Carbonate reservoir pore type seismic prediction method and device based on porous effective medium model

Abstract

The application discloses a carbonate porous effective medium model established based on an extended Keys-Xu model and a Gassmann-Hill equation, and a two-step multiple porosity inversion method, and in addition, a strategy of using a changing porosity aspect ratio as input instead of a fixed porosity aspect ratio is adopted in the inversion process, so that the accuracy of the multiple porosity inversion is improved. The method can not only accurately represent the distribution of three-pore types of the tight carbonate reservoir, but also successfully reveal the micro mechanism of oil and gas migration and accumulation, and provides a theoretical basis and technical support for representing the pore structure of the ultra-deep tight reservoir by using logging and seismic data. The strategy of the multiple porosity inversion of the porous medium model can also be applied to quantitative prediction of pore types of other lithologic tight reservoirs, and solves the problem that the multiple porosity of the tight reservoir is difficult to accurately predict.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of geophysical exploration, and particularly relates to a carbonate reservoir pore type seismic inversion method and device based on a porous effective medium model and electronic equipment. BACKGROUND

[0002] Carbonate reservoirs account for more than 50% of global oil and gas reserves, and have great exploration potential. Unlike conventional clastic reservoirs, carbonate reservoirs have complex pore structures due to cementation, compaction, dissolution, dolomitization and other diagenetic processes. The pore system of carbonate reservoirs usually includes vugular pores, intragranular pores, intergranular pores, intercrystalline pores and fractures (Zhao et al., 2013), which significantly affect the permeability, acoustic properties and seismic interpretation of carbonate reservoirs (Sun et al., 2006; Weger et al., 2009; Jin et al., 2023; Guo et al., 2023; Zhang et al., 2024). Therefore, accurate characterization of pore structure is crucial for evaluating reservoir quality, describing reservoir structure and identifying sweet spots within carbonate reservoirs.

[0003] Velocity deviation logging can be used to identify fractures and rigid pores (Anselmetti and Eberli, 1999); acoustic and density logging can also be used to derive matrix porosity and total porosity through empirical relationships (Du et al., 2024). However, difficulties arise when simultaneously evaluating multiple pore types at well sites (Wu et al., 2016; Sharifi et al., 2018). Therefore, there is an urgent need for a method that can simultaneously quantify the spatial distribution of multiple pore types within carbonate reservoirs.

[0004] The aspect ratio of the pore is defined as the ratio of the short axis to the long axis of the ellipsoidal pore, and is usually used to indicate the pore type (Guo et al., 2015; Fournier et al., 2018; Teillet et al., 2021). Based on the concept of classifying pore types by aspect ratio (rigid pores with aspect ratio 0.7-1.0 correspond to voids or modal pores; reference pores or matrix pores with aspect ratio 0.1-0.25 represent intergranular or intercrystalline pores; soft pores with aspect ratio 0.01-0.05 represent fractures), some studies have explored rock physics-based methods, especially effective medium theory based on inclusions, to characterize the complex pore structure of carbonate reservoirs (Xu and Payne, 2009; Zhao et al., 2013; Li, 2020; Saberi et al., 2020; Guo et al., 2021; Guo et al., 2022). In contrast, pore-type inversion methods such as the iterative method based on the DEM model and the Gassmann equation (Kumar and Han, 2005), the carbonate-specific adaptation of the Xu-White model (Xun and Payne, 2018), and other methods seem more suitable for quantifying complex pore systems. However, these methods are limited to the characterization of two pore types (reference pore / rigid pore or reference pore / fracture) at a single sampling point and are conditioned only on P-wave velocity. Therefore, it is necessary to study pore-type seismic inversion methods based on the multi-porosity assumption.

[0005] To solve the problem that the pore type inversion accuracy is not high due to considering only two pore types, the present application establishes a multi-porosity model of a dense carbonate reservoir based on the extended Keys-Xu model and the Gassmann-Hill equation, and characterizes the multi-pore type and its distribution in a heterogeneous carbonate reservoir by jointly using P-wave and S-wave velocities of logging and seismic data. SUMMARY

[0006] The present application aims to provide a pore type seismic inversion method, device and electronic equipment based on a multi-porosity effective medium model to solve the problems raised in the background art.

[0007] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0008] In a first aspect, a pore type seismic inversion method based on a multi-porosity effective medium model is provided, comprising:

[0009] Step S1: setting initial reservoir pore aspect ratio, reservoir porosity, reservoir fluid properties, and reservoir rock matrix properties; Step S2: calculating P-wave velocity V P,wyllie , V P,HS+ , V P,HS- , VP,KX ;

[0010] Step S3: Difference between the P-wave velocity calculated by the Wylie time average equation, the upper and lower bounds of the HS and the P-wave velocity calculated by the single-pore-type Keys-Xu model, respectively, is calculated, and when the difference between the P-wave velocity calculated by the Wylie time average equation, the upper and lower bounds of the HS and the P-wave velocity calculated by the single-pore-type Keys-Xu model all meet the cutoff condition, iteration is terminated, and the final reservoir pore aspect ratio is obtained, and the iteration calculation formula is as follows:

[0011] |V P,KX -V P,s |<ε,s=wyllie,HS+,HS-

[0012] In the formula, V P,KX represents the P-wave velocity calculated by the single-pore-type Keys-Xu model; V P,wyllie , VP,HS+ and V P,HS- respectively represent the P-wave velocities calculated by the Wylie time average equation, the upper bound of the HS and the lower bound of the HS; and ε represents the given minimum error.

[0013] Step S4: Based on the final reservoir pore aspect ratio obtained in step S3, and in combination with reservoir fluid properties, reservoir rock matrix properties, reservoir porosity, volume fractions of reservoir initial reference pores and reservoir initial fractures, the same are input into the constructed carbonate reservoir porous effective medium model, and P-wave velocity V P,cal and S-wave velocity V S,cal are calculated.

[0014] Step S5: The errors between the P-wave velocity V P,cal and S-wave velocity V S,cal calculated in step S4 and the logging measured values V P,obs and V S,obs are calculated by using the objective function J, and the expression of the objective function J is as follows:

[0015] J=|V P,obs -V P,cal | 2 +|V S,obs -V S,cal | 2

[0016] In the formula, V P,obs and V P,cal respectively represent the logging measured P-wave velocity and the P-wave velocity V S,obs calculated based on the carbonate reservoir porous effective medium model; and V S,cal represents the logging measured S-wave velocity and the S-wave velocity calculated based on the carbonate reservoir porous effective medium model.

[0017] Step S6: traversing the reference pore and fracture volume fractions in a given range with a set step size, so that the target function J in the step S5 is less than a given error σ, and the iteration is terminated, to obtain the final reference pore and fracture volume fractions;

[0018] Step S7: based on the final reference pore and fracture volume fractions obtained in the step S6, the final hard pore volume fraction is calculated;

[0019] Step S8: based on the final reference pore, fracture and hard pore volume fractions obtained in the step S7, combined with the reservoir porosity, the final reference pore, fracture and hard pore porosity is calculated, and the inversion is completed.

[0020] Further, the method for constructing the carbonate reservoir porous effective medium model in the step S4 comprises:

[0021] Step S41: using the Voigt-Reuss-Hill (VRH) model to calculate the bulk modulus and shear modulus of the rock matrix;

[0022] Step S42: using the extended Keys-Xu model to calculate the bulk modulus and shear modulus of the dry rock;

[0023] Step S43: using the Gassmann equation under the low frequency assumption to calculate the bulk modulus and shear modulus of the saturated rock, and using the Gassmann-Hill equation to determine the total bulk modulus and shear modulus of the saturated rock in the carbonate reservoir.

[0024] Further, the method for calculating the bulk modulus and shear modulus of the rock matrix using the Voigt-Reuss-Hill (VRH) model in the step S41 comprises:

[0025]

[0026] In the formula, f i , K i and G i respectively represent the volume fraction, bulk modulus and shear modulus of the i th mineral component; M represents the total number of mineral components contained in the rock matrix.

[0027] Further, the method for calculating the bulk modulus and shear modulus of the dry rock using the extended Keys-Xu model in the step S42 comprises:

[0028] The extended Keys-Xu model suitable for hard pores, reference pores and fractures is used to calculate the bulk modulus and shear modulus of the dry rock, and the formula is as follows:

[0029] K dry = K ma (1-φ)P

[0030] G dry = G ma (1-φ) Q

[0031] where φ represents porosity; P and Q are geometric factors related to the aspect ratio of the pores:

[0032]

[0033] where v s , v r and v c represent the volume fractions of hard pores, reference pores and fractures, respectively; α s , α r and α c represent the aspect ratios of hard pores, reference pores and fractures, respectively; T ijij (α l ) and T iijj (α l ) are functions of the aspect ratio.

[0034] Further, the method for calculating the bulk modulus and shear modulus of the saturated rock in step S43 under the low frequency assumption includes:

[0035]

[0036] G sat = G dry

[0037] where K fl represents the bulk modulus of the pore fluid.

[0038] Further, the method for calculating the bulk modulus and shear modulus of the overall saturated rock in step S43 using the Gassmann-Hill equation includes:

[0039]

[0040] where the bulk modulus K sat,w of the water-saturated rock and the bulk modulus K sat,g of the gas-saturated rock are calculated by the Gassmann equation under the low frequency assumption, and S w represents the water saturation.

[0041] Further, the method for calculating the P-wave velocity V P,wyllie in step S2 using the Wylie time average equation includes:

[0042]

[0043] where φ represents porosity; V P,fl and V P,ma represent the P-wave velocities of fluid and rock matrix, respectively.

[0044] Further, the P-wave velocity V P,HS+ , V P，HS- is calculated in step S2 by using the HS upper and lower bounds.

[0045] Step S21: the bulk modulus and shear modulus of the carbonate rock are calculated by using Hashin-Shtrikman (HS) upper and lower bounds:

[0046]

[0047] where K1, G1 and f1 represent the bulk modulus, shear modulus and volume fraction of the first phase, respectively; K2, G2 and f2 represent the bulk modulus, shear modulus and volume fraction of the second phase, respectively, and the calculation of the HS bounds is determined by switching the order of the first phase and the second phase, and "+" represents the upper bound and "-" represents the lower bound;

[0048] Step S22: the P-wave velocity V P，HS+ , V P，HS- of the carbonate rock reservoir is calculated based on the bulk modulus and shear modulus of the carbonate rock calculated in step S21:

[0049]

[0050] In a second aspect, a device for seismic inversion of pore types of a carbonate rock reservoir based on a porous effective medium model is provided, comprising: an initial setting unit: setting initial reservoir pore aspect ratio, reservoir porosity, reservoir fluid properties, and reservoir rock matrix properties;

[0051] a first P-wave velocity calculation unit: calculating the P-wave velocities V P，wtllie , V P，HS+ , V P，HS- , V P，KX by using the Wylie time-averaging equation, the HS upper and lower bounds, and the single-pore-type Keys-Xu model, respectively.

[0052] a pore aspect ratio calculation unit: the P-wave velocities calculated by the Wylie time-averaging equation and the HS upper and lower bounds are subtracted from the P-wave velocities calculated by the single-pore-type Keys-Xu model, respectively, and when the differences between the P-wave velocities calculated by the Wylie time-averaging equation and the HS upper and lower bounds and the P-wave velocities calculated by the single-pore-type Keys-Xu model both satisfy a cutoff condition, the iteration is terminated, and the final reservoir pore aspect ratio is obtained, and the iterative calculation formula is as follows:

[0053] |V P,KX -V P,s| <ε, s = wyllie, HS+, HS-

[0054] where V P,KX represents the P-wave velocity calculated by the single-porosity Keys-Xu model; V P,wyllie , V P,HS+ and V P,HS- represent the P-wave velocities calculated by the Wyllie time average equation, the HS upper bound and the HS lower bound, respectively; ε represents the given minimum error;

[0055] The second P-wave velocity calculation unit: based on the final reservoir aspect ratio obtained by the aspect ratio calculation unit, and combined with the reservoir fluid properties, reservoir rock matrix properties, reservoir porosity, the volume fractions of reservoir initial reference pores and reservoir initial fractures, the P-wave velocity V P，cal and the S-wave velocity V S,cal are calculated by the constructed carbonate reservoir porous effective medium model.

[0056] The objective function unit: the errors between the P-wave velocity V P，cal and the S-wave velocity V S，cal calculated by the second P-wave velocity calculation unit and their logging measured values V P，obs and V S，obs are calculated by the objective function J, and the expression of the objective function J is as follows:

[0057] J = |V P,obs -V P,cal | 2 + |V S,obs -V S,cal | 2

[0058] where V P,obs and V P,cal represent the P-wave velocities measured by logging and calculated by the carbonate reservoir porous effective medium model, respectively; V S,obs and V S,cal represent the S-wave velocities measured by logging and calculated by the carbonate reservoir porous effective medium model, respectively.

[0059] The reference pore and fracture volume fraction determination unit: the final reference pore and fracture volume fractions are obtained by traversing the reference pore and fracture volume fractions in a given range with a set step size, so that the iteration is terminated when the objective function J in the objective function unit is less than a given error σ.

[0060] The hard pore volume fraction determination unit: based on the final reference pore and fracture volume fractions obtained by the reference pore and fracture volume fraction determination unit, the final hard pore volume fraction is calculated.

[0061] The three-porosity calculation unit calculates the porosities of the final reference pores, cracks and hard pores based on the volume fractions of the hard pores determined by the hard pore volume fraction determination unit and the reservoir porosity, and completes the inversion.

[0062] In a third aspect, an electronic device is provided, comprising: a memory for storing a computer program; and a processor for implementing the steps of the carbonate reservoir pore type seismic inversion method based on the porous effective medium model when executing the computer program.

[0063] In a fourth aspect, a computer readable storage medium is provided, and the computer readable storage medium stores a computer program, and the steps of the carbonate reservoir pore type seismic inversion method based on the porous effective medium model are implemented when the computer program is executed by a processor.

[0064] By adopting the above technical solution, the accuracy of the multiple porosity inversion is improved, and the distribution of the three-porosity types of the dense carbonate reservoir can be accurately characterized.

[0065] Compared with the prior art, the beneficial effects of the present application are:

[0066] The method provided by the present application simultaneously considers the coexistence of the three-porosity types, performs the multiple porosity inversion based on the carbonate porous effective medium model established based on the extended Keys-Xu model and the Gassmann-Hill equation, and adopts the strategy of using the changing porosity aspect ratio as the input in the inversion process instead of the fixed porosity aspect ratio, thereby improving the accuracy of the multiple porosity inversion. The method not only can accurately characterize the distribution of the three-porosity types of the dense carbonate reservoir, but also can successfully reveal the microscopic mechanism of the oil and gas migration and accumulation, and provides a theoretical basis and technical support for characterizing the pore structure of the ultra-deep dense reservoir by using the logging and seismic data. BRIEF DESCRIPTION OF DRAWINGS

[0067] Figure 1 The pore type seismic inversion method based on the porous effective medium model according to the embodiment of the present application is provided, and a flowchart of the implementation is shown in FIG. 1.

[0068] Figure 2 The two-step method for inverting the multiple porosity in the pore type seismic inversion method based on the porous effective medium model according to the embodiment of the present application is provided, and a flowchart of the implementation of the specific details is shown in FIG. 2.

[0069] Figure 3 The method for constructing the carbonate porous effective medium model according to the embodiment of the present application is provided, and a flowchart of the implementation is shown in FIG. 3.

[0070] Figure 4 The method for constructing the carbonate porous effective medium model according to the embodiment of the present application is provided, and a flowchart of the implementation of the specific details is shown in FIG. 4.

[0071] Figure 5 The flow chart of calculating the P-wave velocity on the HS upper and lower boundaries in the pore type seismic inversion method based on the porous effective medium model according to the embodiment of the present application;

[0072] Figure 6 The device structure diagram of the pore type seismic inversion based on the porous effective medium model according to the embodiment of the present application;

[0073] Figure 7 The quantitative relationship between the pore type and the porosity and the P-wave velocity and the S-wave velocity in the limestone and dolomite reservoir according to the embodiment of the present application;

[0074] Figure 8 The result comparison diagram of the pore type seismic inversion method based on the porous effective medium model according to the embodiment of the present application;

[0075] Figure 9 The spatial distribution characteristics of the total porosity and the multiple porosity predicted by the pore type seismic inversion method based on the porous effective medium model according to the embodiment of the present application.

[0076] Figure 10 The structure diagram of an electronic device according to the embodiment of the present application. DETAILED DESCRIPTION

[0077] In order to make the personnel in the art better understand the present application scheme, the technical scheme in the embodiment of the present application will be described clearly and completely below in combination with the drawings in the embodiment of the present application. Obviously, the described embodiment is only a part of the embodiment of the present application, not all. Based on the embodiment in the present application, all other embodiments obtained by the person skilled in the art without creative labor should belong to the scope of protection of the present application.

[0078] It should be noted that the terms "first", "second", and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or a chronological sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0079] Figures 1-2, 5 is a pore type seismic inversion method based on a porous effective medium model provided by an embodiment of the present application, a specific two-step inversion multiple porosity specific detail implementation flowchart, and a P-wave velocity flowchart for calculating the upper and lower boundaries of HS. For ease of description, only parts related to the embodiments of the present application are shown, and are described in detail as follows:

[0080] The pore type seismic inversion method based on the porous effective medium model comprises:

[0081] Step S1: setting initial reservoir pore aspect ratio, reservoir porosity, reservoir fluid properties, and reservoir rock matrix properties;

[0082] Step S2: respectively calculating P-wave velocities V P,wyllie , V P,HS+ , V P,HS- , and V P,KX by using the Wylie time average equation, the upper and lower boundaries of HS, and the single-pore-type Keys-Xu model;

[0083] Step S3: respectively subtracting the P-wave velocities calculated by the Wylie time average equation and the upper and lower boundaries of HS from the P-wave velocities calculated by the single-pore-type Keys-Xu model, and terminating iteration when the differences between the P-wave velocities calculated by the Wylie time average equation and the upper and lower boundaries of HS and the P-wave velocities calculated by the single-pore-type Keys-Xu model both satisfy a cutoff condition, to obtain a final reservoir pore aspect ratio, and the iteration calculation formula is as follows:

[0084] |V P,KX -V P,s |<ε,s=wyllie,HS+,HS-

[0085] In the formula, V P,KX represents the P-wave velocity calculated by the single-pore-type Keys-Xu model; V P,wyllie , V P,HS+ , and V P,HS- respectively represent the P-wave velocities calculated by the Wylie time average equation, the upper boundary of HS, and the lower boundary of HS; and ε represents a given minimum error.

[0086] Step S4: obtaining the final reservoir pore aspect ratio based on step S3, and combining reservoir fluid properties, reservoir rock matrix properties, reservoir porosity, a volume fraction of reservoir initial reference pores, and a volume fraction of reservoir initial fractures to input them into a constructed carbonate reservoir porous effective medium model to calculate P-wave velocity V P,cal and S-wave velocity V S,cal ;

[0087] Step S5: calculating the P-wave velocity V P,cal and the S-wave velocity V S,calIts well logging measurement value V P,obs V S,obs The error between them is expressed by the objective function J as follows:

[0088] J = |V P,obs -V P,cal | 2 +|V S,obs -V S,cal | 2

[0089] In the formula, V P,obs and V P,cal These represent the P-wave velocity measured by well logging and the P-wave velocity V calculated based on the porous effective medium model of carbonate reservoirs, respectively. S,obs and V S,cal These represent the P-wave velocity measured by well logging and the S-wave velocity calculated based on the porous effective medium model of carbonate reservoirs, respectively.

[0090] Step S6: The iteration is terminated when the objective function J in step S5 is less than the given error σ by traversing the reference hole and crack volume fractions within a given range with a set step size, so as to obtain the final reference hole and crack volume fractions.

[0091] Step S7: Based on the final reference hole and crack volume fractions obtained in Step S6, calculate the final hard hole volume fraction;

[0092] Step S8: Based on the final reference pore, fracture, and hard pore volume fractions obtained in Step S7, and combined with the reservoir porosity, calculate the final reference pore, fracture, and hard pore porosity to complete the inversion.

[0093] Specifically, the workflow of the two-step multi-pore type seismic inversion method is as follows:

[0094] (1) Aspect Ratio Estimation of Three Pore Types

[0095] By setting the initial porosity aspect ratio and its search range, the P-wave velocity of carbonate rocks containing rigid pores, reference pores, and fractures is calculated using the Willy time-averaged equation:

[0096]

[0097] In the formula, φ represents porosity; V P,fl and V P,ma These represent the longitudinal wave velocities of the fluid and the rock matrix, respectively.

[0098] Calculate the elastic modulus of carbonate rocks containing hard pores, reference pores, and fractures using the Hashin-Shtrikman (HS) boundary:

[0099]

[0100] where K1, G1and f1represent the bulk modulus, shear modulus and volume fraction of the first phase, respectively; K2, G2and f2represent the bulk modulus, shear modulus and volume fraction of the second phase. The calculation of the HS bounds is determined by swapping the order of the first and second phases.

[0101] The P-wave velocity of carbonate reservoirs with rigid pores, reference pores and fractures is calculated using the HS bounds:

[0102]

[0103] The P-wave velocity of carbonate reservoirs is calculated using the single-pore-type Keys-Xu model by assigning an initial pore aspect ratio, and the difference between the P-wave velocity calculated using the Wylie time-average equation and the P-wave velocity calculated using the HS bounds is used to update the iterative pore aspect ratio. The iteration is terminated when the error between the P-wave velocity calculated using the Wylie time-average equation and the P-wave velocity calculated using the single-pore-type Keys-Xu model satisfies the following condition, and the pore aspect ratio is obtained.

[0104] |V P,KX -V P,s |<ε,s=wyllie,HS+,HS-

[0105] where V P,KX represents the P-wave velocity calculated using the single-pore-type Keys-Xu model; V P,wyllie , V P,HS+ and V P,HS- represent the P-wave velocity calculated using the Wylie time-average equation, the HS upper bound and the HS lower bound, respectively; ε represents the given minimum error.

[0106] In particular, V P,KX represents the P-wave velocity calculated using the single-pore-type Keys-Xu model, and the single-pore-type Keys-Xu model can calculate the bulk modulus and shear modulus of dry rock:

[0107] K dry = K ma (1-φ) P

[0108] G dry = G ma (1-φ) Q

[0109] where φ represents the porosity; P0and Q0are geometric factors related to the pore aspect ratio:

[0110]

[0111] where α represents the pore aspect ratio; Tijij (a) and T iijj (a) is a function of the pore aspect ratio.

[0112] On this basis, the bulk modulus and shear modulus of the saturated rock are calculated using the Gassmann equation under the low frequency assumption:

[0113]

[0114] G sat = G dry

[0115] where K fl represents the bulk modulus of the pore fluid.

[0116] The method for determining the bulk modulus and shear modulus of the overall saturated rock using the Gassmann-Hill equation comprises:

[0117]

[0118] where the bulk modulus of the water-saturated rock K sat,w and the bulk modulus of the gas-saturated rock K sat,g are calculated using the Gassmann equation under the low frequency assumption, S w represents the water saturation. (Specifically, the bulk modulus of the water-saturated rock K sat,w (i.e. calculated when K fl = K w in the above Gassmann equation under the low frequency assumption) can be obtained according to the above formula. The bulk modulus of the gas-saturated rock K sat,g (i.e. calculated when K fl = K g in the above Gassmann equation under the low frequency assumption) can be obtained according to the above formula.

[0119] Thus, the P-wave velocity calculated based on the single-pore-type Keys-Xu model is:

[0120]

[0121] (2) Three-pore-type percentage inversion

[0122] The following carbonate three-porosity effective medium modeling procedure is used to calculate the P-wave and S-wave velocities of the rock using the calculated porosity aspect ratio, total porosity, rock matrix and fluid properties as inputs. The objective function J is used to calculate the error between the P-wave and S-wave velocities calculated by the carbonate three-porosity effective medium model and their measured values. If this error is greater than or equal to a given error σ, then the reference pore and fracture volume fractions that result in an error less than the given error σ are found by traversing the given range of reference pore and fracture volume fractions in a certain step size (grid search method). The objective function is as follows:

[0123] J = |V P,obs -V P,cal | 2 +|V S,obs -V S,cal | 2

[0124] where V P,obs and V P,cal are the measured and calculated P-wave velocities, respectively;

[0125] V S,obs and V S,cal are the measured and calculated S-wave velocities, respectively.

[0126] In particular, first, initial pore aspect ratios (initial pore aspect ratios, hard pores are 0.5, reference pores are 0.1, and cracks are 0.001) are set, porosities (in actual cases, about 2% to 12% in this case), fluid properties (in actual cases, including the elastic modulus, density, and volume fraction of water and gas in this application), and rock matrix properties (in actual cases, including the elastic modulus, density, and volume fraction of dolomite, calcite, quartz, and clay in this application) are used to calculate the P-wave velocity using the Wylie time average equation, the HS boundary, and the single-pore-type Keys-Xu model, the difference between the P-wave velocity calculated by the single-pore-type Keys-Xu model and the P-wave velocity calculated by the Wylie time average equation and the HS boundary is found, and when the difference is greater than 0.1 km / s, the range of the pore aspect ratio is traversed in steps of 0.001 to find the pore aspect ratio that can make the error less than 0.1 km / s. According to the fluid properties (including the elastic modulus, density, and volume fraction of the fluid), rock matrix properties (including the elastic modulus, density, and volume fraction of the rock matrix), calculated pore aspect ratio, total porosity (about 2% to 12% in this application), and given initial reference pore and crack volume fractions (reference pore volume fraction is 1, and crack is 0), the error is calculated according to the objective function, and when the error is greater than 0.1 km / s, the reference pore and crack volume fraction combination that makes the error meet the requirements is traversed in steps of 0.01 in the range of 0 to 1, and the volume fraction of the dissolved pore is obtained by subtracting the volume fraction of the reference pore and the crack from 1; the three porosities are obtained by multiplying the total porosity, respectively. The mineral components and fluid volume fractions involved in this case are obtained from the logging curve, and the elastic modulus and density are shown in Table 1.

[0127] Table 1 Elastic Modulus and Density of Each Mineral Component

[0128]

[0129]

[0130] Figures 3-4 To provide a flowchart of the method for constructing a double-occurrence hydrate reservoir rock physics model according to the embodiments of the present application, and a specific detail implementation flowchart. For ease of description, only parts related to the embodiments of the present application are shown, and are described in detail as follows:

[0131] The method for constructing a carbonate reservoir porous effective medium model comprises:

[0132] Step S41: The Voigt-Reuss-Hill (VRH) model is used to calculate the bulk modulus and shear modulus of the rock matrix.

[0133] Step S42: The extended Keys-Xu model is used to calculate the bulk modulus and shear modulus of the dry rock.

[0134] Step S43: Calculate the bulk modulus and shear modulus of the saturated rock using the Gassmann equation under the low-frequency assumption, and determine the bulk modulus and shear modulus of the total saturated rock in the carbonate reservoir using the Gassmann-Hill equation.

[0135] In particular, the rock physics model based on the porous assumption first uses the VRH average to mix dolomite, calcite, quartz and clay to form a rock matrix; uses the extended Keys-Xu model to add hard pores, reference pores and fractures to the rock matrix to form a dry rock skeleton; and finally uses the Gassmann-Hill equation to fill the pores with fluid to form a saturated rock.

[0136] Specifically, the rock physics modeling process of the porous medium of the tight carbonate reservoir is as follows:

[0137] (1) Calculation of the bulk modulus and shear modulus of the rock matrix

[0138] The carbonate reservoir is mainly composed of calcite and dolomite, and contains a small amount of low quartz, anhydrite and clay minerals. The bulk modulus and shear modulus of each mineral component are known, and the VRH average (Hill, 1952) can be used to calculate the bulk modulus and shear modulus of the rock mechanism:

[0139]

[0140] In the formula, f i , K i and G i respectively represent the volume fraction, bulk modulus and shear modulus of the i-th mineral component; and M represents the total number of mineral components included in the rock matrix.

[0141] (2) Calculation of the bulk modulus and shear modulus of the dry rock

[0142] For the carbonate reservoir, the extended Keys-Xu model suitable for hard pores, reference pores and fractures can be used to calculate the bulk modulus and shear modulus of the dry rock:

[0143] K dry = K ma (1-φ) P

[0144] G dry = G ma (1-φ) Q

[0145] In the formula, φ represents the porosity; and P and Q are geometric factors related to the aspect ratio of the pores:

[0146]

[0147] where v s , v r and v c are the volume fractions of rigid pores, reference pores and fractures, respectively; a s , a r and a c are the pore aspect ratios of rigid pores (hard pores), reference pores and fractures, respectively; T ijij ( a l ) and T iijj ( a l ) are the functions of pore aspect ratio (Berryman, 1980) and are expressed as follows:

[0148] T iijj ( a ) = 3 F1 / F2

[0149]

[0150]

[0151] A = G j / G ma -1

[0152]

[0153] R = (1 - 2 γ m ) / 2 (1 - γ m )

[0154]

[0155] where F 1～9 , θ and are functions of pore aspect ratio; A, B, R and γ m are functions of elastic modulus; K ma and G ma are the bulk and shear moduli of the rock matrix, respectively; K j and G j are the bulk and shear moduli of the inclusions, respectively; a is the pore aspect ratio.

[0156] (3) Calculation of bulk and shear moduli of saturated rock

[0157] To determine the bulk and shear moduli of fluid-saturated rock, the Gassmann equation under the low-frequency assumption is used to calculate the bulk and shear moduli of saturated rock:

[0158]

[0159] G sat = Gdry

[0160] In the formula, K fl This represents the bulk modulus of a pore fluid.

[0161] The bulk modulus K of saturated water rock can be obtained from the above formula. sat,w (that is, when K in the Gassmann equation under the above low-frequency assumption) fl =K w (Calculated at the time).

[0162] The bulk modulus K of saturated gas rocks can be obtained from the above formula. sat,g (that is, when K in the Gassmann equation under the above low-frequency assumption) fl =K g (Calculated at the time).

[0163] In tight carbonate reservoirs, oil, gas, and water are not uniformly distributed in the pore space. The Gassmann-Hill equation can determine the bulk modulus and shear modulus of the overall saturated rock.

[0164]

[0165] In the formula, the bulk modulus of saturated water rock (K) sat,w ) and the bulk modulus (K) of saturated gas rocks sat,g S is calculated from the Gassmann equation based on the low-frequency assumption. w Indicates water saturation.

[0166] Therefore, the longitudinal wave velocity calculated using the extended Keys-Xu model, applicable to hard holes, reference holes, and cracks, is:

[0167]

[0168] The transverse wave velocity calculated using the extended Keys-Xu model, applicable to hard holes, reference holes, and cracks, is:

[0169]

[0170] Figure 6 This is a structural diagram of a device for seismic inversion of pore type based on a porous effective medium model according to an embodiment of the present invention; for ease of description, only the parts related to the embodiment of the present invention are shown, and are detailed below:

[0171] A seismic inversion device based on a porous effective medium model includes:

[0172] Initial setting unit: Sets the initial reservoir porosity, reservoir porosity, reservoir fluid properties, and reservoir rock matrix properties;

[0173] The first P-wave velocity calculation unit calculates the P-wave velocity V using the Willy time-averaged equation, the upper and lower boundaries of HS, and the Keys-Xu model for a single pore type. P，wyllie V P，HS+ V P，HS- V P，KX ;

[0174] Porosity calculation unit: The P-wave velocity calculated using the Willy time-averaged equation and the upper and lower boundaries of the HS is subtracted from the P-wave velocity calculated by the Keys-Xu model for a single pore type. The iteration terminates when the differences between the P-wave velocities calculated using the Willy time-averaged equation, the upper and lower boundaries of the HS, and the Keys-Xu model for a single pore type all meet the cutoff condition, thus obtaining the final reservoir porosity. The iterative calculation formula is as follows:

[0175] |V P,KX -V P，i |<ε,i=wyllie,HS+,HS-

[0176] In the formula, V P,KX V represents the longitudinal wave velocity calculated using the Keys-Xu model for a single pore type. P,wyllie V P,HS+ and V P,HS- ε represents the P-wave velocity calculated using the Willy time-averaged equation, the upper bound of HS, and the lower bound of HS, respectively; ε represents the given minimum error.

[0177] The second P-wave velocity calculation unit: Based on the final reservoir porosity calculated by the porosity aspect ratio calculation unit, and combined with reservoir fluid properties, reservoir rock matrix properties, reservoir porosity, initial reference pore size, and initial fracture volume fraction, this data is input into the constructed porous effective medium model of the carbonate reservoir to calculate the P-wave velocity V. P,cal Shear wave velocity V S,cal ;

[0178] Objective function unit: Calculates the P-wave velocity V calculated in the second P-wave velocity calculation unit using the objective function J. P,cal transverse wave velocity V S,cal Its well logging measurement value V P,obs V S,obs The error between them is expressed by the objective function J as follows:

[0179] J = |V P,obs -V P,cal | 2 +|V S,obs -V S,cal | 2

[0180] In the formula, VP,obs and V P,cal These represent the P-wave velocity measured by well logging and the P-wave velocity V calculated based on the porous effective medium model of carbonate reservoirs, respectively. S,obs and V S,cal These represent the P-wave velocity measured by well logging and the S-wave velocity calculated based on the porous effective medium model of carbonate reservoirs, respectively.

[0181] Reference hole and crack volume fraction determination unit: The iteration terminates when the objective function J in the objective function unit is less than a given error σ by traversing the reference hole and crack volume fraction within a given range with a set step size, thus obtaining the final reference hole and crack volume fraction;

[0182] Hard pore volume fraction determination unit: Based on the final reference pore and crack volume fraction obtained from the reference pore and crack volume fraction determination unit, the final hard pore volume fraction is calculated.

[0183] Three-porosity calculation unit: Based on the volume fraction of the final reference pore, fracture, and hard pore obtained from the hard pore volume fraction determination unit, and combined with the reservoir porosity, the porosity of the final reference pore, fracture, and hard pore is calculated to complete the inversion.

[0184] Figure 7 This invention provides a quantitative relationship between pore type and porosity of limestone and dolomite reservoirs and P-wave velocity and S-wave velocity, according to embodiments of the present invention. For ease of description, only the parts relevant to embodiments of the present invention are shown, and are detailed below:

[0185] The quantitative relationship between pore type and porosity and P-wave velocity and S-wave velocity was determined through experimental testing, as follows: Figure 7 To verify the feasibility of the established model, both P-wave and S-wave velocities decreased with increasing porosity. However, the sensitivity of wave velocity to porosity varied depending on the pore type. In porosity systems dominated by hard pores and reference pores, the velocity decreased linearly with porosity but increased with the proportion of hard pores. In contrast, in porosity systems containing cracks and reference pores, the velocity decreased sharply with increasing porosity and crack fraction. These findings indicate that cracks have a more significant impact on elastic properties compared to hard pores. Overall, template analysis shows that the main pore type includes reference pores, and cracks contribute significantly to porosity.

[0186] Figure 8 This is a comparison of results from the seismic inversion method based on a porous effective medium model according to an embodiment of the present invention; for ease of description, only the parts relevant to the embodiments of the present invention are shown, and are detailed below:

[0187] The 2600-2755m interval of Well Midian 1 in Ordos Basin, Northwest China, is used as the target zone for the prediction of carbonate pore structure. Based on the modeling procedure, multiple porosity inversion is performed with the given initial pore aspect ratio (1.0 for rigid pore, 0.1 for reference pore, and 0.01 for fracture).

[0188] Figure 8 The multiple porosity inversion results of Well Midian 1 based on the TPEM model. (a) P-wave velocity; (b) S-wave velocity; (c) pore aspect ratio; (d) rigid pore porosity; (e) reference pore porosity; (f) fracture porosity. In (a) and (b), the black solid line represents the measured wave velocity; the gray solid line represents the wave velocity inverted with the variable aspect ratio; and the gray dashed line represents the wave velocity inverted with the fixed aspect ratio. In (c), the dark gray solid line represents the rigid pore aspect ratio; the gray solid line represents the reference pore aspect ratio; and the light gray solid line represents the fracture aspect ratio. In (d), (e), and (f), the black solid line represents the corresponding porosity interpreted from the well log; the gray solid line represents the corresponding porosity inverted with the variable aspect ratio; and the gray dashed line represents the corresponding porosity inverted with the fixed aspect ratio.

[0189] Figure 8 The results of the prediction of multiple porosity based on the TPEM model with the fixed and variable pore aspect ratio are shown. Regardless of the specified pore aspect ratio or the variable pore aspect ratio, the P-wave and S-wave velocities predicted using this method are very close to the measured values. The rigid pore porosity predicted based on the TPEM model with the fixed pore aspect ratio is slightly higher than the result of the well log interpretation, the error between the reference pore porosity and the well log interpretation value is small, and the fracture porosity cannot match the high value part of the well log interpretation result; while the reference pore, rigid pore, and fracture porosity predicted based on the TPEM model with the variable pore aspect ratio can basically match the well log interpretation result. This shows that the strategy of using the variable pore aspect ratio in the prediction of multiple porosity can effectively improve the prediction accuracy.

[0190] Figure 9 The pore type seismic inversion method based on the multiple effective medium model provided by the embodiments of the present application can predict the spatial distribution characteristics of total porosity and multiple porosity. For the convenience of description, only the parts related to the embodiments of the present application are shown, and the details are described as follows:

[0191] Figure 9 The spatial distribution characteristics of total porosity and multiple porosity are predicted based on the multiple effective medium model (TPEM model). (a) Total pore spatial distribution; (b) rigid pore spatial distribution; (c) reference pore spatial distribution; and (d) fracture spatial distribution.

[0192] Figure 9The total porosity and the distribution characteristics of the multiple porosities in the three-dimensional space based on the inversion of the porous effective medium model (TPEM model) are obtained. The results show that the total porosity is high around Well Mi Tan 1, and the reference holes and fractures are developed. The fractures are also developed in the fault and uplift zones, which is consistent with the geological conditions and logging measurement results of the Gaojiapu area in the Ordos Basin, proving that the porosity type inversion method based on the TPEM model is effective for identifying favorable reservoirs.

[0193] Figure 10 A structural diagram of an electronic device according to an embodiment of the present application is provided, as shown in Figure 10 The device includes a memory 21 for storing a computer program, and a processor 22 for implementing the steps of the porosity type seismic inversion method based on the porous effective medium model when the computer program is executed. The processor 22 can include one or more processing cores, such as a 4-core processor, an 8-core processor, etc. The processor 22 can be implemented in at least one of the hardware forms of a digital signal processor (DSP), a field-programmable gate array (FPGA), and a programmable logic array (PLA). The processor 22 can also include a main processor and a coprocessor. The main processor is a processor for processing data in an awake state, also known as a central processing unit (CPU). The coprocessor is a low-power processor for processing data in a standby state. In some embodiments, the processor 22 can be integrated with a graphics processor (GPU) that is responsible for rendering and drawing the content required to be displayed on the display screen. In some embodiments, the processor 22 can also include an artificial intelligence (AI) processor for processing machine learning-related computing operations.

[0194] The memory 21 may include one or more computer-readable storage media, which may be non-transitory. The memory 21 may also include high-speed random access memory and non-volatile memory, such as one or more disk storage devices or flash memory devices. In this embodiment, the memory 21 is used to store at least the following computer program 211, which, after being loaded and executed by the processor 22, is capable of implementing the relevant steps of the pore type seismic inversion method based on the porous effective medium model disclosed in any of the foregoing embodiments. In addition, the resources stored in the memory 21 may also include an operating system 212 and data 213, etc., and the storage method may be temporary storage or permanent storage. The operating system 212 may include Windows, Unix, Linux, etc. The data 213 may include, but is not limited to, the data involved in the pore type seismic inversion method based on the porous effective medium model, etc.

[0195] In some embodiments, the electronic device may further include a display screen 23, an input / output interface 24, a communication interface 25, a power supply 26, and a communication bus 27.

[0196] Those skilled in the art will understand that Figure 10 The structures shown do not constitute a limitation on electronic devices and may include more or fewer components than those shown.

[0197] The processor 22 implements the steps of the pore type seismic inversion method based on a porous effective medium model provided in any of the above embodiments by calling the instructions stored in the memory 21.

[0198] For an introduction to the electronic device provided by the present invention, please refer to the above method embodiments. The present invention will not be described in detail here, but it has the same beneficial effects as the above-described pore type seismic inversion method based on a porous effective medium model.

[0199] Furthermore, the present invention also provides a computer-readable storage medium storing a computer program, which, when executed by processor 22, implements the steps of the pore type seismic inversion method based on the porous effective medium model described above.

[0200] It can be understood that if the method in the above embodiment is realized in the form of a software function unit and sold or used as an independent product, it can be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present application essentially or the part of the prior art that contributes to the present application or the whole or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium, and performs all or part of the steps of the method of each embodiment of the present application. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various media that can store program codes.

[0201] For the computer readable storage medium provided by the present application, please refer to the above method embodiment. The present application will not be repeated here, and has the same beneficial effects as the steps of the above-mentioned pore type seismic inversion method based on the porous effective medium model.

[0202] The above describes in detail a pore type seismic inversion method, device, equipment and medium based on a porous effective medium model provided by the present application. Each embodiment in the specification is described in a progressive manner, and each embodiment mainly explains the difference from other embodiments. The same or similar parts of each embodiment can be referred to. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the related parts can be referred to the method part. It should be pointed out that for ordinary skilled in the art, without departing from the principle of the present application, the present application can be improved and modified, and these improvements and modifications also fall within the protection scope of the present application.

[0203] It should be further noted that in the present specification, the relationship terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment. Without more limitation, the element defined by the statement "including a" does not exclude the presence of another same element in the process, method, article or equipment including the element.

Claims

1. A seismic inversion method for pore type of carbonate rocks based on a porous effective medium model, characterized in that, include: Step S1: Set the initial reservoir porosity, reservoir porosity, reservoir fluid properties, and reservoir rock matrix properties; Step S2: Calculate the P-wave velocity V using the Willy time-averaged equation, the upper and lower boundaries of HS, and the Keys-Xu model for a single pore type. P，wyllie V P，HS+ V P，HS- V P，KX ; Step S3: Subtract the P-wave velocity calculated using the Willy time-averaged equation and the upper and lower boundaries of HS from the P-wave velocity calculated using the Keys-Xu model for a single pore type. Terminate the iteration when the differences between the P-wave velocities calculated using the Willy time-averaged equation, the upper and lower boundaries of HS, and the Keys-Xu model for a single pore type all satisfy the cutoff condition. The final reservoir porosity is obtained using the following iterative calculation formula: |V P,KX -V P,s |<ε,s=wyllie,HS+,HS- In the formula, V P,KX V represents the longitudinal wave velocity calculated using the Keys-Xu model for a single pore type. P,wyllie V P,HS+ and V P,HS- These represent the P-wave velocities calculated using the Willy time-averaged equation, the upper bound of HS, and the lower bound of HS, respectively. ε represents the given minimum error; Step S4: Based on the final reservoir porosity obtained in Step S3, and combined with reservoir fluid properties, reservoir matrix properties, reservoir porosity, initial reference pore size, and initial fracture volume fraction, input these into the constructed porous effective medium model of the carbonate reservoir to calculate the P-wave velocity V. P，cal Shear wave velocity V S,cal ; Step S5: Calculate the P-wave velocity V calculated in step S4 using the objective function J. P,cal transverse wave velocity V S,cal Its well logging measurement value V P，obs V S，ovs The error between them is expressed by the objective function J as follows: J=|V P,obs -V P,cal | 2 +|V S,obs -V S,cal | 2 In the formula, V P,obs and V P,cal These represent the P-wave velocity measured by well logging and the P-wave velocity V calculated based on the porous effective medium model of carbonate reservoirs, respectively. S,obs and V S,cal These represent the P-wave velocity measured by well logging and the S-wave velocity calculated based on the porous effective medium model of carbonate reservoirs, respectively. Step S6: The iteration is terminated when the objective function J in step S5 is less than the given error σ by traversing the reference hole and crack volume fractions within a given range with a set step size, so as to obtain the final reference hole and crack volume fractions. Step S7: Based on the final reference hole and crack volume fractions obtained in Step S6, calculate the final hard hole volume fraction; Step S8: Based on the final reference pore, fracture, and hard pore volume fractions obtained in Step S7, and combined with the reservoir porosity, calculate the final reference pore, fracture, and hard pore porosity to complete the inversion.

2. The seismic inversion method for carbonate rock pore type based on a porous effective medium model according to claim 1, characterized in that: The method for constructing the porous effective medium model of the carbonate reservoir in step S4 includes: Step S41: Calculate the bulk modulus and shear modulus of the rock matrix using the Voigt-Reuss-Hill (VRH) model; Step S42: Calculate the bulk modulus and shear modulus of dry rock using the extended Keys-Xu model; Step S43: Calculate the bulk modulus and shear modulus of saturated rocks using the Gassmann equation under the low-frequency assumption, and determine the overall bulk modulus and shear modulus of saturated rocks in carbonate reservoirs using the Gassmann-Hill equation.

3. The seismic inversion method for carbonate rock pore type based on a porous effective medium model according to claim 2, characterized in that: The method for calculating the bulk modulus and shear modulus of the rock matrix using the Voigt-Reuss-Hill (VRH) model in step S41 includes: In the formula, f i K i and G i Let represent the volume fraction, bulk modulus, and shear modulus of the i-th mineral component, respectively; M represents the total number of mineral component types contained in the rock matrix.

4. The seismic inversion method for carbonate rock pore type based on a porous effective medium model according to claim 3, characterized in that: The method for calculating the bulk modulus and shear modulus of dry rock using the extended Keys-Xu model in step S42 includes: The extended Keys-Xu model, applicable to hard pores, reference pores, and fractures, calculates the bulk modulus and shear modulus of dry rock using the following formulas: K dry =K ma (1-φ) P G dry =G ma (1-φ) Q In the formula, φ represents porosity; P and Q are geometric factors related to the aspect ratio of the pores: In the formula, v s v r and v c These represent the volume fractions of hard pores, reference pores, and cracks, respectively; α s α r and α c These represent the aspect ratios of the hard pore, reference pore, and fracture, respectively; T ijij (α l ) and T iijj (α l ) is the aspect ratio function of pores.

5. The seismic inversion method for carbonate rock pore type based on a porous effective medium model according to claim 4, characterized in that: The method for calculating the bulk modulus and shear modulus of saturated rock using the Gassmann equation under the low-frequency assumption in step S43 includes: G sat =G dry In the formula, K fl This represents the bulk modulus of a pore fluid.

6. The seismic inversion method for carbonate rock pore type based on a porous effective medium model according to claim 5, characterized in that: The method for determining the bulk modulus and shear modulus of the overall saturated rock using the Gassmann-Hill equation in step S43 includes: In the formula, K represents the bulk modulus of saturated water rock. sat,w Bulk modulus K of saturated gas rocks sat,g S is calculated from the Gassmann equation based on the low-frequency assumption. w Indicates water saturation.

7. The seismic inversion method for carbonate rock pore type based on a porous effective medium model according to claim 1, characterized in that: In step S2, the P-wave velocity V is calculated using the Willy time-averaged equation. P，wyllie include: In the formula, φ represents porosity; V P,fl and V P,ma These represent the longitudinal wave velocities of the fluid and the rock matrix, respectively.

8. The seismic inversion method for carbonate rock pore type based on a porous effective medium model according to claim 1, characterized in that: In step S2, the longitudinal wave velocity V is calculated using the upper and lower boundaries of HS. P，HS+ V P，HS- The methods include: Step S21: Calculate the bulk modulus and shear modulus of carbonate rocks using the Hashin-Shtrikman (HS) upper and lower boundaries: In the formula, K1, G1 and f1 are the bulk modulus, shear modulus and volume fraction of the first phase, respectively; K2, G2 and f2 represent the bulk modulus, shear modulus and volume fraction of the second phase. The calculation of the upper and lower boundaries of the HS boundary is determined by swapping the order of the first and second phases. "+" represents the upper boundary and "-" represents the lower boundary. Step S22: Calculate the P-wave velocity V of the carbonate reservoir based on the bulk modulus and shear modulus of the carbonate rock obtained in step S21. P，HS+ V P，HS- :

9. A seismic inversion device for carbonate rock pore type based on a porous effective medium model, characterized in that, include: Initial setting unit: Sets the initial reservoir porosity, reservoir porosity, reservoir fluid properties, and reservoir rock matrix properties; The first P-wave velocity calculation unit calculates the P-wave velocity V using the Willy time-averaged equation, the upper and lower boundaries of HS, and the Keys-Xu model for a single pore type. P，wyllie V P，HS+ V P，HS- V P，KX ; Porosity calculation unit: The P-wave velocity calculated using the Willy time-averaged equation and the upper and lower boundaries of the HS is subtracted from the P-wave velocity calculated by the Keys-Xu model for a single pore type. The iteration terminates when the differences between the P-wave velocities calculated using the Willy time-averaged equation, the upper and lower boundaries of the HS, and the Keys-Xu model for a single pore type all meet the cutoff condition, thus obtaining the final reservoir porosity. The iterative calculation formula is as follows: |V P,KX -V P,s |<ε,s=wyllie,HS+,HS- In the formula, V P,KX V represents the longitudinal wave velocity calculated using the Keys-Xu model for a single pore type. P,wyllie V P,HS+ and V P,HS- These represent the P-wave velocities calculated using the Willy time-averaged equation, the upper bound of HS, and the lower bound of HS, respectively. ε represents the given minimum error; The second P-wave velocity calculation unit: Based on the final reservoir porosity calculated by the porosity aspect ratio calculation unit, and combined with reservoir fluid properties, reservoir rock matrix properties, reservoir porosity, initial reference pore size, and initial fracture volume fraction, this data is input into the constructed porous effective medium model of the carbonate reservoir to calculate the P-wave velocity V. P，cal Shear wave velocity V S,cal ; Objective function unit: Calculates the P-wave velocity V calculated in the second P-wave velocity calculation unit using the objective function J. P，cal transverse wave velocity V S，cal Its well logging measurement value V P,obs V S,obs The error between them is expressed by the objective function J as follows: J=|V P,obs -V P,cal | 2 +|V S,obs -V S,cal | 2 In the formula, V P,obs and V P,cal These represent the P-wave velocity measured by well logging and the P-wave velocity V calculated based on the porous effective medium model of carbonate reservoirs, respectively. S,obs and V S,cal These represent the P-wave velocity measured by well logging and the S-wave velocity calculated based on the porous effective medium model of carbonate reservoirs, respectively. Reference hole and crack volume fraction determination unit: The iteration terminates when the objective function J in the objective function unit is less than a given error σ by traversing the reference hole and crack volume fraction within a given range with a set step size, thus obtaining the final reference hole and crack volume fraction; Hard pore volume fraction determination unit: Based on the final reference pore and crack volume fraction obtained from the reference pore and crack volume fraction determination unit, the final hard pore volume fraction is calculated. Three-porosity calculation unit: Based on the volume fraction of the final reference pore, fracture, and hard pore obtained from the hard pore volume fraction determination unit, and combined with the reservoir porosity, the porosity of the final reference pore, fracture, and hard pore is calculated to complete the inversion.

10. An electronic device, characterized in that, include: Memory, used to store computer programs; A processor, configured to execute the computer program to implement the steps of the seismic inversion method for carbonate rock pore type based on a porous effective medium model as described in any one of claims 1-8.

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