Anisotropic rock physics modeling method and device

Abstract

This specification provides an anisotropic rock physics modeling method and device. The method includes: obtaining the volume fraction of each mineral in the target mineral layer and the pore content of the target pore type, wherein the target mineral layer includes at least one of the following: a clastic mineral layer and a carbonate mineral layer; determining the elastic stiffness matrix of the clastic mineral layer and the carbonate mineral layer according to the volume fraction and pore content of each mineral; determining the target elastic stiffness matrix according to the elastic stiffness matrix of the clastic mineral layer and the elastic stiffness matrix of the carbonate mineral layer; determining the anisotropy parameter of the core sample according to the target elastic stiffness matrix; determining the target mineral content and the target pore content, and determining the elastic anisotropy of the core sample according to the anisotropy parameter, the target mineral content, and the target pore content. Based on the above method, anisotropy can be determined more accurately, thereby improving the precision and accuracy of seismic imaging, well logging interpretation, and seismic quantitative prediction.

Description

Technical Field

[0001] This specification belongs to the technical field of oil and gas field exploration and development, and in particular relates to an anisotropic rock physics modeling method and device. Background Art

[0002] In recent years, shale oil and gas exploration has become a key area of ​​unconventional oil and gas exploration. Compared with conventional oil and gas reservoirs, shale reservoirs are more heterogeneous, have complex mineral compositions, and have diverse pore types, often exhibiting strong elastic anisotropy. To fully utilize seismic data in shale gas exploration, it is necessary to establish appropriate anisotropic rock physics models, which serve as a bridge connecting well logging data, reservoir parameters, and seismic attributes. However, existing rock physics modeling methods lack universal applicability and suffer from low modeling accuracy, resulting in low accuracy in seismic imaging, well logging interpretation, and seismic quantitative prediction.

[0003] To address the above issues, no effective solutions have been proposed so far. Summary of the Invention

[0004] This specification provides an anisotropic rock physics modeling method and device, which can effectively improve the accuracy of seismic imaging, well logging interpretation and earthquake quantitative prediction.

[0005] In one aspect, an embodiment of this specification provides an anisotropic rock physics modeling method, comprising:

[0006] Obtaining the volume fraction corresponding to each mineral in the target mineral layer of the core sample, and the pore content and pore aspect ratio corresponding to each pore type in the target pore type of the core sample, wherein the target mineral layer includes at least one of the following: a clastic mineral layer and a carbonate mineral layer;

[0007] Determining an equivalent anisotropic elastic stiffness matrix corresponding to the detrital mineral layer and an equivalent isotropic elastic stiffness matrix corresponding to the carbonate mineral layer according to the volume fraction corresponding to each mineral, the pore content and the pore aspect ratio;

[0008] determining an anisotropic target elastic stiffness matrix of the core sample according to the equivalent anisotropic elastic stiffness matrix of the clastic mineral layer and the equivalent isotropic elastic stiffness matrix of the carbonate mineral layer;

[0009] determining anisotropic parameters of the core sample according to the anisotropic target elastic stiffness matrix;

[0010] Performing a sensitivity analysis on the volume fraction of each mineral in the target mineral layer to obtain the target mineral content in the target mineral layer;

[0011] Performing a sensitivity analysis on the pore content in the target pore type to obtain a target pore content in the target pore type;

[0012] The elastic anisotropy of the core sample is determined according to the anisotropy parameter, the target mineral content, and the target pore content.

[0013] Furthermore, the target pore type includes at least one of the following: carbonate pores, clay pores, and horizontally oriented fractures. Accordingly, determining the equivalent anisotropic elastic stiffness matrix corresponding to the detrital mineral layer in the target mineral layer and the equivalent isotropic elastic stiffness matrix corresponding to the carbonate mineral layer in the target mineral layer according to the volume fraction corresponding to each mineral, the pore content, and the pore aspect ratio includes:

[0014] According to the volume fraction of each mineral in the detrital mineral layer, the pore content and pore aspect ratio of the clay pores, the equivalent anisotropic elastic stiffness matrix of the detrital mineral layer is determined;

[0015] According to the volume fraction of each mineral in the carbonate mineral layer, the pore content and pore aspect ratio of the carbonate pores, the equivalent isotropic elastic stiffness matrix of the carbonate mineral layer is determined.

[0016] Furthermore, before determining the equivalent anisotropic elastic stiffness matrix of the detrital mineral layer based on the volume fraction of each mineral in the detrital mineral layer, the pore content and pore aspect ratio corresponding to the clay pores, the method further includes:

[0017] Obtain the volume fraction, bulk modulus, and shear modulus of saturated oil and kerogen in core samples;

[0018] The saturated oil and kerogen are stored in carbonate pores and clay pores to form equivalent soft matter;

[0019] determining the bulk modulus and shear modulus of the equivalent soft matter according to the volume fraction, bulk modulus and shear modulus of the saturated oil and kerogen;

[0020] The elastic stiffness matrix of the equivalent soft matter is determined according to the bulk modulus and shear modulus of the equivalent soft matter.

[0021] Furthermore, the bulk modulus and shear modulus of the equivalent soft matter are determined according to the following formula:

[0022]

[0023]

[0024] Among them, K equ is the bulk modulus of the equivalent soft matter, G equis the shear modulus of the equivalent soft matter, f1 is the volume fraction of saturated oil, f2 is the volume fraction of kerogen, K1 is the bulk modulus of saturated oil, K2 is the bulk modulus of kerogen, G1 is the shear modulus of saturated oil, and G2 is the shear modulus of kerogen.

[0025] Furthermore, the elastic stiffness matrix of the equivalent soft matter is determined according to the following formula:

[0026]

[0027] Among them, C equ is the elastic stiffness matrix of the equivalent soft material, K equ and G equ are the bulk modulus and shear modulus of the equivalent soft matter, respectively.

[0028] Furthermore, based on the volume fraction of each mineral in the detrital mineral layer, the pore content and pore aspect ratio of the clay pores, the equivalent anisotropic elastic stiffness matrix of the detrital mineral layer is determined, including:

[0029] According to the pore aspect ratio corresponding to the clay pore, the fourth-order tensor controlling the spatial morphology of the inclusions corresponding to the clay pore is determined;

[0030] According to the fourth-order tensor controlling the spatial morphology of inclusions corresponding to the clay pores, the elastic stiffness matrix of the equivalent soft matter, the volume fraction of each mineral in the detrital mineral layer, and the pore content corresponding to the clay pores, the equivalent anisotropic elastic stiffness matrix of the detrital mineral layer is determined according to the following formula:

[0031]

[0032] Among them, C clastic is the equivalent anisotropic elastic stiffness matrix of the detrital mineral layer, v n is the volume fraction of n-phase minerals in the detrital mineral layer, C n is the elastic stiffness tensor of the n-phase mineral in the detrital mineral layer, I is the fourth-order unit tensor, is the fourth-order tensor that controls the spatial morphology of the inclusion, φ clay is the clay porosity, is the fourth-order tensor that controls the spatial morphology of inclusions corresponding to clay pores, C equ is the equivalent soft material elastic stiffness matrix.

[0033] Furthermore, according to the volume fraction of each mineral in the carbonate mineral layer, the pore content and pore aspect ratio of the carbonate pores, the equivalent isotropic elastic stiffness matrix of the carbonate mineral layer is determined, including:

[0034] According to the pore aspect ratio of the carbonate pore, the polarization factor corresponding to the carbonate pore is determined;

[0035] According to the polarization factor, the bulk modulus and shear modulus of the equivalent soft matter, the volume fraction of each mineral in the carbonate mineral layer, the pore content and pore aspect ratio corresponding to the carbonate pores, the equivalent bulk modulus and shear modulus are determined according to the following formula:

[0036]

[0037]

[0038] Among them, x i is the volume fraction of the i-th mineral in the carbonate mineral layer, K i is the bulk modulus of the i-th mineral in the carbonate mineral layer, G i is the shear modulus of the i-th mineral in the carbonate mineral layer, φ car is the carbonate pore content, K equ is the bulk modulus of the equivalent soft matter, G equ is the shear modulus of the equivalent soft matter, K car is the equivalent bulk modulus, G car is the equivalent shear modulus, P i and Q i is the polarization factor;

[0039] According to the equivalent bulk modulus and shear modulus, an equivalent isotropic elastic stiffness matrix of the carbonate mineral layer is determined.

[0040] Furthermore, the target mineral layer further includes a sulfate mineral layer. Accordingly, determining the anisotropic target elastic stiffness matrix of the core sample based on the equivalent anisotropic elastic stiffness matrix of the clastic mineral layer and the equivalent isotropic elastic stiffness matrix of the carbonate mineral layer includes:

[0041] Determine the equivalent isotropic elastic stiffness matrix of the sulfate mineral layer;

[0042] The equivalent elastic stiffness matrix of anisotropic layered rock is determined based on the equivalent anisotropic elastic stiffness matrix of clastic mineral layer, the equivalent isotropic elastic stiffness matrix of carbonate mineral layer and the equivalent isotropic elastic stiffness matrix of sulfate mineral layer.

[0043] According to the equivalent elastic stiffness matrix of anisotropic layered rock and Termas theory, the anisotropic target elastic stiffness matrix of the core sample is determined.

[0044] On the other hand, an embodiment of this specification further provides an anisotropic rock physics modeling device, comprising:

[0045] an acquisition module, configured to acquire the volume fraction corresponding to each mineral in a target mineral layer of a core sample, and the pore content and pore aspect ratio corresponding to each pore type in a target pore type of the core sample, wherein the target mineral layer includes at least one of the following: a clastic mineral layer and a carbonate mineral layer;

[0046] an elastic stiffness matrix determination module, for determining an equivalent anisotropic elastic stiffness matrix corresponding to the detrital mineral layer and an equivalent isotropic elastic stiffness matrix corresponding to the carbonate mineral layer according to the volume fraction corresponding to each mineral, the pore content and the pore aspect ratio;

[0047] a target elastic stiffness matrix determination module, configured to determine an anisotropic target elastic stiffness matrix of the core sample based on the equivalent anisotropic elastic stiffness matrix of the clastic mineral layer and the equivalent isotropic elastic stiffness matrix of the carbonate mineral layer;

[0048] The elastic anisotropy response module is used to determine the anisotropy parameters of the core sample based on the anisotropic target elastic stiffness matrix; perform sensitivity analysis on the volume fraction corresponding to each mineral in the target mineral layer to obtain the target mineral content in the target mineral layer; perform sensitivity analysis on the pore content in the target pore type to obtain the target pore content in the target pore type; and determine the elastic anisotropy of the core sample based on the anisotropy parameters, target mineral content, and target pore content.

[0049] On the other hand, the present application also provides a computer-readable storage medium having computer instructions stored thereon, and the computer-readable storage medium implements the above-mentioned anisotropic rock physics modeling method when executing the instructions.

[0050] This specification provides an anisotropic rock physics modeling method and device. First, the volume fraction corresponding to each mineral in the target mineral layer of the core sample, the pore content and pore aspect ratio corresponding to each pore type in the target pore type of the core sample are obtained, wherein the target mineral layer includes at least one of the following: a detrital mineral layer and a carbonate mineral layer; secondly, based on the volume fraction corresponding to each mineral, the pore content and pore aspect ratio, the equivalent anisotropic elastic stiffness matrix corresponding to the detrital mineral layer and the equivalent isotropic elastic stiffness matrix corresponding to the carbonate mineral layer are determined; further, based on the equivalent anisotropic elastic stiffness matrix of the detrital mineral layer, the equivalent isotropic elastic stiffness matrix of the carbonate mineral layer are determined. The anisotropic elastic stiffness matrix and the equivalent isotropic elastic stiffness matrix of the carbonate mineral layer are used to determine the anisotropic target elastic stiffness matrix of the core sample. Finally, the anisotropic parameters of the core sample are determined based on the anisotropic target elastic stiffness matrix. A sensitivity analysis is performed on the volume fractions of the minerals in the target mineral layer to obtain the target mineral content in the target mineral layer. A sensitivity analysis is performed on the pore content in the target pore type to obtain the target pore content in the target pore type. The elastic anisotropy of the core sample is determined based on the anisotropic parameters, target mineral content, and target pore content. The above scheme can improve the universality and modeling accuracy of rock physics modeling, thereby providing a basis for accurate seismic imaging, well logging interpretation, and seismic quantitative prediction. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the embodiments of this specification, the following is a brief introduction to the drawings required for use in the embodiments. The drawings described below are only some of the embodiments recorded in this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0052] Figure 1 is a flow chart of an anisotropic rock physics modeling method provided by an embodiment of this specification;

[0053] Figure 2 is a schematic diagram of an embodiment of an anisotropic rock physics modeling method provided by an embodiment of this specification, in a scenario example;

[0054] Figure 3 is a schematic diagram of an embodiment of an anisotropic rock physics modeling method provided by an embodiment of this specification, in a scenario example;

[0055] Figure 4 is a schematic diagram of an embodiment of an anisotropic rock physics modeling method provided by an embodiment of this specification, in a scenario example;

[0056] Figure 5Schematic diagram of the structure of an anisotropic rock physics modeling device provided in one embodiment of this specification;

[0057] Figure 6 This is a schematic diagram of the structure of an electronic device provided by an embodiment of this specification. DETAILED DESCRIPTION

[0058] To help those skilled in the art better understand the technical solutions in this specification, the following will provide a clear and complete description of the technical solutions in the embodiments of this specification, in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of this specification, not all of them. All other embodiments derived by those skilled in the art based on the embodiments in this specification without creative effort shall fall within the scope of protection of this specification.

[0059] In recent years, shale oil and gas exploration has become a key area of ​​unconventional oil and gas exploration. Compared with conventional oil and gas reservoirs, shale reservoirs are more heterogeneous, have complex mineral compositions, and have diverse pore types, often exhibiting strong elastic anisotropy. Anisotropic rock physics modeling can establish the relationship between the rock's mineral composition, microstructure, pore distribution, and fluid properties and the overall elastic response of the rock, clarifying the main factors controlling the elastic anisotropy of shale, and thus providing a basis for accurate seismic imaging, well logging interpretation, and seismic quantitative prediction.

[0060] Furthermore, while current rock physics experiments, modeling, and inversion research on shale have become increasingly in-depth, the modeling study areas are mostly limited to shale gas reservoirs in the Longmaxi and Wufeng Formations. Due to significant differences in the mineral composition, pore structure, and organic matter occurrence of shales in different regions, practical applications require tailored modeling schemes tailored to the geological characteristics of the study area to enhance the applicability and prediction accuracy of inversion. Furthermore, current modeling research struggles to determine appropriate model parameters for different reservoirs.

[0061] Based on the above ideas, this manual integrates digital core microstructure characterization and core test analysis, and proposes an anisotropic rock physics modeling method based on the geological background, petrological characteristics, pore structure characteristics and elastic anisotropy law of the study area. First, the volume fraction corresponding to each mineral in the target mineral layer of the core sample, the pore content and pore aspect ratio corresponding to each pore type in the target pore type of the core sample are obtained, wherein the target mineral layer includes at least one of the following: a detrital mineral layer and a carbonate mineral layer; secondly, according to the volume fraction corresponding to each mineral, the pore content and pore aspect ratio, the equivalent anisotropic elastic stiffness matrix corresponding to the detrital mineral layer in the target mineral layer and the equivalent anisotropic elastic stiffness matrix of the carbonate mineral in the target mineral layer are determined. The equivalent isotropic elastic stiffness matrix corresponding to the mineral layer is obtained; further, the anisotropic target elastic stiffness matrix of the core sample is determined based on the equivalent anisotropic elastic stiffness matrix of the clastic mineral layer and the equivalent isotropic elastic stiffness matrix of the carbonate mineral layer; finally, the anisotropic parameters of the core sample are determined based on the anisotropic target elastic stiffness matrix; a sensitivity analysis is performed on the volume fraction corresponding to each mineral in the target mineral layer to obtain the target mineral content in the target mineral layer; a sensitivity analysis is performed on the pore content in the target pore type to obtain the target pore content in the target pore type, and the elastic anisotropy of the core sample is determined based on the anisotropic parameters, target mineral content, and target pore content. Figure 1 As shown, the embodiment of this specification provides an anisotropic rock physics modeling method. In specific implementation, the method may include the following contents.

[0062] S101: Obtain the volume fraction corresponding to each mineral in the target mineral layer of the core sample, the pore content and pore aspect ratio corresponding to each pore type in the target pore type of the core sample, wherein the target mineral layer includes at least one of the following: a clastic mineral layer and a carbonate mineral layer.

[0063] In some embodiments, the core sample may be a sample obtained by drilling sampling. The target mineral layer includes at least one of the following: a clastic mineral layer, a carbonate mineral layer, and a sulfate mineral layer, wherein the clastic mineral layer is mainly composed of clay minerals, quartz, and feldspar, the carbonate mineral layer is mainly composed of dolomite and calcite, and the sulfate mineral layer is mainly composed of glauberite. The volume fraction corresponding to each of the above minerals is the content of each mineral. The target pore type includes at least one of the following: carbonate pores, clay pores, and horizontally oriented fractures (or horizontally oriented fractures), wherein the carbonate mineral-related pores may be referred to as carbonate pores, which are mainly hard pores, the clay mineral-related pores may be referred to as clay pores, which are mainly soft pores, and the horizontally oriented fractures may be relatively larger bedding fractures, extending up to millimeter lengths, which are mainly soft pores.

[0064] In some embodiments, the volume fraction or mineral content of each mineral in the target mineral layer of the core sample can be determined by X-ray diffraction (XRD) analysis. Specifically, the selected core sample can be subjected to X-ray diffraction and its diffraction pattern can be analyzed to obtain the mineral content of each mineral in each mineral layer of the core sample and the total mineral content of each type of mineral layer in each mineral layer. For example, for a detrital mineral layer mainly composed of clay minerals, quartz, and feldspar, the total volume fraction or total mineral content can be f clay ; The carbonate mineral layer mainly composed of dolomite and calcite can have a total volume fraction of f car ; The sulfate mineral layer mainly composed of calcium sulfate can be f sulphate The total volume fraction of each mineral layer satisfies the following formula:

[0065] f clay +f car +f sulphate =1 (1)

[0066] Among them, f clay is the total volume fraction of the clastic mineral layer, f car is the total volume fraction of the carbonate mineral layer, f sulphate is the total volume fraction of the sulfate mineral layer.

[0067] In some embodiments, the total pore content of the rock (total rock porosity) can be determined according to the pore content of the carbonate pores (carbonate pore content), the pore content of the clay pores (clay pore content), and the pore content of the horizontally oriented fractures (horizontally oriented fracture content) using the following formula:

[0068] φ matrix ×φ car +φ clay +φ f (2)

[0069] Among them, φ matrix is the total porosity of the rock, φ car is the carbonate pore content, φ clay is the clay pore content, φ f is the horizontal directional crack content.

[0070] It should be noted that at lower scales, carbonate-related non-oriented near-circular pores (carbonate pores) and oriented clay pores are dominant, and at higher scales, horizontal oriented cracks are dominant. Subsequent modeling processes are all based on this assumption. How to implement the modeling will be explained separately later and will not be repeated in this manual.

[0071] In some embodiments, the total pore content of the rock (φ matrix ) can be obtained by helium porosity measurement, and the horizontal directional crack content (φ f ) can be obtained by micron CT scanning (Computed Tomography, CT), and then by Otsu threshold segmentation. Finally, by performing Otsu threshold segmentation on the scanning electron microscope (SEM) image, the pore ratio F of carbonate pores and clay pores is calculated. car With F clay (Among them, F clay +F car =1), the carbonate pore content (φ) is determined according to the following formula car ) and clay pore content (φ clay ):

[0072]

[0073] Among them, φ matrix is the total porosity of the rock, φ f is the horizontal directional crack content, F car is the pore ratio of carbonate pores, F clay is the pore ratio of clay pores, φ car is the carbonate pore content, φ clay Clay pore content.

[0074] In some embodiments, the above-mentioned pore aspect ratio can be used as one of the parameters for quantitatively describing the pore shape, and its definition can be the ratio of the short axis to the long axis of the ellipsoidal pore. Rocks with complex pore structures can be approximately represented by a series of pore aspect ratios, namely, a pore aspect ratio spectrum. The sum of the porosities of components with different pore aspect ratio values ​​(pore aspect ratio spectrum) constitutes the total porosity of the rock. The above-mentioned pore aspect ratio can be determined as follows: the equivalent pore aspect ratio spectrum and the equivalent volume corresponding to each pore are calculated by the watershed algorithm and the ellipsoid approximation. The volumes corresponding to the equivalent pore aspect ratios are accumulated from low to high until they exceed half of the total pore volume, and the corresponding pore aspect ratio is used as the representative pore aspect ratio parameter α of the core. Rep , the discriminant formula is as follows:

[0075]

[0076] Among them, i is the value of each aspect ratio interval, α Rep is the representative pore aspect ratio parameter, Δα is the statistical aspect ratio interval, V total is the total pore space volume, V(α i ) is the total pore volume in each aspect ratio range.

[0077] It should be noted that the pore aspect ratio of large-scale cracks can be calculated for CT images. For SEM images, the carbonate-related pore aspect ratio can be calculated separately and clay-related pore aspect ratio

[0078] In the above embodiment, by determining the mineral content, pore type, pore content, and pore aspect ratio of each mineral in the core sample, a data foundation can be laid for subsequently accurately establishing an anisotropic rock physics model.

[0079] S102: Determine an equivalent anisotropic elastic stiffness matrix corresponding to the detrital mineral layer and an equivalent isotropic elastic stiffness matrix corresponding to the carbonate mineral layer according to the volume fraction corresponding to each mineral, the pore content and the pore aspect ratio.

[0080] In some embodiments, the target pore type includes at least one of the following: carbonate pores, clay pores, and horizontally oriented fractures. Accordingly, the determination of the equivalent anisotropic elastic stiffness matrix corresponding to the clastic mineral layer and the equivalent isotropic elastic stiffness matrix corresponding to the carbonate mineral layer based on the volume fraction corresponding to each mineral, the pore content, and the pore aspect ratio may include:

[0081] S1: Determine the equivalent anisotropic elastic stiffness matrix of the detrital mineral layer based on the volume fraction of each mineral in the detrital mineral layer, the pore content and pore aspect ratio of the clay pores;

[0082] S2: Determine the equivalent isotropic elastic stiffness matrix of the carbonate mineral layer based on the volume fraction of each mineral in the carbonate mineral layer, the pore content corresponding to the carbonate pores, and the pore aspect ratio.

[0083] In some embodiments, before determining the equivalent anisotropic elastic stiffness matrix of the detrital mineral layer based on the volume fractions of the individual minerals in the detrital mineral layer, the pore content and pore aspect ratio of the clay pores, the specific implementation may further include:

[0084] S1: Obtain the volume fraction, bulk modulus and shear modulus of saturated oil and kerogen in core samples;

[0085] S2: storing the saturated oil and kerogen in carbonate pores and clay pores to form equivalent soft matter;

[0086] S3: determining the bulk modulus and shear modulus of the equivalent soft matter according to the volume fraction, bulk modulus, and shear modulus of the saturated oil and kerogen;

[0087] S4: Determine an elastic stiffness matrix of the equivalent soft matter according to the bulk modulus and shear modulus of the equivalent soft matter.

[0088] In some embodiments, the kerogen content can be measured by performing combustion experiments on core samples to determine the total organic carbon (TOC) content. The measured TOC content is used as the kerogen content, i.e., the kerogen volume fraction. The kerogen distribution is closely related to various primary pores, including intragranular pores within clay grains, intercrystalline pores within dolomite, and intergranular pores. To describe this microscopic characteristic, this specification assumes that kerogen is mixed with saturated oil and co-exists within clay pores and carbonate pores as an equivalent soft matter.

[0089] In some embodiments, the bulk modulus and shear modulus of the equivalent soft matter are determined based on the volume fraction, bulk modulus, and shear modulus of the saturated oil and kerogen. In a specific implementation, the bulk modulus and shear modulus of the equivalent soft matter can be determined according to the following formula:

[0090]

[0091] Among them, K equ is the bulk modulus of the equivalent soft matter, G equ is the shear modulus of the equivalent soft matter, f1 is the volume fraction of saturated oil, f2 is the volume fraction of kerogen, K1 is the bulk modulus of saturated oil, K2 is the bulk modulus of kerogen, G1 is the shear modulus of saturated oil, and G2 is the shear modulus of kerogen.

[0092] It should be noted that the above-mentioned calculation formulas for the bulk modulus and shear modulus of equivalent soft matter are improved based on the traditional Voigt-reuss-hill (VRH) (a synthetic method) averaging, which can more accurately determine the bulk modulus and shear modulus of equivalent soft matter.

[0093] In some embodiments, the elastic stiffness matrix of the equivalent soft material is determined based on the bulk modulus and shear modulus of the equivalent soft material. In a specific implementation, the elastic stiffness matrix of the equivalent soft material can be determined according to the following formula:

[0094]

[0095] Among them, C equ is the elastic stiffness matrix of the equivalent soft material, K equ and G equ are the bulk modulus and shear modulus of the equivalent soft matter, respectively.

[0096] In some embodiments, the above-mentioned determination of the equivalent anisotropic elastic stiffness matrix of the detrital mineral layer based on the volume fraction corresponding to each mineral in the detrital mineral layer, the pore content corresponding to the clay pores, and the pore aspect ratio may include:

[0097] S1: According to the pore aspect ratio corresponding to the clay pore, the fourth-order tensor controlling the spatial morphology of the inclusions corresponding to the clay pore is determined;

[0098] S2: Based on the fourth-order tensor controlling the spatial morphology of inclusions corresponding to the clay pores, the elastic stiffness matrix of the equivalent soft matter, the volume fractions of the minerals in the detrital mineral layer, and the pore content corresponding to the clay pores, the equivalent anisotropic elastic stiffness matrix of the detrital mineral layer is determined according to the following formula:

[0099]

[0100] Among them, C clastic is the equivalent anisotropic elastic stiffness matrix of the detrital mineral layer, v n is the volume fraction of n-phase minerals in the detrital mineral layer, C n is the elastic stiffness tensor of the n-phase mineral in the detrital mineral layer, I is the fourth-order unit tensor, is the fourth-order tensor that controls the spatial morphology of the inclusion, φ clay is the clay porosity, is the fourth-order tensor that controls the spatial morphology of inclusions corresponding to clay pores, C equ is the equivalent soft material elastic stiffness matrix.

[0101] In some embodiments, the fourth-order tensor for controlling the spatial morphology of inclusions corresponding to the clay pores can be determined according to the following formula:

[0102]

[0103] in, is the fourth-order tensor of the spatial morphology of the inclusion, is a fourth-order tensor.

[0104] in, The specific form of the transversely isotropic medium (VTI medium) with a vertical symmetry axis can be:

[0105]

[0106] Where α is the inclusion aspect ratio (0 to 1), c 11 、c 12 、c 13 、c 33 、c 44is the elastic stiffness tensor parameter in Voigt notation.

[0107] In some embodiments, when computing The clay-related pore aspect ratio needs to be brought in when calculating the fourth-order tensor that controls the spatial morphology of inclusions corresponding to clay pores or the fourth-order Eshelby tensor corresponding to clay pores. Then combine it with the above formulas (8) and (9) to determine.

[0108] In some embodiments, before determining the equivalent anisotropic elastic stiffness matrix of the detrital mineral layer, the specific implementation may also include: obtaining the elastic stiffness tensor of each mineral in the detrital mineral layer. For example, the above-mentioned detrital layer may contain multiple minerals such as quartz, feldspar, pyrite and clay. The first three minerals are assumed to be isotropic, and the known mineral elastic parameters are referred to during the calculation. Clay mineral particles have typical hexagonal symmetry, so five independent elastic parameters are required to describe their elastic properties. The known experimental results can be used, assuming that the elastic stiffness tensor of pure clay minerals is C 11 =44.9GPa, C 33 =24.2GPa, C 44 =3.7GPa, C 66 =11.6GPa, C 13 = 18.1 GPa, assuming that the pores contained in clay minerals are primarily coin-shaped pores with small aspect ratios. The equivalent anisotropic (VTI) elastic stiffness matrix of the clastic layer can be obtained by combining quartz, feldspar, pyrite, clay, and clay-related pores (pores filled with equivalent soft matter) in a form without a major phase mineral using the anisotropic SCA model.

[0109] In some embodiments, determining the equivalent isotropic elastic stiffness matrix of the carbonate mineral layer based on the volume fraction of each mineral in the carbonate mineral layer and the pore content and pore aspect ratio of the carbonate pores may include:

[0110] S1: Determine the polarization factor corresponding to the carbonate pores based on the pore aspect ratio corresponding to the carbonate pores;

[0111] S2: Based on the polarization factor, the bulk modulus and shear modulus of the equivalent soft matter, the volume fraction of each mineral in the carbonate mineral layer, the pore content and pore aspect ratio of the carbonate pores, the equivalent bulk modulus and shear modulus are determined according to the following formula:

[0112]

[0113] Among them, x i is the volume fraction of the i-th mineral in the carbonate mineral layer, K iis the bulk modulus of the i-th mineral in the carbonate mineral layer, G i is the shear modulus of the i-th mineral in the carbonate mineral layer, φ car is the carbonate pore content, K equ is the bulk modulus of the equivalent soft matter, G equ is the shear modulus of the equivalent soft matter, K car is the equivalent bulk modulus, G car is the equivalent shear modulus, P i and Q i is the polarization factor.

[0114] S3: Determine an equivalent isotropic elastic stiffness matrix of the carbonate mineral layer according to the equivalent bulk modulus and shear modulus.

[0115] In some embodiments, the polarization factor corresponding to the carbonate pore is determined based on the pore aspect ratio corresponding to the carbonate pore. In specific implementation, it can be determined according to the following formula:

[0116]

[0117] Where α is the inclusion aspect ratio, and for the mineral phase, the aspect ratio is assumed to be 1, and P car and Q car is the carbonate-related pore polarization factor (polarization factor corresponding to carbonate pores). It should be noted that when calculating P car and Q car The carbonate-related pore aspect ratio needs to be included when

[0118] In some embodiments, the elastic stiffness matrix of the isotropic carbonate mineral layer is determined according to the equivalent bulk modulus and shear modulus. In specific implementation, the obtained K car and G car Substitute into formula (6), that is, substitute into the following formula, and the equivalent elastic stiffness matrix (C car ).

[0119]

[0120] It should be noted that the primary minerals in the aforementioned carbonate mineral layers include dolomite and calcite, and they develop a variety of primary and secondary pores (dolomite intercrystalline pores, intergranular pores, and dissolution pores). These pores are primarily ellipsoidal hard pores with high aspect ratios. Numerous studies on carbonate rock physics modeling have considered the crystal structure of carbonate minerals and the distribution of micro- and nanoscale pores within them, arguing that the primary factor contributing to their heterogeneity and anisotropy is the presence of unevenly distributed fracture-vuggy pores. Consequently, modeling of carbonate rock skeletons has often adhered to the isotropic assumption. The numerous submicron-scale micropores within intersalt shale carbonate layers exhibit a uniform distribution, high degree of non-directionality, and a nearly ellipsoidal pore structure, similar to the distribution patterns of background minerals such as dolomite and calcite. Therefore, they can be mixed using the isotropic SCA model, collectively representing a mineral layer with isotropic elastic properties.

[0121] S103: Determine an anisotropic target elastic stiffness matrix of the core sample according to the equivalent anisotropic elastic stiffness matrix of the clastic mineral layer and the equivalent isotropic elastic stiffness matrix of the carbonate mineral layer.

[0122] In some embodiments, the target mineral layer may further include a sulfate mineral layer. Accordingly, the anisotropic target elastic stiffness matrix of the core sample is determined based on the equivalent anisotropic elastic stiffness matrix of the clastic mineral layer and the equivalent isotropic elastic stiffness matrix of the carbonate mineral layer. In specific implementation, refer to Figure 2 As shown, this may include:

[0123] S1: Determine the equivalent isotropic elastic stiffness matrix of the sulfate mineral layer;

[0124] S2: Determine the equivalent elastic stiffness matrix of anisotropic layered rock based on the equivalent anisotropic elastic stiffness matrix of clastic mineral layer, the equivalent isotropic elastic stiffness matrix of carbonate mineral layer, and the equivalent isotropic elastic stiffness matrix of sulfate mineral layer;

[0125] S3: Determine the anisotropic target elastic stiffness matrix of the core sample based on the equivalent elastic stiffness matrix of the anisotropic layered rock and the Termas theory.

[0126] In some embodiments, the above-mentioned determination of the equivalent isotropic elastic stiffness matrix of the sulfate mineral layer can be determined in the following manner during specific implementation: a sulfate mineral layer composed entirely of glauberite minerals with almost no pores is also equivalent to an isotropic layer. Assuming that the mineral composition of the layer is relatively simple, the glauberite content can be obtained and the mineral layer can be established only through XRD analysis. Under the condition that the bulk modulus and shear modulus of glauberite are known, the elastic stiffness matrix (C) of the sulfate layer can be calculated in the same manner as formula (6):sulphate ).

[0127] In some embodiments, the equivalent elastic stiffness matrix of the anisotropic layered rock is determined based on the equivalent anisotropic elastic stiffness matrix of the clastic mineral layer, the equivalent isotropic elastic stiffness matrix of the carbonate mineral layer, and the equivalent isotropic elastic stiffness matrix of the sulfate mineral layer. In specific implementation, it can be carried out as follows: in order to describe the obvious mineral stratification phenomenon in the shale oil reservoir, under the assumption that the equivalent layer thickness is much smaller than the seismic wavelength, the anisotropic Backus average is used to collectively equate the anisotropic clastic layer, the isotropic carbonate layer, and the sulfate layer to a transversely isotropic medium (VTI). The equivalent anisotropic layered shale based on the Backus average is calculated by the following formula:

[0128]

[0129] Among them, C str is the equivalent elastic stiffness matrix of anisotropic layered shale, c 11 、c 12 、c 13 、c 33 、c 44 、c 66 is the elastic stiffness tensor parameter in Voigt notation.

[0130] Among them, C str The intrinsic elastic stiffness tensor parameters are calculated as:

[0131]

[0132] Among them, c 11 、c 12 、c 13 、c 33 、c 44 、c 66 is the elastic stiffness tensor parameter in Voigt notation, When i=1, 2, 3, they represent the clastic mineral layer (C clastic ), carbonate mineral layer (C car ), sulfate mineral layer (C sulphate )The non-zero components of the elastic stiffness matrix, v i is the total volume fraction of the target mineral layer and the pores inside each mineral layer in the target mineral layer.

[0133] It should be noted that, unlike conventional Backus averaging, this application obtains the pore content and equivalent soft matter of the target pore type (carbonate pores, clay pores, horizontal oriented fractures), and can determine the total volume fraction of each mineral layer (including internal pores) according to the following formula:

[0134]

[0135] Among them, v1, v2, and v3 represent the total volume fraction of detrital minerals and the pores inside detrital minerals, the total volume fraction of carbonate minerals and the pores inside carbonate minerals, and the total volume fraction of sulfate minerals and the pores inside sulfate minerals, respectively. clay is the total volume fraction of the clastic mineral layer, f car is the total volume fraction of the carbonate mineral layer, f sulphate is the total volume fraction of the sulfate mineral layer, φ clay is the clay pore content, φ car is the carbonate pore content, φ matrix is the total porosity of the rock.

[0136] In some embodiments, the above-mentioned anisotropic target elastic stiffness matrix of the core sample is determined based on the equivalent elastic stiffness matrix of the anisotropic layered rock and the T-matrix theory. In specific implementation, it can be determined in the following way: based on the T-matrix theory (T-matrix theory), the spatial distribution of inclusions is clearly defined, so that the elastic interaction between inclusions can be considered. Under the same porosity and pore structure settings, by changing the spatial distribution assumption of the inclusion family, the T-matrix theory can be consistent with the prediction results of the Hudson, SCA, and DEM models respectively. Therefore, the T-matrix theory is selected to add the horizontal directional fracture content, and the parameter α is used to adjust the horizontal directional fracture content. d Describing the crack distribution makes the model more applicable in the actual work area.

[0137] Among them, the T-matrix equivalent theory can be: Now assume that in a homogeneous anisotropic medium (C str ) contains a single inclusion family, the inclusions in the family have exactly the same shape and uniform spatial distribution, and the volume fraction of the inclusion family is φ f (crack content determined by CT images), aspect ratio is (equivalent crack aspect ratio determined by CT images), the equivalent stiffness of the medium is calculated by the following formula:

[0138]

[0139] in, is the fourth-order unit tensor, C str is the equivalent elastic stiffness matrix of anisotropic layered rock, <t1>is the first-order scattering correction of the elastic field, and X is the second-order scattering correction.

[0140] in, <t1>、X specific form is:

[0141] <t1>=φ f t (r) (16)

[0142]

[0143] t (r) =ΔC (r) (IG (r) ΔC (r) ) -1 (18)

[0144] ΔC (r) =C (r) -C (0) (19)

[0145] Among them, t (r) is the volume fraction of r-group inclusions, G (r) The fourth-order Eshelby tensor representing the family of inclusions, C (r) is the fourth-order Eshelby tensor of the r-th family inclusion, represents the interaction between inclusion groups, C (0) is the elastic stiffness tensor.

[0146] It should be noted that G (r) and The calculation method of the two is the same as that in formula (7) Consistent, but in calculation The inclusion aspect ratio in formula (9) is The spatial distribution aspect ratio α of the inclusion family needs to be changed d Currently, for a single family of inclusions, it is only necessary to change the spatial distribution aspect ratio α d Set to 1.

[0147] The anisotropic target elastic stiffness matrix of the core sample is obtained by the above method It should be noted that the anisotropic target elastic stiffness matrix of the core sample is similar to the VTI medium elastic stiffness matrix in formula 12.

[0148] By considering the heterogeneity, mineral composition, pore type diversity and elastic anisotropy of shale reservoirs, the anisotropic elastic stiffness matrix of rocks can be established more accurately, thus laying the foundation for anisotropic analysis of logging data and evaluation of mechanical properties.

[0149] S104: Determine anisotropic parameters of the core sample according to the anisotropic target elastic stiffness matrix.

[0150] S105: Perform sensitivity analysis on the volume fraction corresponding to each mineral in the target mineral layer to obtain the target mineral content in the target mineral layer.

[0151] S106: Performing a sensitivity analysis on the pore content in the target pore type to obtain a target pore content in the target pore type.

[0152] S107: Determine the elastic anisotropy of the core sample according to the anisotropy parameter, target mineral content, and target pore content.

[0153] In some embodiments, the anisotropic parameters of the core sample may include parameters ε and γ, which can be used to describe longitudinal wave anisotropy and shear wave anisotropy, respectively. The anisotropic parameters, longitudinal wave velocity, and shear wave velocity of the core sample can be determined according to the following formula:

[0154]

[0155] Among them, ε is the longitudinal wave anisotropy parameter, γ is the transverse wave anisotropy parameter, V p is the longitudinal wave velocity, V SH is the shear wave velocity.

[0156] In some embodiments, a sensitivity analysis can be performed on the volume fractions corresponding to each mineral in the target mineral layer to determine the target mineral content in the target mineral layer. For example, a sensitivity analysis can determine that the clay content in the detrital mineral layer has the greatest impact on the anisotropy of the rock. Therefore, the clay content can be used as one of the sensitive parameters, i.e., the target mineral content. A sensitivity analysis can be performed on the pore content within the target pore type to determine the target pore content within the target pore type. For example, a sensitivity analysis can determine that the fracture content within horizontally oriented fractures is the primary factor affecting the elastic anisotropy of the rock. Therefore, the fracture content can be used as one of the sensitive parameters, i.e., the target pore content. The determined target mineral content and target pore content can then be combined with the anisotropy parameters, P-wave velocity, and S-wave velocity determined above to determine the overall elastic anisotropy of the rock. For example, when the clay content and fracture content increase, the changes in P-wave velocity and S-wave velocity and the changes in the anisotropy parameters can be determined. By analyzing these parameter changes, the elastic response can be determined.

[0157] In some embodiments, after determining the elastic anisotropy of the core sample, the specific implementation may further include:

[0158] S1: Perform logging analysis based on the elastic anisotropy of the core sample to obtain analysis results;

[0159] S3: Guiding oil and gas exploration based on the analysis results.

[0160] The above method is described below in conjunction with a specific embodiment. However, it should be noted that this specific embodiment is only for better illustrating the present application and does not constitute an improper limitation to the present application.

[0161] In specific implementation, first, the volume fraction corresponding to each mineral in the target mineral layer of the core sample, the pore content and pore aspect ratio corresponding to each pore type in the target pore type of the core sample are obtained, wherein the target mineral layer includes at least one of the following: a clastic mineral layer and a carbonate mineral layer; secondly, the volume fraction, bulk modulus and shear modulus of saturated oil and kerogen in the core sample are obtained; the oil and kerogen are placed in carbonate pores and clay pores to form equivalent soft matter; based on the volume fraction, bulk modulus and shear modulus of the saturated oil and kerogen, the bulk modulus and shear modulus of the equivalent soft matter are determined. Shear modulus; Based on the bulk modulus and shear modulus of the equivalent soft matter, the elastic stiffness matrix of the equivalent soft matter is determined; further, based on the volume fractions of the minerals, the pore content, and the pore aspect ratio, the equivalent anisotropic elastic stiffness matrix corresponding to the detrital mineral layer in the target mineral layer and the equivalent isotropic elastic stiffness matrix corresponding to the carbonate mineral layer in the target mineral layer are determined. Then, based on the equivalent anisotropic elastic stiffness matrix of the detrital mineral layer and the equivalent isotropic elastic stiffness matrix of the carbonate mineral layer, the anisotropic target elastic stiffness matrix of the core sample is determined. Finally, based on the anisotropic target elastic stiffness matrix, the anisotropic parameters of the core sample are determined. A sensitivity analysis is performed on the volume fractions of the minerals in the target mineral layer to obtain the target mineral content in the target mineral layer. A sensitivity analysis is performed on the pore content in the target pore type to obtain the target pore content in the target pore type. The elastic anisotropy of the core sample is determined based on the anisotropic parameters, target mineral content, and target pore content. The above method can more accurately and comprehensively establish anisotropic rock physics models, thereby effectively improving the accuracy of seismic imaging, well logging interpretation and seismic quantitative prediction.

[0162] In a specific scenario example, the anisotropic rock physics modeling method provided in the embodiments of this specification can be applied to provide a basis for anisotropic analysis and mechanical property evaluation of well logging data. The specific implementation steps are as follows.

[0163] Step 1: Porosity and mineral composition information of a large number of core samples can be obtained through porosity measurement and XRD mineral analysis. Micron CT scanning and SEM scanning can obtain a two-dimensional grayscale slice sequence and a two-dimensional image of the sample surface.

[0164] Step 2: ① First, for CT scan images, after correcting image artifacts, the matrix and pore space of the sample are segmented using the adaptive Otsu method. According to the CT scan results, it can be found that the pore types of the samples are diverse and the pore sizes vary greatly at the medium and high scales. Micropores are abundantly developed, and micron-sized pores with layered and oriented arrangements are observed in some samples. Larger pores are mainly continuous horizontal fractures, extending up to the millimeter level. The pore aspect ratio is generally low (mainly soft pores), and the presence of fractures is often considered to be the main controlling factor affecting rock anisotropy. ② For SEM scan images, the pore space can be extracted using the adaptive Otsu method. Further, the pore aspect ratio spectrum can be statistically obtained through watershed transformation and ellipsoid approximation. Studies have shown that the microscopic pore types of the Qianjiang Formation shale are mainly intergranular pores and dissolution pores related to carbonate minerals, and intragranular pores related to clay minerals. Intergranular pores and dissolution pores have large aspect ratios, primarily ranging from 0.2 to 0.8 (dominated by hard pores), while clay pores have aspect ratios below 0.2 (dominated by soft pores). Influenced by the shale's depositional environment, clay minerals and their intragranular pores exhibit a distinctly oriented arrangement, while carbonate-related pores are more uniformly distributed and lack apparent orientation. Furthermore, because the organic matter in the Qianjiang Formation shale is mostly immature or low-mature, the content of organic pores is relatively low.

[0165] In summary, combining the types and characteristics of pores at different scales, the pores of the Qianjiang Formation shale can be simplified by scale and distribution into: carbonate-related pores, primarily hard pores; clay-related pores, primarily soft pores; and relatively larger bedding fractures, primarily soft pores. Using the pore structure parameters and pore content calculated in Step 2, combined with the modeling process proposed in this manual, we will consider the impact of these three types of pores on the overall elastic properties of the shale.

[0166] Step 3: Count the various types of pores in the sample as in step 2. Apply the calculation process of steps 2 and 3 to determine the content of various pore types in the model and the initial aspect ratio (see Table 1). Referring to the XRD statistical results, the initial mineral composition of the model was set by taking the mean value of the core mineral content (see Table 2).

[0167] Table 1 Contents of three types of pores and their aspect ratios

[0168]

[0169] Table 2 Model initial component settings

[0170]

[0171] The equivalent soft matter composed of kerogen and oil is calculated according to formula (5) and formula (6).

[0172] Step 5: Calculate the elastic stiffness matrix of the VTI clastic layer composed of quartz, feldspar, pyrite, clay, and clay pores using the anisotropic SCA model according to formulas (7)(8)(9).

[0173] Step 6: Calculate the elastic stiffness matrix of the isotropic carbonate layer composed of dolomite, calcite, and carbonate pores using the isotropic SCA model according to formulas (10) and (11).

[0174] Step 7: Set the elastic stiffness matrix of the sulfate layer according to the XRD statistical results (Table 2) and the elastic modulus of pure glauberite mineral.

[0175] Step 8: According to the mineral components set in Table 2 and the elastic stiffness matrix of the single mineral layer obtained from steps 5 to 7, apply formulas (12) and (13) to calculate the equivalent elastic stiffness matrix of the anisotropic layered shale model.

[0176] Step 9: Calculate the overall elastic stiffness matrix of the rock after adding cracks using the T-matrix theory according to formulas (15) to (19).

[0177] Step 10: According to the above steps, through sensitive parameter analysis, determine the sensitivity parameters, such as: determine the crack content and clay content, and then establish anisotropic rock physics parameters based on the determined sensitivity parameters. By changing the two parameters that are more sensitive to anisotropy, the crack content and clay content, the following results are obtained: Figure 3 (a, b, c) shows the quantity version, Figure 3 (a, b, c) represent the effects of clay content and horizontal crack content (the most important pore type among target pore types) in the minerals of the clastic layer on the overall rock mass. Figure 3 (d, e, f) represent the influence of feldspar, quartz (clastic layer minerals) and clay on the rock as a whole. Figure 3 (g, h, i) represent the influence of clay and carbonate minerals on the rock as a whole. Figure 3 (a, d, g) reflects the effect of changing the content of various stratified minerals and cracks on the overall P-wave velocity ratio and P-wave impedance of the rock. Figure 3 (b, e, h) represent the effects of various stratified mineral contents and cracks on the P-wave anisotropy parameter ε. Figure 3 (c, f, i) represents the influence of various stratified mineral contents and cracks on the longitudinal wave anisotropy parameter γ. Figure 3 The vertical coordinate of (b, e, h) is the longitudinal wave anisotropy parameter ε, Figure 3 The vertical coordinate of (c, f, i) is the shear wave anisotropy parameter γ. It should be noted that the sulfate minerals in the sulfate mineral layer have a very similar effect on the overall rock as the carbonate minerals. If a graph is plotted, the pattern shown in subgraph ghi is almost identical.

[0178] Step 11: Use the velocity, density, porosity and mineral composition measured by the core to verify the anisotropic rock physical quantity plate constructed by the present invention. The results are as follows: Figure 4 shown.

[0179] By applying the embodiments of the present invention, and through the intersection analysis of the Thomsen parameters ε and γ, we found that the anisotropic response of the model is consistent with expectations. Both P- and S-wave anisotropy increase with increasing clay mineral content and fracture porosity, while both P- and S-wave anisotropy significantly decreases as the content of carbonate minerals or silicate minerals such as quartz and feldspar gradually increases. The model's calculation results are also consistent with the characteristic analysis results of the Qianjiang Formation shale in the previous chapter. With increasing clay mineral content and fracture porosity, the anisotropy caused by clay orientation and the presence of horizontal bedding fractures gradually increases. Silicate minerals, as detrital minerals co-deposited with clay minerals, directly affect the distribution of clay. Therefore, especially in the case of high clay content, the increase in silicate minerals significantly reduces the anisotropy of P- and S-waves. Carbonate minerals, as isotropic layers, also weaken the anisotropy of the entire rock in the equivalent mineral stratification.

[0180] Through the introduction of the above embodiments and scenario examples, it can be seen that the above method establishes various anisotropic rock physics models and quantitative plates. The quantitative plates can quantify the elastic anisotropy of Qianjiang Formation shale and the influence of various minerals and various types of pores on the overall elastic properties of the rock, which can provide a basis for anisotropy analysis and mechanical property evaluation of logging data.

[0181] Although this specification provides examples such as the following examples or the accompanying Figure 5 The method operation steps or device structure shown are conventional or without creative labor, but the method or device may include more or fewer operation steps or module units after partial merger. In the steps or structures where there is no necessary causal relationship logically, the execution order of these steps or the module structure of the device is not limited to the execution order or module structure shown in the embodiments or drawings of this specification. When the method or module structure is applied to an actual device, server or terminal product, it can be executed sequentially or in parallel according to the method or module structure shown in the embodiments or drawings (for example, in an environment of parallel processors or multi-threaded processing, or even in an implementation environment of distributed processing and server clusters).

[0182] Based on the above anisotropic rock physics modeling method, this specification also proposes an embodiment of an anisotropic rock physics modeling device. Figure 5 As shown, the device-based system may specifically include the following modules:

[0183] An acquisition module 501 is configured to acquire the volume fraction of each mineral in a target mineral layer of a core sample, and the pore content and pore aspect ratio of each pore type in a target pore type of the core sample, wherein the target mineral layer includes at least one of the following: a clastic mineral layer and a carbonate mineral layer;

[0184] An elastic stiffness matrix determination module 502 is configured to determine an equivalent anisotropic elastic stiffness matrix corresponding to the detrital mineral layer and an equivalent isotropic elastic stiffness matrix corresponding to the carbonate mineral layer based on the volume fraction, pore content, and pore aspect ratio of each mineral.

[0185] A target elastic stiffness matrix determination module 503 is configured to determine an anisotropic target elastic stiffness matrix of the core sample based on the equivalent anisotropic elastic stiffness matrix of the clastic mineral layer and the equivalent isotropic elastic stiffness matrix of the carbonate mineral layer;

[0186] The elastic anisotropy response module 504 is used to determine the anisotropy parameters of the core sample based on the anisotropic target elastic stiffness matrix; perform a sensitivity analysis on the volume fraction corresponding to each mineral in the target mineral layer to obtain the target mineral content in the target mineral layer; perform a sensitivity analysis on the pore content in the target pore type to obtain the target pore content in the target pore type; and determine the elastic anisotropy of the core sample based on the anisotropy parameters, target mineral content, and target pore content.

[0187] In some embodiments, the above-mentioned elastic stiffness matrix determination module 502 can be used to: determine the equivalent anisotropic elastic stiffness matrix of the detrital mineral layer based on the volume fraction corresponding to each mineral in the detrital mineral layer, the pore content and pore aspect ratio corresponding to the clay pores; determine the equivalent isotropic elastic stiffness matrix of the carbonate mineral layer based on the volume fraction corresponding to each mineral in the carbonate mineral layer, the pore content and pore aspect ratio corresponding to the carbonate pores.

[0188] In some embodiments, the elastic stiffness matrix determination module 502 can be specifically implemented to: obtain the volume fraction, bulk modulus and shear modulus of saturated oil and kerogen in the core sample; place the saturated oil and kerogen in carbonate pores and clay pores to form equivalent soft matter; determine the bulk modulus and shear modulus of the equivalent soft matter based on the volume fraction, bulk modulus and shear modulus of the saturated oil and kerogen; and determine the elastic stiffness matrix of the equivalent soft matter based on the bulk modulus and shear modulus of the equivalent soft matter.

[0189] In some embodiments, the elastic stiffness matrix determination module 502 may be used to determine the bulk modulus and shear modulus of the equivalent soft material according to the following formula:

[0190]

[0191]

[0192] Among them, K equ is the bulk modulus of the equivalent soft matter, G equ is the shear modulus of the equivalent soft matter, f1 is the volume fraction of saturated oil, f2 is the volume fraction of kerogen, K1 is the bulk modulus of saturated oil, K2 is the bulk modulus of kerogen, G1 is the shear modulus of saturated oil, and G2 is the shear modulus of kerogen.

[0193] The elastic stiffness matrix of the equivalent soft material is determined according to the following formula:

[0194]

[0195] Among them, C epu is the elastic stiffness matrix of the equivalent soft material, K equ and G equ are the bulk modulus and shear modulus of the equivalent soft matter, respectively.

[0196] In some embodiments, the elastic stiffness matrix determination module 502 may be specifically implemented to: determine the fourth-order tensor corresponding to the clay pores that controls the spatial morphology of the inclusions based on the pore aspect ratio corresponding to the clay pores; and determine the equivalent anisotropic elastic stiffness matrix of the detrital mineral layer based on the fourth-order tensor corresponding to the clay pores that controls the spatial morphology of the inclusions, the elastic stiffness matrix of the equivalent soft matter, the volume fraction of each mineral in the detrital mineral layer, and the pore content corresponding to the clay pores according to the following formula:

[0197]

[0198] Among them, C clastic is the equivalent anisotropic elastic stiffness matrix of the detrital mineral layer, v n is the volume fraction of n-phase minerals in the detrital mineral layer, C n is the elastic stiffness tensor of the n-phase mineral in the detrital mineral layer, I is the fourth-order unit tensor, is the fourth-order tensor that controls the spatial morphology of the inclusion, φ clay is the clay porosity, is the fourth-order tensor that controls the spatial morphology of inclusions corresponding to clay pores, C equ is the equivalent soft material elastic stiffness matrix.

[0199] In some embodiments, the elastic stiffness matrix determination module 502 may be specifically implemented to: determine the polarization factor corresponding to the carbonate pore according to the pore aspect ratio corresponding to the carbonate pore;

[0200] According to the polarization factor, the bulk modulus and shear modulus of the equivalent soft matter, the volume fraction of each mineral in the carbonate mineral layer, the pore content and pore aspect ratio corresponding to the carbonate pores, the equivalent bulk modulus and shear modulus are determined according to the following formula:

[0201]

[0202]

[0203] Among them, x i is the volume fraction of the i-th mineral in the carbonate mineral layer, K i is the bulk modulus of the i-th mineral in the carbonate mineral layer, G i is the shear modulus of the i-th mineral in the carbonate mineral layer, φ car is the carbonate pore content, K equ is the bulk modulus of the equivalent soft matter, G equ is the shear modulus of the equivalent soft matter, K car is the equivalent bulk modulus, G car is the equivalent shear modulus, P i and Q i is the polarization factor;

[0204] The elastic stiffness matrix of the isotropic carbonate mineral layer is determined according to the equivalent bulk modulus and shear modulus.

[0205] In some embodiments, the above-mentioned target elastic stiffness matrix determination module 503 can be used for: determining the equivalent isotropic elastic stiffness matrix of the sulfate mineral layer; determining the equivalent elastic stiffness matrix of the anisotropic layered rock based on the equivalent anisotropic elastic stiffness matrix of the clastic mineral layer, the equivalent isotropic elastic stiffness matrix of the carbonate mineral layer, and the equivalent isotropic elastic stiffness matrix of the sulfate mineral layer; determining the anisotropic target elastic stiffness matrix of the core sample based on the equivalent elastic stiffness matrix of the anisotropic layered rock and the Termas theory.

[0206] It should be noted that the units, devices or modules described in the above embodiments can be implemented by computer chips or entities, or by products with certain functions. For the convenience of description, the above devices are described in terms of functions and are divided into various modules and described separately. Of course, when implementing this specification, the functions of each module can be implemented in the same or multiple software and / or hardware, or the module that implements the same function can be implemented by a combination of multiple sub-modules or sub-units. The device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0207] As can be seen from the above, the anisotropic rock physics modeling device provided in the embodiments of this specification takes into account the relationship between the mineral composition, microstructure, pore distribution and fluid properties of the rock and the overall elastic response of the rock, clarifies the main controlling factors of the anisotropic elastic response of shale, and can provide a basis for accurate seismic imaging, well logging interpretation and quantitative earthquake prediction.

[0208] The embodiment of this specification also provides an electronic device, including a processor and a memory for storing instructions executable by the processor. When the processor is specifically implemented, it can perform the following steps according to the instructions: obtain the volume fraction corresponding to each mineral in the target mineral layer of the core sample, the pore content and pore aspect ratio corresponding to each pore type in the target pore type of the core sample, wherein the target mineral layer includes at least one of the following: a detrital mineral layer and a carbonate mineral layer; according to the volume fraction corresponding to each mineral, the pore content and the pore aspect ratio, determine the equivalent anisotropic elastic stiffness matrix corresponding to the detrital mineral layer and the equivalent isotropic elastic stiffness matrix corresponding to the carbonate mineral layer Matrix; determine the anisotropic target elastic stiffness matrix of the core sample according to the equivalent anisotropic elastic stiffness matrix of the clastic mineral layer and the equivalent isotropic elastic stiffness matrix of the carbonate mineral layer; determine the anisotropic parameters of the core sample according to the anisotropic target elastic stiffness matrix; perform a sensitivity analysis on the volume fraction corresponding to each mineral in the target mineral layer to obtain the target mineral content in the target mineral layer; perform a sensitivity analysis on the pore content in the target pore type to obtain the target pore content in the target pore type; determine the elastic anisotropy of the core sample according to the anisotropic parameters, target mineral content and target pore content.

[0209] In order to complete the above instructions more accurately, refer to Figure 6 As shown, the embodiment of this specification also provides another specific electronic device, wherein the electronic device includes a network communication port 601, a processor 602 and a memory 603, and the above structures are connected through internal cables so that each structure can perform specific data interaction.

[0210] Among them, the network communication port 601 can be specifically used to obtain the volume fraction corresponding to each mineral in the target mineral layer of the core sample, the pore content and pore aspect ratio corresponding to each pore type in the target pore type of the core sample, wherein the target mineral layer includes at least one of the following: a clastic mineral layer and a carbonate mineral layer.

[0211] The processor 602 can be specifically used to determine the equivalent anisotropic elastic stiffness matrix corresponding to the clastic mineral layer and the equivalent isotropic elastic stiffness matrix corresponding to the carbonate mineral layer based on the volume fraction corresponding to each mineral, the pore content and the pore aspect ratio; determine the anisotropic target elastic stiffness matrix of the core sample based on the equivalent anisotropic elastic stiffness matrix of the clastic mineral layer and the equivalent isotropic elastic stiffness matrix of the carbonate mineral layer; determine the anisotropic parameters of the core sample based on the anisotropic target elastic stiffness matrix; perform sensitivity analysis on the volume fraction corresponding to each mineral in the target mineral layer to obtain the target mineral content in the target mineral layer; perform sensitivity analysis on the pore content in the target pore type to obtain the target pore content in the target pore type; determine the elastic anisotropy of the core sample based on the anisotropic parameters, target mineral content and target pore content.

[0212] The memory 603 may be specifically used to store corresponding instruction programs.

[0213] In this embodiment, the network communication port 601 can be a virtual port that is bound to different communication protocols, thereby being capable of sending or receiving different data. For example, the network communication port can be a port responsible for web data communication, a port responsible for FTP data communication, or a port responsible for email data communication. Furthermore, the network communication port can also be a physical communication interface or communication chip. For example, it can be a wireless mobile network communication chip, such as GSM or CDMA; it can also be a Wi-Fi chip; or it can be a Bluetooth chip.

[0214] In this embodiment, the processor 602 may be implemented in any suitable manner. For example, the processor may take the form of a microprocessor or a processor and a computer-readable medium storing computer-readable program code (e.g., software or firmware) executable by the (micro)processor, a logic gate, a switch, an application-specific integrated circuit (ASIC), a programmable logic controller, an embedded microcontroller, etc. This specification is not intended to limit this.

[0215] In this embodiment, the memory 603 may include multiple levels. In a digital system, anything that can store binary data can be a memory. In an integrated circuit, a circuit with a storage function that has no physical form is also called a memory, such as RAM, FIFO, etc. In a system, a storage device with a physical form is also called a memory, such as a memory stick, TF card, etc.

[0216] The embodiment of this specification also provides a computer storage medium based on the above method, wherein the computer storage medium stores computer program instructions, and when the computer program instructions are executed, the following are achieved: obtaining the volume fraction corresponding to each mineral in the target mineral layer of the core sample, the pore content and pore aspect ratio corresponding to each pore type in the target pore type of the core sample, wherein the target mineral layer includes at least one of the following: a detrital mineral layer and a carbonate mineral layer; according to the volume fraction corresponding to each mineral, the pore content and the pore aspect ratio, determining the equivalent anisotropic elastic stiffness matrix corresponding to the detrital mineral layer and the equivalent isotropic elastic stiffness corresponding to the carbonate mineral layer matrix; determine the anisotropic target elastic stiffness matrix of the core sample according to the equivalent anisotropic elastic stiffness matrix of the clastic mineral layer and the equivalent isotropic elastic stiffness matrix of the carbonate mineral layer; determine the anisotropic parameters of the core sample according to the anisotropic target elastic stiffness matrix; perform a sensitivity analysis on the volume fraction corresponding to each mineral in the target mineral layer to obtain the target mineral content in the target mineral layer; perform a sensitivity analysis on the pore content in the target pore type to obtain the target pore content in the target pore type; determine the elastic anisotropy of the core sample according to the anisotropic parameters, target mineral content and target pore content.

[0217] In this embodiment, the storage medium includes, but is not limited to, random access memory (RAM), read-only memory (ROM), cache, hard disk drive (HDD), or memory card. The memory can be used to store computer program instructions. The network communication unit can be an interface configured in accordance with the standards specified by the communication protocol for network connection communication.

[0218] Although this specification provides the method operation steps as described in the embodiments or flow charts, more or fewer operation steps may be included based on conventional or non-creative means. The order of steps listed in the embodiments is only one way of executing the order of many steps and does not represent the only execution order. When the device or client product in practice is executed, it can be executed in sequence or in parallel according to the method shown in the embodiments or the drawings (for example, a parallel processor or a multi-threaded processing environment, or even a distributed data processing environment). The term "comprise", "include" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, product or device including a series of elements includes not only those elements, but also includes other elements that are not explicitly listed, or also includes elements inherent to such process, method, product or device. In the absence of more restrictions, it is not excluded that there are other identical or equivalent elements in the process, method, product or device including the elements. Words such as first and second are used to represent names and do not represent any particular order.

[0219] Those skilled in the art will also appreciate that, in addition to implementing the controller in pure computer-readable program code, it is entirely possible to implement the same functionality by logically programming the method steps in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, embedded microcontrollers, and the like. Therefore, such a controller can be considered a hardware component, and the devices included therein for implementing various functions can also be considered structures within the hardware component. Alternatively, the devices for implementing various functions can be considered both software modules implementing the method and structures within the hardware component.

[0220] This specification may be described in the general context of computer-executable instructions, such as program modules, executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, classes, and the like that perform specific tasks or implement specific abstract data types. This specification may also be practiced in distributed computing environments where tasks are performed by remote processing devices connected through a communications network. In a distributed computing environment, program modules may be located in both local and remote computer storage media, including storage devices.

[0221] Through the description of the above embodiments, it can be seen that those skilled in the art can clearly understand that this specification can be implemented by means of software plus the necessary general hardware platform. Based on this understanding, the technical solution of this specification can essentially be embodied in the form of a software product. This computer software product can be stored in a storage medium such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions for enabling a computer device (which can be a personal computer, a mobile terminal, a server, or a network device, etc.) to execute the methods described in various embodiments or certain parts of the embodiments of this specification.

[0222] The various embodiments in this specification are described in a progressive manner. References to the common or similar parts of the various embodiments are sufficient. Each embodiment focuses on the differences from the other embodiments. This specification can be used in a variety of general-purpose or specialized computer system environments or configurations. For example, personal computers, server computers, handheld or portable devices, tablet devices, multiprocessor systems, microprocessor-based systems, set-top boxes, programmable electronic devices, network PCs, minicomputers, mainframe computers, and distributed computing environments that include any of the above systems or devices.

[0223] Although the present specification has been described with reference to the embodiments, persons skilled in the art will appreciate that there are many variations to the present specification without departing from the spirit of the present specification, and it is intended that the appended claims encompass such variations without departing from the spirit of the present specification.

Claims

1. A method for anisotropic rock physics modeling, characterized in that: include: Obtaining the volume fraction corresponding to each mineral in the target mineral layer of the core sample, and the pore content and pore aspect ratio corresponding to each pore type in the target pore type of the core sample, wherein the target mineral layer includes at least one of the following: a clastic mineral layer and a carbonate mineral layer; Determining an equivalent anisotropic elastic stiffness matrix corresponding to the detrital mineral layer and an equivalent isotropic elastic stiffness matrix corresponding to the carbonate mineral layer according to the volume fraction corresponding to each mineral, the pore content and the pore aspect ratio; determining an anisotropic target elastic stiffness matrix of the core sample according to the equivalent anisotropic elastic stiffness matrix of the clastic mineral layer and the equivalent isotropic elastic stiffness matrix of the carbonate mineral layer; determining anisotropic parameters of the core sample according to the anisotropic target elastic stiffness matrix; Performing a sensitivity analysis on the volume fraction of each mineral in the target mineral layer to obtain the target mineral content in the target mineral layer; Performing a sensitivity analysis on the pore content in the target pore type to obtain a target pore content in the target pore type; The elastic anisotropy of the core sample is determined according to the anisotropy parameter, the target mineral content, and the target pore content.

2. The method according to claim 1, characterized in that The target pore type includes at least one of the following: carbonate pores, clay pores, and horizontal oriented fractures; Accordingly, determining the equivalent anisotropic elastic stiffness matrix corresponding to the detrital mineral layer and the equivalent isotropic elastic stiffness matrix corresponding to the carbonate mineral layer according to the volume fraction corresponding to each mineral, the pore content and the pore aspect ratio includes: According to the volume fraction of each mineral in the detrital mineral layer, the pore content and pore aspect ratio of the clay pores, the equivalent anisotropic elastic stiffness matrix of the detrital mineral layer is determined; According to the volume fraction of each mineral in the carbonate mineral layer, the pore content and pore aspect ratio of the carbonate pores, the equivalent isotropic elastic stiffness matrix of the carbonate mineral layer is determined.

3. The method according to claim 2, characterized in that Before determining the equivalent anisotropic elastic stiffness matrix of the detrital mineral layer based on the volume fraction of each mineral in the detrital mineral layer, the pore content and pore aspect ratio of the clay pores, the following steps are also included: Obtain the volume fraction, bulk modulus, and shear modulus of saturated oil and kerogen in core samples; The saturated oil and kerogen are stored in carbonate pores and clay pores to form equivalent soft matter; determining the bulk modulus and shear modulus of the equivalent soft matter according to the volume fraction, bulk modulus and shear modulus of the saturated oil and kerogen; The elastic stiffness matrix of the equivalent soft matter is determined according to the bulk modulus and shear modulus of the equivalent soft matter.

4. The method according to claim 3, characterized in that The bulk modulus and shear modulus of the equivalent soft matter are determined according to the following formula: Among them, K equ is the bulk modulus of the equivalent soft matter, G equ is the shear modulus of the equivalent soft matter, f1 is the volume fraction of saturated oil, f2 is the volume fraction of kerogen, K1 is the bulk modulus of saturated oil, K2 is the bulk modulus of kerogen, G1 is the shear modulus of saturated oil, and G2 is the shear modulus of kerogen.

5. The method according to claim 4, characterized in that The elastic stiffness matrix of the equivalent soft material is determined according to the following formula: Among them, C equ is the elastic stiffness matrix of the equivalent soft material, K equ and G equ are the bulk modulus and shear modulus of the equivalent soft matter, respectively.

6. The method according to claim 5, characterized in that According to the volume fraction of each mineral in the detrital mineral layer, the pore content and pore aspect ratio of the clay pores, the equivalent anisotropic elastic stiffness matrix of the detrital mineral layer is determined, including: According to the pore aspect ratio corresponding to the clay pore, the fourth-order tensor controlling the spatial morphology of the inclusions corresponding to the clay pore is determined; According to the fourth-order tensor controlling the spatial morphology of inclusions corresponding to the clay pores, the elastic stiffness matrix of the equivalent soft matter, the volume fraction of each mineral in the detrital mineral layer, and the pore content corresponding to the clay pores, the equivalent anisotropic elastic stiffness matrix of the detrital mineral layer is determined according to the following formula: Among them, C clastic is the equivalent anisotropic elastic stiffness matrix of the detrital mineral layer, v n is the volume fraction of n-phase minerals in the detrital mineral layer, C n is the elastic stiffness tensor of the n-phase mineral in the detrital mineral layer, I is the fourth-order unit tensor, is the fourth-order tensor that controls the spatial morphology of the inclusion, φ clay is the clay porosity, is the fourth-order tensor that controls the spatial morphology of inclusions corresponding to clay pores, C equ is the equivalent soft material elastic stiffness matrix.

7. The method according to claim 4, characterized in that According to the volume fraction of each mineral in the carbonate mineral layer, the pore content and pore aspect ratio of the carbonate pores, the equivalent isotropic elastic stiffness matrix of the carbonate mineral layer is determined, including: According to the pore aspect ratio of the carbonate pore, the polarization factor corresponding to the carbonate pore is determined; According to the polarization factor, the bulk modulus and shear modulus of the equivalent soft matter, the volume fraction of each mineral in the carbonate mineral layer, the pore content and pore aspect ratio corresponding to the carbonate pores, the equivalent bulk modulus and shear modulus are determined according to the following formula: Among them, x i is the volume fraction of the i-th mineral in the carbonate mineral layer, K i is the bulk modulus of the i-th mineral in the carbonate mineral layer, G i is the shear modulus of the i-th mineral in the carbonate mineral layer, φ car is the carbonate pore content, K equ is the bulk modulus of the equivalent soft matter, G equ is the shear modulus of the equivalent soft matter, K car is the equivalent bulk modulus, G car is the equivalent shear modulus, P i and Q i is the polarization factor; According to the equivalent bulk modulus and shear modulus, an equivalent isotropic elastic stiffness matrix of the carbonate mineral layer is determined.

8. The method according to claim 1, characterized in that The target mineral layer also includes: a sulfate mineral layer; Accordingly, determining the anisotropic target elastic stiffness matrix of the core sample according to the equivalent anisotropic elastic stiffness matrix of the clastic mineral layer and the equivalent isotropic elastic stiffness matrix of the carbonate mineral layer includes: Determine the equivalent isotropic elastic stiffness matrix of the sulfate mineral layer; The equivalent elastic stiffness matrix of anisotropic layered rock is determined based on the equivalent anisotropic elastic stiffness matrix of clastic mineral layer, the equivalent isotropic elastic stiffness matrix of carbonate mineral layer and the equivalent isotropic elastic stiffness matrix of sulfate mineral layer. According to the equivalent elastic stiffness matrix of anisotropic layered rock and Termas theory, the anisotropic target elastic stiffness matrix of the core sample is determined.

9. An anisotropic rock physics modeling device, characterized in that: include: an acquisition module, configured to acquire the volume fraction corresponding to each mineral in a target mineral layer of a core sample, and the pore content and pore aspect ratio corresponding to each pore type in a target pore type of the core sample, wherein the target mineral layer includes at least one of the following: a clastic mineral layer and a carbonate mineral layer; an elastic stiffness matrix determination module, for determining an equivalent anisotropic elastic stiffness matrix corresponding to the detrital mineral layer and an equivalent isotropic elastic stiffness matrix corresponding to the carbonate mineral layer according to the volume fraction corresponding to each mineral, the pore content and the pore aspect ratio; a target elastic stiffness matrix determination module, configured to determine an anisotropic target elastic stiffness matrix of the core sample based on the equivalent anisotropic elastic stiffness matrix of the clastic mineral layer and the equivalent isotropic elastic stiffness matrix of the carbonate mineral layer; The elastic anisotropy response module is used to determine the anisotropy parameters of the core sample based on the anisotropic target elastic stiffness matrix; perform a sensitivity analysis on the volume fraction corresponding to each mineral in the target mineral layer to obtain the target mineral content in the target mineral layer; perform a sensitivity analysis on the pore content in the target pore type to obtain the target pore content in the target pore type; and determine the elastic anisotropy of the core sample based on the anisotropy parameters, target mineral content, and target pore content.

10. A computer-readable storage medium, characterized in that Computer instructions are stored thereon, and when the instructions are executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

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