Pore structure parameter conversion method and device under different frequencies, equipment and medium
By acquiring multi-component digital cores of shale oil samples, generating echo data using numerical simulation and nuclear magnetic resonance response equations, inverting the T2 distribution, and constructing capillary pressure curves in conjunction with high-pressure mercury intrusion porosimetry experiments, the accuracy and cost issues of pore structure parameter conversion in shale oil reservoirs were resolved, and the operation process was simplified.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA UNIV OF PETROLEUM (BEIJING)
- Filing Date
- 2023-11-30
- Publication Date
- 2026-07-24
AI Technical Summary
Existing technologies struggle to accurately convert pore structure parameters in shale oil reservoirs with different echo intervals, pyrite contents, and nuclear magnetic resonance frequencies, and are costly and complex to operate.
By obtaining multi-component original digital cores of shale oil samples, the nuclear magnetic resonance response characteristics were simulated using numerical simulation methods and the shale oil nuclear magnetic resonance response equation to generate echo data, invert the T2 distribution, and combine the results of high-pressure mercury intrusion porosimetry experiments to construct capillary pressure curves and extract pore structure characteristic parameters.
It achieves accurate conversion of pore structure parameters under different echo intervals, different pyrite contents, and different nuclear magnetic resonance frequencies, simplifies the operation process, reduces costs, and can reflect the influence of a single factor on the nuclear magnetic resonance response.
Smart Images
Figure CN117630078B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of oil and gas exploration and development technology, and in particular to a method, apparatus, equipment and medium for converting pore structure parameters at different frequencies. Background Technology
[0002] The complex and highly heterogeneous mineral composition of shale oil reservoirs presents challenges for characterizing their pore structure. While NMR (Nuclear Magnetic Resonance) technology can effectively characterize the pore structure of conventional reservoirs, the complexity and heterogeneity of shale oil reservoir mineral composition make NMR a difficult technique to apply to pore structure characterization. Currently, NMR logging instruments typically operate at a frequency of 2 MHz, while experimental NMR instruments for shale samples typically operate at frequencies of 21.36 MHz and 200 MHz, indicating a discrepancy. Furthermore, differences exist between the acquisition parameters of laboratory NMR instruments and those used in NMR logging, making accurate conversion of pore structure parameters between laboratory and well-logged measurements impossible. This hinders effective NMR-based pore structure characterization. Additionally, experimental methods struggle to reflect the influence of single factors on NMR measurement results.
[0003] As can be seen from the above, how to accurately convert pore structure parameters with different echo intervals, different pyrite contents, and different nuclear magnetic resonance frequencies, reduce costs, and simplify operations are problems that need to be solved in this field. Summary of the Invention
[0004] In view of this, the purpose of this invention is to provide a method, apparatus, device, and medium for converting pore structure parameters at different frequencies, which can accurately convert pore structure parameters with different echo intervals, different pyrite contents, and different nuclear magnetic resonance frequencies, thereby reducing costs and simplifying operation. The specific solution is as follows:
[0005] In a first aspect, this application discloses a method for converting pore structure parameters at different frequencies, including:
[0006] Obtain multi-component raw digital cores of shale oil samples;
[0007] Numerical simulation methods and preset shale oil nuclear magnetic resonance response equations were used to simulate the nuclear magnetic resonance response characteristics of different pyrite contents based on the multi-component original digital cores, so as to generate echo data.
[0008] The echo data is inverted to obtain the T2 distribution, and combined with the high-pressure mercury intrusion test results of the parallel sample of the shale oil sample corresponding to the multi-component original digital core, to construct capillary pressure curves at different nuclear magnetic resonance frequencies.
[0009] The capillary pressure curves at different nuclear magnetic resonance frequencies are extracted to obtain pore structure characteristic parameters, thereby completing the conversion of the pore structure characteristic parameters at different nuclear magnetic resonance frequencies.
[0010] Optionally, the process of constructing the shale oil nuclear magnetic resonance response equation includes:
[0011] Based on the nuclear magnetic resonance relaxation mechanism of shale oil, nuclear magnetic resonance response equations for shale oil at different nuclear magnetic resonance frequencies are constructed; wherein, the nuclear magnetic resonance relaxation mechanism includes volume relaxation, surface relaxation and diffusion relaxation of inorganic pore water, volume relaxation, surface relaxation and diffusion relaxation of organic pore oil, and volume relaxation of organic matter.
[0012] Optionally, the step of using numerical simulation methods and a preset shale oil nuclear magnetic resonance response equation, and simulating the nuclear magnetic resonance response characteristics of different pyrite contents based on the multi-component original digital core, includes:
[0013] Based on the shale oil nuclear magnetic resonance response equation, the transverse surface relaxation intensity as a function of nuclear magnetic resonance frequency and the three-dimensional spatial distribution of the internal magnetic field gradient at different nuclear magnetic resonance frequencies are determined.
[0014] The nuclear magnetic resonance response characteristics of different pyrite contents were simulated using numerical simulation methods based on the multi-component original digital core, the lateral surface relaxation intensity, and the three-dimensional spatial distribution.
[0015] Optionally, the step of simulating the nuclear magnetic resonance response characteristics of different pyrite contents using numerical simulation methods based on the multi-component original digital core, the lateral surface relaxation intensity, and the three-dimensional spatial distribution includes:
[0016] Construct a multi-component intermediate state digital core based on the original multi-component digital core;
[0017] The nuclear magnetic resonance response characteristics of different pyrite contents were simulated using numerical simulation methods based on the digital core of the multi-component intermediate state, the lateral surface relaxation intensity, and the three-dimensional spatial distribution.
[0018] Optionally, the construction of a multi-component intermediate state digital core based on the original multi-component digital core includes:
[0019] Using a region growing algorithm, digital cores of the multi-component intermediate state with varying pyrite contents, including organic matter, inorganic pore water, organic pore oil, pyrite, and framework, were constructed based on the original multi-component digital cores.
[0020] Optionally, the inversion of the echo data to obtain the T2 distribution, combined with the high-pressure mercury intrusion test results of parallel samples of shale oil samples corresponding to the multi-component original digital core, is used to construct capillary pressure curves at different nuclear magnetic resonance frequencies, including:
[0021] The echo data is inverted using an inversion method to obtain the T2 distribution. The T2 distribution is then accumulated in reverse to obtain the inversely accumulated T2 distributions at different nuclear magnetic resonance frequencies.
[0022] Based on the aforementioned reverse cumulative T2 distribution, and combined with the high-pressure mercury intrusion test results of parallel samples of shale oil samples corresponding to multi-component original digital cores, capillary pressure curves at different nuclear magnetic resonance frequencies were constructed.
[0023] Optionally, the construction of capillary pressure curves at different nuclear magnetic resonance frequencies based on the inverse cumulative T2 distribution and combined with the high-pressure mercury intrusion test results of parallel samples of shale oil samples corresponding to the multi-component original digital cores includes:
[0024] By selecting the capillary pressure conversion equation and combining it with the results of the high-pressure mercury intrusion test, the reverse cumulative T2 distribution is converted into an initial capillary pressure curve, and the conversion coefficient of the capillary pressure conversion equation is determined.
[0025] Based on the T2 distribution at different nuclear magnetic resonance frequencies, the initial capillary pressure curve, and the conversion coefficient, capillary pressure curves at different nuclear magnetic resonance frequencies are constructed.
[0026] Secondly, this application discloses a device for converting pore structure parameters at different frequencies, comprising:
[0027] The raw digital core acquisition module is used to acquire multi-component raw digital cores of shale oil samples;
[0028] The echo data generation module is used to generate echo data by simulating the nuclear magnetic resonance response characteristics of different pyrite contents using numerical simulation methods and preset shale oil nuclear magnetic resonance response equations based on the multi-component original digital core.
[0029] The curve construction module is used to invert the echo data to obtain the T2 distribution, and combine it with the high-pressure mercury intrusion test results of the parallel sample of the shale oil sample corresponding to the multi-component original digital core to construct capillary pressure curves at different nuclear magnetic resonance frequencies.
[0030] The parameter conversion module is used to extract the capillary pressure curves at different nuclear magnetic resonance frequencies to obtain pore structure characteristic parameters, thereby completing the conversion of the pore structure characteristic parameters at different nuclear magnetic resonance frequencies.
[0031] Thirdly, this application discloses an electronic device, including:
[0032] Memory, used to store computer programs;
[0033] A processor is used to execute the computer program to implement the aforementioned method for converting pore structure parameters at different frequencies.
[0034] Fourthly, this application discloses a computer storage medium for storing a computer program; wherein, when the computer program is executed by a processor, it implements the steps of the aforementioned disclosed method for converting pore structure parameters at different frequencies.
[0035] As can be seen, this application provides a method for converting pore structure parameters at different frequencies, including obtaining multi-component original digital cores of shale oil samples; using numerical simulation methods and a preset shale oil nuclear magnetic resonance response equation, and based on the multi-component original digital cores, simulating nuclear magnetic resonance response characteristics with different pyrite contents to generate echo data; inverting the echo data to obtain the T2 distribution, and combining it with the high-pressure mercury intrusion test results of parallel samples of shale oil samples corresponding to the multi-component original digital cores to construct capillary pressure curves at different nuclear magnetic resonance frequencies; extracting the capillary pressure curves at different nuclear magnetic resonance frequencies to obtain pore structure characteristic parameters, thereby completing the conversion of the pore structure characteristic parameters at different nuclear magnetic resonance frequencies. This application utilizes numerical simulation methods and the shale oil NMR response equation to simulate the NMR response characteristics of different pyrite contents, generating echo data. The T2 distribution is obtained by inverting the echo data, and combined with high-pressure mercury intrusion porosimetry results, capillary pressure curves at different NMR frequencies are constructed. Characteristic parameters representing the pore structure are extracted to complete the conversion of pore structure characteristic parameters at different NMR frequencies. This application can realize the conversion of shale oil pore structure parameters under different echo intervals, different pyrite contents, and different NMR frequencies. It not only simplifies operation and saves time but also reflects the influence of single-factor NMR response, reducing costs. Attached Figure Description
[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.
[0037] Figure 1 This is a flowchart of a method for converting pore structure parameters at different frequencies disclosed in this application;
[0038] Figure 2 This is a flowchart of another method for converting pore structure parameters at different frequencies disclosed in this application;
[0039] Figure 3 This is a graph showing the variation of lateral surface relaxation intensity at different NMR frequencies disclosed in this application;
[0040] Figure 4 This is a diagram showing the variation of the internal magnetic field gradient distribution at different NMR frequencies disclosed in this application.
[0041] Figure 5 This is the capillary pressure curve conversion diagram disclosed in this application;
[0042] Figure 6 This is a schematic diagram of a pore structure parameter conversion device at different frequencies disclosed in this application.
[0043] Figure 7 This application provides a structural diagram of an electronic device. Detailed Implementation
[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0045] The complex and highly heterogeneous mineral composition of shale oil reservoirs presents challenges to characterizing their pore structure. While NMR technology can effectively characterize the pore structure of conventional reservoirs, the complexity and heterogeneity of shale oil reservoir mineral composition make NMR pore structure characterization a difficult task. Currently, NMR logging instruments typically operate at 2 MHz, while experimental NMR instruments for shale samples typically operate at 21.36 MHz and 200 MHz, indicating a discrepancy. Furthermore, differences exist between the acquisition parameters of laboratory NMR instruments and NMR logging data, making accurate conversion of pore structure parameters between laboratory and well-logged measurements impossible. This hinders effective NMR-based pore structure characterization. Additionally, experimental methods struggle to reflect the influence of single factors on NMR measurement results. Therefore, achieving accurate conversion of pore structure parameters with different echo intervals, pyrite contents, and NMR frequencies, while reducing costs and simplifying operation, remains a crucial problem to be solved in this field.
[0046] See Figure 1 As shown in the figure, this invention discloses a method for converting pore structure parameters at different frequencies, which may specifically include:
[0047] Step S11: Obtain multi-component raw digital cores of shale oil samples.
[0048] In this embodiment, multi-component raw digital cores of shale oil samples can be obtained in three ways: (1) scanning three-dimensional FIB-SEM (Focused Ion Beam-Scanning Electron Microscope) images; (2) or scanning three-dimensional nano-CT (Computed Tomography) images; (3) or scanning three-dimensional CT images. The obtained three-dimensional images are segmented using thresholding algorithms, watershed algorithms, or deep learning-related algorithms to obtain multi-component raw digital cores containing organic pores, inorganic pores, pyrite, organic matter, and the framework.
[0049] Step S12: Using numerical simulation methods and the preset shale oil nuclear magnetic resonance response equation, and based on the multi-component original digital core, simulate the nuclear magnetic resonance response characteristics of different pyrite contents to generate echo data.
[0050] In this embodiment, the transverse surface relaxation intensity and the three-dimensional spatial distribution of the internal magnetic field gradient at different nuclear magnetic resonance frequencies are determined based on the nuclear magnetic resonance response equation of shale oil. Numerical simulation methods are used to simulate the nuclear magnetic resonance response characteristics of different pyrite contents based on the multi-component original digital core, the transverse surface relaxation intensity, and the three-dimensional spatial distribution to generate echo data.
[0051] The specific simulation process of the nuclear magnetic resonance response characteristics is as follows: a multi-component intermediate state digital core is constructed based on the original multi-component digital core; the nuclear magnetic resonance response characteristics of different pyrite contents are simulated using numerical simulation methods based on the multi-component intermediate state digital core, the lateral surface relaxation intensity, and the three-dimensional spatial distribution.
[0052] The process of constructing a digital core in a multi-component intermediate state is as follows: using a region growing algorithm and based on the original multi-component digital core, construct a digital core in a multi-component intermediate state with different pyrite contents, including organic matter, inorganic pore water, organic pore oil, pyrite, and framework.
[0053] Step S13: Invert the echo data to obtain the T2 distribution, and combine it with the high-pressure mercury intrusion test results of the parallel sample of the shale oil sample corresponding to the multi-component original digital core to construct capillary pressure curves at different nuclear magnetic resonance frequencies.
[0054] Step S14: Extract the capillary pressure curves at different nuclear magnetic resonance frequencies to obtain pore structure characteristic parameters, thereby completing the conversion of the pore structure characteristic parameters at different nuclear magnetic resonance frequencies.
[0055] In this embodiment, multi-component original digital cores of shale oil samples are obtained. Numerical simulation methods and a pre-defined shale oil NMR response equation are used to simulate the NMR response characteristics of different pyrite contents based on the multi-component original digital cores, generating echo data. The echo data is inverted to obtain the T2 distribution, and combined with the high-pressure mercury intrusion porosimetry results of parallel samples of shale oil samples corresponding to the multi-component original digital cores, capillary pressure curves at different NMR frequencies are constructed. Pore structure characteristic parameters are extracted from the capillary pressure curves at different NMR frequencies to complete the conversion of pore structure characteristic parameters at different NMR frequencies. This application utilizes numerical simulation methods and the shale oil NMR response equation to simulate the NMR response characteristics of different pyrite contents, generating echo data. The echo data is inverted to obtain the T2 distribution. Combined with the high-pressure mercury intrusion porosimetry results, capillary pressure curves at different NMR frequencies are constructed, and characteristic parameters representing the pore structure are extracted to complete the conversion of pore structure characteristic parameters at different NMR frequencies. This application enables the conversion of shale oil pore structure parameters under different echo intervals, different pyrite contents, and different nuclear magnetic resonance frequencies. It not only simplifies the operation and saves time, but also reflects the influence of single-factor nuclear magnetic resonance response, thereby reducing costs.
[0056] See Figure 2 As shown in the figure, this invention discloses a method for converting pore structure parameters at different frequencies, which may specifically include:
[0057] Step S21: Obtain multi-component raw digital cores of shale oil samples.
[0058] Step S22: Using numerical simulation methods and the preset shale oil nuclear magnetic resonance response equation, and based on the multi-component original digital core, simulate the nuclear magnetic resonance response characteristics of different pyrite contents to generate echo data.
[0059] In this embodiment, the construction process of the shale oil nuclear magnetic resonance response equation includes: constructing shale oil nuclear magnetic resonance response equations at different nuclear magnetic resonance frequencies based on the nuclear magnetic resonance relaxation mechanism of shale oil; wherein, the nuclear magnetic resonance relaxation mechanism includes volume relaxation, surface relaxation, and diffusion relaxation of inorganic pore water, volume relaxation, surface relaxation, and diffusion relaxation of organic pore oil, and volume relaxation of organic matter (kerogen + bitumen); furthermore, the shale oil nuclear magnetic resonance response equation can also be called the improved Korb model. The improved Korb model can be expressed as:
[0060]
[0061] Among them, T 2RB，W and T 2RB，O T represents the volume relaxation time driven by intermolecular dipole-dipole interactions;2TB，W and T 2TB，O T represents the volume relaxation time driven by intramolecular dipole-dipole interactions; 2B，K T represents the volume relaxation time of organic matter. 2D，W and T 2D，O T represents the diffusion relaxation time of inorganic pore water and organic pore oil, respectively; 2S，W and T 2S，O The surface relaxation times of inorganic pore water and organic pore oil, respectively, can be specifically expressed as follows:
[0062]
[0063]
[0064] Where μ0 is the free permeability, δ W and δ O These represent water and oil at two-dimensional and one-dimensional pore surfaces, respectively. 1 The minimum distance between H and paramagnetic ions; δ S，W and σ S，O Represents the paramagnetic ion concentrations on the inorganic and organic pore surfaces, respectively; ρ W and ρ O S represents the density of water and oil, respectively; p，NMR，W and S p，NMR，O τ represents the specific surface area of inorganic pores and organic pores, respectively; m，W and τ m，O τ represents the translational correlation time for water and oil, respectively; s，W and τ s，O Representing the surface residence time of water and oil respectively; γ I and γ s Represent 1 Magnetic moments of H and paramagnetic ions; ω I and ω s Representing the pore surface 1 Angular frequencies of H and paramagnetic ions. T 2D，W and T 2D，O Let represent the diffusion relaxation times of inorganic pore water and organic pore oil, respectively, which can be expressed as:
[0065]
[0066] In this context, the subscript L can represent inorganic pore water (W) or organic pore oil (O); D W and D O Represent the diffusion coefficients of inorganic porous water and organic porous oil, respectively; γ is the gyromagnetic ratio; G z The internal magnetic field gradient; T E This is the echo interval.
[0067] The above formula can be used to determine the variation of transverse surface relaxation intensity with NMR frequency. In this process, the peak positions of the T2 distribution obtained by inverting echo data from CPMG (Carr-Purcell-Meiboom-Gill) pulse sequences of multi-frequency NMR can be calibrated by inverting the peak positions of the T1-T2 spectrum from multiple sets of echo data with different waiting times obtained by two-dimensional SR-CPMG ((saturation recovery)-(Carr-Purcell-Meiboom-Gill)) pulse sequences or IR-CPMG ((inversion recovery)-(Carr-Purcell-Meiboom-Gill)) pulse sequences. Figure 3 The graph shows the variation of transverse surface relaxation intensity at different NMR frequencies: It illustrates the change of transverse surface relaxation intensity with NMR frequency after the peak positions of the T2 distribution are calibrated. Figure 4 The diagram shows the variation of the internal magnetic field gradient distribution at different NMR frequencies. The three-dimensional spatial distribution of the internal magnetic field gradient at different NMR frequencies with a pyrite content of 1.77% can be calculated using the dipole summation method. A multi-component digital core of shale oil with varying pyrite contents, including organic matter, inorganic pore water, organic pore oil, pyrite, and a framework, is constructed using a region growing algorithm. Based on the lateral surface relaxation intensity and internal magnetic field gradient determined by the improved Korb model, one-dimensional NMR response characteristics with different pyrite contents are simulated using numerical simulation methods to generate echo data.
[0068] Step S23: Invert the echo data using the inversion method to obtain the T2 distribution. Accumulate the T2 distribution in reverse to obtain the inversely accumulated T2 distributions at different nuclear magnetic resonance frequencies. Based on the inversely accumulated T2 distributions and combined with the high-pressure mercury intrusion test results of parallel samples of shale oil samples corresponding to the multi-component original digital cores, construct capillary pressure curves at different nuclear magnetic resonance frequencies.
[0069] In this embodiment, after obtaining the inverse cumulative T2 distributions at different nuclear magnetic resonance frequencies, a capillary pressure conversion equation is selected and combined with the results of the high-pressure mercury intrusion test to convert the inverse cumulative T2 distributions into initial capillary pressure curves, and the conversion coefficient of the capillary pressure conversion equation is determined; based on the T2 distributions at different nuclear magnetic resonance frequencies, the initial capillary pressure curves, and the conversion coefficient, capillary pressure curves at different nuclear magnetic resonance frequencies are constructed.
[0070] In this embodiment, due to 1 / T 2S，W 1 / T 2S，O Both GZ and GZ are related to the throat radius r, therefore, 1 / T² ∝ 1 / r, and the capillary pressure P c=0.735 / r, P c = f(1 / T2);
[0071] A suitable capillary pressure conversion equation is selected to convert the reverse cumulative T2 distribution into a capillary pressure curve. The conversion equation selected here is as follows:
[0072]
[0073] In the formula, a, b, c, d, and e are the coefficients to be determined in the capillary pressure conversion equation; the capillary pressure curves at different NMR frequencies are determined using the T2 distribution at different NMR frequencies. Figure 5 This is a conversion diagram of the capillary pressure curve. Table 1 shows the conversion coefficients of different conversion equations for different echo intervals:
[0074] Table 1
[0075]
[0076] Furthermore, the inversion methods employed in this application include, but are not limited to, the BRD (Butler-Reeds-Dawson) inversion method, the maximum entropy inversion method, and the L1 regularization inversion method.
[0077] Step S24: Extract the capillary pressure curves at different nuclear magnetic resonance frequencies to obtain pore structure characteristic parameters, thereby completing the conversion of pore structure characteristic parameters at different nuclear magnetic resonance frequencies.
[0078] In this embodiment, capillary pressure curves at different NMR frequencies are obtained; based on the extracted pore structure parameters, the conversion of pore structure parameters of the target shale oil sample at different frequencies is completed.
[0079] In this embodiment, multi-component original digital cores of shale oil samples are obtained. Numerical simulation methods and a pre-defined shale oil NMR response equation are used to simulate the NMR response characteristics of different pyrite contents based on the multi-component original digital cores, generating echo data. The echo data is inverted to obtain the T2 distribution, and combined with the high-pressure mercury intrusion porosimetry results of parallel samples of shale oil samples corresponding to the multi-component original digital cores, capillary pressure curves at different NMR frequencies are constructed. Pore structure characteristic parameters are extracted from the capillary pressure curves at different NMR frequencies to complete the conversion of pore structure characteristic parameters at different NMR frequencies. This application utilizes numerical simulation methods and the shale oil NMR response equation to simulate the NMR response characteristics of different pyrite contents, generating echo data. The echo data is inverted to obtain the T2 distribution. Combined with the high-pressure mercury intrusion porosimetry results, capillary pressure curves at different NMR frequencies are constructed, and characteristic parameters representing the pore structure are extracted to complete the conversion of pore structure characteristic parameters at different NMR frequencies. This application enables the conversion of shale oil pore structure parameters under different echo intervals, different pyrite contents, and different nuclear magnetic resonance frequencies. It not only simplifies the operation and saves time, but also reflects the influence of single-factor nuclear magnetic resonance response, thereby reducing costs.
[0080] See Figure 6 As shown, this embodiment of the invention discloses a device for converting pore structure parameters at different frequencies, which may specifically include:
[0081] The raw digital core acquisition module 11 is used to acquire multi-component raw digital cores of shale oil samples;
[0082] The echo data generation module 12 is used to generate echo data by simulating the nuclear magnetic resonance response characteristics of different pyrite contents using numerical simulation methods and preset shale oil nuclear magnetic resonance response equations based on the multi-component original digital core.
[0083] The curve construction module 13 is used to invert the echo data to obtain the T2 distribution, and combine it with the high pressure mercury injection test results of the parallel sample of the shale oil sample corresponding to the multi-component original digital core to construct capillary pressure curves at different nuclear magnetic resonance frequencies.
[0084] The parameter conversion module 14 is used to extract the capillary pressure curves at different nuclear magnetic resonance frequencies to obtain pore structure characteristic parameters, so as to complete the conversion of the pore structure characteristic parameters at different nuclear magnetic resonance frequencies.
[0085] In this embodiment, multi-component original digital cores of shale oil samples are obtained. Numerical simulation methods and a pre-defined shale oil NMR response equation are used to simulate the NMR response characteristics of different pyrite contents based on the multi-component original digital cores, generating echo data. The echo data is inverted to obtain the T2 distribution, and combined with the high-pressure mercury intrusion porosimetry results of parallel samples of shale oil samples corresponding to the multi-component original digital cores, capillary pressure curves at different NMR frequencies are constructed. Pore structure characteristic parameters are extracted from the capillary pressure curves at different NMR frequencies to complete the conversion of pore structure characteristic parameters at different NMR frequencies. This application utilizes numerical simulation methods and the shale oil NMR response equation to simulate the NMR response characteristics of different pyrite contents, generating echo data. The echo data is inverted to obtain the T2 distribution. Combined with the high-pressure mercury intrusion porosimetry results, capillary pressure curves at different NMR frequencies are constructed, and characteristic parameters representing the pore structure are extracted to complete the conversion of pore structure characteristic parameters at different NMR frequencies. This application enables the conversion of shale oil pore structure parameters under different echo intervals, different pyrite contents, and different nuclear magnetic resonance frequencies. It not only simplifies the operation and saves time, but also reflects the influence of single-factor nuclear magnetic resonance response, thereby reducing costs.
[0086] In some specific embodiments, the process of constructing the shale oil nuclear magnetic resonance response equation includes:
[0087] Based on the nuclear magnetic resonance relaxation mechanism of shale oil, nuclear magnetic resonance response equations for shale oil at different nuclear magnetic resonance frequencies are constructed; wherein, the nuclear magnetic resonance relaxation mechanism includes volume relaxation, surface relaxation and diffusion relaxation of inorganic pore water, volume relaxation, surface relaxation and diffusion relaxation of organic pore oil, and volume relaxation of organic matter.
[0088] In some specific embodiments, the echo data generation module 12 may specifically include:
[0089] The intensity and distribution determination module is used to determine the lateral surface relaxation intensity that varies with the nuclear magnetic resonance frequency and the three-dimensional spatial distribution of the internal magnetic field gradient at different nuclear magnetic resonance frequencies based on the nuclear magnetic resonance response equation of the shale oil.
[0090] The simulation module is used to simulate the nuclear magnetic resonance response characteristics of different pyrite contents using numerical simulation methods based on the multi-component original digital core, the lateral surface relaxation intensity, and the three-dimensional spatial distribution.
[0091] In some specific embodiments, the echo data generation module 12 may specifically include:
[0092] The intermediate state digital core construction module is used to construct a multi-component intermediate state digital core based on the multi-component original digital core.
[0093] The response characteristic simulation module is used to simulate the nuclear magnetic resonance response characteristics of different pyrite contents using numerical simulation methods based on the digital core of the multi-component intermediate state, the lateral surface relaxation intensity, and the three-dimensional spatial distribution.
[0094] In some specific embodiments, the echo data generation module 12 may specifically include:
[0095] The specific construction module is used to construct, based on the original multi-component digital core, a digital core of the multi-component intermediate state containing different pyrite contents of organic matter, inorganic pore water, organic pore oil, pyrite, and framework, using a region growth algorithm.
[0096] In some specific embodiments, the curve construction module 13 may specifically include:
[0097] The inversion module is used to invert echo data using an inversion method to obtain a T2 distribution, and then accumulates the T2 distribution in reverse to obtain inversely accumulated T2 distributions at different nuclear magnetic resonance frequencies.
[0098] The curve construction module is used to construct capillary pressure curves at different nuclear magnetic resonance frequencies based on the inverse cumulative T2 distribution and combined with the high-pressure mercury intrusion test results of parallel samples of shale oil samples corresponding to multi-component original digital cores.
[0099] In some specific embodiments, the curve construction module 13 may specifically include:
[0100] The conversion coefficient determination module is used to select the capillary pressure conversion equation and, in conjunction with the high-pressure mercury injection experiment results, convert the reverse cumulative T2 distribution into an initial capillary pressure curve and determine the conversion coefficient of the capillary pressure conversion equation.
[0101] The curve construction module is used to construct the capillary pressure curves at different nuclear magnetic resonance frequencies based on the T2 distribution at different nuclear magnetic resonance frequencies, the initial capillary pressure curve, and the conversion coefficient.
[0102] Figure 7This is a schematic diagram of an electronic device provided in an embodiment of this application. The electronic device 20 may specifically include: at least one processor 21, at least one memory 22, a power supply 23, a communication interface 24, an input / output interface 25, and a communication bus 26. The memory 22 stores a computer program, which is loaded and executed by the processor 21 to implement the relevant steps in the pore structure parameter conversion method at different frequencies disclosed in any of the foregoing embodiments.
[0103] In this embodiment, the power supply 23 is used to provide operating voltage for each hardware device on the electronic device 20; the communication interface 24 can create a data transmission channel between the electronic device 20 and external devices, and the communication protocol it follows can be any communication protocol applicable to the technical solution of this application, and is not specifically limited here; the input / output interface 25 is used to acquire external input data or output data to the outside world, and its specific interface type can be selected according to specific application needs, and is not specifically limited here.
[0104] In addition, the memory 22, as a carrier for resource storage, can be a read-only memory, random access memory, disk or optical disk, etc. The resources stored on it include operating system 221, computer program 222 and data 223, etc., and the storage method can be temporary storage or permanent storage.
[0105] The operating system 221 manages and controls the various hardware devices and computer program 222 on the electronic device 20 to enable the processor 21 to perform calculations and processing on the data 223 in the memory 22. It can be Windows, Unix, Linux, etc. The computer program 222, in addition to including a computer program capable of performing the pore structure parameter conversion method at different frequencies disclosed in any of the foregoing embodiments, may further include computer programs capable of performing other specific tasks. The data 223 may include data received by the pore structure parameter conversion device at different frequencies from data transmitted from external devices, and may also include data collected by its own input / output interface 25.
[0106] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly by hardware, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.
[0107] Furthermore, embodiments of this application also disclose a computer-readable storage medium storing a computer program. When the computer program is loaded and executed by a processor, it implements the steps of the pore structure parameter conversion method at different frequencies disclosed in any of the foregoing embodiments.
[0108] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0109] The present invention has provided a detailed description of a method, apparatus, device, and storage medium for converting pore structure parameters at different frequencies. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.
Claims
1. A method for converting pore structure parameters at different frequencies, characterized in that, include: Obtain multi-component raw digital cores of shale oil samples; Numerical simulation methods and preset shale oil nuclear magnetic resonance response equations were used to simulate the nuclear magnetic resonance response characteristics of different pyrite contents based on the multi-component original digital cores, so as to generate echo data. The echo data is inverted to obtain the T2 distribution, and combined with the high-pressure mercury intrusion test results of the parallel sample of the shale oil sample corresponding to the multi-component original digital core, to construct capillary pressure curves at different nuclear magnetic resonance frequencies. The capillary pressure curves at different nuclear magnetic resonance frequencies are extracted to obtain pore structure characteristic parameters, thereby completing the conversion of the pore structure characteristic parameters at different nuclear magnetic resonance frequencies. The nuclear magnetic resonance response equation for shale oil is an improved Korb model, expressed as: ； in, and These represent the volume relaxation times driven by intermolecular dipole-dipole interactions in inorganic pore water and organic pore oil, respectively. and These represent the volume relaxation times driven by intramolecular dipole-dipole interactions in inorganic pore water and organic pore oil, respectively. Indicates the volume relaxation time of organic matter; and These represent the diffusion relaxation times of inorganic pore water and organic pore oil, respectively. and These represent the surface relaxation times of inorganic porous water and organic porous oil, respectively. The echo data is inverted to obtain the T2 distribution, and combined with the high-pressure mercury intrusion test results of parallel samples of shale oil samples corresponding to the multi-component original digital core, to construct capillary pressure curves at different nuclear magnetic resonance frequencies. This includes: inverting the echo data using an inversion method to obtain the T2 distribution; inverting and accumulating the T2 distributions to obtain inversely accumulated T2 distributions at different nuclear magnetic resonance frequencies; and constructing capillary pressure curves at different nuclear magnetic resonance frequencies based on the inversely accumulated T2 distributions and combined with the high-pressure mercury intrusion test results of parallel samples of shale oil samples corresponding to the multi-component original digital core. The inversion methods include the BRD inversion method, the maximum entropy inversion method, and the L1 regularization inversion method. Based on the inverse cumulative T2 distribution and combined with the high-pressure mercury intrusion test results of parallel samples of shale oil samples corresponding to multi-component original digital cores, capillary pressure curves at different nuclear magnetic resonance frequencies are constructed. This includes: selecting a capillary pressure conversion equation and combining it with the high-pressure mercury intrusion test results to convert the inverse cumulative T2 distribution into an initial capillary pressure curve, and determining the conversion coefficient of the capillary pressure conversion equation; and constructing the capillary pressure curves at different nuclear magnetic resonance frequencies based on the T2 distributions at different nuclear magnetic resonance frequencies, the initial capillary pressure curves, and the conversion coefficient.
2. The method for converting pore structure parameters at different frequencies according to claim 1, characterized in that, The process of constructing the nuclear magnetic resonance response equation for shale oil includes: Based on the nuclear magnetic resonance relaxation mechanism of shale oil, nuclear magnetic resonance response equations for shale oil at different nuclear magnetic resonance frequencies are constructed; wherein, the nuclear magnetic resonance relaxation mechanism includes volume relaxation, surface relaxation and diffusion relaxation of inorganic pore water, volume relaxation, surface relaxation and diffusion relaxation of organic pore oil, and volume relaxation of organic matter.
3. The method for converting pore structure parameters at different frequencies according to claim 1, characterized in that, The method of using numerical simulation and a pre-defined shale oil nuclear magnetic resonance response equation, and simulating the nuclear magnetic resonance response characteristics of different pyrite contents based on the multi-component original digital core, includes: Based on the shale oil nuclear magnetic resonance response equation, the transverse surface relaxation intensity as a function of nuclear magnetic resonance frequency and the three-dimensional spatial distribution of the internal magnetic field gradient at different nuclear magnetic resonance frequencies are determined. The nuclear magnetic resonance response characteristics of different pyrite contents were simulated using numerical simulation methods based on the multi-component original digital core, the lateral surface relaxation intensity, and the three-dimensional spatial distribution.
4. The method for converting pore structure parameters at different frequencies according to claim 3, characterized in that, The method of simulating the nuclear magnetic resonance response characteristics of different pyrite contents using numerical simulation methods based on the multi-component original digital core, the lateral surface relaxation intensity, and the three-dimensional spatial distribution includes: Construct a multi-component intermediate state digital core based on the original multi-component digital core; The nuclear magnetic resonance response characteristics of different pyrite contents were simulated using numerical simulation methods based on the digital core of the multi-component intermediate state, the lateral surface relaxation intensity, and the three-dimensional spatial distribution.
5. The method for converting pore structure parameters at different frequencies according to claim 4, characterized in that, The construction of a multi-component intermediate state digital core based on the original multi-component digital core includes: Using a region growing algorithm, digital cores of the multi-component intermediate state with varying pyrite contents, including organic matter, inorganic pore water, organic pore oil, pyrite, and framework, were constructed based on the original multi-component digital cores.
6. A device for converting pore structure parameters at different frequencies, characterized in that, include: The raw digital core acquisition module is used to acquire multi-component raw digital cores of shale oil samples; The echo data generation module is used to generate echo data by simulating the nuclear magnetic resonance response characteristics of different pyrite contents using numerical simulation methods and preset shale oil nuclear magnetic resonance response equations based on the multi-component original digital core. The curve construction module is used to invert the echo data to obtain the T2 distribution, and combine it with the high-pressure mercury intrusion test results of the parallel sample of the shale oil sample corresponding to the multi-component original digital core to construct capillary pressure curves at different nuclear magnetic resonance frequencies. The parameter conversion module is used to extract the capillary pressure curves at different nuclear magnetic resonance frequencies to obtain pore structure characteristic parameters, so as to complete the conversion of the pore structure characteristic parameters at different nuclear magnetic resonance frequencies. The nuclear magnetic resonance response equation for shale oil is an improved Korb model, expressed as: ； in, and These represent the volume relaxation times driven by intermolecular dipole-dipole interactions in inorganic pore water and organic pore oil, respectively. and These represent the volume relaxation times driven by intramolecular dipole-dipole interactions in inorganic pore water and organic pore oil, respectively. Indicates the volume relaxation time of organic matter; and These represent the diffusion relaxation times of inorganic pore water and organic pore oil, respectively. and These represent the surface relaxation times of inorganic porous water and organic porous oil, respectively. The echo data is inverted to obtain the T2 distribution, and combined with the high-pressure mercury intrusion test results of parallel samples of shale oil samples corresponding to the multi-component original digital core, to construct capillary pressure curves at different nuclear magnetic resonance frequencies. This includes: inverting the echo data using an inversion method to obtain the T2 distribution; inverting and accumulating the T2 distributions to obtain inversely accumulated T2 distributions at different nuclear magnetic resonance frequencies; and constructing capillary pressure curves at different nuclear magnetic resonance frequencies based on the inversely accumulated T2 distributions and combined with the high-pressure mercury intrusion test results of parallel samples of shale oil samples corresponding to the multi-component original digital core. The inversion methods include the BRD inversion method, the maximum entropy inversion method, and the L1 regularization inversion method. Based on the inverse cumulative T2 distribution and combined with the high-pressure mercury intrusion test results of parallel samples of shale oil samples corresponding to multi-component original digital cores, capillary pressure curves at different nuclear magnetic resonance frequencies are constructed. This includes: selecting a capillary pressure conversion equation and combining it with the high-pressure mercury intrusion test results to convert the inverse cumulative T2 distribution into an initial capillary pressure curve, and determining the conversion coefficient of the capillary pressure conversion equation; and constructing the capillary pressure curves at different nuclear magnetic resonance frequencies based on the T2 distributions at different nuclear magnetic resonance frequencies, the initial capillary pressure curves, and the conversion coefficient.
7. An electronic device, characterized in that, include: Memory, used to store computer programs; A processor for executing the computer program to implement the pore structure parameter conversion method at different frequencies as described in any one of claims 1 to 5.
8. A computer-readable storage medium, characterized in that, Used to store computer programs; wherein, when the computer programs are executed by a processor, they implement the pore structure parameter conversion method at different frequencies as described in any one of claims 1 to 5.