Evaluation method for content of movable oil in shale, and device and storage medium

Abstract

The present invention belongs to the field of shale oil exploration. Provided are an evaluation method for the content of movable oil in shale, and a device and a storage medium. The evaluation method comprises the following steps: on the basis of pyrolysis test data of a sample to be tested at different aging times, determining a first recovery coefficient; on the basis of pyrolysis test data of said sample in different sample crushing environments, determining a second recovery coefficient; on the basis of pyrolysis test data of said sample at different crushing particle sizes, determining a third recovery coefficient; on the basis of pyrolysis test data of said sample at different pyrolysis temperatures, determining a fourth recovery coefficient; determining the product of the first recovery coefficient, the second recovery coefficient, the third recovery coefficient and the fourth recovery coefficient to be a light hydrocarbon recovery coefficient; and on the basis of the light hydrocarbon recovery coefficient, evaluating the content of movable oil in shale. The method provided in the present invention offers guidance for quantitatively evaluating the oil content of shale, and a finally determined free oil content result has a relatively small difference from the actual situation.

Description

Method, device and storage medium for evaluating movable oil content in shale Technical Field

[0001] The present invention relates to the technical field of shale oil exploration, and in particular to a method for evaluating the movable oil content in shale, an electronic device, and a computer-readable storage medium. Background Art

[0002] Oil in shale reservoirs exists primarily in two forms: adsorbed and free. Adsorbed oil exists within and on the surfaces of organic matter and inorganic minerals; free oil exists in pores and fractures. A small amount of oil can also exist in a dissolved form within residual pores of oil-wet organic matter, where hydrocarbons are generated. Shale oil content is equal to the sum of free oil and adsorbed, miscible oil. Because adsorbed, miscible crude oil in shale is difficult to mobilize, current shale oil development focuses on free oil within the shale. Free oil is a significant contributor to shale oil production under natural elastic energy extraction.

[0003] Existing methods for quantitatively characterizing the free and adsorbed oil content in shale include solvent step-by-step extraction, rock pyrolysis, nuclear magnetic resonance, and three-dimensional fluorescence quantitative analysis. For example, a Chinese non-patent document published in July 2018, titled "Geochemical Characteristics of Soluble Organic Matter in Different Occurrence States in Low-Maturity Lacustrine Mudstone Source Rocks," proposes a method for characterizing the free shale oil content based on a multi-solvent step-by-step extraction process. This method exploits the differences in the distribution space and molecular polarity of shale oil in different occurrence states, using appropriate solvents to extract both bulk and powder samples. Free shale oil, with its large distribution space and low molecular polarity, is easily extracted; adsorbed shale oil, with its small distribution space and high molecular polarity, is difficult to extract. The resulting chloroform bitumen "A" is then used to analyze the oil content. However, this method has the following defects: (1) The properties of the solvent itself and the solvent volatilization process result in the loss of light hydrocarbons; (2) The occurrence state does not completely correspond to the polarity of the solvent, making it difficult to effectively distinguish between free and adsorbed shale oil; (3) The analysis process is complicated and expensive, and the use of extraction solvents is limited to the scientific research level of typical samples and cannot be applied to production.

[0004] The Chinese non-patent document entitled "Research on Quantitative Characterization Technology and Application of Shale Oil in Different Occurrence States" published in November 2016 proposed a method for characterizing the content of free shale oil based on multi-temperature stage segmented pyrolysis. The basis of this method is that shale oil in different occurrence states has different molecular thermal volatility, and small molecules and free compounds in cracks and large pores are relatively easier to release thermally. By conducting pyrolysis chromatographic analysis of the released hydrocarbon components in different temperature sections, S 1-1 It is a light component of free oil in the interconnected pores of shale and is easy to mobilize under current technical conditions; S 1-2The sum of the two is the free oil content in the shale, i.e., the maximum movable oil content. However, this method has the following drawbacks: (1) it does not take into account the loss of light hydrocarbons during coring, core placement, and the experimental process; (2) the initial temperature is too high, which is inconsistent with the actual geological conditions; and (3) its scope of application is limited, mainly applicable to shale samples within the oil window and highly over-mature shale samples.

[0005] A Chinese non-patent document titled "T1-T2 Two-Dimensional Nuclear Magnetic Resonance Oil Content Detection Method for Shale Oil Reservoirs" published in September 2020 proposes a method for characterizing the free shale oil content based on shale nuclear magnetic resonance results. This method is based on the differences in the longitudinal relaxation times T1 and T1 / T2 of different fluids, establishes a T1-T2 two-dimensional nuclear magnetic resonance spectrum, and conducts oil content detection in shale oil reservoirs based on the different positions of fluid components on the T1-T2 spectrum. However, this method has the following defects: (1) Due to differences in cores and nuclear magnetic resonance instruments, the measured results differ significantly from the idealized interpretation diagram, resulting in poor accuracy and generalizability; (2) There is currently no mature interpretation model. For example, organic pores are not well developed in medium- and high-maturity shale oil formations, and shale oil reservoirs may not contain water. These understandings contradict the current interpretation diagram.

[0006] The Chinese non-patent document published in May 2020 and titled "Analysis of Oil Content and Mobility of Intersalt Shales in the Qianjiang Formation of the Qianjiang Sag in the Jianghan Basin" proposed a method based on the combination of oil saturation index (S1 / TOC) and pyrolysis movable oil volume (S 1-1 A comprehensive method for evaluating the mobility of intersalt shale oil uses techniques such as fluorophore fluorescence (FLUO) and three-dimensional fluorescence quantification. This method identifies rock oil content based on variations in the color and intensity of luminescence from oil within the rock. Specifically, saturated hydrocarbons do not luminesce, while unsaturated hydrocarbons and their derivatives fluoresce. However, this method has strict requirements for sample particle size, extraction solvent, and extraction method. Furthermore, the ideal standard sample is crude oil from the same depth and layer, making it difficult to operate.

[0007] While these methods can all study and determine the free oil content in shale to a certain extent, they fail to account for the loss of light hydrocarbons from core samples during sampling, transportation, preparation, and even experimental manipulation. Furthermore, current methods for preventing light hydrocarbon loss are subject to significant uncertainty, and methods for recovering lost light hydrocarbons are immature. This results in significant discrepancies between experimentally measured free oil content and actual conditions, resulting in poor reliability and credibility, making them unsuitable for shale oil resource evaluation and prediction.

[0008] Therefore, it is necessary to develop a method for determining the free oil content in shale that comprehensively considers the loss of light hydrocarbons. Summary of the Invention

[0009] The purpose of the embodiments of the present invention is to provide a method for evaluating the movable oil content in shale, at least to solve the problem that the existing methods for studying and determining the oil content of shale do not take the loss of light hydrocarbons into consideration.

[0010] In order to achieve the above-mentioned objectives, the first aspect of the present invention provides a method for evaluating the movable oil content in shale, which includes the following steps: determining a first recovery coefficient considering the influence of the sample placement time based on the pyrolysis test data of the samples to be tested at different placement times; determining a second recovery coefficient considering the influence of the sample crushing environment based on the pyrolysis test data of the samples to be tested under different sample crushing environments; determining a third recovery coefficient considering the influence of the sample crushing size based on the pyrolysis test data of the samples to be tested at different crushing sizes; determining a fourth recovery coefficient considering the influence of the sample pyrolysis temperature based on the pyrolysis test data of the samples to be tested at different pyrolysis temperatures; determining the product of the first recovery coefficient, the second recovery coefficient, the third recovery coefficient and the fourth recovery coefficient as the light hydrocarbon recovery coefficient; and evaluating the movable oil content in shale based on the light hydrocarbon recovery coefficient.

[0011] In an exemplary embodiment of the present invention, determining the first recovery coefficient taking into account the influence of the sample placement time based on the pyrolysis test data of the sample to be tested at different placement times may include: obtaining the pyrolysis test data of the sample to be tested at different placement times when the sample to be tested is at a reasonable particle size and a reasonable pyrolysis temperature; determining the recovery coefficient of the sample to be tested at different placement times based on the pyrolysis test data of the sample to be tested at different placement times; and determining the average value of the recovery coefficients of the samples to be tested at different placement times as the first recovery coefficient.

[0012] In an exemplary embodiment of the present invention, the determination of the second recovery coefficient taking into account the influence of the sample crushing environment based on the pyrolysis test data of the sample to be tested under different sample crushing environments may include: obtaining the pyrolysis test data of the sample to be tested under different sample crushing environments when the sample to be tested is at a reasonable particle size and a reasonable pyrolysis temperature; wherein the different sample crushing environments include an open environment and a closed environment; determining the recovery coefficient of the sample to be tested under the different sample crushing environments based on the pyrolysis test data of the sample to be tested under the different sample crushing environments; and determining the average value of the recovery coefficients of the samples to be tested under the different sample crushing environments as the second recovery coefficient.

[0013] In an exemplary embodiment of the present invention, the third recovery coefficient considering the influence of the sample crushing particle size based on the pyrolysis test data of the sample to be tested at different crushing particle sizes may include: obtaining the pyrolysis test data of the sample to be tested at different crushing particle sizes when the sample to be tested is at a reasonable pyrolysis temperature, wherein the different crushing particle sizes include reasonable particle sizes and other particle sizes; determining the recovery coefficient of the sample to be tested at different crushing particle sizes based on the pyrolysis test data of the sample to be tested at different crushing particle sizes; and determining the average value of the recovery coefficients of the samples to be tested at different crushing particle sizes as the third recovery coefficient.

[0014] In an exemplary embodiment of the present invention, determining the fourth recovery coefficient under the influence of the sample pyrolysis temperature based on the pyrolysis test data of the sample to be tested at different pyrolysis temperatures may include: obtaining the pyrolysis test data of the sample to be tested at different pyrolysis temperatures when the sample to be tested is at a reasonable particle size; wherein the different pyrolysis temperatures include a reasonable pyrolysis temperature and a conventional pyrolysis temperature; determining the recovery coefficient of the sample to be tested at different pyrolysis temperatures based on the pyrolysis test data of the sample to be tested at different pyrolysis temperatures; and determining the average value of the recovery coefficients of the samples to be tested at different pyrolysis temperatures as the fourth recovery coefficient.

[0015] In an exemplary embodiment of the present invention, the evaluation method may further include: obtaining porosity test data of different lithologic samples at different crushing particle sizes; determining a fitting relationship between porosity and particle size based on the porosity test data of different lithologic samples at different crushing particle sizes; and determining a reasonable particle size through the fitting relationship between porosity and particle size based on the median value of the effective porosity of shale samples in the target area.

[0016] In an exemplary embodiment of the present invention, the evaluation method may further include: obtaining a full hydrocarbon chromatogram image of a crude oil sample in a shale horizontal well, wherein the crude oil sample and the sample to be tested have the same stratigraphic position; obtaining a full hydrocarbon chromatogram image of multi-temperature-stage pyrolysis hydrocarbons of the sample to be tested in different pyrolysis temperature ranges; comparing the full hydrocarbon chromatogram image of the crude oil sample with the full hydrocarbon chromatogram image of the multi-temperature-stage pyrolysis hydrocarbons, and determining a portion in the full hydrocarbon chromatogram image of the multi-temperature-stage pyrolysis hydrocarbons that is similar to the full hydrocarbon chromatogram image of the crude oil sample; and determining the pyrolysis temperature corresponding to the portion in the full hydrocarbon chromatogram image of the multi-temperature-stage pyrolysis hydrocarbons that is similar to the full hydrocarbon chromatogram image of the crude oil sample as a reasonable pyrolysis temperature.

[0017] In an exemplary embodiment of the present invention, the evaluation method may further include: determining the light hydrocarbon recovery coefficient of the test samples with different Ro values; determining the fitting relationship between the Ro value and the light hydrocarbon recovery coefficient based on the light hydrocarbon recovery coefficient corresponding to different Ro values; and predicting the light hydrocarbon recovery coefficient corresponding to the test sample with a specified Ro value based on the fitting relationship between the Ro value and the light hydrocarbon recovery coefficient.

[0018] A second aspect of the present invention provides an electronic device, comprising a processor and a memory, wherein the memory stores at least one computer program, and the at least one computer program is loaded and executed by one or more of the above-mentioned processors to enable the computer to implement the above-mentioned method for evaluating the movable oil content in shale.

[0019] A third aspect of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores at least one program code, and the program code is loaded and executed by a processor to enable a computer to implement the above-mentioned method for evaluating the movable oil content in shale.

[0020] Through the above technical solution, the beneficial effects of the present invention are as follows:

[0021] (1) Compared with the rock pyrolysis method in the prior art, the method for evaluating the movable oil content in shale of the present invention fully considers the influence of different factors on the loss of light hydrocarbons, and ultimately determines a new parameter that can quantitatively characterize the oil content of shale, namely, the light hydrocarbon recovery coefficient. The light hydrocarbon recovery coefficient can be used to recover the thermally released hydrocarbons S1 (light hydrocarbons) and obtain the pyrolysis measurement value of the complete free oil;

[0022] (2) The present invention combines multiple methods such as sealed crushing, GRI porosity testing, and pyrolysis experiments to determine the reasonable particle size and reasonable pyrolysis temperature of the lithologic samples, forming experimental parameters that are closer to actual geological conditions, which can ensure the rationality of the final light hydrocarbon recovery coefficient;

[0023] (3) The method for evaluating the movable oil content in shale of the present invention is instructive for quantitatively evaluating the oil content of shale oil in the entire region. The free oil content finally determined by the method is less different from the actual situation, has high reliability and credibility, and can be used for the evaluation and prediction of shale oil resources.

[0024] (4) From the perspective of reducing costs and increasing efficiency, the present invention can directly recover light hydrocarbons from old samples, avoiding the waste of a large number of samples in the early stage; it can predict the recovery coefficient of light hydrocarbons with higher maturity, reducing experimental investment.

[0025] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following detailed description, they are used to explain the embodiments of the present invention, but do not constitute a limitation of the embodiments of the present invention. In the accompanying drawings:

[0027] FIG1 is a flow chart of a method for evaluating movable oil content in shale provided by a first embodiment of the present invention;

[0028] FIG2 is a flow chart of a method for evaluating movable oil content in shale provided by a second embodiment of the present invention;

[0029] FIG3 is a flow chart of a method for evaluating movable oil content in shale provided by a third embodiment of the present invention;

[0030] FIG4 is a fitting curve diagram of porosity and particle size provided by the third embodiment of the present invention;

[0031] FIG5 is a schematic structural diagram of an electronic device provided by a fourth embodiment of the present invention.

[0032] DESCRIPTION OF REFERENCE NUMERALS 201 - memory, 202 - processor DETAILED DESCRIPTION

[0033] The following describes the specific implementation of the embodiment of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the embodiment of the present invention and is not used to limit the embodiment of the present invention.

[0034] In the present invention, unless otherwise indicated, directional terms such as "upper, lower, top, and bottom" are generally used to describe the relative positions of components relative to the directions shown in the drawings, or relative to the vertical, perpendicular, or gravitational directions. "First," "second," etc. are merely for convenience of description and distinction and should not be construed as indicating or implying relative importance.

[0035] It should also be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "installation" and "connection" should be understood in a broad sense. For example, they may refer to fixed connection, detachable connection, or integrated connection; direct connection, indirect connection, wired connection, or wireless connection. Those skilled in the art will understand the specific meanings of the above terms in the present invention depending on the specific circumstances.

[0036] Rock pyrolysis is one of the most effective methods for studying and measuring free oil content in shale. However, current rock pyrolysis methods fail to account for light hydrocarbon losses during core sampling, transportation, preparation, and even experimental manipulation. This results in significant discrepancies between experimentally measured free oil content and actual results, resulting in poor reliability and credibility, making it unsuitable for evaluating and predicting shale oil resources. To address this issue, the present invention provides a method for evaluating the mobile oil content in shale to address this technical issue.

[0037] The overall technical concept of the present invention is to obtain a reasonable sample particle size and a reasonable temperature step for pyrolysis that are closer to actual underground conditions by conducting analyses such as the relationship between the crushed particle size and porosity of experimental samples, the similarity between pyrolysis S1 at different temperatures and petroleum chromatographic characteristics, and control experiments on factors affecting oil content, and then determine the reasonable values ​​of the movable hydrocarbon content of the rock and its related parameters (such as the light hydrocarbon recovery coefficient) to accurately evaluate the shale oil resource.

[0038] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0039] Example 1

[0040] As shown in FIG1 , the first embodiment of the present invention provides a method for evaluating movable oil content in shale, the method comprising the following steps:

[0041] Step S101: Based on the pyrolysis test data of the sample to be tested at different placement times, determine the first restitution coefficient K1 considering the influence of the sample placement time.

[0042] For example, different placement times can be determined based on the time the lithologic sample is exposed during sampling, transportation, preparation, or even experimental operation. Specifically, different placement times can be set to 5 minutes, 30 minutes, 1 hour, 2 hours, 4 hours, 0.5 days, 1 day, 3 days, 5 days, 15 days, 30 days, etc.

[0043] Step S102: Based on the pyrolysis test data of the sample to be tested under different sample crushing environments, determine the second restitution coefficient K2 considering the influence of the sample crushing environment.

[0044] For example, different sample crushing environments may include open environments and closed environments, etc.

[0045] Step S103: Based on the pyrolysis test data of the samples to be tested at different crushing particle sizes, a third restitution coefficient K3 is determined taking into account the influence of the sample crushing particle size.

[0046] For example, different crushing particle sizes can be set according to the particle size ranges of different rock types. Specifically, different crushing particle sizes can be set to 0.01mm-0.3mm, 0.05mm-1.0mm, 1.5mm-3.0mm, 3.00mm-5.00mm, 5.00mm-8.00mm, etc.

[0047] Step S104: Based on the pyrolysis test data of the sample to be tested at different pyrolysis temperatures, a fourth recovery coefficient K4 considering the influence of the sample pyrolysis temperature is determined.

[0048] For example, different pyrolysis temperatures can be determined based on the temperature ranges set during conventional pyrolysis and multi-stage pyrolysis. Specifically, different pyrolysis temperatures can be set to 100°C, 150°C, 200°C, 250°C, 300°C, 350°C, 400°C, etc.

[0049] Step S105: determining the product of the first restitution coefficient, the second restitution coefficient, the third restitution coefficient and the fourth restitution coefficient as the light hydrocarbon restitution coefficient.

[0050] Here, it should be noted that the calculation of the light hydrocarbon recovery coefficient needs to consider two parts: the first part is the light hydrocarbon recovery calculation, which mainly involves two experiments, namely, pyrolysis tests with different placement times and different crushing environments. Both experiments are carried out under reasonable particle size and reasonable temperature conditions, and are used to calculate the first recovery coefficient (K1) under different placement times and the second recovery coefficient (K2) under different crushing environments respectively; the second part is the calculation of the movable hydrocarbon content, which mainly involves two experiments, namely, different crushing particle sizes and different pyrolysis temperatures, and are used to calculate the third recovery coefficient (K3) under different crushing particle sizes and the fourth recovery coefficient (K4) under different pyrolysis temperatures respectively. In addition, since the crushing particle size in this experiment is larger than the conventional pyrolysis particle size and the pyrolysis temperature is lower than the conventional pyrolysis temperature, both will cause the movable hydrocarbon content to be reduced compared to conventional pyrolysis. Therefore, when calculating the amount of movable hydrocarbons, it is necessary to restore the reduced part to the amount of hydrocarbons generated under conventional conditions, that is, the loss amount needs to be added.

[0051] Finally, the light hydrocarbon recovery coefficient can be obtained through the first recovery coefficient (K1), the second recovery coefficient (K2), the third recovery coefficient (K3) and the fourth recovery coefficient (K4). That is, the calculation formula of the light hydrocarbon recovery coefficient is: K = K1 × K2 × K3 × K4

[0052] Wherein, K is the light hydrocarbon recovery coefficient; K1 is the first recovery coefficient; K2 is the second recovery coefficient; K3 is the third recovery coefficient; K4 is the fourth recovery coefficient.

[0053] Step S106: Evaluate the movable oil content in the shale based on the light hydrocarbon recovery coefficient.

[0054] Here, it should be noted that the thermally released hydrocarbons S1 (light hydrocarbons) represent the amount of hydrocarbons that have been generated and remain in the rock after the hydrocarbon expulsion effect, that is, the amount of movable oil. Since light hydrocarbons are volatile, some light hydrocarbons have been lost during the sample collection, transportation and storage process. Therefore, the S1 currently measured by the pyrolysis method is not complete free oil, and S1 recovery is required, that is, the light hydrocarbon recovery coefficient needs to be determined. In other words, the light hydrocarbon recovery coefficient determined in this application can quantitatively characterize the oil content of shale. After using the light hydrocarbon recovery coefficient to correct the S1 measured by the pyrolysis method, a measurement result of complete free oil that is closer to the actual geological conditions can be obtained.

[0055] In this embodiment, in order to ensure the accuracy of the pyrolysis test data under different influencing factors (i.e., sample crushing environment, storage time, crushing particle size, and pyrolysis temperature), the same pyrolysis temperature should be used when conducting rock pyrolysis experiments under different sample crushing environments and different storage times, and the particle size of the samples to be tested should be the same. In addition, when conducting rock pyrolysis experiments under different pyrolysis temperatures, the particle size of the samples to be tested should be the same as the particle size used in rock pyrolysis experiments under different sample crushing environments and different storage times; when conducting rock pyrolysis experiments under different crushing particle sizes, the pyrolysis temperature should be the same as the pyrolysis temperature used in rock pyrolysis experiments under different sample crushing environments and different storage times.

[0056] Furthermore, the reasonable particle size and pyrolysis temperature that conform to actual geological conditions can be determined first. The test sample can then be processed into rock samples of reasonable particle size. Pyrolysis experiments can then be conducted at reasonable pyrolysis temperatures under different influencing factors (i.e., sample crushing environment, storage time, crushing size, and pyrolysis temperature). Multiple sets of pyrolysis test data can then be obtained. This ensures the authenticity and rationality of the pyrolysis test data and allows for the determination of reasonable light hydrocarbon recovery coefficients.

[0057] Illustratively, based on the pyrolysis test data of the tested sample at different placement times, the process of determining the first restitution coefficient considering the influence of the sample placement time includes but is not limited to the following sub-steps S1011 to S1013.

[0058] Sub-step S1011: When the sample to be tested has a reasonable particle size and a reasonable pyrolysis temperature, obtain pyrolysis test data of the sample to be tested at different storage times.

[0059] Sub-step S1012: Based on the pyrolysis test data of the sample to be tested at different placement times, determine the recovery coefficient of the sample to be tested at different placement times.

[0060] Sub-step S1013: determining an average value of the recovery coefficients of the samples to be tested at different placement times as a first recovery coefficient.

[0061] Illustratively, based on the pyrolysis test data of the sample to be tested under different sample crushing environments, the process of determining the second recovery coefficient considering the influence of the sample crushing environment includes but is not limited to the following sub-steps S1021 to S1023.

[0062] Sub-step S1021: When the sample to be tested has a reasonable particle size and a reasonable pyrolysis temperature, obtain pyrolysis test data of the sample to be tested under different sample crushing environments, wherein the different sample crushing environments include open environments and closed environments.

[0063] Sub-step S1022: Based on the pyrolysis test data of the sample to be tested under different sample crushing environments, determine the recovery coefficient of the sample to be tested under different sample crushing environments.

[0064] Sub-step S1023: determining an average value of the recovery coefficients of the samples to be tested under different sample crushing environments as a second recovery coefficient.

[0065] For example, based on the pyrolysis test data of the tested samples at different crushing sizes, the process of determining the third restitution coefficient considering the influence of the sample crushing size includes but is not limited to the following sub-steps S1031 to S1033.

[0066] Sub-step S1031: When the sample to be tested is at a reasonable pyrolysis temperature, obtain pyrolysis test data of the sample to be tested at different crushing particle sizes, wherein the different crushing particle sizes include reasonable particle sizes and other particle sizes.

[0067] Sub-step S1032: Determine the recovery coefficient of the sample to be tested at different crushing particle sizes based on the pyrolysis test data of the sample to be tested at different crushing particle sizes.

[0068] Sub-step S1033: determining the average value of the coefficients of restitution of the samples to be tested at different crushing particle sizes as the third coefficient of restitution.

[0069] Illustratively, based on the pyrolysis test data of the samples to be tested at different pyrolysis temperatures, the process of determining the fourth recovery coefficient under the influence of the sample pyrolysis temperature includes but is not limited to the following sub-steps S1041 to S1043.

[0070] Sub-step S1041: When the sample to be tested has a reasonable particle size, obtain pyrolysis test data of the sample to be tested at different pyrolysis temperatures, wherein the different pyrolysis temperatures include a reasonable pyrolysis temperature and a conventional pyrolysis temperature.

[0071] Sub-step S1042: determining the recovery coefficient of the sample to be tested at different pyrolysis temperatures based on the pyrolysis test data of the sample to be tested at different pyrolysis temperatures.

[0072] Sub-step S1043: determining an average value of the recovery coefficients of the samples to be tested at different pyrolysis temperatures as a fourth recovery coefficient.

[0073] Here, the reasonable particle size and reasonable pyrolysis temperature can be inferred based on relevant historical measurement data of actual geology, or they can be determined by assigning empirical values ​​based on the pyrolysis test results of rocks with similar lithology.

[0074] Of course, the present invention is not limited thereto, and the reasonable particle size and reasonable pyrolysis temperature can also be obtained by combined analysis using methods such as nuclear magnetic resonance and chromatography analysis.

[0075] For example, the process of determining a reasonable particle size is as follows:

[0076] (a) Obtain porosity test data of different lithology samples at different crushing sizes.

[0077] (b) Based on the porosity test data of different lithologic samples at different crushing sizes, the fitting relationship between porosity and particle size is determined.

[0078] (c) Based on the median effective porosity of shale samples in the target area, the reasonable particle size is determined by fitting the relationship between porosity and particle size.

[0079] Exemplarily, the process for determining a reasonable pyrolysis temperature is as follows:

[0080] (a) Obtaining a full hydrocarbon chromatogram of a crude oil sample from a horizontal shale well. The crude oil sample and the sample to be tested are from the same stratigraphic layer.

[0081] (b) Obtain the full hydrocarbon chromatogram image of the multi-temperature-stage pyrolysis hydrocarbons of the tested sample in different pyrolysis temperature ranges.

[0082] (c) Comparing the total hydrocarbon chromatogram image of the crude oil sample with the total hydrocarbon chromatogram image of the multi-temperature stage pyrolysis hydrocarbon, determining the portion in the total hydrocarbon chromatogram image of the multi-temperature stage pyrolysis hydrocarbon that is similar to the total hydrocarbon chromatogram image of the crude oil sample.

[0083] (d) The pyrolysis temperature corresponding to the portion of the full hydrocarbon chromatogram image of the multi-temperature-stage pyrolysis hydrocarbons that is similar to the full hydrocarbon chromatogram image of the crude oil sample is determined as the reasonable pyrolysis temperature.

[0084] It should be noted that the porosity involved in the method for evaluating the movable oil content in shale of the present invention represents the movable porosity of the free oil, which corresponds to the movable oil. However, adsorbed oil and dead pore oil cannot be mobilized under current engineering conditions and are therefore not considered in the present invention.

[0085] In addition, the implementation environment of this embodiment includes at least one terminal and a server, and the method is executed on the terminal or the server respectively. The terminal and the server can be connected in communication to realize the interactive transmission of information.

[0086] Among them, the terminal can be any electronic product that can interact with the user through one or more methods such as keyboard, touchpad, touch screen, voice interaction, etc., such as PC (Personal Computer), PPC (Pocket Personal Computer), tablet computer, etc.

[0087] A server can be a single server or a server cluster consisting of multiple servers. It can also be a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, CDN (Content Delivery Network), as well as big data and artificial intelligence platforms.

[0088] Example 2

[0089] As shown in FIG2 , a second embodiment of the present invention provides a method for evaluating movable oil content in shale, the method comprising the following steps:

[0090] Step S201: Determine samples to be tested of different lithologies and determine a reasonable particle size.

[0091] Illustratively, the process of determining the sample to be tested and determining the reasonable particle size includes but is not limited to the following sub-steps S2011 to S2016.

[0092] Sub-step S2011: First, an XRD measurement experiment is carried out, and three shales with different lithologies, namely, felsic shale, mixed shale, and dolomitic shale, are selected as test samples, and the porosity of the three test samples is tested respectively.

[0093] Sub-step S2012: Conduct a TOC determination experiment, and select several groups of different TOC values ​​as particle size test samples for the samples to be tested.

[0094] For example, felsic shale, mixed shale, and dolomitic shale with TOC values ​​of 1.0, 1.5, and 2.0 can be selected as particle size test samples, respectively.

[0095] Sub-step S2013: For each group of particle size test samples (i.e., test samples with the same TOC and the same lithology), different particle sizes are crushed and porosity is measured using a nuclear magnetic resonance instrument to obtain the porosity of each group of particle size test samples at different particle sizes.

[0096] Sub-step S2014: Fitting the different particle sizes and the porosities corresponding to the different particle sizes in sub-step S2013 into a regression equation to obtain a porosity-particle size fitting curve for each group of particle size test samples.

[0097] Sub-step S2015: Repeat sub-steps S2013 to S2014 to determine the porosity-particle size fitting curves for each of the nine groups of particle size test samples.

[0098] Sub-step S2016: Substitute the median value of the effective porosity of the shale samples in the target area into the porosity-particle size fitting curve of the corresponding particle size test samples to determine the reasonable particle size of the samples to be tested with different lithologies.

[0099] Here, it should be noted that the normal distribution of shale porosity in the target area can be statistically analyzed, and the median range in the normal distribution can be determined as the median of the effective porosity of shale samples in the target area.

[0100] Step S202: Determine a reasonable pyrolysis temperature.

[0101] Illustratively, the process of determining a reasonable pyrolysis temperature includes but is not limited to the following sub-steps S2021 to S2024.

[0102] Sub-step S2021: select three barrels of crude oil samples with different lithologies for full hydrocarbon chromatography analysis, and obtain full hydrocarbon chromatographic images of the three crude oil samples respectively.

[0103] Sub-step S2022: After the three samples to be tested are crushed into the reasonable particle size in step S201, a multi-temperature stage pyrolysis experiment is carried out to obtain full hydrocarbon chromatogram images of the multi-temperature stage pyrolysis hydrocarbons of the three samples to be tested in different pyrolysis temperature ranges.

[0104] Among them, multi-temperature stage pyrolysis experiments should select five temperature ranges that are closer to geological conditions as pyrolysis temperatures for experiments.

[0105] Sub-step S2023: For each sample to be tested, the full hydrocarbon chromatogram image of the multi-temperature-stage pyrolysis hydrocarbons in different pyrolysis temperature ranges is compared with the full hydrocarbon chromatogram image of the crude oil sample, and the portion of the full hydrocarbon chromatogram image of the multi-temperature-stage pyrolysis hydrocarbons that is similar to the full hydrocarbon chromatogram image of the crude oil sample is determined.

[0106] Sub-step S2024: For each sample to be tested, the pyrolysis temperature corresponding to the portion of the full hydrocarbon chromatogram of the multi-temperature-stage pyrolysis hydrocarbons that is similar to the full hydrocarbon chromatogram of the crude oil sample is determined as the reasonable pyrolysis temperature of the sample to be tested.

[0107] Step S203: For each sample to be tested, when the sample to be tested is at a reasonable particle size and a reasonable pyrolysis temperature, a rock pyrolysis experiment of the sample to be tested is carried out at different placement times to determine the first restitution coefficient K1 considering the influence of the sample placement time.

[0108] For example, based on the reasonable particle size determined in step S201 and the reasonable pyrolysis temperature determined in step S202, the same lithology samples to be tested can be used to conduct control pyrolysis experiments with different placement times after crushing, and the recovery coefficient K considering the influence of sample placement time can be obtained. 时间 Repeat the above steps to carry out multiple groups of control pyrolysis experiments with different placement times, and calculate the recovery coefficient K corresponding to the multiple groups of control pyrolysis experimental data. 时间 An average value calculation is performed, and the obtained average value is determined as the final first restitution coefficient K1.

[0109] Step S204: For each sample to be tested, pyrolysis experiments are conducted on the sample under different crushing environments, with the sample having a reasonable particle size and a reasonable pyrolysis temperature, to determine a second restitution coefficient under the influence of the crushing environment. The different crushing environments may include open environments and closed environments.

[0110] For example, based on the reasonable particle size determined in step S201 and the reasonable pyrolysis temperature determined in step S202, the open crushed sample and the closed crushed sample control pyrolysis experiment can be carried out using the test sample of the same lithology, and the recovery coefficient K considering the influence of the sample crushing environment can be obtained. 开闭 Repeat the above steps to carry out multiple groups of control pyrolysis experiments with different sample crushing environments, and calculate the recovery coefficient K corresponding to the multiple groups of control pyrolysis experimental data under the influence of the sample crushing environment. 开闭 An average value calculation is performed, and the obtained average value is determined as the final second restitution coefficient K2.

[0111] Step S205: For each sample to be tested, conduct rock pyrolysis experiments on the sample at different crushing sizes while maintaining the sample at a reasonable pyrolysis temperature, and determine the third restitution coefficient under the influence of the sample crushing size. The different crushing sizes should include reasonable particle sizes and other particle sizes.

[0112] For example, multiple crushing particle sizes can be set according to the reasonable particle size determined in step S201, and the reasonable pyrolysis temperature determined in step S202 can be used to perform control pyrolysis experiments of different crushing particle sizes using the tested samples of the same lithology, and the recovery coefficient K considering the influence of the sample particle size can be obtained. 粒级 Repeat the above steps to carry out multiple groups of control pyrolysis experiments with different crushing particle sizes, and calculate the recovery coefficient K corresponding to the multiple groups of control pyrolysis experimental data under the influence of the sample crushing particle size. 粒 级 An average value calculation is performed, and the obtained average value is determined as the final third restitution coefficient K3.

[0113] Step S206: For each sample to be tested, conduct rock pyrolysis experiments on the sample to be tested at different pyrolysis temperatures to determine the fourth restitution coefficient under the influence of the sample pyrolysis temperature. The different pyrolysis temperatures should include reasonable pyrolysis temperatures and other pyrolysis temperatures.

[0114] For example, multiple groups of pyrolysis temperatures (such as conventional pyrolysis and multi-temperature-step pyrolysis) can be set based on the reasonable particle size determined in step S201 and the reasonable pyrolysis temperature determined in step S202. The conventional pyrolysis and multi-temperature-step pyrolysis control experiments are performed on the tested samples of the same lithology, and the recovery coefficient K is calculated considering the influence of the sample pyrolysis temperature. 常规多温 Repeat the above steps to carry out multiple groups of control pyrolysis experiments with different crushing particle sizes, and calculate the recovery coefficient K corresponding to the multiple groups of control pyrolysis experimental data under the influence of sample pyrolysis temperature. 常规多温 An average value calculation is performed, and the obtained average value is determined as the final fourth restitution coefficient K4.

[0115] Step S207: determining the light hydrocarbon recovery coefficient of the test sample based on the recovery coefficient corresponding to the rock pyrolysis experiment under different influencing factors.

[0116] The light hydrocarbon recovery coefficient K of the sample to be tested can be obtained by multiplying the above four recovery coefficients, that is, K = K1×K2×K3×K4.

[0117] Step S208: Repeat steps S203 to S207 to carry out control experiments on samples with different Ro values, and determine the light hydrocarbon recovery coefficients of the tested samples with the same lithology at different Ro values.

[0118] For example, for each sample to be tested, using MPV-SP microphotometer, multifunctional microscope and other testing methods, samples with Ro of 0.6, 0.7, 0.8 and 0.9 are selected as maturity samples to be tested.

[0119] Step S209: Based on the light hydrocarbon recovery coefficients corresponding to different Ro values, a fitting relationship between the Ro value and the light hydrocarbon recovery coefficient is determined.

[0120] Step S210: Based on the fitting relationship between the Ro value and the light hydrocarbon recovery coefficient, the light hydrocarbon recovery coefficient corresponding to the sample to be tested with any other Ro value is predicted.

[0121] Because the Ro values ​​of lithologic samples used in pyrolysis experiments are generally less than 0.9, and samples with higher Ro values ​​are difficult to obtain, the light hydrocarbon recovery coefficients of samples with higher Ro values ​​can be calculated through data fitting, ultimately clarifying the light hydrocarbon recovery coefficients at different evolutionary levels. For example, based on the fitting relationship between Ro and light hydrocarbon recovery coefficients, the K value corresponding to the tested sample with an Ro value of 1.0 to 1.2 can be predicted.

[0122] In this embodiment, it should be noted that TOC refers to the total organic carbon content, that is, the mass of organic carbon per unit mass of rock, usually expressed as mass fraction (%).

[0123] Ro refers to the vitrinite reflectance, which is an important index characterizing the maturity of source rocks. Generally, the evolution of organic matter can be divided into three stages according to the change of vitrinite reflectance. When Ro ≤ 0.5%, the organic matter is in the immature stage; when 0.5% < Ro < 1.6%, the sample is in the mature stage, which is conducive to the formation of oil and gas. Among them, when Ro is 0.5% - 0.8%, it enters the initial stage of the mature stage; when Ro is 0.8% - 1.2%, it is in the middle stage of the mature stage; when Ro is 1.2% - 1.6%, it is in the late stage of the mature stage. However, when Ro ≥ 1.6%, it belongs to the over-maturity stage and no longer forms oil and gas. The organic matter maturity of each set of source rocks in the basin is directly related to whether they can generate oil and gas, so it is one of the key factors for the evaluation of oil and gas resources in the basin.

[0124] Example 3

[0125] As shown in Figure 3, the third embodiment of the present invention provides a method for evaluating the movable oil content in shale, which includes the following steps:

[0126] Step S301: Take three kinds of lithologic samples and measure their porosities respectively.

[0127] In step S301, for the felsic shale in the second member of Kongdian Formation in Cangdong Sag, the mixed shale in the upper part of the third member of Shahejie Formation in Qikou Sag, and the dolomitic shale in the lower part of the first member of Shahejie Formation, 24 large pieces of samples of different lithologies from three horizons in two areas are taken respectively, totaling 72 pieces of shale. The diameter of each rock sample is generally not less than 10 cm in length, not less than 6 cm in width, and not less than 6 cm in height.

[0128] In step S301, take 1 piece of each of the three kinds of lithologic samples for nuclear magnetic pore measurement to obtain the corresponding porosity of the core samples, and the process enters step 302.

[0129] Step S302: Select rock samples with TOC of 1.0, 1.5, and 2.0 as the samples to be tested.

[0130] In step S302, crush the 72 samples into powder samples of about 200 meshes, with a dosage of 1 g, and conduct experiments about 72 times using an X-ray diffractometer SmartLab or TTR to determine the true lithology (felsic shale, mixed shale, dolomitic shale) of the 72 samples.

[0131] After crushing the 72 rock samples respectively, sieve the samples with a sieve less than 0.2 mm, with a sample amount of not less than 5 g, and conduct experiments about 72 times on different rock samples using a CS-i carbon-sulfur analyzer and a CS230 carbon-sulfur analyzer to determine the TOC values of different rock samples. Finally, select rock samples with TOC of 1.0, 1.5, and 2.0 as the samples to be tested, and the process enters step 303.

[0132] Step S303: crush the sample to be tested into 8 particle sizes and measure the porosity.

[0133] In step S303, samples with the same TOC and the same lithology are selected and crushed and mixed, and then a piece is picked out and crushed into different particle sizes (8 crushing particle sizes are set: 0.08mm, 0.15mm, 0.3mm, 0.6mm, 1.0mm, 1.5mm, 3mm, and 8mm). The porosity of samples of different particle sizes is measured using a nuclear magnetic resonance instrument to obtain the porosity of samples at different particle sizes, and the process enters step 304.

[0134] Step S304: Fit the relationship between porosity and particle size to obtain a reasonable particle size.

[0135] In step S304, the porosity and particle size obtained in step S303 are fitted into a regression equation to obtain a porosity-particle size correlation curve. Substituting the porosity values ​​of the three rock samples into the equation, the corresponding reasonable particle sizes are approximated. Figure 4 shows the fitted porosity-particle size curve. As shown in Figure 4, based on the currently measured effective porosity of 2% to 4%, it can be considered that a crushed particle size of 1 mm or larger is more reasonable, i.e., a reasonable particle size of 1 mm is considered.

[0136] Step S305: Performing total hydrocarbon chromatography analysis on crude oil samples of the three lithologies.

[0137] In step S305, one bottle of crude oil sample corresponding to each of the three shale types is taken, each bottle containing about 5 ml, and a total hydrocarbon chromatographic analysis is performed on the three crude oil samples. The mass fractions of each component of normal alkanes, pristane, and phytane in the crude oil are measured using an HP-7890 gas chromatograph to obtain a total hydrocarbon chromatogram of the crude oil sample, and the process enters step S306.

[0138] Step S306: performing multi-temperature-step pyrolysis on the three lithologic samples and performing total hydrocarbon chromatography analysis.

[0139] In step S306, the three lithologic samples are crushed into the reasonable particle size determined in step S304, and multi-stage pyrolysis is carried out in five temperature sections closer to geological conditions. The temperature sections are 150°C for 1 min, 150-200°C for 1 min, 200-250°C for 1 min, 250-300°C for 1 min, and 300-350°C for 1 min, with a heating rate of 25°C / min. Full hydrocarbon chromatographic analysis is completed respectively, and full hydrocarbon chromatographic images of multi-stage pyrolysis hydrocarbons are obtained. The process then enters step S307.

[0140] Step S307: Compare the chromatograms and determine the appropriate pyrolysis temperature.

[0141] In step S307, the full hydrocarbon chromatogram images of the multi-temperature stage pyrolysis hydrocarbons generated by each lithologic sample at different temperature segments are compared with the full hydrocarbon chromatogram of the crude oil sample, and the portion of the full hydrocarbon chromatogram image of the multi-temperature stage pyrolysis hydrocarbons that is more similar to the full hydrocarbon chromatogram of the crude oil sample is determined, and the temperature corresponding to the portion is determined as the reasonable pyrolysis temperature of the lithologic sample, and the process enters step S308.

[0142] Step S308: Carry out four groups of control experiments under different conditions to obtain the light hydrocarbon recovery coefficient.

[0143] In step S308, based on the reasonable particle size obtained in step S304 and the reasonable pyrolysis temperature obtained in step S307, samples of the same lithology are used to conduct control pyrolysis experiments under four different conditions, including open and closed crushing, different crushing particle sizes, different storage times after crushing, conventional pyrolysis and multi-temperature stage pyrolysis.

[0144] The process for the pyrolysis experiment comparing the sample placement time after crushing is as follows: One large piece of rock sample from each of three different lithologies was divided into two groups. After crushing to a reasonable particle size, one group was placed for 24 hours before the pyrolysis experiment, while the other group was immediately subjected to the pyrolysis experiment, resulting in two different S1 values. To obtain more reliable experimental data, this step was repeated for another set of experiments, ultimately obtaining two sets of S1 data with different placement times and two sets of recovery coefficients. The average of these two recovery coefficients was taken as the more reliable first recovery coefficient (K1) that takes into account the influence of different placement times.

[0145] The process for the open and closed sample crushing comparison pyrolysis experiment is as follows: One large piece of rock sample from each of three different lithologies is crushed and divided into two groups. Open crushing and closed liquid nitrogen freezing are performed separately. The samples are then crushed to the appropriate particle size determined in step S304. Using a pyrolysis instrument, the sample is held at the appropriate pyrolysis temperature determined in step S307 for 3 minutes to obtain a set of S1. To obtain more reliable experimental data, this step is repeated for another set of experiments, ultimately yielding two sets of S1 data for different crushing environments and two sets of recovery coefficients. The average of these two recovery coefficients is taken as the more reliable second recovery coefficient (K2) that accounts for the influence of different crushing environments.

[0146] The process for the crushing particle size control pyrolysis experiment is as follows: One large piece of rock sample from each of three different lithologies is crushed to the appropriate particle size obtained in step S304 and the particle size used in conventional pyrolysis. Pyrolysis experiments are then performed separately. The sample is then held constant for 3 minutes at the appropriate pyrolysis temperature obtained in step S307 to obtain a new set of S1. To obtain more reliable experimental data, this step is repeated for another set of experiments, ultimately yielding two sets of S1 data for different crushing particle sizes and two sets of recovery coefficients. The average of these two sets of recovery coefficients is taken as the more reliable third recovery coefficient (K3) that accounts for the influence of different crushing particle sizes.

[0147] The pyrolysis experiment comparing conventional and multi-step pyrolysis was conducted as follows: One large block of rock samples from three different lithologies was divided into two groups. After crushing to a reasonable particle size, one group underwent conventional pyrolysis (S1), while the other group underwent multi-step pyrolysis at a reasonable temperature, resulting in two different S1 sets. To obtain more reliable experimental data, this procedure was repeated for another set of experiments, ultimately yielding two sets of S1 data from different pyrolysis procedures and two sets of recovery coefficients. The average of these two recovery coefficients was taken as the more reliable fourth recovery coefficient (K4), which accounts for the influence of different pyrolysis temperatures.

[0148] Finally, the light hydrocarbon recovery coefficient K is obtained by multiplying the four recovery coefficients K1, K2, K3, and K4, and the process proceeds to step S309.

[0149] Step S309: Select samples with Ro values ​​of 0.6, 0.7, 0.8, and 0.9 respectively.

[0150] In step S309, the maturity of the sample is determined by measuring the ratio of the reflected light intensity from the polished vitrinite surface to the vertical incident light intensity at a wavelength of 546 nm ± 5 nm (green light) using an MPV-SP microphotometer and a multifunctional microscope. The processed kerogen samples are then prepared into optical slices to measure the vitrinite reflectance. Finally, samples with Ro values ​​of 0.6, 0.7, 0.8, and 0.9 (i.e., lithologic samples restored to a reasonable particle size) are selected, and the process proceeds to step S310.

[0151] Step S310: Calculate K through control experiments, fit K and Ro, and predict the light hydrocarbon recovery coefficient corresponding to high Ro.

[0152] In step S310, the four control experiments described above are performed using samples of the same lithology with different Ro values ​​(one group for each lithology), such as samples with maturity levels of 0.5, 0.6, 0.7, and 0.8. This yields K1, K2, K3, and K4 corresponding to different Ro values, and further calculates the coefficient of restitution, K. K is then fitted to the Ro curve to derive the relationship between Ro and K, thereby predicting the K value corresponding to a Ro range of 1.0 to 1.2.

[0153] Example 4

[0154] A fourth embodiment of the present invention provides an electronic device, see Figure 5, which includes a processor 201 and a memory 202, wherein the memory stores at least one computer program, and the at least one computer program is loaded and executed by one or more of the above-mentioned processors to enable the computer to implement the method for evaluating the movable oil content in shale as described above.

[0155] Of course, the electronic device may also have components such as a wired or wireless network interface, a keyboard, and an input / output interface for input and output. The electronic device may also include other components for realizing various functions of the device, which will not be described in detail here.

[0156] The fourth embodiment of the present invention further provides a computer-readable storage medium, in which at least one program code is stored. The program code is loaded and executed by a processor to enable a computer to implement the method for evaluating movable oil content in shale as described above.

[0157] Optionally, the computer-readable storage medium may be a read-only memory (ROM), a random access memory (RAM), a compact disc (CD-ROM), a magnetic tape, a floppy disk, and an optical disc data storage device. Those skilled in the art will appreciate that all or part of the steps in the above-mentioned embodiment method can be accomplished by instructing the relevant hardware through a program, and the program is stored in a storage medium, including several instructions for enabling a single-chip microcomputer, a chip, or a processor to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disc.

[0158] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0159] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0160] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the spirit of the present invention, they should also be regarded as the contents disclosed by the present invention. Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the specific embodiments of the present invention can still be modified or replaced by equivalents, and any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for evaluating the content of mobile oil in shale, characterized in that, The evaluation method includes: Based on the pyrolysis test data of the sample to be tested at different placement times, determine the first recovery coefficient considering the influence of the sample placement time; Based on the pyrolysis test data of the sample to be tested in different sample crushing environments, determine the second recovery coefficient considering the influence of the sample crushing environment; Based on the pyrolysis test data of the sample to be tested at different crushing particle sizes, determine the third recovery coefficient considering the influence of the sample crushing particle size; Based on the pyrolysis test data of the sample to be tested at different pyrolysis temperatures, determine the fourth recovery coefficient considering the influence of the sample pyrolysis temperature; Determine the product of the first recovery coefficient, the second recovery coefficient, the third recovery coefficient, and the fourth recovery coefficient as the light hydrocarbon recovery coefficient; Based on the light hydrocarbon recovery coefficient, evaluate the content of mobile oil in shale.

2. The method for evaluating the movable oil content in shale according to claim 1, wherein The step of determining the first recovery coefficient considering the influence of the sample placement time based on the pyrolysis test data of the sample to be tested at different placement times includes: When the sample to be tested is at a reasonable particle size and a reasonable pyrolysis temperature, obtain the pyrolysis test data of the sample to be tested at different placement times; Based on the pyrolysis test data of the sample to be tested at different placement times, determine the recovery coefficient of the sample to be tested at different placement times; Determine the average value of the recovery coefficients of the sample to be tested at different placement times as the first recovery coefficient.

3. The method for evaluating the movable oil content in shale according to claim 1, wherein The step of determining the second recovery coefficient considering the influence of the sample crushing environment based on the pyrolysis test data of the sample to be tested in different sample crushing environments includes: When the sample to be tested is at a reasonable particle size and a reasonable pyrolysis temperature, obtain the pyrolysis test data of the sample to be tested in different sample crushing environments; wherein, the different sample crushing environments include an open environment and a closed environment; Based on the pyrolysis test data of the sample to be tested in different sample crushing environments, determine the recovery coefficient of the sample to be tested in different sample crushing environments; Determine the average value of the recovery coefficients of the sample to be tested at different crushing particle sizes as the second recovery coefficient.

4. The method for evaluating the movable oil content in shale according to claim 1, wherein The step of determining the third recovery coefficient considering the influence of the sample crushing particle size based on the pyrolysis test data of the sample to be tested at different crushing particle sizes includes: When the sample to be tested is at a reasonable pyrolysis temperature, obtain the pyrolysis test data of the sample to be tested at different crushing particle sizes, wherein, the different crushing particle sizes include a reasonable particle size and other particle sizes; Based on the pyrolysis test data of the sample to be tested at different crushing particle sizes, determine the recovery coefficient of the sample to be tested at different crushing particle sizes; Determine the average value of the recovery coefficients of the sample to be tested at different crushing particle sizes as the third recovery coefficient.

5. The method for evaluating the movable oil content in shale according to claim 1, wherein The step of determining the fourth recovery coefficient considering the influence of the sample pyrolysis temperature based on the pyrolysis test data of the sample to be tested at different pyrolysis temperatures includes: When the sample to be tested is at a reasonable particle size, obtain the pyrolysis test data of the sample to be tested at different pyrolysis temperatures; wherein, the different pyrolysis temperatures include a reasonable pyrolysis temperature and a conventional pyrolysis temperature; Based on the pyrolysis test data of the sample to be tested at different pyrolysis temperatures, determine the recovery coefficient of the sample to be tested at different pyrolysis temperatures; Determine the average value of the recovery coefficients of the sample to be tested at different pyrolysis temperatures as the fourth recovery coefficient.

6. The method for evaluating the movable oil content in shale according to any one of claims 2 to 5, characterized in that, The evaluation method further includes: Obtain porosity test data of samples with different lithologies under different crushing particle sizes; Based on the porosity test data of samples with different lithologies under different crushing particle sizes, determine the fitting relationship between porosity and particle size; Based on the median of the effective porosity of shale samples in the target area, determine the reasonable particle size through the fitting relationship between porosity and particle size.

7. The method for evaluating the movable oil content in shale according to any one of claims 2 to 5, characterized in that The evaluation method further includes: Obtain the total hydrocarbon chromatogram image of the crude oil sample in the shale horizontal well, wherein the stratum position of the crude oil sample is the same as that of the sample to be tested; Obtain the total hydrocarbon chromatogram images of multi-temperature stage pyrolysis hydrocarbons of the sample to be tested in different pyrolysis temperature ranges; Compare the total hydrocarbon chromatogram image of the crude oil sample and the total hydrocarbon chromatogram images of multi-temperature stage pyrolysis hydrocarbons, and determine the part in the total hydrocarbon chromatogram image of multi-temperature stage pyrolysis hydrocarbons that is similar to the total hydrocarbon chromatogram image of the crude oil sample; Determine the reasonable pyrolysis temperature as the pyrolysis temperature corresponding to the part in the total hydrocarbon chromatogram image of multi-temperature stage pyrolysis hydrocarbons that is similar to the total hydrocarbon chromatogram image of the crude oil sample.

8. The method for evaluating the movable oil content in shale according to claim 1, wherein The evaluation method further includes: Determine the light hydrocarbon recovery coefficients of samples to be tested with different Ro values; Based on the light hydrocarbon recovery coefficients corresponding to different Ro values, determine the fitting relationship between Ro value and light hydrocarbon recovery coefficient; Based on the fitting relationship between Ro value and light hydrocarbon recovery coefficient, predict the light hydrocarbon recovery coefficient corresponding to the sample to be tested with a specified Ro value.

9. An electronic device, characterized in that, The electronic device includes a processor and a memory. At least one computer program is stored in the memory, and the at least one computer program is loaded and executed by one or more of the above processors to enable the computer to implement the evaluation method for the movable oil content in shale according to any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that, At least one program code is stored in the computer-readable storage medium, and the program code is loaded and executed by the processor to enable the computer to implement the evaluation method for the movable oil content in shale according to any one of claims 1 to 8.

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