Rock physics model construction method, device, storage medium and electronic device

Abstract

The present invention relates to the technical field of rock physics, and particularly to a method, device, storage medium and electronic device for constructing a rock physics model. The method includes: obtaining the density of a target rock; performing physical modeling on the target rock through an inclusion model to obtain a reference elastic modulus M0; performing physical modeling on the target rock through an uncemented sandstone model to obtain an elastic modulus M at a pressure of P0 P0 and an elastic modulus M at a pressure of P1 P1 ; based on the elastic modulus M P0 and the elastic modulus M P1 , obtaining a change in elastic modulus ΔM; based on the reference elastic modulus M0 and the change in elastic modulus ΔM, obtaining an elastic modulus M1 after a pressure change; based on the elastic modulus M1 and the density, obtaining a longitudinal wave velocity VP and a shear wave velocity VS. The influence of pressure change on the elastic modulus is considered when constructing the rock physics model, improving the accuracy and rationality of rock physics modeling.

Description

Technical Field

[0001] The present application relates to the technical field of rock physics, and particularly to a method, device, storage medium and electronic device for constructing a rock physics model. Background Art

[0002] Rock physics modeling is a fundamental technology in the reservoir prediction technology sequence. The accuracy and rationality of rock physics modeling directly affect the reliability of subsequent reservoir prediction, physical property inversion, etc. And in application scenarios such as time-lapse seismic, the influence of pressure change on the elastic modulus of rocks usually needs to be considered. Common rock physics models include the inclusion model and the grain contact model. The uncemented sandstone model in the grain contact model is a rock physics model considering pressure change suitable for loose sandstone; the inclusion model is a widely used rock physics model, applicable to various rock types. Usually, compared with the coordination number parameter of the grain contact model, the pore ellipsoid ratio parameter in the inclusion model can describe pore rocks better and more flexibly.

[0003] Since the uncemented sandstone model incorporates the influence of pressure change on the elastic modulus, it is applicable to rock physics modeling in application scenarios such as time-lapse seismic. However, on the one hand, the applicable range of the uncemented sandstone model is relatively narrow, and on the other hand, compared with the inclusion model, the modeling effect of the uncemented sandstone model is not satisfactory.

[0004] One difficulty in constructing a rock physics model in application scenarios such as time-lapse seismic is to consider the influence of pressure change on the elastic modulus. The present invention proposes a comprehensive rock physics model construction method considering pressure change, which improves the accuracy and rationality of rock physics modeling. Summary of the Invention

[0005] In view of the above problems, the present application provides a method, device, storage medium and electronic device for constructing a rock physics model. In application scenarios such as time-lapse seismic, a comprehensive rock physics model construction method combining pressure change is adopted, which improves the accuracy and rationality of rock physics modeling.

[0006] In the first aspect of the present invention, a method for constructing a rock physics model is provided, and the method includes:

[0007] Obtain the density of the target rock;

[0008] Perform physical modeling on the target rock through the inclusion model to obtain the reference elastic modulus M0;

[0009] Perform physical modeling on the target rock through the uncemented sandstone model to obtain the elastic modulus M when the pressure is P0 P0 and the elastic modulus M when the pressure is P1 P1 ;

[0010] Based on the elastic modulus M P0 and the elastic modulus M P1 , obtain the change in elastic modulus ΔM;

[0011] Based on the reference elastic modulus M0 and the change in elastic modulus ΔM, obtain the elastic modulus M1 after the pressure change;

[0012] Based on the elastic modulus M1 and the density, obtain the longitudinal wave velocity VP and the transverse wave velocity VS.

[0013] In some embodiments, obtaining the density of the target rock includes:

[0014] Obtain the density of the target rock based on well logging data.

[0015] In some embodiments, based on the elastic modulus M P0 and the elastic modulus M P1 , obtaining the change in elastic modulus ΔM includes:

[0016] Take the difference between the elastic modulus M P1 and the elastic modulus M P0 as the change in elastic modulus ΔM.

[0017] In some embodiments, based on the reference elastic modulus M0 and the change in elastic modulus ΔM, obtaining the elastic modulus M1 after the pressure change includes:

[0018] Take the sum of the reference elastic modulus M0 and the change in elastic modulus ΔM as the elastic modulus M1 after the pressure change.

[0019] In the second aspect of the present invention, the present invention provides a device for constructing a rock physics model, the device includes:

[0020] A density acquisition unit for acquiring the density of the target rock;

[0021] A first elastic modulus acquisition unit for physically modeling the target rock through an inclusion model, the reference elastic modulus M0;

[0022] A second elastic modulus acquisition unit for physically modeling the target rock through an uncemented sandstone model, obtaining the elastic modulus M when the pressure is P0 P0 and the elastic modulus M when the pressure is P1 P1 ;

[0023] An elastic modulus change acquisition unit for based on the elastic modulus M P0 and the elastic modulus M P1 , obtain the change in elastic modulus ΔM;

[0024] A third elastic modulus acquisition unit, configured to acquire an elastic modulus M1 after pressure change based on the reference elastic modulus M0 and the change in elastic modulus ΔM;

[0025] A wave velocity acquisition unit, configured to acquire a longitudinal wave velocity VP and a shear wave velocity VS based on the elastic modulus M1 and the density.

[0026] In some embodiments, the density acquisition unit is configured to acquire the density of a target rock based on logging data.

[0027] In some embodiments, the elastic modulus change acquisition unit is configured to use the difference between the elastic modulus M P1 and the elastic modulus M P0 as the change in elastic modulus ΔM.

[0028] In some embodiments, the third elastic modulus acquisition unit is configured to use the sum of the reference elastic modulus M0 and the change in elastic modulus ΔM as the elastic modulus M1 after pressure change.

[0029] In a third aspect of the present invention, the present application provides a storage medium storing a computer program, which when executed by a processor, implements the rock physics model construction method as described above.

[0030] In a fourth aspect of the present invention, the present application provides an electronic device, including: a processor and a memory, wherein the memory stores a computer program, which when executed by the processor, implements the rock physics model construction method as described above.

[0031] Applying the rock physics model construction method of the present invention, in application scenarios such as time-lapse seismic, the influence of pressure change on the elastic modulus is considered when constructing the rock physics model, improving the accuracy and rationality of rock physics modeling. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention, and those of ordinary skill in the art can also obtain other drawings according to the provided drawings without creative efforts.

[0033] Figure 1 It is a flowchart of a rock physics model construction method provided by an embodiment of the present application;

[0034] Figure 2 It is an original logging curve diagram of a turbidite reservoir area provided by an embodiment of the present application;

[0035] Figure 3 The curve graph of the modeling result of the inclusion model provided by the embodiment of the present application;

[0036] Figure 4 The curve graph of the modeling result of the uncemented sandstone model provided by the embodiment of the present application;

[0037] Figure 5 The curve graph of the effective elastic modulus of the uncemented sandstone model under different pressures provided by the embodiment of the present application;

[0038] Figure 6 The curve graph of the variation of the P-wave and S-wave velocities with the effective pressure under the condition of water saturation provided by the embodiment of the present application;

[0039] Figure 7 The curve graph of the variation of the P-wave and S-wave velocities with the effective pressure under the condition of oil saturation provided by the embodiment of the present application;

[0040] Figure 8 The curve graph of the variation of the P-wave and S-wave velocities with the effective stress provided by the embodiment of the present application;

[0041] Figure 9 The structural schematic diagram of a rock physics model construction device provided by the embodiment of the present application;

[0042] Figure 10 The connection block diagram of an electronic device provided by the embodiment of the present application. Detailed implementation manners

[0043] The following will combine the accompanying drawings and embodiments to detail the implementation manners of the present application, so as to fully understand how the present invention uses technical means to solve technical problems and the implementation process of achieving corresponding technical effects and implement accordingly. Each feature in the embodiments of the present application and the embodiments can be combined with each other on the premise of not conflicting, and the formed technical solutions are all within the protection scope of the present application.

[0044] As can be seen from the background technology, rock physics modeling is a basic technology in the reservoir prediction technology sequence. The accuracy and rationality of rock physics modeling directly affect the reliability of subsequent reservoir prediction, physical property inversion, etc. And in application scenarios such as time-lapse seismic, the influence of pressure change on the elastic modulus of rocks usually needs to be considered. Commonly used rock physics models include the inclusion model and the particle contact model. The uncemented sandstone model in the particle contact model is a rock physics model considering pressure change applicable to loose sandstone; the inclusion model is a widely used rock physics model applicable to various rock types. Usually, compared with the coordination number parameter of the particle contact model, the pore ellipsoid ratio parameter in the inclusion model can describe pore rocks better and more flexibly.

[0045] Since the uncemented sandstone model incorporates the influence of pressure changes on the elastic modulus, it is applicable to rock physics modeling in applications such as time-lapse seismic. However, on the one hand, the applicable range of the uncemented sandstone model is relatively narrow, and on the other hand, compared with the inclusion model, the modeling effect of the uncemented sandstone model is not satisfactory.

[0046] In view of this, the present invention proposes a method for constructing a comprehensive rock physics model considering pressure changes, which improves the accuracy and rationality of rock physics modeling.

[0047] Example 1

[0048] In 1996, Dvorkin and Nur proposed an uncemented sandstone model applicable to highly porous sandstone. The core of this model is to obtain the pressure-related high-porosity end-point modulus through the Hertz-Mindlin theory, and then use the modified Hashin-Strikman lower bound to obtain the effective modulus of different porosities.

[0049] The contact Hertz-Mindlin theory gives the effective bulk modulus (K HM ) and shear modulus (μ HM ) of the skeleton under hydrostatic pressure P:

[0050]

[0051]

[0052] Where C is the coordination number, μ and υ are the shear modulus and Poisson's ratio of the solid particles respectively, φ0 is the porosity, and P is the hydrostatic pressure. The high-porosity end-point can be obtained not only through the Hertz-Mindlin theory but also through experimental measurements of highly porous sandstone.

[0053] The effective modulus of different porosities can be obtained using the modified Hashin-Strikman lower bound:

[0054]

[0055]

[0056] Although the above uncemented sandstone model considers the influence of pressure changes on the elastic modulus, its drawback is that it fails to fully utilize the numerous information obtained from well logging.

[0057] The inclusion model is a widely used rock physics model that makes full use of the information provided by logging and uses the pore ellipsoid ratio to characterize the effect of pore morphology on the elastic modulus. Structurally, the inclusion model does not conform to sandstone, but from the concept of equivalent elasticity, it is appropriate to describe sandstone with the inclusion model.

[0058] Here, taking the differential equivalent medium model as an example, the core of the inclusion model is briefly described. The differential equivalent medium theory simulates a two-phase mixture by gradually adding the inclusion phase to the solid mineral phase. The solid mineral is used as phase 1, and then the material of phase 2 is gradually added until the content of each component reaches the predetermined content value, and then the addition of the material of phase 2 is stopped. The coupled differential equations of the equivalent volume and shear modulus K * and μ * can be expressed by the following equations respectively:

[0059]

[0060]

[0061] Wherein, represents the derivative with respect to y, P and Q are the geometric factors of the bulk strain and shear strain, and the superscript eff2 of P (*2) and Q (*2) means that this geometric strain factor is for the inclusion material 2 in the background medium with equivalent moduli and The initial conditions are K * (0) = K1 and μ * (0) = μ1, K1 and μ1 are the bulk modulus and shear modulus of the initial main phase material, K2 and μ2 are the bulk modulus and shear modulus of the gradually added inclusion, and y is the content of phase 2. For fluid inclusions and empty inclusions, y is the porosity φ.

[0062] It should be noted that the above-mentioned predetermined content value can be set according to actual needs.

[0063] In some embodiments, a two-phase mixture is simulated by gradually adding the inclusion phase to the solid mineral phase. The solid mineral is used as phase 1, and then the material of phase 2 is gradually added until phase 1 reaches the saturation state.

[0064] Considering the respective advantages and disadvantages of the uncemented sandstone model and the inclusion model, this embodiment provides a method for constructing a comprehensive rock physics model that combines the inclusion model and the uncemented sandstone model. Figure 1 It is a schematic flowchart of a method for constructing a rock physics model provided by an embodiment of the present application. As Figure 1 shown, the method of this embodiment includes the following steps:

[0065] S100. Obtain the density of the target rock.

[0066] Specifically, obtain the density of the target rock from the logging curve data.

[0067] S200. Physically model the target rock through an inclusion model to obtain the reference elastic modulus M0.

[0068] In some embodiments, the elastic modulus M0 can be obtained using the following formula, and this elastic modulus M0 is used as the reference elastic modulus:

[0069]

[0070]

[0071] where the initial condition is K * (0) = K1 and μ * (0) = μ1, K1 and μ1 are the bulk modulus and shear modulus of the initial matrix material, K2 and μ2 are the bulk modulus and shear modulus of the gradually added inclusions, and y is the content of phase 2. For fluid inclusions and empty inclusions, y is the porosity φ.

[0072] S300. Physically model the target rock through an uncemented sandstone model to obtain the elastic modulus M at pressure P0 P0 and the elastic modulus M at pressure P1 P1 .

[0073] In some embodiments, the elastic modulus M at pressure P0 can be obtained through the following formula P0 and the elastic modulus M at pressure P1 P1 :

[0074]

[0075]

[0076]

[0077]

[0078] where K HM is the effective bulk modulus of the skeleton, and μ HM is the shear modulus.

[0079] S400. Based on the elastic modulus M P0 and the elastic modulus M P1 , obtain the change in elastic modulus ΔM.

[0080] In some embodiments, based on the elastic modulus M P0 and the elastic modulus M P1, obtaining the change in elastic modulus ΔM, including:

[0081] Taking the difference between the elastic modulus M P1 and the elastic modulus M P0 as the change in elastic modulus ΔM.

[0082] S500. Based on the reference elastic modulus M0 and the change in elastic modulus ΔM, obtain the elastic modulus M1 after the pressure change.

[0083] In some embodiments, the obtaining the elastic modulus M1 after the pressure change based on the reference elastic modulus M0 and the change in elastic modulus ΔM includes:

[0084] Taking the sum of the reference elastic modulus M0 and the change in elastic modulus ΔM as the elastic modulus M1 after the pressure change.

[0085] S600. Based on the elastic modulus M1 and the density, obtain the longitudinal wave velocity VP and the shear wave velocity VS.

[0086] Furthermore, comprehensively analyze the physical modeling results of the target rock to provide data support for subsequent reservoir prediction.

[0087] The above analysis results based on the rock physics model considering pressure changes can be used to evaluate the rationality of describing reservoir changes through time-lapse seismic data; and combined with the inversion results of multiple time-lapse seismic data, the pressure changes inside the reservoir during the development process can be quantitatively analyzed, laying a foundation for the efficient development of the reservoir in the next step.

[0088] In this embodiment, the density of the target rock is obtained; the target rock is physically modeled through an inclusion model to obtain the reference elastic modulus M0; the target rock is physically modeled through an uncemented sandstone model to obtain the elastic modulus M P0 when the pressure is P0 and the elastic modulus M P1 when the pressure is P1; based on the elastic modulus M P0 and the elastic modulus M P1, obtain the change in elastic modulus ΔM; based on the reference elastic modulus M0 and the change in elastic modulus ΔM, obtain the elastic modulus M1 after pressure change; based on the elastic modulus M1 and the density, obtain the longitudinal wave velocity VP and the shear wave velocity VS. The analysis result based on the rock physics model considering pressure change in this embodiment can be used to evaluate the rationality of describing reservoir changes through time-lapse seismic data; and combined with the inversion results of multiple time-lapse seismic data, the pressure change inside the reservoir during the development process can be quantitatively analyzed, laying a foundation for the efficient development of the next step of the reservoir. In application scenarios such as time-lapse seismic, the comprehensive rock physics model construction method considering pressure change improves the accuracy and rationality of rock physics modeling.

[0089] Embodiment 2

[0090] In 1996, Dvorkin and Nur proposed an uncemented sandstone model applicable to high-porosity sandstone. The core of this model is to obtain the high-porosity end-point modulus related to pressure through the Hertz-Mindlin theory, and then use the improved Hashin-Strikman lower bound to obtain the effective modulus of different porosities.

[0091] The contact Hertz-Mindlin theory gives the effective bulk modulus (K HM ) and shear modulus (μ HM ) of the skeleton under hydrostatic pressure P:

[0092]

[0093]

[0094] where C is the coordination number, μ and υ are the shear modulus and Poisson's ratio of solid particles respectively, φ0 is the porosity, and P is the hydrostatic pressure. The high-porosity end-point can be obtained not only through the Hertz-Mindlin theory, but also through experimental measurement of high-porosity sandstone.

[0095] The effective modulus of different porosities can be obtained using the improved Hashin-Strikman lower bound:

[0096]

[0097]

[0098] Although the above uncemented sandstone model considers the influence of pressure change on elastic modulus, its shortcoming is that it fails to fully utilize the many information obtained from well logging.

[0099] The inclusion model is a widely used rock physics model that makes full use of the information provided by logging and uses the pore ellipsoid ratio to characterize the effect of pore morphology on the elastic modulus. Structurally, the inclusion model does not conform to sandstone, but from the concept of equivalent elasticity, it is appropriate to describe sandstone with the inclusion model.

[0100] Here, taking the differential equivalent medium model as an example, the core of the inclusion model is briefly described. The differential equivalent medium theory simulates a two-phase mixture by gradually adding an inclusion phase to the solid mineral phase. The solid mineral is used as phase 1, and then the material of phase 2 is gradually added until the content of each component reaches the predetermined content value, and then the addition of the material of phase 2 is stopped. The coupled differential equations of the equivalent volume and shear modulus K * and μ * can be expressed by the following equations respectively:

[0101]

[0102]

[0103] Among them, represents the derivative with respect to y. P and Q are the geometric factors of the bulk strain and shear strain. The superscript eff2 of P (*2) and Q (*2) means that this geometric strain factor is for the inclusion material 2 in the background medium with equivalent moduli and The initial conditions are K * (0) = K1 and μ * (0) = μ1. K1 and μ1 are the bulk modulus and shear modulus of the initial main phase material, K2 and μ2 are the bulk modulus and shear modulus of the gradually added inclusion, and y is the content of phase 2. For fluid inclusions and empty inclusions, y is the porosity φ.

[0104] It should be noted that the above-mentioned predetermined content value can be set according to actual needs.

[0105] In some embodiments, a two-phase mixture is simulated by gradually adding an inclusion phase to the solid mineral phase. The solid mineral is used as phase 1, and then the material of phase 2 is gradually added until phase 1 reaches the saturation state.

[0106] A specific example provided in this embodiment is to verify the rationality and superiority of the comprehensive rock physics model considering pressure changes proposed by the present invention in this embodiment. The method of this embodiment includes the following steps:

[0107] First step, physically model the target rock through the inclusion model to obtain the modeling result.

[0108] Specifically, select the rock in a turbidite rock work area as the target rock. The original logging curves of this turbidite rock work area are as shown in Figure 2 shown below, Figure 2 which is the original logging curve graph of the turbidite rock work area provided by the embodiment of the present application; use the inclusion model to physically model this rock, and the modeling result of this target rock is as shown in Figure 3 shown below, Figure 3 which is the modeling result curve graph of the inclusion model provided by the embodiment of the present application.

[0109] Second step, physically model the target rock through the uncemented sandstone model to obtain the modeling result.

[0110] Specifically, when physically modeling the target rock through the uncemented sandstone model, the original effective pressure is set to 30 MPa, and the modeling result is as shown in Figure 4 shown below, Figure 4 which is the modeling result curve graph of the uncemented sandstone model provided by the embodiment of the present application.

[0111] It should be noted that it can be seen from Figure 3 and Figure 4 that the modeling result of the inclusion model is better than that of the uncemented sandstone model. Therefore, the elastic modulus obtained by using the inclusion model is used as the reference elastic modulus.

[0112] Third step, obtain the elastic modulus under certain pressure conditions.

[0113] In some embodiments, a two-phase mixture can be simulated by gradually adding an inclusion phase to the solid mineral phase (target rock). The solid mineral is phase 1, and then the material of phase 2 is gradually added until the predetermined content of each component is reached.

[0114] In some embodiments, phase 2 can be selected as water or oil.

[0115] Figure 5 This is the effective elastic modulus curve graph of the uncemented sandstone model under different pressures provided by the embodiment of the present application. Substitute the modulus change in Figure 5 into the reference elastic modulus calculated by the inclusion model, and calculate the elastic parameters after the pressure change, as shown in Figure 6 , Figure 7 shown below, where Figure 6 is the longitudinal and transverse wave velocity change curve graph with the effective pressure under the condition of saturated water provided by the embodiment of the present application, Figure 7 is the longitudinal and transverse wave velocity change curve graph with the effective pressure under the condition of saturated oil provided by the embodiment of the present application.

[0116] Fourth step, obtain the curve graph of the longitudinal and transverse wave velocities changing with the effective stress according to the above curve graphs. For details, see Figure 8 , Figure 8The graph shows the variation of P-wave and S-wave velocities with effective stress provided by the embodiments of the present application.

[0117] From Figure 8 it can be seen that the P-wave and S-wave velocities increase significantly with the increase of effective stress, and the increase amount decreases with the increase of effective stress. This characteristic is caused by the decrease in the sensitivity of the compacted rock to effective stress.

[0118] The above analysis results based on the rock physics model considering pressure changes can be used to evaluate the rationality of describing reservoir changes through time-lapse seismic data; and combined with the inversion results of multiple time-lapse seismic data, the pressure changes inside the reservoir during the development process can be quantitatively analyzed, laying a foundation for the efficient development of the reservoir in the next step.

[0119] In this embodiment, physical modeling of rocks in turbidite areas is carried out to verify the rationality and superiority of the comprehensive rock physics model considering pressure changes proposed by the present invention. In application scenarios such as time-lapse seismic, the method for constructing a comprehensive rock physics model considering pressure changes improves the accuracy and rationality of rock physics modeling.

[0120] Embodiment III

[0121] In 1996, Dvorkin and Nur proposed an uncemented sandstone model suitable for high-porosity sandstone. The core of this model is to obtain the high-porosity end-point modulus related to pressure through Hertz-Mindlin theory, and then use the improved Hashin-Strikman lower boundary to obtain the effective modulus of different porosities.

[0122] The contact Hertz-Mindlin theory gives the effective bulk modulus (K HM ) and shear modulus (μ HM ) of the skeleton under hydrostatic pressure P:

[0123]

[0124]

[0125] where C is the coordination number, μ and υ are the shear modulus and Poisson's ratio of solid particles respectively, φ0 is the porosity, and P is the hydrostatic pressure. The high-porosity end-point can be obtained not only through Hertz-Mindlin theory but also through experimental measurement of high-porosity sandstone.

[0126] The effective modulus of different porosities can be obtained by using the improved Hashin-Strikman lower boundary:

[0127]

[0128]

[0129] Although the above uncemented sandstone model considers the influence of pressure change on the elastic modulus, its shortcoming is that it fails to make full use of the many pieces of information obtained from well logging.

[0130] The inclusion model is a widely used petrophysical model. It makes full use of the information provided by well logging and uses the pore ellipsoid ratio to characterize the influence of pore morphology on the elastic modulus. Structurally, the inclusion model does not conform to sandstone, but from the concept of equivalent elasticity, it is appropriate to use the inclusion model to describe sandstone.

[0131] Here, taking the differential equivalent medium model as an example, the core of the inclusion model is briefly described. The differential equivalent medium theory simulates a two-phase mixture by gradually adding an inclusion phase to the solid mineral phase. The solid mineral is used as phase 1, and then the material of phase 2 is gradually added until the content of each component reaches the predetermined content value, and then the addition of the material of phase 2 is stopped. The differential equations coupling the equivalent volume and the shear modulus K * and μ * can be respectively expressed by the following formulas:

[0132]

[0133]

[0134] Among them, represents the derivative with respect to y, P and Q are the geometric factors of the bulk strain and the shear strain, and the superscript eff2 of P (*2) and Q (*2) means that this geometric strain factor is for the inclusion material 2 in the background medium with the equivalent modulus and . The initial condition is K * (0) = K1 and μ * (0) = μ1, where K1 and μ1 are the bulk modulus and the shear modulus of the initial main phase material, K2 and μ2 are the bulk modulus and the shear modulus of the gradually added inclusion, and y is the content of phase 2. For fluid inclusions and empty inclusions, y is the porosity φ.

[0135] It should be noted that the above-mentioned predetermined content value can be set according to actual needs.

[0136] In some embodiments, a two-phase mixture is simulated by gradually adding an inclusion phase to the solid mineral phase. The solid mineral is used as phase 1, and then the material of phase 2 is gradually added until phase 1 reaches the saturation state.

[0137] Considering the respective advantages and disadvantages of the uncemented sandstone model and the inclusion model, this embodiment provides a comprehensive rock physical model construction device combining the inclusion model and the uncemented sandstone model.Figure 9 The structural schematic diagram of a rock physics model construction device provided by an embodiment of the present application. As Figure 9 shown, the device of this embodiment includes:

[0138] A density acquisition unit 901, configured to acquire the density of a target rock.

[0139] In some embodiments, the density acquisition unit 901 is configured to acquire the density of the target rock based on logging data.

[0140] In some embodiments, the density acquisition unit 901 acquires the density of the target rock from logging curve data.

[0141] A first elastic modulus acquisition unit 902, configured to perform physical modeling on the target rock through an inclusion model, with a reference elastic modulus M0.

[0142] In some embodiments, the first elastic modulus acquisition unit 902 can obtain the elastic modulus M0 through the following formula and use this elastic modulus M0 as the reference elastic modulus:

[0143]

[0144]

[0145] where the initial conditions are K * (0)=K1 and μ * (0)=μ1, K1 and μ1 are the bulk modulus and shear modulus of the initial matrix material, K2 and μ2 are the bulk modulus and shear modulus of the gradually added inclusions, and y is the content of phase 2. For fluid inclusions and empty inclusions, y is the porosity φ.

[0146] A second elastic modulus acquisition unit 903, configured to perform physical modeling on the target rock through a non-cemented sandstone model to obtain the elastic modulus M at a pressure of P0 P0 and the elastic modulus M at a pressure of P1 P1 .

[0147] In some embodiments, the second elastic modulus acquisition unit 903 can obtain the elastic modulus M at a pressure of P0 through the following formula P0 and the elastic modulus M at a pressure of P1 P1 :

[0148]

[0149]

[0150]

[0151]

[0152] Among them, K HM is the effective bulk modulus of the skeleton, and μ HM is the shear modulus.

[0153] The elastic modulus change acquisition unit 904 is configured to obtain the elastic modulus change ΔM based on the elastic modulus M P0 and the elastic modulus M P1 .

[0154] In some embodiments, the elastic modulus change acquisition unit 904 is configured to use the difference between the elastic modulus M P1 and the elastic modulus M P0 as the elastic modulus change ΔM.

[0155] The third elastic modulus acquisition unit 905 is configured to obtain the elastic modulus M1 after the pressure change based on the reference elastic modulus M0 and the elastic modulus change ΔM.

[0156] In some embodiments, the third elastic modulus acquisition unit 905 is configured to use the sum of the reference elastic modulus M0 and the elastic modulus change ΔM as the elastic modulus M1 after the pressure change.

[0157] The wave velocity acquisition unit 906 is configured to obtain the longitudinal wave velocity VP and the shear wave velocity VS based on the elastic modulus M1 and the density.

[0158] Furthermore, by comprehensively analyzing the physical modeling results of the target rock, it provides data support for subsequent reservoir prediction.

[0159] The above analysis results based on the rock physics model considering pressure change can be used to evaluate the rationality of describing the changes in the oil and gas reservoir through time-lapse seismic data; and combined with the inversion results of multiple time-lapse seismic data, it can quantitatively analyze the pressure changes inside the oil and gas reservoir during the development process, laying a foundation for the efficient development of the next step of the oil and gas reservoir.

[0160] This embodiment provides a comprehensive rock physics model construction device 900 combining the inclusion model and the uncemented sandstone model. The density acquisition unit 901 is configured to obtain the density of the target rock; the first elastic modulus acquisition unit 902 is configured to perform physical modeling on the target rock through the inclusion model to obtain the reference elastic modulus M0; the second elastic modulus acquisition unit 903 is configured to perform physical modeling on the target rock through the uncemented sandstone model to obtain the elastic modulus M P0 when the pressure is P0 and the elastic modulus M P1 when the pressure is P1; the elastic modulus change acquisition unit 904 is configured to obtain the elastic modulus M P0and the elastic modulus M P1 , obtaining the change in elastic modulus ΔM; a third elastic modulus obtaining unit 905, configured to obtain the elastic modulus M1 after pressure change based on the reference elastic modulus M0 and the change in elastic modulus ΔM; a wave velocity obtaining unit 906, configured to obtain the longitudinal wave velocity VP and the shear wave velocity VS based on the elastic modulus M1 and the density. In this embodiment, based on the analysis result of the rock physics model considering pressure change, it can be used to evaluate the rationality of describing the change of oil and gas reservoirs through time-lapse seismic data; and combined with the inversion results of multiple time-lapse seismic data, the pressure change inside the oil and gas reservoirs during the development process can be quantitatively analyzed, laying a foundation for the efficient development of the next step of the oil and gas reservoirs. In application scenarios such as time-lapse seismic, the comprehensive rock physics model construction method considering pressure change improves the accuracy and rationality of rock physics modeling.

[0161] Embodiment 4

[0162] In 1996, Dvorkin and Nur proposed an uncemented sandstone model applicable to high-porosity sandstone. The core of this model is to obtain the high-porosity end-point modulus related to pressure through the Hertz-Mindlin theory, and then use the improved Hashin-Strikman lower bound to obtain the effective modulus of different porosities.

[0163] The contact Hertz-Mindlin theory gives the effective bulk modulus (K HM ) and shear modulus (μ HM ) of the skeleton under hydrostatic pressure P:

[0164]

[0165]

[0166] where C is the coordination number, μ and υ are the shear modulus and Poisson's ratio of the solid particles respectively, φ0 is the porosity, and P is the hydrostatic pressure. The high-porosity end-point can be obtained not only through the Hertz-Mindlin theory but also through experimental measurement of high-porosity sandstone.

[0167] The effective modulus of different porosities can be obtained using the improved Hashin-Strikman lower bound:

[0168]

[0169]

[0170] Although the above uncemented sandstone model considers the influence of pressure change on the elastic modulus, its deficiency is that it fails to fully utilize the many information obtained from well logging.

[0171] The inclusion model is a widely used rock physics model that makes full use of the information provided by logging and uses the pore ellipsoid ratio to characterize the influence of pore morphology on the elastic modulus. Structurally, the inclusion model does not conform to sandstone, but from the concept of equivalent elasticity, it is appropriate to describe sandstone with the inclusion model.

[0172] Here, taking the differential equivalent medium model as an example, the core of the inclusion model is briefly described. The differential equivalent medium theory simulates a two-phase mixture by gradually adding the inclusion phase to the solid mineral phase. The solid mineral is used as phase 1, and then the material of phase 2 is gradually added until the content of each component reaches the predetermined content value, and then the addition of the material of phase 2 is stopped. The equivalent volume and shear modulus K * and μ * The coupled differential equations can be expressed by the following equations respectively:

[0173]

[0174]

[0175] Among them, represents the derivative with respect to y. P and Q are the geometric factors of the bulk strain and shear strain. The superscript eff2 of P (*2) and Q (*2) means that this geometric strain factor is for the inclusion material 2 in the background medium with equivalent moduli and The initial conditions are K * (0) = K1 and μ * (0) = μ1. K1 and μ1 are the bulk modulus and shear modulus of the initial main phase material, K2 and μ2 are the bulk modulus and shear modulus of the gradually added inclusions, and y is the content of phase 2. For fluid inclusions and empty inclusions, y is the porosity φ.

[0176] It should be noted that the above-mentioned predetermined content value can be set according to actual needs.

[0177] In some embodiments, a two-phase mixture is simulated by gradually adding the inclusion phase to the solid mineral phase. The solid mineral is used as phase 1, and then the material of phase 2 is gradually added until phase 1 reaches the saturation state.

[0178] Considering the respective advantages and disadvantages of the uncemented sandstone model and the inclusion model, another aspect of the present invention provides a storage medium in which a computer program is stored. When the computer program is executed by a processor, the rock physics model construction method as described above is implemented:

[0179] Obtain the density of the target rock and perform physical modeling on the target rock through the inclusion model to obtain the reference elastic modulus M0;

[0180] Physically model the target rock through a non-cemented sandstone model to obtain the elastic modulus M at a pressure of P0 P0 and the elastic modulus M at a pressure of P1 P1 ;

[0181] Based on the elastic modulus M P0 and the elastic modulus M P1 , obtain the change in elastic modulus ΔM;

[0182] Based on the reference elastic modulus M0 and the change in elastic modulus ΔM, obtain the elastic modulus M1 after the pressure change;

[0183] Based on the elastic modulus M1 and the density, obtain the longitudinal wave velocity VP and the shear wave velocity VS.

[0184] In some embodiments, obtain the density of the target rock from the logging curve.

[0185] In some embodiments, the following formula can be used to obtain the elastic modulus M0 and use this elastic modulus M0 as the reference elastic modulus:

[0186]

[0187]

[0188] where the initial conditions are K * (0) = K1 and μ * (0) = μ1, K1 and μ1 are the bulk modulus and shear model of the initial matrix material, K2 and μ2 are the bulk modulus and shear modulus of the gradually added inclusions, and y is the content of phase 2. For fluid inclusions and empty inclusions, y is the porosity φ.

[0189] In some embodiments, the elastic modulus M at a pressure of P0 can be obtained through the following formula P0 and the elastic modulus M at a pressure of P1 P1 :

[0190]

[0191]

[0192]

[0193]

[0194] where K HM is the effective bulk modulus of the skeleton, and μ HM is the shear modulus.

[0195] In some embodiments, based on the elastic modulus M P0 and the elastic modulus M P1 , an elastic modulus change ΔM is obtained, including:

[0196] Taking the difference between the elastic modulus M P1 and the elastic modulus M P0 as the elastic modulus change ΔM.

[0197] In some embodiments, based on the reference elastic modulus M0 and the elastic modulus change ΔM, an elastic modulus M1 after pressure change is obtained, including:

[0198] Taking the sum of the reference elastic modulus M0 and the elastic modulus change ΔM as the elastic modulus M1 after pressure change.

[0199] In some embodiments, the physical modeling results of the target rock are comprehensively analyzed to provide data support for subsequent reservoir prediction.

[0200] Among them, the storage medium may also separately include a computer program, a data file, a data structure, etc., or include a combination thereof. The storage medium or the computer program can be specifically designed and understood by those skilled in the computer software field, or the storage medium may be known and available to those skilled in the computer software field. Examples of the storage medium include: magnetic media, such as hard disks, floppy disks, and magnetic tapes; optical media, such as CD-ROM discs and DVDs; magneto-optical media, such as optical discs; and hardware devices specifically configured to store and execute computer programs, such as read-only memory (ROM), random access memory (RAM), flash memory; or servers, app application stores, etc. Examples of computer programs include machine code (e.g., code generated by a compiler) and files containing high-level code that can be executed by a computer by using an interpreter. The described hardware devices can be configured to act as one or more software modules to perform the operations and methods described above, and vice versa. Additionally, the storage medium can be distributed in a networked computer system and can store and execute program code or computer programs in a decentralized manner.

[0201] In this embodiment, the density of the target rock is obtained; the target rock is physically modeled through an inclusion model to obtain a reference elastic modulus M0; the target rock is physically modeled through an uncemented sandstone model to obtain the elastic modulus M P0 when the pressure is P0 and the elastic modulus M P1 when the pressure is P1; based on the elastic modulus M P0 and the elastic modulus M P1, obtain the change in elastic modulus ΔM; based on the reference elastic modulus M0 and the change in elastic modulus ΔM, obtain the elastic modulus M1 after pressure change; based on the elastic modulus M1 and the density, obtain the longitudinal wave velocity VP and the shear wave velocity VS. The analysis result based on the rock physics model considering pressure change in this embodiment can be used to evaluate the rationality of describing the changes in oil and gas reservoirs through time-lapse seismic data; and combined with the inversion results of multiple time-lapse seismic data, the pressure changes inside the oil and gas reservoirs during the development process can be quantitatively analyzed, laying a foundation for the efficient development of the next step of the oil and gas reservoirs. In application scenarios such as time-lapse seismic, the comprehensive rock physics model construction method considering pressure change improves the accuracy and rationality of rock physics modeling.

[0202] Embodiment Five

[0203] In 1996, Dvorkin and Nur proposed an uncemented sandstone model applicable to highly porous sandstones. The core of this model is to obtain the high-porosity end-point modulus related to pressure through the Hertz-Mindlin theory, and then use the improved Hashin-Strikman lower bound to obtain the effective modulus of different porosities.

[0204] The contact Hertz-Mindlin theory gives the effective bulk modulus (K HM ) and shear modulus (μ HM ) of the skeleton under hydrostatic pressure P:

[0205]

[0206]

[0207] where C is the coordination number, μ and υ are the shear modulus and Poisson's ratio of the solid particles respectively, φ0 is the porosity, and P is the hydrostatic pressure. The high-porosity end-point can be obtained not only through the Hertz-Mindlin theory, but also through experimental measurement of highly porous sandstones.

[0208] The effective modulus of different porosities can be obtained using the improved Hashin-Strikman lower bound:

[0209]

[0210]

[0211] Although the above uncemented sandstone model considers the influence of pressure change on the elastic modulus, its shortcoming is that it fails to fully utilize the many information obtained from logging.

[0212] The inclusion model is a widely used petrophysical model that makes full use of the information provided by logging and uses the pore ellipsoid ratio to characterize the influence of pore morphology on the elastic modulus. Structurally, the inclusion model does not conform to sandstone, but from the concept of equivalent elasticity, it is appropriate to describe sandstone with the inclusion model.

[0213] Here, taking the differential equivalent medium model as an example, the core of the inclusion model is briefly described. The differential equivalent medium theory simulates a two-phase mixture by gradually adding the inclusion phase to the solid mineral phase. The solid mineral is used as phase 1, and then the material of phase 2 is gradually added until the content of each component reaches the predetermined content value, and then the addition of the material of phase 2 is stopped. The coupled differential equations of the equivalent volume and shear modulus K * and μ * can be expressed by the following formulas respectively:

[0214]

[0215]

[0216] Among them, represents the derivative with respect to y, P and Q are the geometric factors of the bulk strain and shear strain, and the superscript of P (*2) and Q (*2) refers to that this geometric strain factor is for the inclusion material 2 in the background medium with equivalent moduli eff2 and and . The initial conditions are K * (0) = K1 and μ * (0) = μ1, where K1 and μ1 are the bulk modulus and shear modulus of the initial main phase material, K2 and μ2 are the bulk modulus and shear modulus of the gradually added inclusion, and y is the content of phase 2. For fluid inclusions and empty inclusions, y is the porosity φ.

[0217] It should be noted that the above-mentioned predetermined content value can be set according to actual needs.

[0218] In some embodiments, a two-phase mixture is simulated by gradually adding the inclusion phase to the solid mineral phase. The solid mineral is used as phase 1, and then the material of phase 2 is gradually added until phase 1 reaches the saturation state.

[0219] Considering the respective advantages and disadvantages of the uncemented sandstone model and the inclusion model, another aspect of the present invention provides an electronic device. Figure 10 This is a connection block diagram of an electronic device provided by an embodiment of the present application. As Figure 10 shown, the electronic device 500 may include: a processor 501, a memory 502, a multimedia component 503, an input / output (I / O) interface 504, and a communication component 505.

[0220] Among them, the processor 501 is used to execute all or part of the steps in the rock physics model construction method in the first embodiment. The memory 502 is used to store various types of data, which may include, for example, instructions of any application or method in the electronic device, as well as application-related data.

[0221] The processor 501 can be implemented by an application specific integrated circuit (ASIC), a digital signal processor (DSP), a digital signal processing device (DSPD), a programmable logic device (PLD), a field programmable gate array (FPGA), a controller, a microcontroller, a microprocessor or other electronic components, and is used to execute the rock physics model construction method in the first embodiment above.

[0222] The memory 502 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as a static random access memory (SRAM), an electrically erasable programmable read-only memory (EEPROM), an erasable programmable read-only memory (EPROM), a programmable read-only memory (PROM), a read-only memory (ROM), a magnetic memory, a flash memory, a magnetic disk or an optical disk.

[0223] The multimedia component 503 may include a screen and an audio component. The screen may be a touch screen. The audio component is used to output and / or input audio signals. For example, the audio component may include a microphone for receiving external audio signals. The received audio signals may be further stored in the memory or sent through the communication component. The audio component further includes at least one speaker for outputting audio signals.

[0224] The I / O interface 504 provides an interface between the processor 501 and other interface modules, and the other interface modules may be a keyboard, a mouse, buttons, etc. These buttons may be virtual buttons or physical buttons.

[0225] The communication component 505 is used for the electronic device 500 to communicate with other devices in a wired or wireless manner. Wireless communication, such as Wi-Fi, Bluetooth, Near Field Communication (NFC), 2G, 3G or 4G, or a combination of one or more of them. Accordingly, the communication component 505 may include: a Wi-Fi module, a Bluetooth module, an NFC module.

[0226] In summary, a method, an apparatus, a storage medium and an electronic device for constructing a rock physics model provided in this application, the method includes: obtaining the density of a target rock; performing physical modeling on the target rock through an inclusion model to obtain a reference elastic modulus M0; performing physical modeling on the target rock through an uncemented sandstone model to obtain an elastic modulus M when the pressure is P0 P0 and an elastic modulus M when the pressure is P1 P1 ; based on the elastic modulus M P0 and the elastic modulus M P1 , obtaining an elastic modulus change ΔM; based on the reference elastic modulus M0 and the elastic modulus change ΔM, obtaining an elastic modulus M1 after the pressure change; based on the elastic modulus M1 and the density, obtaining a longitudinal wave velocity VP and a shear wave velocity VS. The analysis result of the rock physics model considering the pressure change in this embodiment can be used to evaluate the rationality of describing the change of the oil and gas reservoir through time-lapse seismic data; and combined with the inversion results of multiple time-lapse seismic data, the pressure change inside the oil and gas reservoir during the development process can be quantitatively analyzed, laying a foundation for the efficient development of the next step of the oil and gas reservoir. In application scenarios such as time-lapse seismic, the comprehensive rock physics model construction method considering the pressure change improves the accuracy and rationality of rock physics modeling.

[0227] In several embodiments provided in this application, they can all be used to execute the rock physics model construction method described above. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the corresponding method provided above, and will not be elaborated here.

[0228] In addition, it should be understood that the methods disclosed in several embodiments provided in the embodiments of the present application can also be implemented in other ways. The method embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architectures, functions, and operations of the methods and devices according to multiple embodiments of the present invention. In this regard, each block in the flowchart or block diagram may represent a module, a computer program segment, or a part of a computer program. A module, a computer program segment, or a part of a computer program contains one or more computer programs for implementing the specified logical functions. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than marked in the accompanying drawings. In fact, they can be executed substantially in parallel, and they can sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram and / or flowchart, as well as the combination of blocks in the block diagram and / or flowchart, can be implemented by a dedicated hardware-based system for performing the specified functions or actions, or can be implemented by a combination of dedicated hardware and a computer program.

[0229] In the present invention, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the phrase "comprising a..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element; in the present invention, if there is a description of "first", "second", etc., it is only for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence of the indicated technical features; in the description of the present invention, unless otherwise clearly defined, terms such as "logging data" and "physical modeling" should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meaning of the terms in the present invention in combination with the specific content of the technical solution. In addition, in the description of the present application, unless otherwise stated, the meaning of "multiple" and "many" refers to at least two.

[0230] Finally, it should be noted that in the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "one example" or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0231] Although the embodiments disclosed in the present invention are as above, the content described is only an embodiment adopted for the convenience of understanding the present invention and is not intended to limit the present invention. Any person skilled in the art within the technical field to which the present invention pertains may make any modifications and changes in the form of implementation and details without departing from the spirit and scope disclosed by the present invention. However, the protection scope of the present invention shall still be subject to the scope defined by the appended claims.

Claims

1. A method for constructing a rock physics model, characterized in that, The method includes: Obtaining the density of the target rock; Physically modeling the target rock through an inclusion model to obtain a reference elastic modulus M0; Physically model the target rock through a non-cemented sandstone model to obtain the elastic modulus M at a pressure of P0 P0 and the elastic modulus M at a pressure of P1 P1 ; Based on the elastic modulus M P0 and the elastic modulus M P1 , obtain the change in elastic modulus ΔM; Based on the reference elastic modulus M0 and the change in elastic modulus ΔM, obtaining the elastic modulus M1 after the pressure change; Based on the elastic modulus M1 and the density, obtaining the longitudinal wave velocity VP and the shear wave velocity VS.

2. The method according to claim 1, wherein The obtaining the density of the target rock includes: Obtaining the density of the target rock based on logging data.

3. The method according to claim 1, wherein Based on the elastic modulus M P0 and the elastic modulus M P1 , obtaining a change in elastic modulus ΔM, including: Take the difference between the elastic modulus M P1 and the elastic modulus M P0 as the change in elastic modulus ΔM.

4. The method according to claim 1, wherein The obtaining the elastic modulus M1 after the pressure change based on the reference elastic modulus M0 and the change in elastic modulus ΔM includes: Taking the sum of the reference elastic modulus M0 and the change in elastic modulus ΔM as the elastic modulus M1 after the pressure change.

5. A rock physics model construction device, characterized in that, It includes: A density acquisition unit for obtaining the density of the target rock; A first elastic modulus acquisition unit for physically modeling the target rock through an inclusion model, the reference elastic modulus M0; A second elastic modulus acquisition unit, configured to perform physical modeling on the target rock through a non-cemented sandstone model to obtain an elastic modulus M at a pressure of P0 P0 and an elastic modulus M at a pressure of P1 P1 ; The elastic modulus change acquisition unit is configured to obtain a change in elastic modulus ΔM based on the elastic modulus M P0 and the elastic modulus M P1 , and obtain a change in elastic modulus ΔM; A third elastic modulus acquisition unit for obtaining the elastic modulus M1 after the pressure change based on the reference elastic modulus M0 and the change in elastic modulus ΔM; A wave velocity acquisition unit for obtaining the longitudinal wave velocity VP and the shear wave velocity VS based on the elastic modulus M1 and the density.

6. The device according to claim 5, wherein, The density acquisition unit is used to obtain the density of the target rock based on logging data.

7. The device according to claim 5, characterized in that, The elastic modulus change obtaining unit is configured to use the difference between the elastic modulus M P1 and the elastic modulus M P0 as the elastic modulus change ΔM.

8. The device according to claim 5, characterized in that, The third elastic modulus acquisition unit is used to take the sum of the reference elastic modulus M0 and the change in elastic modulus ΔM as the elastic modulus M1 after the pressure change.

9. A storage medium, characterized in that, The computer program stored in this storage medium can be executed by one or more processors and can be used to implement the rock physics model construction method described in any one of claims 1 to 4.

10. An electronic device, characterized in that, It includes a memory and a processor. A computer program is stored on the memory. The memory and the processor are communicatively connected to each other. When the computer program is executed by the processor, it executes the rock physics model construction method described in any one of claims 1 to 4.

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