Method, system and terminal device for obtaining grit size of a sandstone

Abstract

This invention discloses a method, system, and terminal equipment for obtaining the grain size of sandstone and conglomerate. The method includes acquiring grain size experimental data from sandstone and conglomerate cores of different grain sizes; establishing sensitive logging curves for sandstone and conglomerate cores of different grain sizes based on the grain size experimental data; establishing a formula for calculating the sandstone and conglomerate content index based on the sensitive logging curves; establishing a formula for calculating the porosity index based on the sensitive logging curves; establishing a grain size index formula based on the sandstone and conglomerate content index formula and the porosity index formula; and establishing a grain size calculation formula based on the grain size index formula and the grain size experimental data. The grain size of sandstone and conglomerate of different grain sizes is obtained through the grain size calculation formula. This invention introduces the sandstone and conglomerate content index and the porosity index to establish a highly universal quantitative calculation model for sandstone and conglomerate grain size. Theoretically, this model better conforms to actual stratigraphic and petrophysical characteristics, has higher calculation accuracy and reliable theoretical basis, and is convenient, simple, versatile, and widely applicable.

Description

Technical Field

[0001] This invention belongs to the field of formation logging evaluation technology for sandstone and conglomerate oil and gas reservoirs, and relates to a method, system and terminal equipment for obtaining the grain size of sandstone and conglomerate. Background Technology

[0002] In conglomerate oil and gas exploration, rock grain size is a key parameter for determining reservoir lithology and evaluating reservoir effectiveness, and it is also closely related to parameters such as reservoir porosity and permeability. Therefore, accurate grain size calculation is particularly important in conglomerate well logging evaluation.

[0003] As oil and gas exploration deepens, complex formations such as sandstone and conglomerate are gradually becoming the focus of exploration. Compared with conventional clastic oil and gas reservoirs, sandstone and conglomerate reservoirs are characterized by diverse parent rock compositions, wide grain size distribution, and strong heterogeneity. Currently, researchers at home and abroad mostly use methods such as electro-imaging logging for gravel picking and conventional logging curve single-parameter or multi-parameter fitting methods to calculate the grain size of sandstone and conglomerate, which have achieved certain results in evaluating grain size. However, electro-imaging data cannot quantitatively characterize the grain size of sandstone or gravelly sandstone, and conventional logging curve single-parameter or multi-parameter fitting methods are only applicable to local areas. Different logging curves are required for calculations in different areas and at different stratigraphic levels, and the methods lack universality and generalizability. Therefore, it is necessary to establish a universal grain size calculation model for sandstone and conglomerate from a theoretical analysis perspective. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention provides a method, system and terminal equipment for obtaining the grain size of sandstone and conglomerate, thereby realizing the universality of the grain size calculation method for conglomerate reservoirs.

[0005] This invention is achieved through the following technical solution:

[0006] A method for obtaining the grain size of sandstone and conglomerate includes the following steps:

[0007] S1: Obtain grain size experimental data of sandstone and conglomerate cores with different grain sizes;

[0008] S2: Establish sensitive logging curves for sandstone and conglomerate cores of different grain sizes based on the grain size experimental data.

[0009] S3: Based on the sensitive logging curves, establish the formulas for calculating the gravel content index of the sand and conglomerate cores of different grain sizes and the formulas for calculating the porosity index of the sand and conglomerate cores of different grain sizes.

[0010] S4: Based on the gravel content index calculation formula and the porosity index calculation formula, establish the grain size index calculation formula for the gravel cores of different grain sizes.

[0011] S5: Based on the grain size index calculation formula and the grain size experimental data, establish a grain size calculation formula for sandstone and conglomerate cores of different grain sizes, and obtain the grain size of sandstone and conglomerate of different grain sizes through the grain size calculation formula.

[0012] Preferably, in step S1, the grain size experimental data of the sandstone and conglomerate cores of different grain sizes are obtained by experimentally analyzing the grain size of clastic rocks.

[0013] Preferably, in step S2, the sensitive logging curve is established based on the grain size experimental data of the sandstone cores of different grain sizes and the influence relationship between the resistivity, neutron porosity, density value and sonic transit time of the sandstone cores of different grain sizes.

[0014] Preferably, in step S3, based on the sensitive logging curves and the deep lateral logging and density logging values ​​of the sand and gravel cores with different grain sizes, a formula for calculating the sand and gravel content index is established, specifically as follows:

[0015] S = (LogRt) DEN ;

[0016] In the formula, S is the gravel content index of the sand and conglomerate cores of different grain sizes; Rt is the deep lateral logging value of the sand and conglomerate cores of different grain sizes; DEN is the density logging value of the sand and conglomerate cores of different grain sizes; and Log is the natural logarithm.

[0017] Preferably, in step S3, based on the sensitive logging curves and the neutron porosity and acoustic porosity of the sandstone cores with different grain sizes, a formula for calculating the porosity index is established, specifically as follows:

[0018]

[0019] In the formula, P i The porosity index is the porosity index of the sandstone and conglomerate cores with different grain sizes. The acoustic porosity of the sandstone and conglomerate cores with different grain sizes is given. The neutron porosity is the value of the sandstone and conglomerate cores with different grain sizes.

[0020] Preferably, in step S4, the particle size index calculation formula is as follows:

[0021]

[0022] In the formula, P s is the grain size index of the sandstone and conglomerate cores with different grain sizes.

[0023] Preferably, in step S5, the particle size calculation formula is as follows:

[0024]

[0025] In the formula, P si denoted as , where is the grain size of the sandstone and conglomerate with different grain sizes; a and b are constants.

[0026] A system for obtaining the grain size of sandstone and conglomerate includes:

[0027] Data acquisition unit: used to acquire grain size experimental data of sandstone and conglomerate cores with different grain sizes;

[0028] First processing unit: used to establish sensitive logging curves for sandstone and conglomerate cores of different grain sizes based on grain size experimental data;

[0029] The second processing unit is used to establish, based on the sensitive logging curves, the formulas for calculating the gravel content index of the sand and conglomerate cores of different grain sizes and the formulas for calculating the porosity index of the sand and conglomerate cores of different grain sizes.

[0030] The third processing unit is used to establish the grain size index calculation formula for the sand and gravel content index and the porosity index calculation formula.

[0031] The fourth processing unit is used to establish a grain size calculation formula for sandstone and conglomerate cores of different grain sizes based on the grain size index calculation formula and the grain size experimental data, and to obtain the grain size of sandstone and conglomerate of different grain sizes through the grain size calculation formula.

[0032] A terminal device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the method described above.

[0033] A computer-readable storage medium storing a computer program, characterized in that the computer program, when executed by a processor, implements the steps of the above-described method.

[0034] Compared with the prior art, the present invention has the following beneficial technical effects:

[0035] A method for obtaining the grain size of sandstone and conglomerate involves first selecting sandstone and conglomerate cores with different grain sizes to determine the grain size experimental data for these cores; then, using the grain size experimental data from the core samples of different grain sizes, determining sensitive logging curves reflecting grain size; using these sensitive logging curves, establishing formulas for calculating the sandstone content index and porosity index; next, based on the constructed formulas for calculating the sandstone content index and porosity index, constructing a grain size index formula; finally, combining the determined grain size experimental data to obtain the grain size calculation formula, ultimately yielding the grain size of sandstone and conglomerate with different grain sizes. This invention solves the difficulties of existing sandstone and conglomerate grain size calculation methods, which suffer from poor universality and limited applicability. By introducing the sandstone content index and porosity index, a highly universal quantitative calculation model for sandstone and conglomerate grain size is finally established. Theoretically, this model better conforms to actual stratigraphic and petrophysical characteristics, possesses higher calculation accuracy and reliable theoretical basis, and is convenient, simple, universal, and widely applicable. Attached Figure Description

[0036] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a flowchart of a method for obtaining the grain size of sandstone and conglomerate according to the present invention;

[0038] Figure 2 This is a schematic diagram of a system structure for obtaining the grain size of sandstone and conglomerate according to the present invention;

[0039] Figure 3 This is a graph showing the relationship between the particle size index constructed in Example 2 of the present invention and the particle size measured in the laboratory.

[0040] Figure 4 This is a graph showing the correlation between the calculated and analyzed grain size of sandstone and conglomerate in Example 2 of the present invention.

[0041] Figure 5 This is an application effect diagram of the present invention. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0043] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0044] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0045] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0046] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0047] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0048] The present invention will now be described in further detail with reference to the accompanying drawings:

[0049] Example 1

[0050] like Figure 1 As shown, a method for obtaining the grain size of sandstone and conglomerate includes the following steps:

[0051] S1: Obtain grain size experimental data of sandstone and conglomerate cores with different grain sizes;

[0052] Specifically, conglomerate cores with different grain sizes are selected, classified, and screened as core samples. Then, experiments are conducted on the core samples to determine their grain size data. The grain size data of the core samples in this step are obtained through clastic rock grain size analysis methods. The core samples include one or more of the following: conglomerate, medium conglomerate, small conglomerate, pebbly sandstone, coarse sandstone, fine sandstone, and siltstone.

[0053] S2: Based on the grain size experimental data of sandstone and conglomerate cores of different grain sizes, the response characteristics were analyzed on conventional logging curves to establish sensitive logging curves for sandstone and conglomerate cores of different grain sizes.

[0054] Specifically, based on the grain size experimental data of sandstone and conglomerate cores of different grain sizes and the influence of resistivity, neutron porosity, density value and sonic transit time of sandstone and conglomerate cores of different grain sizes, the correlation between grain size experimental data and conventional logging data is established, namely the sensitive logging curve.

[0055] S3: Based on the sensitive logging curves, establish the calculation formulas for the gravel content index and the porosity index of sandstone cores with different grain sizes.

[0056] Specifically, based on sensitive logging curves and resistivity logging values ​​(i.e., deep lateral logging values ​​and density logging values) of sandstone and conglomerate cores of different grain sizes, a formula for calculating the sandstone and conglomerate content index is established. The formula is as follows:

[0057] S = (LogRt) DEN ;

[0058] In the formula, S is the gravel content index of the sand and conglomerate cores of different grain sizes; Rt is the deep lateral logging value of the sand and conglomerate cores of different grain sizes; DEN is the density logging value of the sand and conglomerate cores of different grain sizes; and Log is the natural logarithm.

[0059] Based on sensitive logging curves and neutron logging values ​​from sandstone and conglomerate cores of different grain sizes, namely neutron porosity and sonic porosity, a formula for calculating the porosity index is established, specifically as follows:

[0060]

[0061] In the formula, P i The porosity index is the porosity index of the sandstone and conglomerate cores with different grain sizes. The acoustic porosity of the sandstone and conglomerate cores with different grain sizes is given. The neutron porosity is defined as the neutron porosity of the sandstone and conglomerate cores with different grain sizes. The sonic porosity is calculated using sonic logging data.

[0062] S4: Based on the formulas for calculating the gravel content index and porosity index, and combined with well logging theory, a formula for calculating the grain size index of sandstone and conglomerate cores with different grain sizes is established. The specific formula is as follows:

[0063]

[0064] In the formula, P s is the grain size index of the sandstone and conglomerate cores with different grain sizes.

[0065] S5: Based on the grain size index calculation formula and grain size experimental data, establish a grain size calculation formula for sandstone and conglomerate cores of different grain sizes, and obtain the grain size of sandstone and conglomerate of different grain sizes through the grain size calculation formula. The specific grain size formula is as follows:

[0066]

[0067] In the formula, P si denoted as , representing the grain size of sandstone and conglomerate of different sizes; a and b are constants.

[0068] The method in this invention first selects sandstone and conglomerate cores with different grain sizes, classifies and screens them as core samples, and then conducts experiments on the core samples to determine their grain size data. The response characteristics of the grain size experimental data of core samples with different grain sizes on conventional logging curves are analyzed to determine sensitive logging curves reflecting grain size. Using these sensitive logging curves, formulas for calculating the sandstone content index and porosity index are established. Based on these formulas and logging theory, a grain size index calculation formula is then constructed. Finally, combined with the experimentally determined rock grain size data, a linear fitting is performed to obtain the grain size calculation formula, ultimately yielding the grain size of sandstone and conglomerate with different grain sizes. This invention solves the problems of poor universality and limited applicability of existing sandstone and conglomerate grain size calculation methods. By introducing the sandstone content index and porosity index, a highly universal quantitative calculation model for sandstone and conglomerate grain size is established. Theoretically, this model better conforms to actual formation and rock physical characteristics, has higher calculation accuracy and reliable theoretical basis, is convenient and simple to calculate, highly universal, and widely applicable.

[0069] like Figure 2 As shown, the present invention also provides a system for obtaining the grain size of sandstone and conglomerate, comprising:

[0070] Data acquisition unit 100: used to acquire grain size experimental data of sandstone and conglomerate cores of different grain sizes; the acquired data is obtained by the user through experiments using experimental instruments.

[0071] First processing unit 200: used to establish sensitive logging curves for sandstone and conglomerate cores of different grain sizes based on the grain size experimental data of the sandstone and conglomerate cores of different grain sizes;

[0072] The second processing unit 300 is used to establish, based on the sensitive logging curves, the calculation formulas for the gravel content index of the sand and conglomerate cores of different grain sizes and the calculation formulas for the porosity index of the sand and conglomerate cores of different grain sizes.

[0073] The third processing unit 400 is used to establish a grain size index calculation formula for the sand and gravel content index and the porosity index calculation formula.

[0074] The fourth processing unit 500 is used to establish a grain size calculation formula for sandstone and conglomerate cores of different grain sizes based on the grain size index calculation formula and the grain size experimental data, and to obtain the grain size of sandstone and conglomerate of different grain sizes through the grain size calculation formula.

[0075] This invention provides a terminal device comprising: a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the method for obtaining the grain size of sandstone and conglomerate described above. Alternatively, when the processor executes the computer program, it implements the functions of each module / unit in the various device embodiments described above.

[0076] The computer program can be divided into one or more modules / units, which are stored in the memory and executed by the processor to complete the present invention.

[0077] The terminal device may be a desktop computer, laptop, handheld computer, or cloud server, etc. The terminal device may include, but is not limited to, a processor and a memory.

[0078] The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0079] The memory can be used to store the computer program and / or module. The processor implements various functions of the terminal device by running or executing the computer program and / or module stored in the memory and calling the data stored in the memory.

[0080] If the modules / units integrated in the terminal device are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments of the present invention can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the above-mentioned methods for establishing integrated three-dimensional well logging interpretation and evaluation charts. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content contained in the computer-readable medium may be appropriately added to or subtracted from the content as required by the legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium may not include electrical carrier signals and telecommunication signals.

[0081] Example 2

[0082] In this embodiment, a sandstone and conglomerate stratum from an oilfield block was selected as the target layer for study. The specific process for obtaining the grain size of the sandstone and conglomerate is as follows:

[0083] S1: Core and well logging data of the target formation were collected, and 28 representative sandstone and conglomerate core samples were selected based on these data. In this embodiment, the so-called representative core refers to sandstone and conglomerate samples whose lithology was determined based on conventional well logging, core description, and special well logging data, according to the lithology identification chart established in the area. Grain size experimental data were determined according to the clastic rock grain size analysis method. That is, based on the core and well logging data of the sandstone and conglomerate formation, sandstone and conglomerate core samples with different grain sizes were selected, and rock grain size analysis experiments were conducted to determine their grain size experimental data.

[0084] S2: Well logging response is a comprehensive reflection of lithology, porosity, pore structure, and fluid properties, and is particularly sensitive to lithology. Due to differences in parent rock composition, natural gamma ray logging in sandstone and conglomerate reservoirs has limitations in lithological classification. When the grain size of sandstone and conglomerate cores changes, various curve characteristics will change accordingly: larger grain sizes in sandstone and conglomerate cores lead to increased resistivity, increased density, decreased neutron porosity, and decreased sonic transit time. Therefore, resistivity, density, neutron, and sonic logging curves are identified as grain size-sensitive curves.

[0085] S3: Without considering the influence of reservoir fluids, the larger the grain size of sandstone and conglomerate, the higher the resistivity and density logging values. Simultaneously, to reduce the weight of electrical properties and increase the influence of density on grain size, a formula for calculating the sandstone and conglomerate content index of the selected core sample is constructed:

[0086] S = (LogRt) DEN

[0087] Rt is the deep lateral logging value, in Ω·m;

[0088] DEN is the density logging value, in g / cm³. 3 .

[0089] Furthermore, without considering the influence of reservoir fluids, the smaller the grain size of the sandstone and conglomerate, the larger the neutron logging value and sonic logging value. Therefore, a formula for calculating the porosity index P of the selected core sample is constructed. i :

[0090]

[0091] Acoustic porosity, in %;

[0092] Neutron porosity, in percentages.

[0093] S4: Based on the constructed formulas for calculating the gravel content index and porosity index, and combined with well logging theory, a higher gravel content index indicates a larger formation rock grain size, while a higher porosity index indicates a smaller formation rock grain size. Therefore, a grain size index calculation formula P is constructed. s :

[0094]

[0095] S5: Based on the constructed grain size index calculation formula and the experimentally determined rock grain size data, establish the grain size calculation formula P. si Using granular data from experimental analysis, the constant coefficients a and b in the formula are determined through linear fitting. This patent uses experimental data calibration as an example, such as... Figure 3 As shown in the figure, the slope and intercept of the linear equation for the linear fit are a and b, respectively, i.e., a = 22.73 and b = -1.5528. The final particle size calculation formula is:

[0096]

[0097] The grain size calculated by this method agrees well with the grain size analyzed from the core. Figure 4 As shown.

[0098] like Figure 5The figure shows the results of grain size calculation for sandstone and conglomerate. From left to right, the first line is the natural gamma curve, the second is the depth line, the third is the lithological profile, the fourth is the cored lithological profile, the fifth is the deep lateral resistivity curve, the sixth is the porosity curve, the seventh is the calculated grain size index curve, and the eighth is the calculated grain size curve (circular dots represent the analyzed grain size). The figure shows good consistency between the calculated and analyzed grain sizes, thus verifying the reliability of this method.

[0099] In summary, this invention discloses a method for calculating the grain size of sandstone and conglomerate based on conventional well logging. The method includes: selecting sandstone and conglomerate cores with different grain sizes, classifying and screening the cores as core samples; conducting experiments on the core samples to determine their grain size data; analyzing the response characteristics of the grain size experimental data of core samples with different grain sizes on conventional well logging curves to determine sensitive well logging curves reflecting grain size; using the obtained sensitive well logging curves, establishing formulas for calculating the sandstone content index and porosity index; further, following up on the constructed formulas for calculating the sandstone content index and porosity index, and combining them with well logging theory, constructing a grain size index calculation formula; and finally, combining the experimentally determined rock grain size data, linearly fitting to obtain the grain size calculation formula, ultimately obtaining the grain size of sandstone and conglomerate with different grain sizes. This invention, based on sandstone and conglomerate petrological experiments, utilizes conventional well logging data combined with theoretical knowledge to achieve quantitative grain size calculation, with good consistency with the grain size obtained from core analysis. This method overcomes the limitations of commonly used methods in calculating the grain size of sandstone and conglomerate, which lack universality and scalability. It has higher calculation accuracy and reliable theoretical basis, is convenient and simple to calculate, and can improve the accuracy of sandstone and conglomerate lithology discrimination.

[0100] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

[0101] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for obtaining the grain size of sandstone and conglomerate, characterized in that, Includes the following steps: S1: Obtain grain size experimental data of sandstone and conglomerate cores with different grain sizes; S2: Establish sensitive logging curves for sandstone and conglomerate cores of different grain sizes based on the grain size experimental data. S3: Based on the sensitive logging curves, establish the formulas for calculating the gravel content index of the sand and conglomerate cores of different grain sizes and the formulas for calculating the porosity index of the sand and conglomerate cores of different grain sizes. S4: Based on the gravel content index calculation formula and the porosity index calculation formula, establish the grain size index calculation formula for the gravel cores of different grain sizes. S5: Based on the grain size index calculation formula and the grain size experimental data, establish a grain size calculation formula for sandstone and conglomerate cores of different grain sizes, and obtain the grain size of sandstone and conglomerate of different grain sizes through the grain size calculation formula; In step S3, based on the sensitive logging curves and the deep lateral logging and density logging values ​​of the sand and gravel cores with different grain sizes, a formula for calculating the sand and gravel content index is established, specifically as follows: ； In the formula, The gravel content index is the gravel content index of the sandstone cores with different grain sizes. These are the deep lateral logging values ​​for the sandstone and conglomerate cores of different grain sizes; The density logging values ​​are for the sandstone and conglomerate cores of different grain sizes. It is the natural logarithm; In step S3, based on the sensitive logging curves and the neutron porosity and acoustic porosity of the sandstone and conglomerate cores of different grain sizes, the porosity index calculation formula is established, specifically as follows: ； In the formula, The porosity index is the porosity index of the sandstone and conglomerate cores with different grain sizes. The acoustic porosity of the sandstone and conglomerate cores with different grain sizes is given. The neutron porosity of the sandstone and conglomerate cores with different grain sizes; In step S4, the specific formula for calculating the particle size index is as follows: In the formula, The grain size index is the grain size index of the sandstone and conglomerate cores with different grain sizes. In step S5, the particle size calculation formula is as follows: In the formula, The grain size of the sandstone and conglomerate with different grain sizes; , It is a constant.

2. The method for obtaining the grain size of sandstone and conglomerate according to claim 1, characterized in that, In step S1, the grain size experimental data of the sandstone and conglomerate cores of different grain sizes are obtained by using the clastic rock grain size analysis method.

3. The method for obtaining the grain size of sandstone and conglomerate according to claim 1, characterized in that, In step S2, the sensitive logging curve is established based on the grain size experimental data of the sandstone cores of different grain sizes and the influence relationship of resistivity, neutron porosity, density value and sonic transit time of the sandstone cores of different grain sizes.

4. A system for obtaining the grain size of sandstone and conglomerate, characterized in that, A method for obtaining the grain size of sandstone or conglomerate according to any one of claims 1 to 3, comprising: Data acquisition unit: used to acquire grain size experimental data of sandstone and conglomerate cores with different grain sizes; First processing unit: used to establish sensitive logging curves for sandstone and conglomerate cores of different grain sizes based on grain size experimental data; The second processing unit is used to establish, based on the sensitive logging curves, the formulas for calculating the gravel content index of the sand and conglomerate cores of different grain sizes and the formulas for calculating the porosity index of the sand and conglomerate cores of different grain sizes. The third processing unit is used to establish the grain size index calculation formula for the sand and gravel content index and the porosity index calculation formula. The fourth processing unit is used to establish a grain size calculation formula for sandstone and conglomerate cores of different grain sizes based on the grain size index calculation formula and the grain size experimental data, and to obtain the grain size of sandstone and conglomerate of different grain sizes through the grain size calculation formula.

5. A terminal device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method as described in any one of claims 1 to 3.

6. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method as described in any one of claims 1 to 3.

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