characterizes the free hydrocarbon content in the retained hydrocarbons of shale, reflecting its oil content. S1 is a component of petroleum hydrocarbons in shale oil, mainly consisting of hydrocarbon compounds volatilized when the rock is heated to no more than 300°C. However, the loss of S1 light hydrocarbons in the tested shale samples can occur during the process of transporting the core from the well bottom to the surface, during the placement of the core in the core storage chamber, and during the pre-experiment crushing process. The loss rate can be as high as 30% to 50%, resulting in measured values ​​that are lower than the actual values ​​of the underground samples.

[0004] Currently, domestic and international scholars mainly rely on comparing the pyrolysis results of oil-bearing rock samples after different storage times, and comparing the pyrolysis results of fresh frozen samples or sealed core samples with samples stored for different times. However, the loss of light free hydrocarbons is a continuous process, and the free hydrocarbon content measured in the laboratory varies greatly depending on the storage time of shale core samples. The method of compensating for S1 by comparing the pyrolysis results of samples stored for different times is time-consuming, has poor operability, and cannot recover the light hydrocarbon loss during the simulated process of shale samples rising from the well bottom to the surface. While the sealed core method can improve accuracy, it is expensive and difficult to promote on a large scale. Furthermore, the light hydrocarbon recovery results established by comparing the pyrolysis data of fresh samples with samples stored for different times cannot accurately reflect the original oil-bearing information of the samples, while the light hydrocarbon recovery results established by comparing the pyrolysis data of sealed core samples with samples stored for different times cannot be widely promoted and applied. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a method for compensating and correcting light hydrocarbons in the S1 parameter of shale oil content, which can significantly improve the accuracy of recovering light hydrocarbon losses in shale samples. The specific scheme is as follows:

[0006] A method for compensating and correcting the S1 light hydrocarbon content parameter of shale oil content includes:

[0007] Online pyrolysis was performed on simulated mudstone and shale samples and downhole mudstone and shale samples of corresponding maturity from natural evolution profiles, respectively.

[0008] Quantitative analysis of hydrocarbon components was performed on the pyrolysis products of the simulated shale sample and the downhole shale sample;

[0009] The proportion of light hydrocarbons in the total hydrocarbons of the simulated shale sample and the downhole shale sample were obtained from the quantitative analysis results.

[0010] Based on the comparison of the proportion of light hydrocarbons in the total hydrocarbons of the simulated shale sample and the downhole shale sample, the oil content parameter S1 of the downhole shale sample is compensated and corrected for light hydrocarbons.

[0011] Preferably, in the above-mentioned method for compensating and correcting the oil content parameter S1 of shale and mudstone provided in the embodiments of the present invention, after compensating and correcting the oil content parameter S1 of the downhole shale and mudstone sample for light hydrocarbons, the method further includes:

[0012] Establish a light hydrocarbon compensation chart corresponding to the downhole mudstone and shale samples with multiple maturity levels;

[0013] Based on the light hydrocarbon compensation chart of the shale sample, the compensation coefficients corresponding to other shale samples of different maturity were obtained and light hydrocarbon compensation corrections were performed.

[0014] Preferably, in the above-mentioned method for compensating and correcting the light hydrocarbon content parameter S1 of shale oil content provided in the embodiments of the present invention, before performing online pyrolysis on simulated shale samples and downhole shale samples of corresponding maturity in natural evolution profiles, the method further includes:

[0015] Pyrolysis was performed on low-maturity coal samples from field geological profiles or mines to determine the vitrinite reflectance at different temperature points and to calibrate the maturity at different temperature points.

[0016] Select the downhole mudstone and shale sample with a maturity corresponding to the vitrinite reflectance.

[0017] Preferably, in the above-mentioned method for compensating and correcting light hydrocarbon content parameters S1 of shale oil content provided in the embodiments of the present invention, the online pyrolysis process includes:

[0018] The target temperature of the downhole mudstone and shale sample is set to a first constant value;

[0019] The target temperature of the simulated mudstone and shale sample is set to different temperature points measured by the coal sample; the heating rate is different for the different target temperatures of the simulated mudstone and shale sample.

[0020] Preferably, in the above-mentioned method for compensating and correcting the light hydrocarbon content parameter S1 of shale oil content provided in the embodiments of the present invention, online pyrolysis is performed on simulated shale samples and downhole shale samples of corresponding maturity in natural evolution profiles, including:

[0021] Online pyrolysis was performed on simulated mudstone and shale samples and downhole mudstone and shale samples of corresponding maturity from natural evolution profiles using a pyrolysis instrument.

[0022] Preferably, in the above-mentioned method for compensating and correcting the light hydrocarbon content parameter S1 of shale oil content provided in the embodiments of the present invention, quantitative analysis of hydrocarbon components is performed on the pyrolysis products of the simulated shale sample and the downhole shale sample, including:

[0023] Gas chromatography-mass spectrometry was used to quantitatively analyze the hydrocarbon components of the pyrolysis products of the simulated shale sample and the downhole shale sample.

[0024] Preferably, in the above-mentioned method for compensating and correcting light hydrocarbons in the oil content parameter S1 of shale provided in the embodiments of the present invention, before performing online pyrolysis, the method further includes:

[0025] The temperature of the transfer line between the pyrolysis instrument and the gas chromatography-mass spectrometry instrument is set to a second constant value.

[0026] Preferably, in the above-mentioned method for compensating and correcting light hydrocarbons for the oil content parameter S1 of shale provided in the embodiments of the present invention, the quantitative analysis of hydrocarbon components includes:

[0027] After both the downhole mudstone and shale samples have reached their respective target temperatures and been kept at a constant temperature for a set period of time, the pyrolysis products are enriched using a liquid nitrogen thermos placed at the front end of the chromatographic column.

[0028] After the pyrolysis products are enriched, they are transferred to the gas chromatography-mass spectrometry instrument via the chromatographic column for quantitative analysis of hydrocarbon components.

[0029] Preferably, in the above-mentioned method for compensating and correcting the light hydrocarbon content parameter S1 of shale oil content provided in the embodiments of the present invention, before selecting the downhole shale sample with maturity corresponding to the vitrinite reflectance, the method further includes:

[0030] The maturity of the downhole mudstone and shale sample is determined based on its depth.

[0031] As can be seen from the above technical solution, the present invention provides a method for compensating and correcting the light hydrocarbon content of the shale oil content parameter S1, which includes: performing online pyrolysis on simulated shale samples and downhole shale samples of corresponding maturity in natural evolution profiles; quantitatively analyzing the hydrocarbon components of the pyrolysis products of the simulated shale samples and downhole shale samples; obtaining the proportion of light hydrocarbons in the total hydrocarbons of the simulated shale samples and downhole shale samples from the quantitative analysis results; and compensating and correcting the oil content parameter S1 of the downhole shale samples for light hydrocarbons based on the comparison results of the proportion of light hydrocarbons in the total hydrocarbons of the simulated shale samples and downhole shale samples.

[0032] The above-mentioned method for compensating and correcting light hydrocarbons in the oil content parameter S1 of shale provided by this invention adopts online pyrolysis and product detection methods. By comparing the proportion of light hydrocarbons in the total hydrocarbons of simulated shale samples and downhole shale samples of corresponding maturity in natural evolution profiles, the method compensates and corrects the light hydrocarbons of simulated shale samples of different maturity, which significantly improves the accuracy of recovering the light hydrocarbon loss of shale samples, effectively reduces experimental costs, shortens the time cycle, and facilitates large-scale application based on existing data. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0034] Figure 1 A flowchart of a method for compensating and correcting light hydrocarbons in the oil content parameter S1 of shale provided in an embodiment of the present invention;

[0035] Figure 2 A schematic diagram of the thermal simulation experiment of mudstone and shale samples provided in an embodiment of the present invention;

[0036] Figure 3 This is a schematic diagram showing the distribution of the lost, remaining, and unlost portions of n-alkane in the pyrolysis products of simulated mudstone and shale samples and downhole mudstone and shale samples provided in embodiments of the present invention.

[0037] Figures 4a to 4f The images show gas chromatograms of n-alkanes in the pyrolysis products of the simulated mudstone and shale sample TNH-15 from the Chang 7 section of the Ordos Basin under different pyrolysis temperatures, provided in this embodiment of the invention.

[0038] Figures 5a to 5f The images show the n-alkane gas chromatograms of pyrolysis products from downhole mudstone and shale samples of different maturity levels from the Chang 7 section of the Ordos Basin, provided in the embodiments of the present invention.

[0039] Figure 6 A light hydrocarbon compensation chart of the Chang 7 section shale in the Ordos Basin provided for an embodiment of the present invention. Detailed Implementation

[0040] 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.

[0041] This invention provides a method for compensating and correcting the S1 light hydrocarbon content parameter of shale oil content, such as... Figure 1 As shown, it includes the following steps:

[0042] S101. Online pyrolysis was performed on simulated mudstone and shale samples and downhole mudstone and shale samples of corresponding maturity from natural evolution profiles, respectively.

[0043] It should be noted that the aforementioned downhole mudstone and shale samples refer to drilling geological mudstone and shale samples.

[0044] In specific implementation, step S101 involves online pyrolysis of the simulated shale sample and the corresponding maturity of the downhole shale sample from the natural evolution profile. Specifically, this may include using a pyrolysis instrument to perform online pyrolysis of the simulated shale sample and the corresponding maturity of the downhole shale sample from the natural evolution profile. The pyrolysis instrument can be replaced with other closed-system thermal simulation devices.

[0045] Preferably, the simulated mudstone and shale sample is a low-maturity sample, and the vitrinite reflectance (Ro) of the sample should be less than 0.7%.

[0046] S102. Quantitative analysis of hydrocarbon components in the pyrolysis products of simulated shale and downhole shale samples.

[0047] In specific implementation, step S102 involves quantitative analysis of hydrocarbon components in the pyrolysis products of the simulated shale and underground shale samples. This can specifically include: using gas chromatography-mass spectrometry (GC-MS) to quantitatively analyze the hydrocarbon components in the pyrolysis products of the simulated shale and geological shale samples. Alternatively, GC-MS can be performed using only a gas chromatograph. In this invention, based on pyrolysis-GC-MS technology, quantitative analysis results are obtained through online pyrolysis and product detection methods.

[0048] S103. Obtain the proportion of light hydrocarbons in the total hydrocarbons of the simulated shale sample and the downhole shale sample from the quantitative analysis results.

[0049] S104. Based on the comparison of the proportion of light hydrocarbons in the total hydrocarbons of simulated shale samples and downhole shale samples, the oil content parameter S1 of downhole shale samples is compensated and corrected for light hydrocarbons.

[0050] In the above-mentioned method for compensating and correcting light hydrocarbons in the oil content parameter S1 of shale provided in the embodiments of the present invention, an online pyrolysis and product detection method is adopted. By comparing the proportion of light hydrocarbons in the total hydrocarbons of simulated shale samples and downhole shale samples of corresponding maturity in natural evolution profiles, the light hydrocarbons of simulated shale samples of different maturity are compensated and corrected. This significantly improves the accuracy of recovering the light hydrocarbon loss of shale samples, effectively reduces experimental costs, shortens the time cycle, and facilitates large-scale application based on existing data.

[0051] Furthermore, in a specific implementation, in the above-mentioned method for compensating and correcting light hydrocarbons for the oil content parameter S1 of shale and mudstone provided in the embodiments of the present invention, after performing step S104 to compensate and correct the light hydrocarbons for the oil content parameter S1 of the downhole shale and mudstone sample, it may further include: establishing a light hydrocarbon compensation chart corresponding to downhole shale and mudstone samples with multiple maturity levels; and obtaining the compensation coefficients corresponding to other maturity levels of shale and mudstone samples and performing light hydrocarbon compensation and correction based on the light hydrocarbon compensation chart of the shale and mudstone samples.

[0052] It should be noted that, by comparing the total hydrocarbon content of light hydrocarbons (C) in simulated shale samples of different maturity and downhole shale samples of different maturity in natural evolution profiles, the results show that... 15 - The proportion of light hydrocarbons can be used to compensate and correct the light hydrocarbons in downhole shale samples of different maturity levels, thereby establishing a light hydrocarbon compensation chart (also known as a light hydrocarbon recovery chart) for shale samples of different maturity levels. Based on the light hydrocarbon compensation coefficient (also known as the recovery coefficient) of shale samples of different maturity levels, the original S1 value of shale samples of different maturity levels can be recovered for light hydrocarbons.

[0053] In specific implementation, in the above-mentioned light hydrocarbon compensation and correction method for the oil content parameter S1 of shale provided in the embodiments of the present invention, before performing online pyrolysis of simulated shale samples and underground shale samples of corresponding maturity in natural evolution profiles in step S101, the method may further include: firstly, pyrolyzing low-maturity coal samples from field geological profiles or mines, measuring the vitrinite reflectance at different temperature points, and calibrating the maturity corresponding to different temperature points; then, selecting underground shale samples with maturity corresponding to their vitrinite reflectance values. Vitrinite reflectance is a commonly used indicator of organic matter maturity and is used to calibrate the degree of thermal evolution of organic matter from early diagenesis to deep metamorphic stages. Preferably, underground shale samples with the same or similar maturity as the measured vitrinite reflectance values ​​can be selected.

[0054] Specifically, to accurately calibrate the thermal evolution maturity of underground shale samples corresponding to different temperature points, low-maturity coal samples were selected to begin the thermal simulation experiment. The temperature points were calibrated by measuring the vitrinite reflectance at different temperature points on the coal samples. Preferably, different temperature points could be selected such as 360, 390, 420, 450, 480, and 510℃.

[0055] Furthermore, in specific implementation, before selecting a downhole shale sample with maturity corresponding to vitrinite reflectivity in the above steps, the following step may be added: determining the maturity of the downhole shale sample based on its depth. In other words, the maturity of the downhole shale sample can be determined based on the relationship between depth and maturity.

[0056] In specific implementation, in the above-mentioned light hydrocarbon compensation and correction method for the oil content parameter S1 of shale provided in the embodiments of the present invention, during the online pyrolysis process in step S101, the following may be included: setting the target temperature of the downhole shale sample to a first constant value (e.g., 300℃); setting the target temperature of the simulated shale sample to different temperature points measured by the coal sample, such as: setting the target temperature of the simulated shale sample to 360, 390, 420, 450, 480, 510℃, etc.; the heating rate is different for different target temperatures of the simulated shale sample.

[0057] In specific implementation, in the above-mentioned light hydrocarbon compensation and correction method for the oil content parameter S1 of mudstone and shale provided in the embodiment of the present invention, before performing online pyrolysis in step S101, the method further includes: setting the temperature of the transmission connection line between the pyrolysis instrument and the gas chromatograph-mass spectrometer to a second constant value (e.g., 250°C).

[0058] In specific implementation, in the above-mentioned light hydrocarbon compensation and correction method for the oil content parameter S1 of shale provided in the embodiments of the present invention, the process of performing quantitative analysis of hydrocarbon components in step S102 may specifically include: after both the downhole shale sample and the simulated shale sample have reached the corresponding target temperature and the temperature has been kept constant for a set period of time, the pyrolysis products are enriched using a liquid nitrogen thermos placed at the front end of the chromatographic column; after the pyrolysis products are enriched, the pyrolysis products are transferred to a gas chromatography-mass spectrometry instrument through the chromatographic column for quantitative analysis of hydrocarbon components.

[0059] The following example uses a pyrolysis instrument with a programmable CDS-Pyroprobe 5000, a gas chromatography-mass spectrometry (GC-MS) system with a 5975i mass spectrometer and a 6890 gas chromatograph, an HP-PONA column (length: 50m, inner diameter: 200μm, coating: 0.5μm), liquid nitrogen (for enriching pyrolysis products), and helium as the carrier gas. Figure 2The following example illustrates the process of online deheating and quantitative analysis of hydrocarbon components in the above-mentioned shale oil content parameter S1 light hydrocarbon compensation correction method provided by the present invention:

[0060] First, crush the blocky mudstone and shale sample to 100 mesh (0.15 mm). Seal one end of the quartz glass tube with quartz wool. Then, fill the tube with about 2 mg of mudstone and shale sample from the other end and seal it with quartz wool. Next, after the pyrolysis instrument has cooled to room temperature, use tweezers to place the sealed quartz tube into the platinum heating wire in the heating probe. Finally, place the heating probe into the heating furnace inside the instrument and wait for the programmed temperature rise.

[0061] During the experiment, the transfer line temperature between the pyrolysis instrument and the gas chromatography-mass spectrometry (GC-MS) system was set to 250℃. The initial temperature of the GC-MS column was set to 40℃, with a stabilization time of 40 min; then, the temperature was increased to 310℃ at a rate of 5℃ / min and held for 10 min. The split ratio of the GC-MS inlet was set to 1:10. After the GC-MS system was ready, the pyrolysis instrument was started, with an initial temperature set to 30℃. The target temperature for geological mudstone and shale samples of different maturity was set to 300℃, and a purging time of 20 min was applied. The target temperatures for simulated mudstone and shale samples were set to 360, 390, 420, 450, 480, and 510℃, with a heating time of 15 min. Different heating rates were set according to different target temperatures; the specific heating programs are shown in Table 1.

[0062] Table 1. Heating conditions for Py-GC-MS thermal simulation experiments on shale samples.

[0063]

[0064] After reaching the target temperature, maintain the temperature for 20 minutes and then purge. A liquid nitrogen insulated cup is placed at the front end of the chromatographic column to enrich the pyrolysis products. After purging, the liquid nitrogen insulated cup is removed, and the products pass through the chromatographic column into a gas chromatography-mass spectrometry (GC-MS) instrument for analysis. The experimental principle diagram is shown below. Figure 2 As shown.

[0065] It is understandable that, assuming no loss of hydrocarbons generated from source rocks in thermal simulation experiments, the amount and composition of hydrocarbons generated by low-maturity shale at different thermal evolution stages can be obtained through thermal simulation experiments (thermal cracking-gas chromatography-mass spectrometry analysis). This invention employs the thermal cracking-gas chromatography-mass spectrometry method for shale samples. By comparing the gas chromatography-mass spectrometry characteristics of pyrolysis products obtained from thermal simulations of low-maturity shale samples under different temperature conditions (representing different maturity levels) with the S1 gas chromatography-mass spectrometry characteristics obtained from thermal simulations of similar shale samples of the same maturity level, the amount of light hydrocarbons lost can be quantitatively calculated.

[0066] Taking n-alkanes as an example, such as Figure 3 As shown, based on their ease of volatilization, the n-alkanes in shale are divided into three parts, including n-alkanes with fewer than 15 carbon atoms (nC). 15 - The components that have been lost, and n-alkanes with fewer than 15 carbon atoms in the sample (nC 15 - The residual portion of the component, and n-alkanes with more than 15 carbon atoms (nC) 15 + Components (generally not lost). Figure 3 The left side corresponds to the simulated sample (i.e., simulated mudstone and shale sample), and the right side corresponds to the actual sample (i.e., downhole mudstone and shale sample).

[0067] Assuming that the nC content of the thermally simulated rock products is similar to that of other samples of the same maturity... 15 - / nC 15 + The values ​​of ([lost light components + residual light components] / unlost components) are equal, that is:

[0068]

[0069] in, This represents the pyrolysis products of n-alkane components with fewer than 15 carbon atoms in simulated shale samples. This indicates the pyrolysis products of n-alkane components with a carbon number greater than 15 that were not lost in the simulated mudstone and shale sample. This indicates the residual pyrolysis products of n-alkane components with less than 15 carbon atoms in the shale samples from the well. This indicates that the n-alkane components with fewer than 15 carbon atoms in the shale sample from the well have been lost through pyrolysis. This indicates the pyrolysis products of n-alkane components with a carbon number greater than 15 in the underground mudstone and shale samples that have not been lost.

[0070] The amount of hydrocarbons lost in S1 can be calculated using the above formula:

[0071]

[0072]

[0073]

[0074] All parameter values ​​in the formula are expressed in terms of peak area.

[0075] S 1散失量 =a×S1×(nC) 15 (Previously, the peak area of ​​n-alkanes lost was divided into the total peak area of ​​n-alkanes) + b × S1 × (nC) 15(Previous peak area of ​​other hydrocarbons / total area of ​​other hydrocarbons) (5)

[0076] Where a and b are the ratios of the peak areas of residual n-alkanes and other hydrocarbons (isomers) in the downhole sample, respectively, and the calculation formulas are as follows:

[0077] a = Peak area of ​​n-alkane / (Peak area of ​​n-alkane + Peak area of ​​other hydrocarbons) (6)

[0078] b = 1 - a (7)

[0079] The following explanation uses the black shale of the 7th section (Chang 7th section) of the Triassic Yanchang Formation in the Ordos Basin as an example. Figures 4a to 4f The gas chromatograms of n-alkanes in the pyrolysis products of the low-maturity simulated mudstone and shale sample (TNH-15) from the Chang 7 section of the Ordos Basin under different pyrolysis temperature conditions are shown (a schematic diagram reflecting the distribution of some n-alkanes). Figures 5a to 5f The following are gas chromatograms of n-alkanes from the pyrolysis products of some downhole mudstone and shale samples of different maturity levels in the Chang 7 section of the Ordos Basin (partial schematic diagram reflecting the distribution of n-alkanes). By comparing the hydrocarbon distribution characteristics of the low-maturity simulated mudstone and shale samples of Chang 7 section with those of downhole mudstone and shale samples of corresponding maturity levels, C in downhole mudstone and shale samples of different maturity levels can be analyzed according to formulas (2)-(7). 15 - Quantitative compensation and correction are performed on hydrocarbon losses to establish... Figure 6 The diagram shows the light hydrocarbon compensation of the S1 shale at different maturity levels in seven long sections. Figure 6 The recovery coefficient is calculated as S1 after recovery / S1 before recovery.

[0080] Based on the established light hydrocarbon compensation chart of the Chang 7 shale, for sample points at known depths, the corresponding maturity can be determined according to the maturity-depth relationship diagram. Then, the S1 in the pyrolysis data can be compensated and corrected according to the maturity.

[0081] In summary, this invention, by combining a pyrolysis device with gas chromatography-mass spectrometry, yielded the hydrocarbon component distribution characteristics in simulated shale samples and downhole shale samples of corresponding maturity. By comparing the total hydrocarbon content (C) in the simulated samples... 15 - The proportion of hydrocarbon components was used to quantitatively recover lost hydrocarbons in shale and mudstone samples of corresponding maturity levels, which significantly improved the accuracy of recovering light hydrocarbon losses in shale and mudstone samples.

[0082] For more detailed information on the above methods, please refer to the relevant content disclosed in the foregoing embodiments, which will not be repeated here.

[0083] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0084] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0085] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly by hardware, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0086] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0087] The above provides a detailed description of the S1 light hydrocarbon compensation and correction method for oil content parameter in shale and mudstone provided by this invention. Specific examples have been used to illustrate the principle and implementation of this invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​this invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​this invention. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A method for compensating and correcting light hydrocarbon content in the oil content parameter S1 of shale and mudstone, characterized in that, include: Pyrolysis was performed on low-maturity coal samples from field geological profiles or mines to determine the vitrinite reflectance at different temperature points and to calibrate the maturity at different temperature points. Select downhole mudstone and shale samples with maturity corresponding to the vitrinite reflectance; The simulated mudstone and shale samples and the downhole mudstone and shale samples were subjected to online pyrolysis, respectively. Quantitative analysis of hydrocarbon components was performed on the pyrolysis products of the simulated shale sample and the downhole shale sample; The quantitative analysis of hydrocarbon components includes: after both the downhole shale sample and the simulated shale sample reach the corresponding target temperature and are kept at the same temperature for a set time period, the pyrolysis products are enriched using a liquid nitrogen thermos placed at the front end of the chromatographic column; after the pyrolysis products are enriched, the pyrolysis products are transferred to a gas chromatography-mass spectrometry instrument through the chromatographic column for quantitative analysis of hydrocarbon components. The proportion of light hydrocarbons in the total hydrocarbons of the simulated shale sample and the downhole shale sample were obtained from the quantitative analysis results. Based on the comparison of the proportion of light hydrocarbons in the total hydrocarbons of the simulated shale sample and the downhole shale sample, the oil content parameter S1 of the downhole shale sample is compensated and corrected for light hydrocarbons. By comparing the proportion of light hydrocarbons in the total hydrocarbons of simulated mudstone and shale samples of different maturity and downhole mudstone and shale samples of different maturity in natural evolution profiles, the light hydrocarbons of downhole mudstone and shale samples of different maturity are compensated and corrected, and a light hydrocarbon compensation chart corresponding to downhole mudstone and shale samples of different maturity is established. Based on the light hydrocarbon compensation charts corresponding to downhole shale samples of different maturity, the light hydrocarbon compensation coefficients corresponding to shale samples of different maturity are obtained, and the oil content parameter S1 of shale samples of different maturity is recovered based on the light hydrocarbon compensation coefficients.

2. The method for compensating and correcting light hydrocarbon content in shale oil content parameter S1 according to claim 1, characterized in that, The online pyrolysis process includes: The target temperature of the downhole mudstone and shale sample is set to a first constant value; The target temperature of the simulated mudstone and shale sample is set to different temperature points measured by the coal sample; the heating rate is different for the different target temperatures of the simulated mudstone and shale sample.

3. The method for compensating and correcting light hydrocarbon content in shale oil content parameter S1 according to claim 2, characterized in that, Online pyrolysis was performed on simulated shale samples and downhole shale samples of corresponding maturity from natural evolution profiles, including: Online pyrolysis was performed on simulated mudstone and shale samples and downhole mudstone and shale samples of corresponding maturity from natural evolution profiles using a pyrolysis instrument.

4. The method for compensating and correcting light hydrocarbon content in shale oil content parameter S1 according to claim 3, characterized in that, Quantitative analysis of hydrocarbon components was performed on the pyrolysis products of the simulated shale sample and the downhole shale sample, including: Gas chromatography-mass spectrometry was used to quantitatively analyze the hydrocarbon components of the pyrolysis products of the simulated shale sample and the downhole shale sample.

5. The method for compensating and correcting light hydrocarbon content in shale oil content parameter S1 according to claim 4, characterized in that, Before online pyrolysis, the following is also included: The temperature of the transfer line between the pyrolysis instrument and the gas chromatography-mass spectrometry instrument is set to a second constant value.

6. The method for compensating and correcting light hydrocarbon content in shale oil content parameter S1 according to claim 1, characterized in that, Before selecting the downhole shale sample with a maturity corresponding to the vitrinite reflectance, the process also includes: The maturity of the downhole mudstone and shale sample is determined based on its depth.

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