A method and apparatus for determining transverse relaxation times of different carbon chain lengths in shale oil

Abstract

The application provides a method and equipment for determining transverse relaxation time of shale oil with different carbon chain lengths, and belongs to the field of oil and gas exploration. The method comprises the following steps: constructing a shale oil precursor model with a target carbon chain length; determining the correlation time corresponding to the shale oil with the target carbon chain length by performing molecular dynamics simulation on the shale oil precursor model; and inputting the correlation time into a relaxation time calculation model to obtain the transverse relaxation time corresponding to the shale oil with the target carbon chain length. The influence of the carbon chain length, shale oil composition and structure on the nuclear magnetic resonance relaxation time is fully considered, the transverse relaxation time of the shale oil with different carbon chain lengths under various environments can be obtained, and the problem that the hydrocarbons in the organic pores and other micro-nano pores in the shale oil reservoir cannot be effectively detected under the current experimental conditions is solved.

Description

Technical Field

[0001] This application relates to the field of oil and gas exploration, and in particular to a method and apparatus for determining the lateral relaxation time of different carbon chain lengths in shale oil. Background Technology

[0002] Core nuclear magnetic resonance (NMR) and NMR logging techniques play a crucial role in the evaluation of complex and unconventional reservoirs, serving as important methods for studying pore structure and fluid properties. Currently, commonly used NMR models include surface relaxation models and volume relaxation models.

[0003] However, in shale oil reservoirs, shale oil contained in micro- and nanopores such as organic matter pores has high viscosity and carbon chain length, resulting in very short relaxation times. Therefore, commonly used surface relaxation and volume relaxation models cannot be used to characterize hydrocarbons within these reservoirs. The aforementioned methods make it difficult to distinguish hydrocarbons in micro- and nanopores from relaxor components such as clay-bound water, thus affecting reservoir evaluation. Summary of the Invention

[0004] This application provides a method and apparatus for determining the transverse relaxation time of shale oil with different carbon chain lengths. This method can obtain the transverse relaxation time of shale oil with different carbon chain lengths, solving the problem of the inability to effectively detect some hydrocarbons in shale oil reservoirs. The technical solution is as follows:

[0005] On one hand, embodiments of this application provide a method for determining the transverse relaxation time of shale oil with different carbon chain lengths, the method comprising:

[0006] A shale oil parent material model with a target carbon chain length is constructed, which is used to characterize the shale structure and the composition of shale oil.

[0007] By performing molecular dynamics simulations on the shale oil parent material model, the relevant time corresponding to the shale oil with the target carbon chain length is determined;

[0008] The relevant time is input into the relaxation time calculation model to obtain the lateral relaxation time corresponding to the target carbon chain length of shale oil. The relaxation time calculation model is fitted with the conversion relationship between lateral relaxation time and relevant time.

[0009] On the other hand, embodiments of this application provide an apparatus for determining the transverse relaxation time of shale oil with different carbon chain lengths, the apparatus comprising:

[0010] The model building module is used to build a shale oil parent material model with a target carbon chain length. The shale oil parent material model is used to characterize the shale structure and the composition of shale oil.

[0011] The determination module is used to determine the relevant time corresponding to the shale oil with the target carbon chain length by performing molecular dynamics simulation on the shale oil parent material model;

[0012] The acquisition module is used to input the relevant time into the relaxation time calculation model to obtain the lateral relaxation time corresponding to the target carbon chain length of shale oil. The relaxation time calculation model is fitted with a conversion relationship between lateral relaxation time and relevant time.

[0013] On the other hand, embodiments of this application provide a computer device, the computer device including a processor and a memory; the memory stores at least one instruction, at least one program, code set or instruction set, the at least one instruction, the at least one program, the code set or instruction set being loaded and executed by the processor to implement the method for determining the transverse relaxation time of different carbon chain lengths of shale oil as described above.

[0014] On the other hand, embodiments of this application provide a computer-readable storage medium storing at least one instruction, at least one program, code set, or instruction set, wherein the at least one instruction, at least one program, code set, or instruction set is loaded and executed by a processor to implement the method for determining the transverse relaxation time of different carbon chain lengths in shale oil as described above.

[0015] According to one aspect of this application, a computer program product or computer program is provided, comprising computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computer device to perform a method for determining the transverse relaxation time of different carbon chain lengths in shale oil, provided in various alternative implementations of the above aspect.

[0016] The technical solution provided in this application includes at least the following beneficial effects:

[0017] This application provides a method, apparatus, and equipment for determining the transverse relaxation time of shale oil with different carbon chain lengths. The method involves constructing a shale oil parent material model and performing molecular dynamics simulations to obtain the relevant times of the shale oil. A relaxation time calculation model is then used to calculate the transverse relaxation time of the shale oil based on these relevant times. This method fully considers the influence of carbon chain length, shale oil composition, and structure on the nuclear magnetic resonance relaxation time, enabling the determination of the transverse relaxation time of shale oil with different carbon chain lengths under various conditions. This addresses the current limitations of experimental methods for effectively detecting hydrocarbons in micro- and nano-pores such as organic matter pores in shale oil reservoirs, providing a reliable basis for subsequent shale oil component identification and content calculation. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0019] Figure 1 This is a flowchart illustrating a method for determining the transverse relaxation time of shale oil with different carbon chain lengths, provided in an exemplary embodiment of this application.

[0020] Figure 2 This is a flowchart of a method for determining the lateral relaxation time of shale oil with different carbon chain lengths, provided by another exemplary embodiment of this application;

[0021] Figure 3 This is a graph showing the relationship between carbon chain length and relevant time, provided in an exemplary embodiment of this application.

[0022] Figure 4 This is a graph showing the relationship between carbon chain length and transverse relaxation time, provided in an exemplary embodiment of this application.

[0023] Figure 5 This is a flowchart of a method for determining the lateral relaxation time of shale oil with different carbon chain lengths, provided by another exemplary embodiment of this application;

[0024] Figure 6 This is a structural block diagram of an apparatus for determining the transverse relaxation time of shale oil with different carbon chain lengths, provided in an exemplary embodiment of this application;

[0025] Figure 7 This is a structural block diagram of a computer device provided in an exemplary embodiment of this application. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0027] Example 1

[0028] Please refer to Figure 1 This document illustrates a flowchart of a method for determining the transverse relaxation time of shale oil with different carbon chain lengths, provided in an exemplary embodiment of this application. This embodiment uses the application of this method to a computer device as an example, and the method includes the following steps:

[0029] Step 101: Construct a shale oil parent material model with the target carbon chain length. The shale oil parent material model is used to characterize the shale structure and the composition of shale oil.

[0030] In one possible implementation, a computer device acquires relevant data on the shale oil to be tested and constructs a shale oil parent material model corresponding to each carbon chain length using a model building program. This model simulates the environment in which the shale oil is located and its composition. This shale oil parent material model is then used by the computer device to simulate and analyze the physical motion of molecules to calculate transverse relaxation times. Specifically, the shale oil parent material model is a dataset that records shale oil-related data in a specific format, including mineral framework, clay type, nanopores, kerogen, and hydrocarbon components. It reflects the shale oil environment and provides data support for subsequent molecular dynamics simulations and other steps.

[0031] The lateral relaxation time of shale oil is affected by various factors such as temperature, gas pressure, and carbon chain length. However, in practical applications, for shale oil in the same region, technicians mainly study the lateral relaxation time of shale oil with different carbon chain lengths under the same shale environment. Therefore, computer equipment constructs a shale oil parent material model corresponding to each carbon chain length based on the input carbon chain length and other relevant data.

[0032] The relevant data used to construct the shale oil parent material model can be obtained by technicians through equipment measurements, such as temperature, gas pressure, clay type, and mineral composition. Technicians then set the carbon chain length according to the calculation requirements. If it is necessary to calculate the transverse relaxation time of shale oil with various carbon chain lengths, different shale oil parent material models can be constructed by changing the target carbon chain length, and the calculations can be performed separately.

[0033] Step 102: By performing molecular dynamics simulations on the shale oil parent material model, the relevant time corresponding to the shale oil with the target carbon chain length is determined.

[0034] Molecular dynamics simulation is a method based on Newtonian mechanics to simulate the physical trajectories and states of atoms and molecules. This method uses computers to directly simulate the motion of atomic nuclei and calculates the interactions between microscopic particles to obtain the system's structure and properties. In a liquid, molecules or atoms oscillate around an equilibrium center for approximately time t before jumping to a new position; t is the correlation time. Relaxation time, on the other hand, refers to the time required to reach thermodynamic equilibrium, i.e., the time it takes for a substance to gradually recover from a certain state to an equilibrium state. In the embodiments of this application, those skilled in the art studied the relationship between correlation time and transverse relaxation time and created a relaxation time calculation model, enabling computer equipment to obtain the transverse relaxation time of shale oil based on the correlation time.

[0035] In one possible implementation, after the computer device constructs a shale oil parent material model, it starts a molecular dynamics simulation program to perform molecular dynamics simulation on the shale oil parent material model with the target carbon chain length, and analyzes and obtains the relevant time corresponding to the shale oil with the target carbon chain length.

[0036] Step 103: Input the relevant time into the relaxation time calculation model to obtain the lateral relaxation time corresponding to the target carbon chain length of shale oil. The relaxation time calculation model is fitted with the conversion relationship between lateral relaxation time and relevant time.

[0037] In one possible implementation, the computer device in this embodiment is equipped with a relaxation time calculation model. After obtaining relevant times through molecular dynamics simulations, the computer device inputs these relevant times into the relaxation time calculation model to output the lateral relaxation time of shale oil.

[0038] Optionally, technicians can change the target carbon chain length or adjust the shale oil parent material model by changing parameters to calculate the transverse relaxation time of shale oil with different carbon chain lengths in different regions. That is, the method provided in this application embodiment can be used to calculate the transverse relaxation time of carbon chain lengths for shale oil in different regions and of different types.

[0039] In summary, the method provided in this application for determining the transverse relaxation time of shale oil with different carbon chain lengths involves constructing a shale oil parent material model and performing molecular dynamics simulations to obtain the relevant times of the shale oil. A relaxation time calculation model is then used to calculate the transverse relaxation time of the shale oil based on these relevant times. This method fully considers the influence of carbon chain length, shale oil composition, and structure on the nuclear magnetic resonance relaxation time, enabling the determination of the transverse relaxation time of shale oil with different carbon chain lengths under various conditions. It addresses the current limitations of experimental methods for effectively detecting hydrocarbons in micro- and nano-pores such as organic matter pores in shale oil reservoirs, providing a reliable basis for subsequent shale oil component identification and content calculation.

[0040] Example 2

[0041] In one possible implementation, a computer device obtains parameters such as the spatial trajectory, bond length, and bond angle of hydrocarbon components through molecular dynamics simulations, and then calculates the relevant time and relaxation time. Please refer to [reference needed]. Figure 2 This document illustrates a flowchart of a method for determining the transverse relaxation time of shale oil with different carbon chain lengths, provided by another exemplary embodiment of this application. This embodiment uses the application of this method to a computer device as an example, and the method includes the following steps:

[0042] Step 201: Construct a shale oil parent material model with the target carbon chain length. The shale oil parent material model is used to characterize the shale structure and the composition of shale oil.

[0043] The specific implementation of step 201 can be referred to step 101 in the above embodiments, and will not be repeated here in the embodiments of this application.

[0044] Step 202: By performing molecular dynamics simulations on the shale oil parent material model, the time correlation function of the hydrogen nuclei of hydrocarbon components in shale oil with the target carbon chain length is determined.

[0045] This application provides a time correlation function, which a computer device integrates to obtain the time correlation function of the hydrogen nuclei of hydrocarbon components in shale oil with a target carbon chain length. In one possible implementation, step 202 specifically includes the following steps:

[0046] Step 202a: Determine the spatial trajectory function of the hydrogen nuclei of hydrocarbon components by performing molecular dynamics simulation on the shale oil parent material model.

[0047] Computer equipment performs molecular dynamics simulations on a shale oil parent material model to determine the spatial trajectory function of hydrogen nuclei in hydrocarbon components with target carbon chain lengths. This spatial trajectory function characterizes the motion trajectory of the hydrogen nuclei. The expression for the spatial trajectory of the i-th hydrogen nucleus is: x i y i z i .

[0048] Step 202b: Determine the time correlation function of the hydrogen nuclei of hydrocarbon components based on the spatial trajectory function of the hydrogen nuclei of hydrocarbon components.

[0049] In one possible implementation, step 202b specifically includes the following steps:

[0050] The bond lengths and bond angles of the hydrogen nuclei of hydrocarbon components are calculated based on the spatial trajectory function of the hydrogen nuclei of hydrocarbon components; the time correlation function of the hydrogen nuclei of hydrocarbon components is calculated based on the spatial trajectory function, bond lengths, and bond angles of the hydrogen nuclei of hydrocarbon components.

[0051] First, the computer calculates the bond lengths and bond angles of the hydrogen nuclei in the hydrocarbon component based on the spatial trajectory function of the hydrogen nuclei. Illustratively, the expression for the bond length is:

[0052]

[0053] The expression for the key angle is:

[0054]

[0055] In the above formula, i, j, and k represent the i-th, j-th, and k-th hydrogen nuclei, respectively, and r ij x represents the bond length between the i-th hydrogen nucleus and the j-th hydrogen nucleus. i y i and z i θ represents the spatial trajectory coordinates of the i-th hydrogen nucleus. ij It is the bond angle formed by the i, j, and k hydrogen nuclei.

[0056] The computer device calculates the time correlation function of the hydrogen nuclei of the hydrocarbon component based on the spatial trajectory function of the hydrogen nuclei, bond length, and bond angle. Illustratively, the expression of the time correlation function in this embodiment is as follows:

[0057]

[0058] In the above formula, Let t be Planck's constant, N be the number of hydrogen nuclei, Δt be the time step, and r be the pore radius.

[0059] Step 203: By integrating the time correlation function, the relevant time corresponding to the shale oil with the target carbon chain length is obtained.

[0060] The computer equipment obtains the correlation time corresponding to the target carbon chain length of shale oil by integrating the time correlation function. The calculation formula is as follows:

[0061]

[0062] Where, τ c Indicates the relevant time.

[0063] Step 204: Input the relevant time into the relaxation time calculation model to obtain the lateral relaxation time corresponding to the shale oil with the target carbon chain length. The relaxation time calculation model is fitted with the conversion relationship between the lateral relaxation time and the relevant time.

[0064] In one possible implementation, technicians pre-construct and optimize a relaxation time calculation model using experimentally measured sample relaxation times, their corresponding sample correlation times, and related parameters. This model is then deployed on a computer. For example, technicians first measure the relaxation times of certain hydrocarbon components whose relaxation times are easily measurable, obtain the sample relaxation times, and then use molecular dynamics simulations to obtain the corresponding sample correlation times, adjusting the model parameters accordingly.

[0065] Therefore, prior to step 204, during the model building and optimization phase, the method provided in this application embodiment further includes the following steps:

[0066] Based on the pre-collected sample relaxation time and sample correlation time, the parameters of the initial relaxation time calculation model are adjusted to obtain the relaxation time calculation model.

[0067] The expressions for the relaxation time calculation model include:

[0068]

[0069] Where T2 is the transverse relaxation time, μ o Let be the permeability of vacuum, and γ be the gyromagnetic ratio of hydrogen protons. Let τ be Planck's constant. c For the correlation time, r is the pore radius; D is the diffusion coefficient; N s denoted as the number of hydrogen protons per unit volume; a and b are fitting parameters.

[0070] The computer equipment inputs the relevant time into the relaxation time calculation model described above to obtain the lateral relaxation time corresponding to the target carbon chain length of shale oil.

[0071] In this embodiment, the relevant times of shale oil are obtained by constructing a shale oil parent material model and performing molecular dynamics simulations. The lateral relaxation time of the shale oil is then obtained based on these relevant times using a relaxation time calculation model. By fully considering the influence of carbon chain length, shale oil composition, and structure on the nuclear magnetic resonance relaxation time, the lateral relaxation times of shale oil with different carbon chain lengths under various environments can be obtained. This solves the problem that current experimental conditions cannot effectively detect hydrocarbons in micro- and nano-pores such as organic matter pores in shale oil reservoirs, providing a reliable basis for subsequent shale oil component identification and content calculation.

[0072] Schematic illustration: By employing the method for determining the lateral relaxation time of shale oil provided in the above embodiments, a computer device calculates the relevant times and lateral relaxation times corresponding to various shale oils with carbon chain lengths of 6 to 10 under a certain shale oil environment. The calculation results are as follows: Figure 3 and Figure 4 As shown. From Figure 3 As can be seen, the correlation time of hydrogen protons increases with the increase of carbon chain length; in this embodiment, the correlation time increases linearly with the carbon chain length. Figure 4 As can be seen, the lateral relaxation time of shale oil decreases with increasing carbon chain length. In this embodiment, the lateral relaxation time exhibits a power-law decay relationship with carbon chain length. Optionally, technicians can pre-calculate the lateral relaxation times corresponding to shale oil with different carbon chain lengths under various environments to construct a relaxation time database for direct querying and use later.

[0073] Example 3

[0074] Regarding the relevant information required for constructing the shale oil parent material model, optionally, step 101 in the above embodiments includes the following steps:

[0075] Step 1: Obtain shale oil information, including the mineral composition, clay type, kerogen type, and shale pore size distribution.

[0076] Step 2: Based on shale oil information, construct a shale oil parent material model with a mineral framework, kerogen, clay, nanopores, and hydrocarbon components.

[0077] Technicians can collect information on the mineral composition, clay type, kerogen type, and shale pore size distribution of the shale oil in the area to be tested, and input this information into a computer system according to a standardized format. The computer system then constructs a shale oil parent material model based on this information. This shale oil parent material model includes a mineral framework, kerogen, clay, nanopores, and hydrocarbon components.

[0078] In one possible implementation, after the computer equipment constructs a model of the shale oil parent material, the model's rationality is first verified before molecular dynamics simulations are performed to ensure the accuracy of the calculation results.

[0079] Please refer to Figure 5 This document illustrates a flowchart of a method for determining the transverse relaxation time of shale oil with different carbon chain lengths, provided by another exemplary embodiment of this application. This embodiment uses the application of this method to a computer device as an example, and the method includes the following steps:

[0080] Step 501: Construct a shale oil parent material model with the target carbon chain length. The shale oil parent material model is used to characterize the shale structure and the composition of shale oil.

[0081] The specific implementation of step 501 can be referred to step 101 above, and will not be repeated here in the embodiments of this application.

[0082] Step 502: Perform geometric optimization of the shale oil parent material model through molecular dynamics simulation.

[0083] In one possible implementation, after the computer device generates the shale oil parent material model, it first performs geometric optimization on the shale oil parent material model through molecular dynamics simulation to improve the rationality of the shale oil parent material model and reduce the impact of environmental data measurement errors on the calculation results.

[0084] Step 503: Verify the rationality of the shale oil parent material model based on density calculation, and obtain the verification results. The verification results are used to represent the degree of approximation between the shale oil parent material model and actual shale oil.

[0085] Optionally, after performing geometric optimization on the shale oil parent material model, the computer equipment verifies the model's rationality. In one possible implementation, the computer equipment verifies the rationality of the shale oil parent material model based on density calculations.

[0086] For example, technicians first measure the density of shale oil samples directly in the laboratory to obtain density 'a', which is then input into a computer along with the model building parameters. After constructing the parent material model and performing geometric optimization, the computer calculates the density 'b' from the shale oil parent material model. The computer then verifies the reasonableness of the density by comparing density 'a' and density 'b' (e.g., determining reasonableness based on the ratio of density 'a' to density 'b', with a ratio in the range of 0.7 to 1.3 considered reasonable).

[0087] Step 504: If the verification results indicate that the model is reasonable, perform molecular dynamics simulation on the shale oil parent material model to determine the relevant time corresponding to the shale oil with the target carbon chain length.

[0088] In one possible implementation, if the rationality verification result indicates that the model is reasonable, the computer device continues to execute the step of determining the relevant time corresponding to the shale oil with the target carbon chain length by performing molecular dynamics simulation on the shale oil parent material model; if the rationality verification result indicates that the model is unreasonable, the computer device stops the calculation and displays the rationality verification result.

[0089] The process of determining the relevant time corresponding to the target carbon chain length of shale oil by performing molecular dynamics simulation on the shale oil parent material model can be referred to step 102 above, and will not be repeated here in the embodiments of this application.

[0090] Step 505: Input the relevant time into the relaxation time calculation model to obtain the lateral relaxation time corresponding to the target carbon chain length of shale oil. The relaxation time calculation model is fitted with the conversion relationship between lateral relaxation time and relevant time.

[0091] The specific implementation of step 505 can be referred to step 103 above, and will not be repeated here in the embodiments of this application.

[0092] In this embodiment, a shale oil parent material model is constructed and molecular dynamics simulations are performed to obtain the relevant times of shale oil. A relaxation time calculation model is then used to obtain the transverse relaxation time of the shale oil based on these relevant times. This addresses the problem that current experimental conditions cannot effectively detect hydrocarbons in the micro- and nano-pores such as organic matter pores in shale oil reservoirs. Furthermore, based on the model construction, the shale oil parent material model is geometrically optimized, making the computer-generated model more closely resemble shale oil in its natural environment. In addition, the model's rationality is verified before performing relaxation time calculations; continuing the calculation process under reasonable model conditions improves the accuracy of the calculation results.

[0093] Example 4

[0094] Figure 6This is a structural block diagram of an apparatus for determining the transverse relaxation time of shale oil with different carbon chain lengths, provided in an exemplary embodiment of this application. The apparatus includes the following structure:

[0095] The model building module 601 is used to build a shale oil parent material model with a target carbon chain length. The shale oil parent material model is used to characterize the shale structure and the composition of shale oil.

[0096] The determination module 602 is used to determine the relevant time corresponding to the shale oil with the target carbon chain length by performing molecular dynamics simulation on the shale oil parent material model;

[0097] The acquisition module 603 is used to input the relevant time into the relaxation time calculation model to obtain the lateral relaxation time corresponding to the target carbon chain length of shale oil. The relaxation time calculation model is fitted with a conversion relationship between the lateral relaxation time and the relevant time.

[0098] Optionally, the determining module 602 includes:

[0099] The first determining unit is used to determine the time correlation function of the hydrogen nucleus of the hydrocarbon component in the shale oil with the target carbon chain length by performing molecular dynamics simulation on the shale oil parent material model;

[0100] The second determining unit is used to obtain the relevant time corresponding to the shale oil with the target carbon chain length by integrating the time correlation function.

[0101] Optionally, the first determining unit is further configured to:

[0102] The spatial trajectory function of the hydrogen nuclei of the hydrocarbon components was determined by performing molecular dynamics simulations on the shale oil parent material model.

[0103] The time correlation function of the hydrogen nuclei of the hydrocarbon components is determined based on the spatial trajectory function of the hydrogen nuclei of the hydrocarbon components.

[0104] Optionally, the first determining unit is further configured to:

[0105] The bond lengths and bond angles of the hydrogen nuclei of the hydrocarbon components are calculated based on the spatial trajectory function of the hydrogen nuclei of the hydrocarbon components.

[0106] Based on the spatial trajectory function, bond length, and bond angle of the hydrogen nuclei of the hydrocarbon component, the time correlation function of the hydrogen nuclei of the hydrocarbon component is calculated.

[0107] Optionally, the device further includes:

[0108] The adjustment module is used to adjust the parameters of the initial relaxation time calculation model based on the pre-collected sample relaxation time and sample correlation time to obtain the relaxation time calculation model.

[0109] The expression for the relaxation time calculation model includes:

[0110]

[0111] Where T2 is the transverse relaxation time, μ o Let be the permeability of vacuum, and γ be the gyromagnetic ratio of hydrogen protons. Let τ be Planck's constant. c For the correlation time, r is the pore radius; D is the diffusion coefficient; N s denoted as the number of hydrogen protons per unit volume; a and b are fitting parameters.

[0112] Optionally, the model building module 601 includes:

[0113] The acquisition unit is used to acquire shale oil information, which includes the mineral composition, clay type, kerogen type, and shale pore size distribution of the shale oil.

[0114] The model building unit is used to construct a model of the shale oil parent material with a mineral skeleton, kerogen, clay, nanopores, and hydrocarbon components based on the shale oil information.

[0115] Optionally, the device further includes:

[0116] The optimization module is used to perform geometric optimization of the shale oil parent material model through molecular dynamics simulation;

[0117] The verification module is used to verify the rationality of the shale oil parent material model based on density calculation, and obtain the verification result. The verification result is used to indicate the degree of approximation between the shale oil parent material model and actual shale oil.

[0118] The determining module 602 includes:

[0119] The third determining unit is used to determine the relevant time corresponding to the shale oil with the target carbon chain length by performing molecular dynamics simulation on the shale oil parent material model, provided that the verification result indicates the model is reasonable.

[0120] Example 5

[0121] Please refer to Figure 7 The diagram illustrates a structural schematic of a computer device provided in one embodiment of this application.

[0122] The computer device 700 in this application may include one or more of the following components: processor 710 and memory 720.

[0123] Processor 710 may include one or more processing cores. Processor 710 connects to various parts within the computer device 700 using various interfaces and lines, and performs various functions and processes data of the computer device 700 by running or executing instructions, programs, code sets, or instruction sets stored in memory 720, and by calling data stored in memory 720. Optionally, processor 710 may be implemented using at least one hardware form of Digital Signal Processing (DSP), Field-Programmable Gate Array (FPGA), or Programmable Logic Array (PLA). Processor 710 may integrate one or a combination of several of the following: Central Processing Unit (CPU), Graphics Processing Unit (GPU), and modem.

[0124] The memory 720 may include random access memory (RAM) or read-only memory (ROM). Optionally, the memory 720 may include a non-transitory computer-readable storage medium. The memory 720 may be used to store instructions, programs, code, code sets, or instruction sets. The memory 720 may include a program storage area and a data storage area, wherein the program storage area may store instructions for implementing an operating system, instructions for implementing at least one function (such as touch functionality, sound playback functionality, image playback functionality, etc.), instructions for implementing the various method embodiments described above, etc. The data storage area may also store data created by the computer device 700 during use.

[0125] In addition, those skilled in the art will understand that the structure of the computer device 700 shown in the above figures does not constitute a limitation on the computer device 700. The computer device may include more or fewer components than shown, or combine certain components, or have different component arrangements. For example, the computer device 700 also includes radio frequency circuits, audio circuits, Wi-Fi components, power supplies, Bluetooth components, etc., which will not be described in detail here.

[0126] This application also provides a computer-readable storage medium storing at least one instruction, which is loaded and executed by a processor to implement a method for determining the transverse relaxation time of different carbon chain lengths in shale oil as described in the above embodiments.

[0127] According to one aspect of this application, a computer program product or computer program is provided, comprising computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computer device to perform a method for determining the transverse relaxation time of different carbon chain lengths in shale oil, provided in various alternative implementations of the above aspect.

[0128] Those skilled in the art will recognize that the functions described in the embodiments of this application in one or more of the above examples can be implemented using hardware, software, firmware, or any combination thereof. When implemented using software, these functions can be stored in a computer-readable storage medium or transmitted as one or more instructions or code on a computer-readable storage medium. Computer-readable storage media include computer storage media and communication media, wherein communication media include any medium that facilitates the transmission of a computer program from one place to another. Storage media can be any available medium accessible to a general-purpose or special-purpose computer.

[0129] 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 transverse relaxation time of shale oil with different carbon chain lengths, characterized in that, The method includes: A shale oil parent material model with a target carbon chain length is constructed, which is used to characterize the shale structure and the composition of shale oil. By performing molecular dynamics simulations on the shale oil parent material model, the relevant time corresponding to the shale oil with the target carbon chain length is determined; The relevant time is input into the relaxation time calculation model to obtain the lateral relaxation time corresponding to the target carbon chain length of shale oil. The relaxation time calculation model is fitted with the conversion relationship between lateral relaxation time and relevant time. The step of determining the relevant time corresponding to the shale oil with the target carbon chain length by performing molecular dynamics simulations on the shale oil parent material model includes: By performing molecular dynamics simulations on the shale oil parent material model, the time correlation function of the hydrogen nuclei of hydrocarbon components in shale oil with the target carbon chain length was determined. By integrating the time correlation function, the correlation time corresponding to the shale oil with the target carbon chain length is obtained; Before inputting the relevant time into the relaxation time calculation model to obtain the lateral relaxation time corresponding to the shale oil with the target carbon chain length, the method further includes: Based on the pre-collected sample relaxation time and sample correlation time, the parameters of the initial relaxation time calculation model are adjusted to obtain the relaxation time calculation model. The expression for the relaxation time calculation model includes: in, For the lateral relaxation time, The magnetic permeability of vacuum. The gyromagnetic ratio of hydrogen protons. It is Planck's constant. The relevant time is r, where r is the pore radius. The diffusion coefficient is denoted as . denoted as the number of hydrogen protons per unit volume; a and b are fitting parameters.

2. The method according to claim 1, characterized in that, The step of determining the time correlation function of the hydrogen nuclei of hydrocarbon components in shale oil with the target carbon chain length by performing molecular dynamics simulations on the shale oil parent material model includes: The spatial trajectory function of the hydrogen nuclei of the hydrocarbon components was determined by performing molecular dynamics simulations on the shale oil parent material model. The time correlation function of the hydrogen nuclei of the hydrocarbon components is determined based on the spatial trajectory function of the hydrogen nuclei of the hydrocarbon components.

3. The method according to claim 2, characterized in that, The determination of the time correlation function of the hydrogen nucleus of the hydrocarbon component based on the spatial trajectory function of the hydrogen nucleus of the hydrocarbon component includes: The bond lengths and bond angles of the hydrogen nuclei of the hydrocarbon components are calculated based on the spatial trajectory function of the hydrogen nuclei of the hydrocarbon components. Based on the spatial trajectory function, bond length, and bond angle of the hydrogen nuclei of the hydrocarbon component, the time correlation function of the hydrogen nuclei of the hydrocarbon component is calculated.

4. The method according to any one of claims 1 to 2, characterized in that, The construction of the shale oil parent material model corresponding to the target hydrocarbon component includes: Obtain shale oil information, including the mineral composition, clay type, kerogen type, and shale pore size distribution of the shale oil; Based on the shale oil information, a shale oil parent material model with a mineral framework, kerogen, clay, nanopores, and hydrocarbon components is constructed.

5. The method according to any one of claims 1 to 2, characterized in that, Before determining the relevant time corresponding to the shale oil with the target carbon chain length by performing molecular dynamics simulations on the shale oil parent material model, the method further includes: The geometric optimization of the shale oil parent material model was performed using molecular dynamics simulations. The rationality of the shale oil parent material model is verified based on density calculation, and the verification results are used to indicate the degree of approximation between the shale oil parent material model and actual shale oil. The step of determining the relevant time corresponding to the shale oil with the target carbon chain length by performing molecular dynamics simulations on the shale oil parent material model includes: If the verification results indicate that the model is reasonable, the relevant time corresponding to the shale oil with the target carbon chain length is determined by performing molecular dynamics simulation on the shale oil parent material model.

6. An apparatus for determining the transverse relaxation time of shale oil with different carbon chain lengths, used in implementing the method for determining the transverse relaxation time of shale oil with different carbon chain lengths as described in any one of claims 1-5, characterized in that, The device includes: The model building module is used to build a shale oil parent material model with a target carbon chain length. The shale oil parent material model is used to characterize the shale structure and the composition of shale oil. The determination module is used to determine the relevant time corresponding to the shale oil with the target carbon chain length by performing molecular dynamics simulation on the shale oil parent material model; The acquisition module is used to input the relevant time into the relaxation time calculation model to obtain the lateral relaxation time corresponding to the target carbon chain length of shale oil. The relaxation time calculation model is fitted with a conversion relationship between lateral relaxation time and relevant time.

7. A computer device, characterized in that, The computer device includes a processor and a memory; the memory stores at least one instruction, at least one program, a code set, or an instruction set, wherein the at least one instruction, the at least one program, the code set, or the instruction set is loaded and executed by the processor to implement a method for determining the lateral relaxation time of different carbon chain lengths in shale oil as described in any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores at least one instruction, at least one program, code set, or instruction set, wherein the at least one instruction, at least one program, code set, or instruction set is loaded and executed by a processor to implement a method for determining the lateral relaxation time of different carbon chain lengths in shale oil as described in any one of claims 1 to 5.

9. A computer program product, characterized in that, The computer program product runs on the processor of a computer device, causing the computer device to perform a method for determining the lateral relaxation time of different carbon chain lengths in shale oil as described in any one of claims 1 to 5.

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