Shale oil maximum movable oil quantity evaluation method and system based on centrifugation and application

Abstract

The invention discloses a shale oil maximum movable oil quantity evaluation method and system based on centrifugation and application, and relates to the technical field of unconventional oil and gas geology evaluation. Comprising the following steps: acquiring the total oil content Qoil1 and the free oil content Qfoil in a fresh closed shale sample; determining the movable oil mass Qmov based on the free oil mass Qfoil and the total oil content Qoil2 of the fresh closed shale sample after centrifugation; establishing a relationship between different types of Qfoil and Qmov, and determining the bound oil mass Mth of different types of fresh closed shale samples; establishing a shale oil maximum momentum model based on the free oil quantity Qfoil and the bound oil quantity Mth classification; and obtaining continuous free oil quantities Qfoil and TOC according to a logging curve, and then obtaining shale oil maximum momentum vertical distribution through a shale oil maximum momentum model. When the method is used for predicting the maximum momentum of the shale oil in the vertical direction, fine evaluation of the maximum momentum of the shale oil can be achieved, reliable basic parameters are provided for sweet spot evaluation of the shale oil, and therefore the exploration precision of the shale oil is improved.

Description

Technical Field

[0001] This invention relates to the field of unconventional oil and gas geological evaluation technology, specifically to a method, system, and application for evaluating the maximum movable oil volume of shale oil based on centrifugation. Background Technology

[0002] Shale oil is a liquid hydrocarbon preserved in the pores and fractures of organic-rich strata, exhibiting characteristics of in-situ and short-distance migration. Although my country possesses enormous potential for continental shale oil resources, only recoverable shale oil has economic value. The strong heterogeneity and mobility of continental shale, influenced by various factors, pose significant challenges to exploration and development. Therefore, identifying the main controlling factors of shale oil mobility, accurately characterizing its properties, and establishing a scientific evaluation model for shale oil mobility are crucial for significantly improving the efficiency of shale oil exploration and development. Currently, the main evaluation methods for shale oil mobility fall into three categories:

[0003] The first method is the geochemical parameter method, which uses the S1 / TOC ratio, also known as the oil saturation index (OSI), to assess the mobility of shale oil. Jarvie, through his study of the productivity characteristics of marine shale oil in multiple basins in the United States, found that in productive shale formations, the S1 value is generally higher than its TOC value. Therefore, he set 100 × S1 / TOC > 100 mg / g as the standard for selecting favorable shale oil formations. However, this standard did not fully consider the differences between continental and marine shale oil, so its applicability to shale oil resource evaluation in my country remains controversial. Furthermore, Chinese shale oil is characterized by high viscosity, high clay content, low maturity, and strong heterogeneity, which leads to differences in the lower limit of mobility for shale oil in different basins. Meanwhile, during the S1 measurement process, different experimental methods and preservation conditions can lead to significant differences in the test results of the core. This causes a contradiction between the actual production capacity and S1 when the OSI method is directly applied, thus limiting its accuracy in evaluating the mobility of shale oil.

[0004] The second evaluation method is based on one-dimensional nuclear magnetic resonance (NMR) centrifugation. This method determines a T2 cutoff value by comparing the difference in the one-dimensional NMR T2 spectra before and after centrifugation. The portion above this cutoff value is considered mobile fluid, while the portion below is considered bound fluid. Furthermore, this method utilizes the change in the integral of the NMR T2 spectra before and after centrifugation to calculate the mobility of shale oil through signal conversion. However, it is worth noting that, based on the T2 spectra before and after centrifugation, even portions above the T2 cutoff value may contain some bound fluid, while portions below the T2 cutoff value may contain some mobile fluid. In addition, the T2 cutoff values ​​differ significantly among shale formations and TOC (total organic carbon) contents; therefore, using a uniform T2 cutoff value to evaluate shale mobility will introduce substantial errors. Furthermore, one-dimensional nuclear magnetic resonance (NMR) technology itself has limitations in distinguishing between free and adsorbed oil in shale. Even when using formula calculations and Gaussian functions to decompose the NMR T2 spectrum to identify fluids, significant errors may still occur, making it difficult to accurately reveal the complex relationship between mobility and adsorption. In addition, the selection of centrifugal force and centrifugation time has a significant impact on the evaluation results of this method; therefore, it is necessary to clarify the correspondence between the production pressure differential in the actual development process and the selected centrifugal force during application.

[0005] The third evaluation method is based on the adsorption-free oil model. This method first uses experimental techniques such as nuclear magnetic resonance or stepwise pyrolysis to quantitatively assess the amount of free and adsorbed oil in shale, and considers the amount of free oil as the maximum potential mobility of shale oil. However, this method has several limitations. First, due to the loss of light hydrocarbons during sample storage, it may not accurately reflect the amount of free and adsorbed oil in its original state. Second, during pyrolysis pretreatment, a large amount of light hydrocarbons in the free oil is also easily lost, which further affects the accuracy of the assessment. In addition, the capillary force binding the fluid in the nanopores of shale cannot be ignored, and there are also interaction forces between adsorbed and free oil molecules. These factors mean that not all free oil is mobile. Therefore, the mobility assessed using this method is often overestimated.

[0006] Chinese patent application CN117804957A describes a simple, accurate, and practical evaluation process for the mobility and microstructure distribution of shale oil based on a combined saturation-centrifugation-nuclear magnetic resonance (NMR) experiment, which is suitable for geological applications. However, the formulas used to determine parameters such as adsorption thickness, adsorption density, and optimal surface relaxation rate of shale oil based on the functional relationship of adsorbed oil volume are complex and require extensive calculations. Furthermore, one-dimensional NMR requires calculating the free oil and adsorbed oil content based on the functional relationship between the cumulative mobile oil volume and the centrifugal pressure difference under each centrifugal pressure difference condition, which is cumbersome and prone to errors. Summary of the Invention

[0007] The purpose of this invention is to propose a centrifugal-based method, system, and application for evaluating the maximum movable oil volume of shale oil. By establishing a maximum movable oil volume evaluation model for shale oil, the accuracy of sweet spot evaluation and exploration and development efficiency of shale oil can be improved.

[0008] According to a first aspect of the present disclosure, a method for evaluating the maximum movable oil volume of shale oil based on centrifugation is provided, comprising the following steps:

[0009] The total oil content Qoil1 and free oil content Qfoil were obtained from fresh, sealed shale samples.

[0010] Based on the free oil content Qfoil and the total oil content Qoil2 after centrifugation of fresh sealed shale samples, the movable oil content Qmov was determined.

[0011] Based on the inflection point relationship of TOC and cumulative movable efficiency curves of fresh closed shale samples, the relationship between Qfoil and Qmov for different types is established, and the amount of bound oil M_th for different types of fresh closed shale samples is determined.

[0012] A maximum mobility model for shale oil is established based on the classification of free oil quantity Qfoil and bound oil quantity M_th.

[0013] The continuous free oil volume Qfoil and TOC are obtained from the well logging curves, and then the vertical distribution of the maximum mobility of shale oil is obtained through the shale oil maximum mobility model.

[0014] In one embodiment, the total oil content Qoil1 and free oil content Qfoil in a fresh, sealed shale sample are obtained based on two-dimensional nuclear magnetic resonance (NMR) testing. The two-dimensional NMR testing method is as follows:

[0015] Remove the sealing liquid from the surface of the fresh, sealed shale sample to prevent signal interference;

[0016] The nuclear magnetic resonance analyzer was calibrated, and the prepared fresh, sealed shale sample was placed in the instrument for testing, resulting in a series of echo trains.

[0017] Then, nuclear magnetic resonance inversion was performed to obtain the T1-T2 spectrum, and the T1-T2 spectrum was thresholded using a two-dimensional nuclear magnetic resonance fluid identification chart to obtain the signal quantity of each fluid component;

[0018] The signal quantity is converted into mass using the fluid calibration equation to obtain the corresponding total oil content Qoil1 and free oil content Qfoil.

[0019] In one embodiment, the movable oil quantity Qmov is determined based on the free oil quantity Qfoil and the total oil content Qoil2 after centrifugation of a fresh, sealed shale sample as follows:

[0020] Fresh, sealed shale samples that have undergone two-dimensional nuclear magnetic resonance testing are centrifuged in a centrifuge and then quickly placed in a nuclear magnetic resonance analyzer for calibration to obtain a series of echo trains.

[0021] Then, the T1-T2 spectrum is obtained by nuclear magnetic resonance inversion, and the T1-T2 spectrum is thresholded by a two-dimensional nuclear magnetic resonance fluid identification chart to obtain the signal quantity of each fluid component.

[0022] The corresponding total oil content Qoil2 after centrifugation is obtained through the fluid calibration equation, and the movable oil content Qmov = Qoil1 - Qoil2.

[0023] In one embodiment, the TOC of the fresh sealed shale sample is obtained by grinding the fresh sealed shale sample to 100-120 mesh, adding an excess of hydrochloric acid solution to remove inorganic carbon, then dripping water to remove the hydrochloric acid, and finally heating it in a CS-230 carbon-sulfur analyzer to obtain the TOC.

[0024] In one embodiment, the cumulative mobility efficiency curve is obtained as follows: let the mobility efficiency n be the mobility oil volume Qmov divided by the free oil volume Qfoil of the fresh closed shale sample, i.e., n = Qmov / Qfoil. The n values ​​of different samples are accumulated according to the TOC from small to large to obtain the curve of the cumulative mobility efficiency n as a function of TOC.

[0025] In one embodiment, the TOC interval is divided according to the inflection point of the change curve. Based on this interval, the relationship between the movable oil volume Qmov and Qfoil of different types is obtained by linear fitting method, Qmov=a*Qfoil+b, where -b / a is the bound oil volume of the sample of this type.

[0026] In one embodiment, the maximum mobility model of the shale oil is: Qm = Qfoil - M_th.

[0027] In one embodiment, based on well logging curves and core analysis data, the relationship between well logging curves and TOC and free oil quantity Qfoil is established. TOC and free oil quantity Qfoil are predicted in the vertical direction. Based on continuous TOC, continuous bound oil quantity M_th is obtained. Then, the vertical distribution Qm of the maximum mobility of shale oil is obtained through the shale oil maximum mobility model.

[0028] According to a second aspect of the present disclosure, a centrifugation-based system for evaluating the maximum movable oil volume of shale oil is provided, comprising:

[0029] The module for obtaining total oil content and free oil content point values ​​is used to obtain the total oil content Qoil1 and free oil content Qfoil in fresh closed shale samples;

[0030] The movable oil volume point value acquisition module determines the movable oil volume Qmov based on the free oil volume Qfoil and the total oil content Qoil2 after centrifugation of the fresh sealed shale sample.

[0031] The module for obtaining bound oil volume points establishes the relationship between Qfoil and Qmov for different types of fresh closed shale samples based on the inflection point relationship between TOC and cumulative movable efficiency curves, and determines the bound oil volume M_th for different types of fresh closed shale samples.

[0032] The model building module establishes a maximum mobility model for shale oil based on the classification of free oil quantity Qfoil and bound oil quantity M_th;

[0033] The shale oil maximum mobility acquisition module obtains continuous free oil volume (Qfoil) and total charge (TOC) based on well logging curves, and then obtains the vertical distribution of shale oil maximum mobility through the shale oil maximum mobility model.

[0034] According to a third aspect of the present disclosure, the above-described centrifugation-based method for evaluating the maximum movable oil volume of shale oil is applied to the screening of shale oil development zones.

[0035] According to a fourth aspect of the present disclosure, an electronic device is provided, including a memory, a processor, and a computer program stored in the memory and running on the memory, wherein the processor executes the program to implement the centrifugation-based method for evaluating the maximum movable oil content of shale oil.

[0036] According to a fifth aspect of the present disclosure, a computer-readable storage medium is provided having a computer program stored thereon that, when executed by a processor, implements the centrifugation-based method for evaluating the maximum movable oil volume of shale oil.

[0037] Compared with existing technologies, the technical solution adopted in this invention has the following advantages: Based on actual geological conditions, and considering the differences in shale oil mobility in shale with different TOC (Total Organic Carbon) contents, a method combining two-dimensional nuclear magnetic resonance (NMR) and centrifugation analysis is used to accurately identify the amount of mobile oil in sealed shale samples. In this process, the capillary binding force on free oil in the micro- and nano-pores of shale, as well as the influence of the interaction between adsorbed and free oil, are fully considered. Through this analysis, the amount of bound oil in different types of shale samples is obtained, and an evaluation model for the maximum mobile oil volume of shale oil is further constructed. Finally, by combining the relationship between well logging curves and continuous free oil volume and TOC, the vertical distribution characteristics of the maximum mobile shale oil volume are obtained. Attached Figure Description

[0038] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application.

[0039] Figure 1 The flowchart shows the method for evaluating the maximum movable oil volume of shale oil based on centrifugation.

[0040] Figure 2 A schematic diagram of the process for creating a two-dimensional nuclear magnetic resonance (NMR) plate;

[0041] Figure 3 A graph showing the relationship between the inflection points of the TOC and cumulative mobility efficiency curves;

[0042] Figure 4 This is a schematic diagram of the maximum mobility model for shale oil. Detailed Implementation

[0043] The present disclosure will be further described below with reference to the accompanying drawings and embodiments.

[0044] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0045] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0046] It should be noted that the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of methods and systems according to various embodiments of this disclosure. It should be noted that each block in a flowchart or block diagram may represent a module, segment, or portion of code, which may include one or more executable instructions for implementing the logical functions specified in the various embodiments. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than that shown in the drawings. For example, two consecutively represented blocks may actually be executed substantially in parallel, or they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the flowcharts and / or block diagrams, and combinations of blocks in the flowcharts and / or block diagrams, may be implemented using a dedicated hardware-based system that performs the specified functions or operations, or using a combination of dedicated hardware and computer instructions.

[0047] This invention addresses the challenge of evaluating the maximum mobility of shale oil due to capillary forces in the micro- and nano-pores of shale oil reservoirs and the interaction between adsorbed and free oil. It proposes a centrifugation-based method, system, and application for evaluating the maximum mobility of shale oil. This method fully considers the differences in the amount of bound free oil in shale with different TOC (Total Organic Carbon) values, achieving a precise evaluation of the maximum mobility of shale oil and providing valuable technical support for shale oil exploration and evaluation.

[0048] Example 1:

[0049] like Figure 1 As shown in the figure, this embodiment provides a method for evaluating the maximum movable oil volume of shale oil based on centrifugation. Taking a certain exploration area in my country as an example, the method includes the following steps:

[0050] S1. Obtain the total oil content Qoil1 and free oil content Qfoil in a fresh, sealed shale sample;

[0051] Specifically, the total oil content Qoil1 and free oil content Qfoil in fresh, sealed shale samples were obtained based on two-dimensional nuclear magnetic resonance (NMR) testing. The two-dimensional NMR testing method is as follows:

[0052] S11. Remove the sealing liquid from the surface of the fresh, sealed shale sample;

[0053] In one embodiment, the fresh sealed shale sample is tested using FID sequence to find the dominant frequency position and 90° pulse; then the sample is pretreated by processing the fresh sealed shale sample into suitable small pieces and wiping the sealing liquid off the surface.

[0054] S12. Calibrate the nuclear magnetic resonance (NMR) analyzer, place the processed fresh sealed shale sample in the instrument for testing, and obtain a series of echo trains.

[0055] In one embodiment, the NMR analyzer is preferably of the MesoMR23 - 060H–I type. The sequence used is IR - CPMG. The waiting time TW can be set to 2 s, the echo spacing TE can be 0.07 ms, the 90° pulse is 5.6 μs, the number of echoes can be 4000, and the number of inversion times can be 25.

[0056] Quickly place the fresh sealed shale sample after removing the sealing liquid into the NMR analyzer for testing using the IR - CPMG sequence, effectively avoiding the volatilization of oil and gas and the signal interference of the sealing liquid.

[0057] S13. Then perform NMR inversion to obtain the T1 - T2 spectrum, and perform threshold segmentation on the T1 - T2 spectrum through a two - dimensional NMR fluid identification chart to obtain the signal amounts of each fluid component.

[0058] In one embodiment, perform NMR inversion on the collected echo train signals with a resolution of 64×64 to obtain the T1 - T2 spectrum. The process of establishing the two - dimensional NMR chart in this embodiment is as Figure 2 shown. Place the original sample ( Figure 2 a) After testing, extract the soluble organic matter in a 3:1 solution of dichloromethane and toluene, and then place it in a vacuum drying oven at 110 °C for drying. The remaining signals are the signals of kerogen and bound water in the shale sample, located in the ( Figure 2 b) T2 < 0.2 ms region. Considering that kerogen is a solid - like substance with a relatively high T1 / T2, the region where T1 > 10 ms is defined as the kerogen signal, and T1 < 10 ms, T2 < 0.2 ms is the bound water signal. Saturate the sample after washing with oil and drying with formation water and crude oil respectively, as Figure 2 c and Figure 2 d shown. It can be determined that the free water signal is located in the region of 0.2 ms < T2 < 10 ms, 1 < T1 / T2 < 10, and the free oil signal is located in the region of T1 / T2 > 10, T2 > 1 ms. Since the adsorbed oil has a faster T2 relaxation time compared to the free oil, the region of 0.2 ms < T2 < 1 ms, T1 > 10 ms is defined as the adsorbed oil region. The NMR identification chart is as Figure 2 e shown.

[0059] S14. Perform mass conversion on the signal amounts through the fluid calibration equation to obtain the corresponding total oil content Qoil1 and free oil content Qfoil.

[0060] In one embodiment, tests are conducted using formation water and crude oil of known mass. The resulting signal quantities are correlated with their respective masses to obtain their respective conversion coefficients, such as... Figure 2 As shown in f, the conversion coefficients of crude oil and formation water in this embodiment are 0.4934 mg / au and 0.5403 mg / au, respectively. After threshold segmentation, the signal quantities of each part are converted to obtain the free oil content Qfoil and total oil content Qoil1 of the fresh closed shale sample, where the total oil content Qoil1 is the sum of free oil Qfoil and adsorbed oil Qaoil.

[0061] S2. Based on the free oil content Qfoil and the total oil content Qoil2 after centrifugation of fresh sealed shale samples, determine the movable oil content Qmov;

[0062] Specifically, a GM-12 centrifuge can be used to centrifuge fresh, sealed shale samples. The main parameters can be set to a rotation speed of 10,000 r / min and an outer rotation radius of 12.96 cm. The process is as follows: the fresh, sealed shale samples to be centrifuged are balanced to ensure that the mass difference between each sample placed in the centrifuge does not exceed 0.1 g. In this embodiment, after approximately three hours of centrifugation, the signal intensity of the samples remains essentially unchanged. The difference in total oil content signal between this state and the state of the fresh, sealed shale samples is considered the maximum movable amount of shale oil. The total oil content Qoil2 after centrifugation is obtained through the aforementioned two-dimensional nuclear magnetic resonance (NMR) test, and the movable oil content is Qmov = Qoil1 - Qoil2.

[0063] S3. Based on the inflection point relationship between TOC and cumulative movable efficiency curves of fresh closed shale samples, establish the relationship between Qfoil and Qmov for different types of samples, and determine the amount of bound oil M_th for different types of fresh closed shale samples.

[0064] Specifically, fresh, sealed shale samples are ground to 100-120 mesh, then excess hydrochloric acid solution is added to remove inorganic carbon, followed by dripping water to remove the hydrochloric acid, and finally heated in a CS-230 carbon-sulfur analyzer to obtain TOC.

[0065] The mobility efficiency n is calculated by dividing the movable oil volume Qmov by the free oil volume Qfoil in a fresh, sealed shale sample, i.e., n = Qmov / Qfoil. By accumulating the n values ​​for different samples according to TOC from smallest to largest, the cumulative mobility efficiency n as a function of TOC is obtained. Figure 3As shown, it is evident that TOC and cumulative mobility efficiency n have two inflection points. Therefore, samples are categorized into three types: TOC < 1%; 1% < TOC < 1.8%; and TOC > 1.8%. For samples in different TOC ranges, the relationship between movable oil quantity Qmov and Qfoil is obtained through linear fitting: Qmov = a * Qfoil + b, where -b / a is the bound oil quantity of that type of sample. For example, when TOC < 1%, the fitted curve is Qmov = 0.245 * Qfoil - 0.1363, and the calculated bound oil quantity for this range is 0.556 mg / g.

[0066] S4. Establish a maximum mobility model for shale oil based on the classification of free oil quantity Qfoil and bound oil quantity M_th;

[0067] Specifically, in determining the amount of movable oil, the first step is to quantitatively characterize the amount of adsorbed oil and free oil, taking free oil as the maximum movable amount. However, due to the limitations of micro- and nano-pore throats in shale, and the interaction between adsorbed and free oil, not all free oil is movable. Therefore, based on this, the maximum movable amount of shale oil, Qm, is defined as the amount of free oil, Qfoil, minus the amount of bound oil, M_th, in a fresh, closed shale sample, i.e., Qm = Qfoil - M_th.

[0068] S5. Obtain continuous free oil volume Qfoil and TOC based on the logging curves, and then obtain the vertical distribution of maximum mobility of shale oil through the maximum mobility model of shale oil.

[0069] Specifically, based on well logging curves and core analysis data, the relationship between well logging curves and TOC and free oil quantity Qfoil is established through methods such as multiple regression, machine learning, and neural networks. TOC and free oil quantity Qfoil are predicted vertically. Based on continuous TOC, continuous bound oil quantity M_th is obtained. Then, the vertical distribution Qm of the maximum mobility of shale oil is obtained through the shale oil maximum mobility model.

[0070] This invention predicts the maximum vertical mobility of shale oil, enabling a precise assessment of this mobility and providing reliable fundamental parameters for evaluating the sweet spot value of shale oil, thereby improving the accuracy of shale oil exploration. This method is highly feasible, reliable, and widely applicable, providing strong technical support for shale oil exploration and significantly contributing to the expansion and effective advancement of exploration and development in unconventional oil and gas sectors.

[0071] Example 2:

[0072] This embodiment provides a centrifugation-based system for evaluating the maximum movable oil volume of shale oil, including:

[0073] The module for obtaining total oil content and free oil content point values ​​is used to obtain the total oil content Qoil1 and free oil content Qfoil in fresh closed shale samples;

[0074] The movable oil volume point value acquisition module determines the movable oil volume Qmov based on the free oil volume Qfoil and the total oil content Qoil2 after centrifugation of the fresh sealed shale sample.

[0075] The module for obtaining bound oil volume points establishes the relationship between Qfoil and Qmov for different types of fresh closed shale samples based on the inflection point relationship between TOC and cumulative movable efficiency curves, and determines the bound oil volume M_th for different types of fresh closed shale samples.

[0076] The model building module establishes a maximum mobility model for shale oil based on the classification of free oil quantity Qfoil and bound oil quantity M_th;

[0077] The shale oil maximum mobility acquisition module obtains continuous free oil volume (Qfoil) and total charge (TOC) based on well logging curves, and then obtains the vertical distribution of shale oil maximum mobility through the shale oil maximum mobility model.

[0078] Example 3:

[0079] The centrifugation-based method for evaluating the maximum movable oil volume of shale oil, as described in Example 1, was applied to the screening of shale oil development zones.

[0080] Example 4:

[0081] An electronic device includes a memory, a processor, and a computer program stored in the memory and running thereon. When the processor executes the program, it implements the aforementioned method for evaluating the maximum movable oil content of shale oil based on centrifugation, comprising:

[0082] The total oil content Qoil1 and free oil content Qfoil were obtained from fresh, sealed shale samples.

[0083] Based on the free oil content Qfoil and the total oil content Qoil2 after centrifugation of fresh sealed shale samples, the movable oil content Qmov was determined.

[0084] Based on the inflection point relationship of TOC and cumulative movable efficiency curves of fresh closed shale samples, the relationship between Qfoil and Qmov for different types is established, and the amount of bound oil M_th for different types of fresh closed shale samples is determined.

[0085] A maximum mobility model for shale oil is established based on the classification of free oil quantity Qfoil and bound oil quantity M_th.

[0086] The continuous free oil volume Qfoil and TOC are obtained from the well logging curves, and then the vertical distribution of the maximum mobility of shale oil is obtained through the shale oil maximum mobility model.

[0087] Example 5:

[0088] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the aforementioned method for evaluating the maximum movable oil content of shale oil based on centrifugation, comprising:

[0089] The total oil content Qoil1 and free oil content Qfoil were obtained from fresh, sealed shale samples.

[0090] Based on the free oil content Qfoil and the total oil content Qoil2 after centrifugation of fresh sealed shale samples, the movable oil content Qmov was determined.

[0091] Based on the inflection point relationship of TOC and cumulative movable efficiency curves of fresh closed shale samples, the relationship between Qfoil and Qmov for different types is established, and the amount of bound oil M_th for different types of fresh closed shale samples is determined.

[0092] A maximum mobility model for shale oil is established based on the classification of free oil quantity Qfoil and bound oil quantity M_th.

[0093] The continuous free oil volume Qfoil and TOC are obtained from the well logging curves, and then the vertical distribution of the maximum mobility of shale oil is obtained through the shale oil maximum mobility model.

[0094] Those skilled in the art will understand that the modules or steps described above can be implemented using general-purpose computer devices. Optionally, they can be implemented using computer-executable program code, which can then be stored in a storage device for execution by a computer device. Alternatively, they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. This disclosure is not limited to any particular combination of hardware and software.

[0095] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

[0096] While the specific embodiments of this disclosure have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of this disclosure. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of this disclosure are still within the scope of protection of this disclosure.

Claims

1. A method for evaluating the maximum movable oil volume of shale oil based on centrifugation, characterized in that, Includes the following steps: The total oil content Qoil1 and free oil content Qfoil were obtained from fresh, sealed shale samples. Based on the free oil content Qfoil and the total oil content Qoil2 after centrifugation of fresh sealed shale samples, the movable oil content Qmov was determined. Based on the inflection point relationship of TOC and cumulative movable efficiency curves of fresh closed shale samples, the relationship between Qfoil and Qmov for different types is established, and the amount of bound oil M_th for different types of fresh closed shale samples is determined. A maximum mobility model for shale oil is established based on the classification of free oil quantity Qfoil and bound oil quantity M_th. The continuous free oil volume Qfoil and TOC are obtained from the well logging curves, and then the vertical distribution of the maximum mobility of shale oil is obtained through the shale oil maximum mobility model.

2. The method for evaluating the maximum movable oil volume of shale oil based on centrifugation according to claim 1, characterized in that, The total oil content Qoil1 and free oil content Qfoil in fresh sealed shale samples were obtained based on two-dimensional nuclear magnetic resonance (NMR) testing. The two-dimensional NMR testing method was to remove the sealing liquid from the surface of the fresh sealed shale sample. The nuclear magnetic resonance analyzer was calibrated, and the prepared fresh, sealed shale sample was placed in the instrument for testing, resulting in a series of echo trains. Then, nuclear magnetic resonance inversion was performed to obtain the T1-T2 spectrum, and the T1-T2 spectrum was thresholded using a two-dimensional nuclear magnetic resonance fluid identification chart to obtain the signal quantity of each fluid component; The signal quantity is converted into mass using the fluid calibration equation to obtain the corresponding total oil content Qoil1 and free oil content Qfoil.

3. The method for evaluating the maximum movable oil volume of shale oil based on centrifugation according to claim 1, characterized in that, Based on the free oil content Qfoil and the total oil content Qoil2 after centrifugation of fresh sealed shale samples, the movable oil content Qmov is determined as follows: Fresh, sealed shale samples that have undergone two-dimensional nuclear magnetic resonance testing are centrifuged in a centrifuge and then quickly placed in a nuclear magnetic resonance analyzer for calibration to obtain a series of echo trains. Then, the T1-T2 spectrum is obtained by nuclear magnetic resonance inversion, and the T1-T2 spectrum is thresholded by a two-dimensional nuclear magnetic resonance fluid identification chart to obtain the signal quantity of each fluid component. The total oil content Qoil2 after centrifugation is obtained by the fluid calibration equation, and the movable oil content is Qmov=Qoil1-Qoil2.

4. The method for evaluating the maximum movable oil volume of shale oil based on centrifugation according to claim 1, characterized in that, The TOC of the fresh, sealed shale sample was obtained by grinding the sample to 100-120 mesh, adding an excess of hydrochloric acid solution to remove inorganic carbon, then dripping water to remove the hydrochloric acid, and finally heating the sample in a CS-230 carbon-sulfur analyzer to obtain the TOC.

5. The method for evaluating the maximum movable oil volume of shale oil based on centrifugation according to claim 1, characterized in that, The cumulative mobility efficiency curve is obtained as follows: Let the mobility efficiency n be the mobility oil volume Qmov divided by the free oil volume Qfoil of the fresh closed shale sample, i.e., n = Qmov / Qfoil. The n values ​​of different samples are accumulated according to the TOC from small to large to obtain the curve of the cumulative mobility efficiency n as a function of TOC.

6. The method for evaluating the maximum movable oil volume of shale oil based on centrifugation according to claim 5, characterized in that, The TOC interval is divided according to the inflection point of the change curve. Based on this interval, the relationship between the movable oil volume Qmov and Qfoil of different types is obtained by linear fitting method. Qmov=a*Qfoil+b, where -b / a is the bound oil volume of the sample of this type.

7. The method for evaluating the maximum movable oil volume of shale oil based on centrifugation according to claim 1, characterized in that, The maximum mobility model for shale oil is: Qm = Qfoil - M_th.

8. The method for evaluating the maximum movable oil volume of shale oil based on centrifugation according to claim 1, characterized in that, Based on well logging curves and core analysis data, the relationship between well logging curves and TOC and free oil quantity Qfoil is established. TOC and free oil quantity Qfoil are predicted in the vertical direction. Based on continuous TOC, continuous bound oil quantity M_th is obtained. Then, the vertical distribution Qm of the maximum mobility of shale oil is obtained through the shale oil maximum mobility model.

9. A centrifugal-based system for evaluating the maximum movable oil volume of shale oil, characterized in that, include: The module for obtaining total oil content and free oil content point values ​​is used to obtain the total oil content Qoil1 and free oil content Qfoil in fresh closed shale samples; The movable oil volume point value acquisition module determines the movable oil volume Qmov based on the free oil volume Qfoil and the total oil content Qoil2 after centrifugation of the fresh sealed shale sample. The module for obtaining bound oil volume points establishes the relationship between Qfoil and Qmov for different types of fresh closed shale samples based on the inflection point relationship between TOC and cumulative movable efficiency curves, and determines the bound oil volume M_th for different types of fresh closed shale samples. The model building module establishes a maximum mobility model for shale oil based on the classification of free oil quantity Qfoil and bound oil quantity M_th; The shale oil maximum mobility acquisition module obtains continuous free oil volume (Qfoil) and total charge (TOC) based on well logging curves, and then obtains the vertical distribution of shale oil maximum mobility through the shale oil maximum mobility model.

10. The centrifugation-based method for evaluating the maximum movable oil volume of shale oil, as described in any one of claims 1-8, is applied to the screening of shale oil development zones.

11. An electronic device, comprising a memory, a processor, and a computer program stored in the memory and running thereon, wherein the processor executes the program to implement the centrifugation-based method for evaluating the maximum movable oil volume of shale oil as described in any one of claims 1-8.

12. A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the centrifugation-based method for evaluating the maximum movable oil volume of shale oil as described in any one of claims 1-8.

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