Continental facies lamina type shale mineral quantitative interpretation and rock physical modeling method and medium

Abstract

The invention discloses a continental facies lamina type shale mineral quantitative interpretation and rock physical modeling method and a medium. The method comprises the following steps: determining geologic features of continental facies shale through fine description of a rock core, and obtaining mineral components and density of a shale formation; calculating the mineral content through core testing and logging data; and constructing a continental facies shale rock physical model according to the lamina density and the mineral content. The method can be applied to quantitative interpretation of logging minerals, the precision of mineral content calculation is improved, and the actual rock physical characteristics of continental facies shale can be described more accurately.

Description

Technical Field

[0001] The present invention relates to the field of oil and gas exploration and development, and more specifically, to a method and medium for quantitative interpretation and rock physics modeling of continental laminar shale minerals. Background Art

[0002] Seismic rock physics model is a bridge between seismic information and the most basic parameters of rocks, and is the physical basis for reservoir prediction. Clastic rock and carbonate rock models are widely used in conventional oil and gas exploration. Rock physics models for shale gas are mainly concentrated in the marine shale gas field. With the advancement of integrated exploration and development, geological understanding is relatively clear, and marine shale rock physics modeling technology has basically matured. At present, an equivalent rock physics model for marine shale has been established, and the response characteristics of sweet spot parameters have been clarified, which supports the seismic prediction of sweet spot parameters.

[0003] The exploration of continental shale oil and gas started early, but substantial breakthroughs and discoveries were made relatively late, and rock physics research was not in-depth enough. The geological differences between continental shale and marine shale are significant. The Jurassic continental shale in the Sichuan Basin is semi-deep lake sediments with complex lithology, developed laminae and interlayers, thin reservoirs, and strong heterogeneity, which is very different from marine shale. The technical methods formed in the early stage are no longer applicable to continental shale oil and gas.

[0004] The mineral composition of continental shales is complex, and there is a lack of systematic mineral content data. The X-ray diffraction data is accurate, but the measurement point data is sparse, and there is a lack of complete layer mineral description data, so the rock physics modeling accuracy is not high. At the same time, in recent years, through fine geological descriptions, it has been found that the lamination fabric characteristics of continental shales are unique to continental shales. Evaluation studies have found that the lamination structure is closely related to shale quality, fracturing conditions, reservoir conditions, etc. It is necessary to consider its influencing factors in the modeling process, but the current shale rock physics model does not take these differences into account, which also restricts the accuracy of the rock physics model to a certain extent.

[0005] Therefore, it is necessary to develop a quantitative interpretation and rock physics modeling method and medium for continental laminar shale minerals to accurately describe the characteristics of continental shales and support the optimization and prediction of sweet spot sensitive parameters.

[0006] The information disclosed in the background technology section of the present invention is only intended to deepen the understanding of the general background technology of the present invention, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art already known to those skilled in the art. Summary of the invention

[0007] The present invention proposes a method and medium for quantitative interpretation and rock physics modeling of continental laminar shale minerals, deepens the mineral interpretation method, calculates the accurate mineral composition and content, and considers the influence of laminae on the rock physics model.

[0008] In a first aspect, the present disclosure provides a method for quantitative interpretation and rock physics modeling of continental laminar shale minerals, including:

[0009] Determine the geological characteristics of continental shale through detailed core description, and obtain the mineral composition and density of shale laminae;

[0010] Calculate mineral content through core testing and logging data;

[0011] A continental shale rock physics model is constructed based on the laminae density and the mineral content.

[0012] Preferably, determining the geological characteristics of continental shale through core fine description includes:

[0013] The geological characteristics of the continental shale are determined through core data, wherein the geological characteristics of the continental shale include mineral composition, contact relationship, pore characteristics, fractures, and anisotropy.

[0014] Preferably, obtaining the mineral composition and density of shale lamina includes:

[0015] The cores were observed to identify the mineral composition of the laminae and the difference in light and dark between the laminae and non-laminae. The number of laminae developed was extracted from each core piece using image recognition technology to calculate the laminae density.

[0016] Preferably, the laminae density is calculated by formula (1):

[0017] ρ w =N / L (1)

[0018] Where N is the number of laminae in a single core; L is the length of a single core; ρ w is the layer density.

[0019] Preferably, the calculation of mineral content through core testing and logging data includes:

[0020] Based on the core analysis data, the logging response matrix is ​​established:

[0021] Classify and combine minerals, establish a multi-mineral rock volume physical model, and then establish a loss function;

[0022] The response parameters of various minerals are determined by using an optimization method, and the mineral composition and content curve of the uncored layer section or uncored well is calculated based on the multi-mineral rock physical volume model.

[0023] Preferably, the logging response matrix is:

[0024] T=P*V+ε rand (2)

[0025] Among them, T is the logging response matrix, that is, the logging data measured by the instrument; P is the component response value parameter matrix, that is, the logging response value of each mineral, pore fluid, etc. when it exists at 100%; V is the component content matrix, that is, the volume content of each component, ε rand is a random measurement error.

[0026] Preferably, the loss function:

[0027]

[0028] In the period, min F is the loss function, is the actual logging curve value, is the logging value, and n is the number of core samples.

[0029] Preferably, constructing a continental shale rock physics model according to the laminae density and the mineral content includes:

[0030] Performing mineral mixing, mixing the minerals according to the mineral content, applying the SCA model, and calculating the mineral elastic modulus;

[0031] According to the laminae density, the laminae content per unit length of the core is calculated, and laminae are added;

[0032] Based on the mineral composition of the laminae, the elastic modulus of the laminae is determined, and combined with the mineral elastic modulus, the equivalent matrix modulus of the mixture of minerals and laminae is obtained based on the Backus average;

[0033] Adding pores to the equivalent matrix modulus based on the DEM model to obtain the skeleton elastic modulus;

[0034] Using the Eshelby-Cheng model of anisotropic media, the elastic modulus along the crack is added to the skeleton elastic modulus to obtain the equivalent anisotropic elastic modulus.

[0035] The modulus and density of different types of fluids after mixing are calculated using the Wood formula, and the elastic modulus of continental shale saturated with fluid is obtained by applying the Gassmann model to construct the continental shale rock physics model.

[0036] Preferably, the laminae content per unit length of the core is calculated by formula (4):

[0037] X=ρ w *ΔL / H (4)

[0038] Among them, ρ w is the lamina density, X is the lamina content per unit length of the core, ΔL is the lamina thickness, and H is the thickness of the rock layer.

[0039] In a second aspect, an embodiment of the present disclosure further provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the method for quantitative interpretation and rock physics modeling of continental laminar shale minerals.

[0040] The methods and apparatus of the present invention have other features and advantages that will be apparent from, or will be described in detail in, the accompanying drawings and subsequent detailed descriptions incorporated herein, which together serve to explain the specific principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0042] Figure 1 A flowchart showing the steps of a method for quantitative interpretation of continental laminar shale minerals and rock physics modeling according to an embodiment of the present invention.

[0043] Figure 2 A schematic diagram showing the calculation results of mineral content of Well TY1 in the FX area based on the continental laminar shale rock physics model according to an embodiment of the present invention.

[0044] Figure 3 A flow chart of modeling a continental shale seismic rock physics model according to an embodiment of the present invention is shown.

[0045] Figure 4 A schematic diagram comparing the predicted elastic parameter results according to the conventional modeling method and the present method is shown. DETAILED DESCRIPTION

[0046] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0047] The present invention provides a method for quantitative interpretation and rock physics modeling of continental laminar shale minerals, comprising:

[0048] Determine the geological characteristics of continental shale through detailed core description, and obtain the mineral composition and density of shale laminae;

[0049] Calculate mineral content through core testing and logging data;

[0050] A rock physics model of continental shale is constructed based on laminae density and mineral content.

[0051] In one example, the geological characteristics of continental shale are determined through core fine characterization, including:

[0052] The geological characteristics of continental shale are determined through core data, including mineral composition, contact relationship, pore characteristics, fractures, and anisotropy.

[0053] In one example, obtaining the mineral composition and density of shale lamina includes:

[0054] Observe the core to clarify the mineral composition of the lamina and the light and dark differences between the lamina and non-lamina. Use image recognition technology to extract the number of lamina development core by core and calculate the lamina density.

[0055] In one example, the laminae density is calculated by formula (1):

[0056] ρ w =N / L (1)

[0057] Where N is the number of laminae in a single core; L is the length of a single core; ρ w is the layer density.

[0058] In one example, from core testing and well logging data, calculation of mineral content includes:

[0059] Based on the core analysis data, the logging response matrix is ​​established:

[0060] Classify and combine minerals, establish a multi-mineral rock volume physical model, and then establish a loss function;

[0061] The optimization method is used to determine the response parameters of various minerals, and the mineral composition and content curves of uncored layers or uncored wells are calculated based on the multi-mineral rock physics volume model.

[0062] In one example, the well logging response matrix is:

[0063] T=P*V+ε rand (2)

[0064] Among them, T is the logging response matrix, that is, the logging data measured by the instrument; P is the component response value parameter matrix, that is, the logging response value of each mineral, pore fluid, etc. when it exists at 100%; V is the component content matrix, that is, the volume content of each component, ε rand is a random measurement error.

[0065] In an example, the loss function:

[0066]

[0067] In the period, min F is the loss function, is the actual logging curve value, is the logging value, and n is the number of core samples.

[0068] In one example, based on the density of laminae and mineral content, a continental shale rock physics model is constructed including:

[0069] Mix the minerals, apply the SCA model to mix the minerals according to the mineral content, and calculate the mineral elastic modulus;

[0070] According to the laminae density, the laminae content per unit length of the core is calculated and laminae are added;

[0071] Based on the mineral composition of the laminae, the elastic modulus of the laminae is determined, and combined with the mineral elastic modulus, the equivalent matrix modulus of the mixture of minerals and laminae is obtained based on the Backus average;

[0072] The skeleton elastic modulus was obtained by adding pores to the equivalent matrix modulus based on the DEM model;

[0073] Using the Eshelby-Cheng model of anisotropic media, the elastic modulus along the crack is added to the skeleton elastic modulus to obtain the equivalent anisotropic elastic modulus.

[0074] The Wood formula is used to calculate the modulus and density of different types of fluids after mixing. The Gassmann model is applied to obtain the elastic modulus of continental shale saturated with fluid and to construct a rock physics model of continental shale.

[0075] In one example, the laminae content per unit length of the core is calculated by formula (4):

[0076] X=ρ w *ΔL / H (4)

[0077] Among them, ρ w is the lamina density, X is the lamina content per unit length of the core, ΔL is the lamina thickness, and H is the thickness of the rock layer.

[0078] Specifically, the geological characteristics of continental shale are clarified through detailed core description, and the mineral composition and density of shale lamina are obtained; the mineral content is obtained through core testing and logging data solution; and a theoretical model that is optimally adapted considering mineral composition, content, lamina development, porosity, fractures, fluid, etc. is constructed to construct a rock physics model of continental shale.

[0079] The core is carefully described to clarify the geological characteristics. Through core observation, X-ray diffraction, microscopic photos and other data, the characteristics of continental shale mineral composition, contact relationship, pore characteristics, fractures, anisotropy, etc. are analyzed and clarified; the core is carefully observed to clarify the mineral composition of the lamina, the light and dark difference between the lamina and non-lamina, and the number of lamina development N is extracted from each core using image recognition technology. The density of the lamina can be calculated using formula (1).

[0080] Quantitative interpretation of minerals. Based on the core analysis data, the test response matrix equation T function is established as formula (2). According to the principle of "similar physical properties and similar logging response characteristics", the minerals are classified and combined to establish a multi-mineral rock volume model: the response equations of different series of logging values ​​(GR, AC, DEN, CNL, KTH and K) are combined to establish a loss function as formula (3). The optimization method is used to solve the response parameters of various minerals, and the mineral composition and content curves of the uncored layer or uncored well are calculated based on the multi-mineral rock volume model.

[0081] Construct a rock physics model for continental shale. First, mineral mixing is performed: in continental shale, clay, silica, carbonate minerals, organic matter, etc. have the same effect on the matrix. The mineral content is used to mix the minerals using the SCA (self-compatible approximation) model to calculate the mineral elastic modulus K m , μ m .

[0082] Secondly, add laminae: Assuming that the laminae thickness is ΔL, combined with the laminae density obtained from the detailed description of the core, the laminae content per unit length of the core is calculated as formula (4), and the mineral matrix content is:

[0083] Y=TX (5)

[0084] Where X is the proportion of mineral components in different laminae, T is the total mineral content, and Y is the mineral matrix content.

[0085] Based on the laminar mineral composition, the laminar elastic modulus is given as Kw, μw, ρw, combined with the mineral elastic modulus K m , μ m , m , the equivalent matrix modulus of the mixture of minerals and laminae is obtained based on the Backus average. Pores are added to the above matrix based on the DEM (differential equivalent medium) model to obtain the skeleton elastic modulus. Using the Eshelby-Cheng model of anisotropic media, the modulus along the cracks is added to the skeleton elastic modulus to obtain the equivalent anisotropic elastic modulus. The modulus K of different types of fluids after mixing is calculated using the Wood formula f and density ρ f , the Gassmann model is applied to obtain the elastic modulus of continental shale saturated with fluid.

[0086] The present invention also provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, it implements the above-mentioned quantitative interpretation and rock physics modeling method of continental laminar shale minerals.

[0087] To facilitate understanding of the solutions and effects of the embodiments of the present invention, two specific application examples are given below. Those skilled in the art should understand that the examples are only for facilitating understanding of the present invention, and any specific details thereof are not intended to limit the present invention in any way.

[0088] Example 1

[0089] Figure 1 A flowchart showing the steps of a method for quantitative interpretation of continental laminar shale minerals and rock physics modeling according to an embodiment of the present invention.

[0090] like Figure 1 As shown, the method for quantitative interpretation and rock physics modeling of continental laminar shale minerals includes: step 101, determining the geological characteristics of continental shale through detailed core description, and obtaining the mineral composition and laminar density of shale; step 102, calculating the mineral content through core testing and logging data; step 103, constructing a continental shale rock physics model based on the laminar density and mineral content.

[0091] Collect and organize logging data and core analysis tests in the work area. Logging data mainly include natural gamma, uranium-free gamma, photoelectric absorption cross-section index, acoustic wave time difference, compensated neutron, lithology density, uranium, thorium, potassium, and deep lateral resistivity. Core analysis data mainly include the content of clay, quartz, potassium feldspar, sodium feldspar, calcite, dolomite, pyrite, and organic matter obtained by whole-rock X-ray diffraction analysis.

[0092] Based on the detailed geological description of a single well in the work area, the laminae development characteristics are clarified, and the number of laminae is identified by combining image recognition. The laminae density curve is calculated using formula (1).

[0093] Figure 2 A schematic diagram showing the calculation results of mineral content of Well TY1 in the FX area based on the continental laminar shale rock physics model according to an embodiment of the present invention.

[0094] Based on the core analysis data, according to the logging response matrix equation T function of formula (2), the response equations of different series of logging values ​​(GR, AC, DEN, CNL, KTH and K) are combined to establish the loss function, namely formula (3). The optimization method is used to solve and calculate the mineral composition and content curves of the uncored layer or uncored well. Compared with the conventional method, the prediction error is reduced from 7.6% to 3.9%. Figure 2 shown.

[0095] Figure 3 A flow chart of modeling a continental shale seismic rock physics model according to an embodiment of the present invention is shown.

[0096] Figure 4 A schematic diagram comparing the predicted elastic parameter results according to the conventional modeling method and the present method is shown.

[0097] like Figure 3 As shown in the figure, mineral content, contact relationship, lamination development, pores, fractures, fluids, etc. are fully considered, and minerals, laminations, pores, fractures, fluids, etc. are gradually added to obtain the elastic modulus of the final continental shale. The P- and S-wave velocities calculated based on this model are more accurate than those of conventional methods and are more consistent with actual logging data, such as Figure 4 shown.

[0098] Example 2

[0099] An embodiment of the present disclosure provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the method for quantitative interpretation of continental laminar shale minerals and rock physics modeling.

[0100] According to the computer-readable storage medium of the embodiment of the present disclosure, non-transitory computer-readable instructions are stored thereon. When the non-transitory computer-readable instructions are executed by a processor, all or part of the steps of the above-mentioned methods of each embodiment of the present disclosure are executed.

[0101] The above-mentioned computer-readable storage media include, but are not limited to: optical storage media (e.g., CD-ROM and DVD), magneto-optical storage media (e.g., MO), magnetic storage media (e.g., magnetic tape or mobile hard disk), media with built-in rewritable non-volatile memory (e.g., memory card) and media with built-in ROM (e.g., ROM box).

[0102] Those skilled in the art should understand that the purpose of the above description of the embodiments of the present invention is only to exemplarily illustrate the beneficial effects of the embodiments of the present invention, and is not intended to limit the embodiments of the present invention to any given examples.

[0103] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for quantitative interpretation and rock physics modeling of continental laminar shale minerals, characterized in that: include: Determine the geological characteristics of continental shale through detailed core description, and obtain the mineral composition and density of shale laminae; Calculate mineral content through core testing and logging data; A continental shale rock physics model is constructed based on the laminae density and the mineral content.

2. The method for quantitative interpretation and rock physics modeling of continental laminar shale minerals according to claim 1, wherein: The geological characteristics of continental shale determined through detailed core description include: The geological characteristics of the continental shale are determined through core data, wherein the geological characteristics of the continental shale include mineral composition, contact relationship, pore characteristics, fractures, and anisotropy.

3. The method for quantitative interpretation and rock physics modeling of continental laminar shale minerals according to claim 1, wherein: Obtaining the mineral composition and density of shale laminae includes: The cores were observed to identify the mineral composition of the laminae and the difference in light and dark between the laminae and non-laminae. The number of laminae developed was extracted from each core piece using image recognition technology to calculate the laminae density.

4. The method for quantitative interpretation and rock physics modeling of continental laminar shale minerals according to claim 3, wherein: The laminae density is calculated by formula (1): r w =N / L (1) Where N is the number of laminae in a single core; L is the length of a single core; ρ w is the layer density.

5. The method for quantitative interpretation and rock physics modeling of continental laminar shale minerals according to claim 1, wherein: Through core testing and logging data, the mineral content is calculated including: Based on the core analysis data, the logging response matrix is ​​established: Classify and combine minerals, establish a multi-mineral rock volume physical model, and then establish a loss function; The response parameters of various minerals are determined by using an optimization method, and the mineral composition and content curve of the uncored layer section or uncored well is calculated based on the multi-mineral rock physical volume model.

6. The method for quantitative interpretation and rock physics modeling of continental laminar shale minerals according to claim 5, wherein: The logging response matrix is: T=P*V+ε rand (2) Among them, T is the logging response matrix, that is, the logging data measured by the instrument; P is the component response value parameter matrix, that is, the logging response value of each mineral, pore fluid, etc. when it exists at 100%; V is the component content matrix, that is, the volume content of each component, ε rand is a random measurement error.

7. The method for quantitative interpretation and rock physics modeling of continental laminar shale minerals according to claim 5, wherein: The loss function: In the period, min F is the loss function, is the actual logging curve value, is the logging value, and n is the number of core samples.

8. The method for quantitative interpretation and rock physics modeling of continental laminar shale minerals according to claim 1, wherein: According to the laminae density and the mineral content, constructing a continental shale rock physics model includes: Performing mineral mixing, mixing the minerals according to the mineral content, applying the SCA model, and calculating the mineral elastic modulus; According to the laminae density, the laminae content per unit length of the core is calculated, and laminae are added; Based on the mineral composition of the laminae, the elastic modulus of the laminae is determined, and combined with the mineral elastic modulus, the equivalent matrix modulus of the mixture of minerals and laminae is obtained based on the Backus average; Adding pores to the equivalent matrix modulus based on the DEM model to obtain the skeleton elastic modulus; Using the Eshelby-Cheng model of anisotropic media, the elastic modulus along the crack is added to the skeleton elastic modulus to obtain the equivalent anisotropic elastic modulus. The modulus and density of different types of fluids after mixing are calculated using the Wood formula, and the elastic modulus of continental shale saturated with fluid is obtained by applying the Gassmann model to construct the continental shale rock physics model.

9. The method for quantitative interpretation and rock physics modeling of continental laminar shale minerals according to claim 8, wherein: The laminae content per unit length of core is calculated by formula (4): X=ρ w *ΔL / H (4) Among them, ρ w is the lamina density, X is the lamina content per unit length of the core, ΔL is the lamina thickness, and H is the thickness of the rock layer.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the method for quantitative interpretation and rock physics modeling of continental laminar shale minerals according to any one of claims 1 to 9.

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