Method, device and apparatus for determining vitrinite reflectance of shale

Abstract

The embodiment of the present application provides a method, device and equipment for determining the reflectivity of vitrinite in shale, which comprises the following steps: firstly, collecting the T1-T2 spectrum of the target shale by using a T1-T2 two-dimensional nuclear magnetic resonance device; then, calculating the signal peak ratio for representing the reflectivity of vitrinite based on the T1-T2 spectrum of the target shale; finally, determining the reflectivity of vitrinite in the target shale according to the signal peak ratio and a pre-established relationship model, wherein the relationship model is used to represent the mapping relationship between the signal peak ratio and the reflectivity of vitrinite. The target shale does not need to be crushed, and the target shale will not be physically damaged irreversibly; only the T1-T2 spectrum of the target shale needs to be collected, the measurement period is short, and the reflectivity of vitrinite in shale is measured quickly, economically and non-destructively.

Description

Technical Field

[0001] This invention relates to the field of petroleum engineering technology, specifically to a method, apparatus, and equipment for determining the reflectivity of shale vitrinite based on T1-T2 two-dimensional nuclear magnetic resonance. Background Technology

[0002] vitrinite reflectance R o Vitrinite reflectance is the most important indicator of organic matter maturity, and it can be used to characterize the thermal evolution of organic matter from early diagenesis to deep metamorphic stages. Vitrinite reflectance in shale is crucial for evaluating the exploitation value of shale oil and gas; therefore, accurately determining vitrinite reflectance in shale is of great value.

[0003] Geochemical experiments to determine vitrinite reflectance R o It is currently the most widely used and mature method. However, the measurement process of this method is cumbersome, takes a long time to measure a single sample, and requires crushing the shale sample during the measurement process, which is not conducive to conducting other experimental studies on the shale sample.

[0004] In conclusion, there is an urgent need for a rapid and economical method to determine the vitrinite reflectance of shale. Summary of the Invention

[0005] This invention provides a method, apparatus, and equipment for determining the reflectance of shale vitrinite based on T1-T2 two-dimensional nuclear magnetic resonance, thereby solving the problem of using geochemical experiments to determine the reflectance R of shale vitrinite in the prior art. o The shortcomings that exist.

[0006] In a first aspect, embodiments of the present invention provide a method for determining the reflectance of shale vitrinite, comprising:

[0007] Obtain the target shale to be tested;

[0008] The T1-T2 spectra of the target shale were acquired using a T1-T2 two-dimensional nuclear magnetic resonance (NMR) instrument.

[0009] The signal peak ratio used to characterize the reflectance of vitrinite was calculated based on the T1-T2 spectrum of the target shale.

[0010] The vitrinite reflectance of the target shale is determined based on the signal peak ratio and a pre-established relational model, which represents the mapping relationship between the signal peak ratio and the vitrinite reflectance.

[0011] In one embodiment, a T1-T2 two-dimensional nuclear magnetic resonance (NMR) device is used to acquire the T1-T2 spectrum of the target shale according to the following parameters:

[0012] The magnetic field strength is (20±5)MHz, the probe aperture is not less than 15mm, the pulse sequence is the inversion recovery method, the echo interval is 0.06ms, the waiting time is 10ms, and the inversion method is the regularization method.

[0013] In one embodiment, the signal peak ratio used to characterize the vitrinite reflectance is calculated based on the T1-T2 spectrum of the target shale, including:

[0014] Calculate the area of ​​the first signal within the first region on the T1-T2 spectrum. The first region is the region on the T1-T2 spectrum where 15ms≤T1≤500ms and 1≤T1 / T2≤40.

[0015] Calculate the area of ​​the second signal within the second region on the T1-T2 spectrum. The second region is the area on the T1-T2 spectrum where 15ms≤T1≤500ms and 30≤T1 / T2≤600.

[0016] The ratio of the first signal area to the second signal area is determined as the signal peak ratio used to characterize the reflectivity of vitrinite.

[0017] In one embodiment, the method further includes: identifying the pore fluid type and occurrence state of the shale reservoir based on the T1-T2 spectrum of the target shale.

[0018] In one embodiment, before acquiring the target shale to be detected, the method further includes establishing a relational model according to the following process:

[0019] Obtain a predetermined number of shale samples;

[0020] The T1-T2 spectra of each shale sample were acquired using a T1-T2 two-dimensional nuclear magnetic resonance device;

[0021] The signal peak ratio for characterizing vitrinite reflectance for each shale sample is calculated based on the T1-T2 spectrum of each shale sample.

[0022] Vitrin reflectance analysis was performed on each shale sample to obtain the vitrin reflectance of each shale sample;

[0023] Statistical analysis was performed on the signal peak ratio and vitrinite reflectance of a predetermined number of shale samples to establish a relational model representing the mapping relationship between the signal peak ratio and vitrinite reflectance.

[0024] In one embodiment, the relational model is a linear model or an exponential model.

[0025] In one embodiment, when the relational model is a linear model, the relational model is as follows:

[0026] R o = 0.0148 × R + 0.6719;

[0027] Among them, R o R represents the vitrinite reflectance, and R represents the signal peak ratio.

[0028] Secondly, embodiments of the present invention provide an apparatus for determining the reflectivity of shale vitrinite, comprising:

[0029] The acquisition module is used to acquire the target shale to be detected;

[0030] The acquisition module is used to acquire the T1-T2 spectrum of the target shale using a T1-T2 two-dimensional nuclear magnetic resonance device;

[0031] The calculation module is used to calculate the signal peak ratio, which is used to characterize the reflectance of vitrinite, based on the T1-T2 spectrum of the target shale.

[0032] The processing module is used to determine the vitrinite reflectance of the target shale based on the signal peak ratio and a pre-established relational model. The relational model is used to represent the mapping relationship between the signal peak ratio and the vitrinite reflectance.

[0033] Thirdly, embodiments of the present invention provide an electronic device, comprising:

[0034] At least one processor and memory;

[0035] The memory stores the instructions that the computer executes;

[0036] At least one processor executes computer execution instructions stored in memory, causing the at least one processor to perform a method for determining the reflectivity of shale vitrinite as described in any of the first aspects.

[0037] Fourthly, embodiments of the present invention provide a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the method for determining the reflectivity of shale vitrinite as described in any of the first aspects.

[0038] The method, apparatus, and equipment for determining the vitrinite reflectance of shale provided in this invention first acquire the T1-T2 spectrum of the target shale using a T1-T2 two-dimensional nuclear magnetic resonance (NMR) device; then, based on the T1-T2 spectrum of the target shale, the signal peak ratio (SPR) used to characterize the vitrinite reflectance is calculated; finally, the vitrinite reflectance of the target shale is determined according to the SPR and a pre-established relational model, wherein the relational model represents the mapping relationship between the SPR and the vitrinite reflectance. This method eliminates the need to crush the target shale, avoiding irreversible physical damage; it only requires acquiring the T1-T2 spectrum of the target shale, has a short measurement cycle, and achieves rapid, economical, and non-destructive determination of the vitrinite reflectance of shale. Attached Figure Description

[0039] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0040] Figure 1 This is a flowchart of a method for determining the reflectance of shale vitrinite according to an embodiment of the present invention;

[0041] Figure 2 A schematic diagram of the T1-T2 spectrum of shale obtained using existing methods;

[0042] Figure 3 A schematic diagram of the T1-T2 spectrum of shale obtained by the method of the present invention according to an embodiment of the present invention;

[0043] Figure 4 A flowchart of a method for determining the reflectance of shale vitrinite, provided in another embodiment of the present invention;

[0044] Figure 5 A flowchart for establishing a relationship model is provided in one embodiment of the present invention;

[0045] Figure 6 This is a schematic diagram illustrating the intersection of signal peak ratio and vitrinite reflectivity according to an embodiment of the present invention.

[0046] Figure 7 A schematic diagram of the T1-T2 spectrum of a target shale provided in an embodiment of the present invention;

[0047] Figure 8 A schematic diagram of the structure of a device for determining the reflectivity of shale vitrinite according to an embodiment of the present invention;

[0048] Figure 9 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention.

[0049] The accompanying drawings have illustrated specific embodiments of the invention, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0050] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings. Similar elements in different embodiments are referred to by associated similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of this application. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, certain operations related to this application are not shown or described in the specification. This is to avoid obscuring the core parts of this application with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0051] Furthermore, the features, operations, or characteristics described in the specification can be combined in any suitable manner to form various embodiments. At the same time, the steps or actions in the method description can be rearranged or adjusted in a manner obvious to those skilled in the art. Therefore, the various orders in the specification and drawings are only for the clear description of a particular embodiment and do not imply a necessary order, unless otherwise stated that a particular order must be followed.

[0052] The serial numbers assigned to components in this document, such as "first" and "second," are used only to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages).

[0053] Example 1

[0054] Figure 1 This is a flowchart illustrating a method for determining the reflectance of shale vitrinite according to an embodiment of the present invention. Figure 1 As shown, the method for determining the reflectance of shale vitrinite provided in this embodiment may include:

[0055] S101. Obtain the target shale to be detected.

[0056] Shale typically contains liquids and / or gases, making its state not very stable. Therefore, in order to ensure the accuracy of the measurement results, fresh shale can be obtained as the target shale to be tested in this embodiment.

[0057] S102. The T1-T2 spectrum of the target shale was acquired using a T1-T2 two-dimensional nuclear magnetic resonance device.

[0058] When acquiring the T1-T2 spectrum of the target shale using a T1-T2 two-dimensional nuclear magnetic resonance (NMR) device, it is not necessary to crush the target shale, thus avoiding any irreversible physical damage. Here, T1 represents the longitudinal relaxation time, and T2 represents the transverse relaxation time. To improve the accuracy of the shale vitrinite reflectance, this embodiment can adjust the parameters of the T1-T2 NMR device to ensure that the obtained T1-T2 spectrum of the target shale has a high signal-to-noise ratio (SNR) and at least three signal peaks. For example, a SNR threshold can be set to ensure that the SNR of the target shale's T1-T2 spectrum exceeds the threshold.

[0059] S103. Calculate the signal peak ratio to characterize the reflectance of vitrinite based on the T1-T2 spectrum of the target shale.

[0060] The signals on the T1-T2 spectrum can reflect the content of various substances in the target shale to a certain extent. In this embodiment, the ratio of the signal areas in the two regions can be determined as the signal peak ratio for characterizing vitrinite reflectance.

[0061] S104. Determine the vitrinite reflectance of the target shale based on the signal peak ratio and the pre-established relational model. The relational model is used to represent the mapping relationship between the signal peak ratio and the vitrinite reflectance.

[0062] Before testing the target shale, a mapping model representing the relationship between the signal peak ratio and vitrinite reflectance can be established in advance. For example, a large number of fresh shale samples can be collected. For each shale sample, T1-T2 two-dimensional nuclear magnetic resonance analysis is first used to determine its corresponding signal peak ratio for characterizing vitrinite reflectance. Then, geochemical experiments are used to measure its corresponding vitrinite reflectance. Finally, machine learning methods are used to learn the mapping relationship between the signal peak ratio and vitrinite reflectance, establishing a relational model. It should be noted that, to improve the accuracy of shale vitrinite reflectance, all parameters used in the target shale testing process must be consistent with those used in establishing the relational model. For example, the parameters used when collecting T1-T2 spectra and the parameters used when calculating the signal peak ratio for characterizing vitrinite reflectance.

[0063] After obtaining the signal peak ratio in the T1-T2 spectrum of the target shale used to characterize the vitrinite reflectance, it is only necessary to input it into a pre-established relational model to determine the vitrinite reflectance of the target shale.

[0064] The method for determining the vitrinite reflectance of shale provided in this embodiment first uses a T1-T2 two-dimensional nuclear magnetic resonance (NMR) device to acquire the T1-T2 spectrum of the target shale; then, based on the T1-T2 spectrum of the target shale, the signal peak ratio (SPR) used to characterize the vitrinite reflectance is calculated; finally, the vitrinite reflectance of the target shale is determined according to the SPR and a pre-established relational model, where the relational model represents the mapping relationship between the SPR and the vitrinite reflectance. This method eliminates the need to crush the target shale, avoiding irreversible physical damage; it only requires acquiring the T1-T2 spectrum of the target shale, has a short measurement cycle, and achieves rapid, economical, and non-destructive determination of the vitrinite reflectance of shale.

[0065] Example 2

[0066] During the acquisition of T1-T2 spectra using a T1-T2 two-dimensional nuclear magnetic resonance (NMR) device, the T1-T2 spectra obtained with different parameters exhibit uncertainties. Please refer to [reference needed]. Figure 2 , Figure 2 This is a schematic diagram of the T1-T2 spectrum of shale obtained using existing methods. Figure 2 The magnetic field frequency used in [a] was 21.36 MHz. The obtained T1-T2 spectrum showed peak overlap, and the hydrocarbon signals included kerogen, adsorbed oil, and mobile oil. Figure 2 The magnetic field frequency used in [b] was 12 MHz. The hydrocarbon signals in the obtained T1-T2 spectrum included kerogen and mobile oil. The position of the kerogen signal was related to... Figure 2 Medium [a] is equivalent. Figure 2 The magnetic field frequency used in [c] was 23.7 MHz. The hydrocarbon signals in the obtained T1-T2 spectra included kerogen and methane in the porous medium. The long axis direction of the kerogen signal was parallel to... Figure 2 [a] and Figure 2 There are differences in [b]. Figure 2 The numerical meanings shown in the signal peaks are as follows: 1: Kerogen; 2: Adsorbed oil; 3: Free oil; 4: Structural water; 5: Free water; 6: Adsorbed water; 7: Organic matter; 8: Methane; 9: Clay structural water; 10: Pore water; 11: Crack water; 12: Kerogen; 13: Hydroxyl groups; 14: Methane in porous media; 15: Water (clay water, intergranular water). Figure 2 It is evident that the distribution of signal peaks in the T1-T2 spectrum obtained by existing methods using different parameters is chaotic and not conducive to effective analysis.

[0067] Therefore, based on the above embodiments, in order to further improve the standardization and accuracy of the process for determining the vitrinite reflectance of shale, and to avoid human error in parameter selection during the process, this embodiment provides a method for determining the vitrinite reflectance of shale. The method uses a T1-T2 two-dimensional nuclear magnetic resonance (NMR) device to acquire the T1-T2 spectrum of the target shale according to the following parameters: magnetic field strength of (20±5) MHz, probe aperture of not less than 15 mm, pulse sequence using the inversion recovery method, echo interval of 0.06 ms, waiting time of 10 ms, and inversion method using the regularization method. Figure 3 This is a schematic diagram of the T1-T2 spectrum of shale obtained using the method of the present invention, provided as an embodiment of the present invention. (See diagram below.) Figure 3 As shown, the shale T1-T2 spectrum obtained by the method of the present invention has a high signal-to-noise ratio, a relatively regular distribution of signal peaks, and four signal peaks. Each signal peak can be clearly separated by adjusting the amplitude contour lines.

[0068] After obtaining a T1-T2 spectrum with high signal-to-noise ratio, regular signal peak distribution, and clear separation according to the above acquisition parameters, the signal peak ratio used to characterize the vitrinite reflectance is calculated based on the T1-T2 spectrum of the target shale, including:

[0069] Calculate the first signal area A within the first region on the T1-T2 spectrum. p1 The first region is the region on the T1-T2 spectrum where 15ms≤T1≤500ms and 1≤T1 / T2≤40;

[0070] Calculate the area A of the second signal within the second region on the T1-T2 spectrum. p2 The second region is the area on the T1-T2 spectrum where 15ms≤T1≤500ms and 30≤T1 / T2≤600.

[0071] It should be noted that if the signals in each region cannot be separated from the signals in other regions, the boundary values ​​of the regions can be slightly adjusted. Specifically, this can be done by adjusting the contour lines of the T1-T2 two-dimensional spectrum or by finding the lowest value between signal peaks in the spectrum data table as the dividing point. In other words, the size of the first and second regions can be adjusted by adjusting the contour lines of the T1-T2 spectrum to separate the signals in each region; alternatively, the size of the first and second regions can be adjusted based on the lowest value between the signal peaks in the T1-T2 spectrum as the dividing point to separate the signals in each region.

[0072] The ratio of the first signal area to the second signal area is determined as the signal peak ratio used to characterize the reflectivity of vitrinite. Specifically, the signal peak ratio R used to characterize the reflectivity of vitrinite can be determined according to the following expression: R = A p1 / A p2 .

[0073] The method for determining vitrinite reflectance of shale provided in this embodiment, based on the above embodiment, further specifies the parameters used when collecting the T1-T2 spectrum of the target shale, and further clarifies the specific method for calculating the signal peak ratio used to characterize vitrinite reflectance based on the T1-T2 spectrum of the target shale. This not only improves the standardization of the process for determining vitrinite reflectance of shale, but also effectively improves the accuracy of vitrinite reflectance determination.

[0074] Example 3

[0075] In the study of shale oil and shale gas, T1-T2 two-dimensional nuclear magnetic resonance technology is often used to determine the pore fluid type and occurrence state of shale reservoirs. Figure 4 A flowchart of a method for determining the reflectance of shale vitrinite provided in another embodiment of the present invention is shown below. Figure 4 As shown, in order to improve the efficiency of determining the reflectivity of vitrinite, the method provided in this embodiment may include:

[0076] S401. Obtain the target shale to be detected;

[0077] S402. The T1-T2 spectrum of the target shale was acquired using a T1-T2 two-dimensional nuclear magnetic resonance device;

[0078] S403. Identify the pore fluid type and occurrence state of shale reservoirs based on the T1-T2 spectrum of the target shale.

[0079] S404. Calculate the signal peak ratio to characterize vitrinite reflectance based on the T1-T2 spectrum of the target shale;

[0080] S405. Determine the vitrinite reflectance of the target shale based on the signal peak ratio and the pre-established relational model. The relational model is used to represent the mapping relationship between the signal peak ratio and the vitrinite reflectance.

[0081] It should be noted that the execution order of steps S403 and S404 is not limited in this embodiment. When identifying the pore fluid type and occurrence state of shale reservoirs based on the T1-T2 spectrum of the target shale, methods in the prior art can be used, and this embodiment does not limit the specific implementation method. The specific implementation methods of other steps can refer to the implementation in Embodiment 1, and will not be repeated here.

[0082] The method for determining the vitrinite reflectance of shale provided in this embodiment, after obtaining the T1-T2 spectrum of the target shale, not only identifies the pore fluid type and occurrence state of the shale reservoir based on the T1-T2 spectrum, but also determines the vitrinite reflectance of the target shale based on the T1-T2 spectrum. This method can determine the vitrinite reflectance of the target shale at a very low cost while identifying the pore fluid type and occurrence state of the target shale reservoir, achieving rapid and economical determination of the vitrinite reflectance of shale and improving the efficiency of determining the vitrinite reflectance of shale.

[0083] The vitrinite reflectance R was calculated by obtaining high-quality T1-T2 spectra. o This method evaluates the maturity of source rocks and overcomes the limitations imposed by different instrument parameters and measurement parameters on the vitrinite reflectance content (R) of shale. o This approach overcomes the uncertainties in characterization and the inaccuracies in quantification, avoiding the cumbersome procedures and irreversible damage to test samples inherent in geochemical experiments. It enables the evaluation of source rock characteristics simultaneously with the assessment of oil and water content in shale reservoirs, filling a gap in the evaluation of R-values ​​using T1-T2 spectra. o Evaluation of blank and logging fields R o The blank space was filled, which enabled R. o The evaluation method for migrating from the laboratory to the drilling site is characterized by its simplicity, cost-effectiveness, and high accuracy, and has a very broad application scope and promising prospects.

[0084] Example 4

[0085] Understandably, a relationship model needs to be established beforehand to detect the target shale. Please refer to [reference needed]. Figure 5 In the method for determining the reflectance of shale vitrinite provided in this embodiment, the process of establishing a relational model before acquiring the target shale to be detected may include:

[0086] S501. Obtain a preset number of shale samples.

[0087] Collect a series of fresh and well-preserved shale samples. Understandably, the more shale samples collected, the higher the accuracy of the resulting relational model, but also the higher the computational complexity. Therefore, the preset number can be determined comprehensively based on the accuracy requirements of the relational model and the computational complexity requirements.

[0088] S502. The T1-T2 spectrum of each shale sample was acquired using a T1-T2 two-dimensional nuclear magnetic resonance device.

[0089] A T1-T2 two-dimensional nuclear magnetic resonance analyzer was used, with a magnetic field strength of 20±5MHz, a probe diameter of not less than 15mm, an inversion recovery method (IR-CPMG) pulse sequence, an echo interval (TE) of 0.06ms, a waiting time (TW) of 10ms, and a regularization method for inversion. T1-T2 spectra were acquired for each shale sample. The acquired T1-T2 spectra had a high signal-to-noise ratio and at least 3 signal peaks.

[0090] S503. Calculate the signal peak ratio for characterizing vitrinite reflectance for each shale sample based on the T1-T2 spectrum of each shale sample.

[0091] For each shale sample's T1-T2 spectrum, the signal area (A) within the interval of 15ms ≤ T1 ≤ 500ms and 1 ≤ T1 / T2 ≤ 40 was calculated or read. p1 The signal area (A) within the interval 15ms≤T1≤500ms and 30≤T1 / T2≤600 p2 Note: If the signals in the two regions cannot be separated, the boundary value can be slightly adjusted. The adjustment method is to adjust the contour lines of the T1-T2 two-dimensional spectrum or find the lowest value between the signal peaks in the spectrum data table as the dividing point.

[0092] Finally, calculate A. p1 and A p2 The ratio of these two values ​​is the signal peak ratio R, which is used to characterize the reflectivity of vitrinite: R = A p1 / A p2 .

[0093] S504. Perform vitrinite reflectance analysis on each shale sample to obtain the vitrinite reflectance of each shale sample.

[0094] In order to obtain accurate values ​​of vitrinite reflectance of shale samples, in this embodiment, after performing T1-T2 two-dimensional nuclear magnetic resonance analysis on the shale samples, geochemical experiments or well logging curve fitting methods can be used to perform vitrinite reflectance analysis on each shale sample to obtain the vitrinite reflectance of each shale sample.

[0095] S505. Perform statistical analysis on the signal peak ratio and vitrinite reflectance of a preset number of shale samples, and establish a relational model to represent the mapping relationship between the signal peak ratio and vitrinite reflectance.

[0096] Through statistical analysis, a relationship model between R and vitrinite reflectance was established. The relationship model can be either a linear model or an exponential model.

[0097] The following example, using eight shale samples, illustrates the process of establishing the relational model. Please refer to [link / reference needed]. Figure 6 , Figure 6 The image shows a cross-plot of the signal peak ratios and vitrinite reflectance of these eight shale samples. A linear model was used to fit the data, showing a high correlation (correlation coefficient as high as 0.77). Therefore, a linear model was employed for fitting. The resulting relationship model is as follows:

[0098] R o = 0.0148 × R + 0.6719;

[0099] Among them, R o R represents the vitrinite reflectance, and R represents the signal peak ratio.

[0100] To further verify the accuracy of the relational model provided in this embodiment, pressure-maintaining drilling and core sampling were performed on the target section of shale oil well X, and the core samples were frozen with liquid nitrogen. One core sample was taken at a resonant frequency of 19MHz, a probe coil diameter of 25mm, a pullback interval (TE) of 0.06ms, and a waiting time (TW) of 10ms. The measured T1-T2 spectra are shown below. Figure 7 The calculated R is 2.28, and the vitrinite reflectance R is obtained according to the relational model. o The value was 0.71. Subsequently, geochemical experiments were conducted on the core, and the measured vitrinite reflectance R0 was... o The value is 0.73, and the absolute error is 0.02, indicating a small error and reliable results.

[0101] The method for determining vitrinite reflectance of shale provided in this embodiment, based on any of the above embodiments, further elaborates in detail the process of establishing a relational model before acquiring the target shale to be tested. Multiple fresh and well-preserved shale samples are collected, and high-frequency T1-T2 two-dimensional nuclear magnetic resonance analysis and vitrinite reflectance R0 analysis are performed sequentially on the same sample. o Analysis: The magnetic field strength of the T1-T2 two-dimensional nuclear magnetic resonance analyzer is 20±5 MHz, the probe aperture is not less than 15 mm, the pulse sequence is the inversion recovery method (IR-CPMG), the echo interval (TE) is 0.06 ms, the waiting time (TW) is 10 ms, and the inversion method is the regularization method; the measured T1-T2 spectrum should have a high signal-to-noise ratio and the number of signal peaks should not be less than 3; the vitrinite reflectance R is calculated and characterized based on the T1-T2 nuclear magnetic resonance spectrum. o The signal peak ratio R; through statistical analysis, establish R and R o The relationship model is used to calculate the vitrinite reflectance R of the target sample based on the R of the T1-T2 spectrum of the target sample and the established relationship model. o This invention overcomes the problem of varying vitrinite reflectance content (R0) in shale due to different instrument parameters and measurement parameters. oThis approach overcomes the uncertainties and inaccuracies in characterization, avoids the cumbersome procedures and irreversible damage to test samples in geochemical experiments, and enables the evaluation of source rock characteristics simultaneously with the assessment of oil and water content in shale reservoirs. It fills the gap in evaluating R-values ​​using T1-T2 spectra. o Evaluation of blank and logging fields R o The blank space was filled, which enabled R. o The evaluation method for migrating from the laboratory to the drilling site is characterized by its simplicity, cost-effectiveness, and high accuracy, and has a very broad application scope and promising prospects.

[0102] Example 5

[0103] Figure 8 This is a schematic diagram of a device for determining the reflectivity of shale vitrinite according to an embodiment of the present invention. Figure 8 As shown, the device 80 for determining the reflectivity of shale vitrinite provided in this embodiment may include: an acquisition module 801, a collection module 802, a calculation module 803, and a processing module 804.

[0104] Acquisition module 801 is used to acquire the target shale to be detected;

[0105] The acquisition module 802 is used to acquire the T1-T2 spectrum of the target shale using a T1-T2 two-dimensional nuclear magnetic resonance device;

[0106] Calculation module 803 is used to calculate the signal peak ratio value for characterizing vitrinite reflectance based on the T1-T2 spectrum of the target shale;

[0107] The processing module 804 is used to determine the vitrinite reflectance of the target shale based on the signal peak ratio and a pre-established relational model. The relational model is used to represent the mapping relationship between the signal peak ratio and the vitrinite reflectance.

[0108] The apparatus of this embodiment can be used to perform Figure 1 The technical solutions of the method embodiments shown are similar in principle and in effect, and will not be described again here.

[0109] In one embodiment, the acquisition module 802 is used to acquire the T1-T2 spectrum of the target shale using a T1-T2 two-dimensional nuclear magnetic resonance device according to the following parameters:

[0110] The magnetic field strength is (20±5)MHz, the probe aperture is not less than 15mm, the pulse sequence is the inversion recovery method, the echo interval is 0.06ms, the waiting time is 10ms, and the inversion method is the regularization method.

[0111] In one embodiment, the calculation module 803 for calculating the signal peak ratio for characterizing vitrinite reflectance based on the T1-T2 spectrum of the target shale may specifically include:

[0112] Calculate the area of ​​the first signal within the first region on the T1-T2 spectrum. The first region is the region on the T1-T2 spectrum where 15ms≤T1≤500ms and 1≤T1 / T2≤40.

[0113] Calculate the area of ​​the second signal within the second region on the T1-T2 spectrum. The second region is the area on the T1-T2 spectrum where 15ms≤T1≤500ms and 30≤T1 / T2≤600.

[0114] The ratio of the first signal area to the second signal area is determined as the signal peak ratio used to characterize the reflectivity of vitrinite.

[0115] In one embodiment, the processing module 804 is further used to identify the pore fluid type and occurrence state of the shale reservoir based on the T1-T2 spectrum of the target shale.

[0116] In one embodiment, the apparatus 80 for determining the reflectance of shale vitrinite may further include a statistical analysis module (not shown in the figure) for establishing a relational model according to the following process before acquiring the target shale to be detected:

[0117] Obtain a predetermined number of shale samples;

[0118] The T1-T2 spectra of each shale sample were acquired using a T1-T2 two-dimensional nuclear magnetic resonance device;

[0119] The signal peak ratio for characterizing vitrinite reflectance for each shale sample is calculated based on the T1-T2 spectrum of each shale sample.

[0120] Vitrin reflectance analysis was performed on each shale sample to obtain the vitrin reflectance of each shale sample;

[0121] Statistical analysis was performed on the signal peak ratio and vitrinite reflectance of a predetermined number of shale samples to establish a relational model representing the mapping relationship between the signal peak ratio and vitrinite reflectance.

[0122] In one embodiment, the relational model is a linear model or an exponential model.

[0123] In one embodiment, when the relational model is a linear model, the relational model is as follows:

[0124] R o = 0.0148 × R + 0.6719;

[0125] Among them, R o R represents the vitrinite reflectance, and R represents the signal peak ratio.

[0126] Example 6

[0127] This invention also provides an electronic device, please refer to [link to relevant documentation]. Figure 9 As shown, the embodiments of the present invention are only used as examples. Figure 9 The invention is illustrated by example and is not limited to this. Figure 9 This is a schematic diagram of the structure of an electronic device provided according to an embodiment of the present invention. Figure 9 As shown, the electronic device 90 provided in this embodiment may include: a memory 901, a processor 902, and a bus 903. The bus 903 is used to connect the various components.

[0128] The memory 901 stores a computer program, which, when executed by the processor 902, can implement the technical solutions of any of the above method embodiments.

[0129] The memory 901 and processor 902 are electrically connected directly or indirectly to enable data transmission or interaction. For example, these components can be electrically connected to each other via one or more communication buses or signal lines, such as bus 903. The memory 901 stores a computer program that implements a method for determining the reflectivity of shale vitrinite, including at least one software functional module that can be stored in the memory 901 in the form of software or firmware. The processor 902 executes various functional applications and data processing by running the software program and modules stored in the memory 901.

[0130] The memory 901 can be, but is not limited to, Random Access Memory (RAM), Read Only Memory (ROM), Programmable Read-Only Memory (PROM), Erasable Programmable Read-Only Memory (EPROM), Electrically Erasable Programmable Read-Only Memory (EEPROM), etc. The memory 901 stores programs, and the processor 902 executes the programs after receiving execution instructions. Furthermore, the software programs and modules within the memory 901 may also include an operating system, which may include various software components and / or drivers for managing system tasks (such as memory management, storage device control, power management, etc.) and can communicate with various hardware or software components to provide an operating environment for other software components.

[0131] Processor 902 can be an integrated circuit chip with signal processing capabilities. The aforementioned processor 902 can be a general-purpose processor, including a Central Processing Unit (CPU), a Network Processor (NP), etc. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this invention. The general-purpose processor can be a microprocessor or any conventional processor. It is understood that... Figure 9 The structure shown is for illustrative purposes only and may include more... Figure 9 The more or fewer components shown, or having the same Figure 9 The different configurations shown. Figure 9 The components shown can be implemented in hardware and / or software.

[0132] This invention also provides a computer-readable storage medium storing a computer program thereon, which is executed by a processor to implement the technical solutions of any of the above method embodiments.

[0133] The various embodiments in this disclosure are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0134] The scope of protection of this disclosure is not limited to the embodiments described above. Obviously, those skilled in the art can make various modifications and variations to this disclosure without departing from its scope and spirit. If such modifications and variations fall within the scope of the claims of this disclosure and their equivalents, then the intent of this disclosure also includes such modifications and variations.

Claims

1. A method for determining the reflectance of shale vitrinite, characterized in that, include: Obtain the target shale to be tested; The T1-T2 spectrum of the target shale was acquired using a T1-T2 two-dimensional nuclear magnetic resonance device with the following parameters: magnetic field strength of (20±5) MHz, probe aperture of not less than 15 mm, pulse sequence of inversion recovery method, echo interval of 0.06 ms, waiting time of 10 ms, and inversion method of regularization method. The signal peak ratio used to characterize the vitrinite reflectance is calculated based on the T1-T2 spectrum of the target shale. The vitrinite reflectance of the target shale is determined based on the signal peak ratio and a pre-established relational model, wherein the relational model is used to represent the mapping relationship between the signal peak ratio and the vitrinite reflectance. The calculation of the signal peak ratio for characterizing vitrinite reflectance based on the T1-T2 spectrum of the target shale includes: Calculate the first signal area within the first region on the T1-T2 spectrum, where the first region is the region on the T1-T2 spectrum where 15ms ≤ T1 ≤ 500ms and 1 ≤ T1 / T2 ≤ 40; Calculate the second signal area within the second region on the T1-T2 spectrum, where the second region is the area on the T1-T2 spectrum where 15ms ≤ T1 ≤ 500ms and 30 ≤ T1 / T2 ≤ 600; The ratio of the first signal area to the second signal area is determined as the signal peak ratio used to characterize the reflectivity of vitrinite.

2. The method according to claim 1, characterized in that, The method further includes: identifying the pore fluid type and occurrence state of the shale reservoir based on the T1-T2 spectrum of the target shale.

3. The method according to any one of claims 1-2, characterized in that, Before acquiring the target shale to be detected, the method further includes establishing the relationship model according to the following process: Obtain a predetermined number of shale samples; The T1-T2 spectra of each shale sample were acquired using a T1-T2 two-dimensional nuclear magnetic resonance device; The signal peak ratio for characterizing vitrinite reflectance for each shale sample is calculated based on the T1-T2 spectrum of each shale sample. Vitrin reflectance analysis was performed on each shale sample to obtain the vitrin reflectance of each shale sample; Statistical analysis was performed on the signal peak ratio and vitrinite reflectance of the preset number of shale samples to establish a relational model representing the mapping relationship between the signal peak ratio and vitrinite reflectance.

4. The method according to claim 3, characterized in that, The relationship model is either a linear model or an exponential model.

5. The method according to claim 4, characterized in that, When the relational model is a linear model, the relational model is: in, Indicates the reflectance of vitrinite. This indicates the peak-to-peak ratio of the signal.

6. An apparatus for determining the reflectivity of shale vitrinite, characterized in that, include: The acquisition module is used to acquire the target shale to be detected; The acquisition module is used to acquire the T1-T2 spectrum of the target shale using a T1-T2 two-dimensional nuclear magnetic resonance device according to the following parameters: magnetic field strength is (20±5) MHz, probe aperture is not less than 15 mm, pulse sequence is inversion recovery method, echo interval is 0.06 ms, waiting time is 10 ms, and inversion method is regularization method; The calculation module is used to calculate the signal peak ratio, which is used to characterize the reflectance of vitrinite, based on the T1-T2 spectrum of the target shale; The calculation of the signal peak ratio for characterizing vitrinite reflectance based on the T1-T2 spectrum of the target shale includes: Calculate the first signal area within the first region on the T1-T2 spectrum, where the first region is the region on the T1-T2 spectrum where 15ms ≤ T1 ≤ 500ms and 1 ≤ T1 / T2 ≤ 40; Calculate the second signal area within the second region on the T1-T2 spectrum, where the second region is the area on the T1-T2 spectrum where 15ms ≤ T1 ≤ 500ms and 30 ≤ T1 / T2 ≤ 600; The ratio of the first signal area to the second signal area is determined as the signal peak ratio used to characterize the reflectivity of vitrinite. The processing module is used to determine the vitrinite reflectance of the target shale based on the signal peak ratio and a pre-established relational model, wherein the relational model represents the mapping relationship between the signal peak ratio and the vitrinite reflectance.

7. An electronic device, characterized in that, include: At least one processor and memory; The memory stores computer-executed instructions; The at least one processor executes computer execution instructions stored in the memory, causing the at least one processor to perform the method for determining the reflectivity of shale vitrinite as described in any one of claims 1-5.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the method for determining the reflectivity of shale vitrinite as described in any one of claims 1-5.

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