Rock physics modeling method and apparatus based on pore fluid filling

Abstract

Disclosed in the present disclosure are a rock physics modeling method and apparatus based on pore fluid filling. The method comprises: on the basis of elastic information of a mixed mineral matrix, constructing a mixed mineral matrix model; using a differential effective medium method to obtain a mixed mineral matrix containing a pore-saturating fluid, and constructing a mixed mineral rock model containing the pore-saturating fluid; using the differential effective medium method to obtain a mixed mineral matrix containing the pore-saturating fluid and a microfracture-saturating fluid, and constructing a mixed mineral rock model containing the pore-saturating fluid and the microfracture-saturating fluid; adding a fracture-saturating fluid to the mixed mineral matrix containing the pore-saturating fluid and the microfracture-saturating fluid, and calculating corresponding rock elastic characteristics; and obtaining a rock physics model on the basis of the rock elastic characteristics. The present disclosure can overcome difficulties in common rock physics modeling caused by the diversity of pore types.

Description

Porosity fluid-filled rock physics modeling method and device

[0001] Related Applications

[0002] This application claims priority to Chinese Patent Application No. 202411088243.5, filed on August 08, 2024, and incorporates by reference the entire disclosure of the aforementioned patent application as part of this application. TECHNICAL FIELD

[0003] The present disclosure relates to the field of oil and gas exploration, and more particularly to a porosity fluid-filled rock physics modeling method and device. BACKGROUND

[0004] Shale oil reservoirs are usually low-porosity and low-permeability tight reservoirs (i.e., very low porosity and very low permeability). Due to the characteristics of shale oil reservoirs rich in organic matter and multiple mineral components, the relationship between reservoir evaluation parameters and seismic elastic parameters is not clear, making it difficult to predict favorable reservoirs. Rock physics modeling plays an important role in seismic wave propagation, seismic data interpretation, reservoir prediction, and fluid identification. Rock physics modeling is a bridge between physical parameters, such as porosity, fluid saturation, and mineral composition, and elastic parameters, such as P-wave velocity, S-wave velocity, and impedance. Rock physics modeling has become an indispensable part of oil and gas exploration, development, and monitoring. In the past decade, rock physics has received increasing attention and has become a very active research field. CN117458519A discloses a rock physics modeling method and device for fractured-porous reservoirs. The method includes: obtaining rock attribute information of the fractured-porous reservoir, wherein the rock attribute information includes mineral component information, fluid composition information, and pore structure information of the fractured-porous reservoir; mixing mineral particles of different mineral components to obtain a rock matrix model; adding wet isolated pores to the rock matrix model to obtain a solid matrix model; adding dry connected pores to the solid matrix model to obtain a dry pore skeleton model; fluid filling the connected pores in the dry pore skeleton model to obtain a saturated pore skeleton model; and adding saturated fractures to the saturated pore skeleton model using a modified linear slip model to obtain a saturated rock model. However, traditional rock physics modeling methods do not consider different pore types, which cannot solve the problem of rock physics modeling difficulty caused by the diversity of pore types. SUMMARY

[0005] The present disclosure provides a porosity fluid-filled rock physics modeling method to solve the problem of common rock physics modeling difficulty caused by the diversity of pore types. The method includes:

[0006] obtain the elastic information of the mixed mineral matrix in the shale oil reservoir; the elastic information includes elastic modulus, bulk modulus and shear modulus;

[0007] construct a mixed mineral matrix model according to the elastic information of the mixed mineral matrix;

[0008] add the pore-saturated fluid to the mixed mineral matrix by using the differential effective medium method to obtain the mixed mineral matrix containing the pore-saturated fluid, and construct a mixed mineral rock model containing the pore-saturated fluid on the basis of the mixed mineral matrix model and according to the elastic information of the mixed mineral matrix containing the pore-saturated fluid;

[0009] add the micro-fracture-saturated fluid to the mixed mineral matrix containing the pore-saturated fluid by using the differential effective medium method to obtain the mixed mineral matrix containing the pore-saturated fluid and the micro-fracture-saturated fluid, and construct a mixed mineral rock model containing the pore-saturated fluid and the micro-fracture-saturated fluid on the basis of the mixed mineral rock model containing the pore-saturated fluid and according to the elastic information of the mixed mineral matrix containing the pore-saturated fluid and the micro-fracture-saturated fluid;

[0010] add the fracture-saturated fluid to the mixed mineral matrix containing the pore-saturated fluid and the micro-fracture-saturated fluid on the basis of the mixed mineral rock model containing the pore-saturated fluid and the micro-fracture-saturated fluid, and calculate the rock elastic characteristics of the mixed mineral matrix containing the pore-saturated fluid, the micro-fracture-saturated fluid and the fracture-saturated fluid;

[0011] obtain a rock physics model according to the rock elastic characteristics.

[0012] The embodiments of the present disclosure further provide a porosity fluid-filled rock physics modeling device to solve the problem of difficulty in commonly used rock physics modeling caused by various pore types, and the device comprises:

[0013] an elastic information obtaining module configured to obtain the elastic information of the mixed mineral matrix in the shale oil reservoir; the elastic information includes elastic modulus, bulk modulus and shear modulus;

[0014] a mixed mineral matrix model constructing module configured to construct a mixed mineral matrix model according to the elastic information of the mixed mineral matrix;

[0015] a mixed mineral rock model containing pore-saturated fluid constructing module configured to add the pore-saturated fluid to the mixed mineral matrix by using the differential effective medium method to obtain the mixed mineral matrix containing the pore-saturated fluid, and construct a mixed mineral rock model containing the pore-saturated fluid on the basis of the mixed mineral matrix model and according to the elastic information of the mixed mineral matrix containing the pore-saturated fluid;

[0016] The mixed mineral rock model containing pores saturated with fluid and micro-fractures saturated with fluid is constructed by adding micro-fractures saturated with fluid to the mixed mineral matrix containing pores saturated with fluid by using a differential effective medium method, to obtain a mixed mineral matrix containing pores saturated with fluid and micro-fractures saturated with fluid.

[0017] The rock elastic feature calculation module is configured to add fractures saturated with fluid to the mixed mineral matrix containing pores saturated with fluid and micro-fractures saturated with fluid on the basis of the mixed mineral rock model containing pores saturated with fluid and micro-fractures saturated with fluid, and calculate rock elastic features of a mixed mineral matrix containing pores saturated with fluid, micro-fractures saturated with fluid and fractures saturated with fluid.

[0018] The rock physical model determination module is configured to obtain a rock physical model according to the rock elastic features.

[0019] The embodiments of the present disclosure further provide a computer device, which comprises a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor implements the rock physical modeling method with fluid filling in porosity when executing the computer program.

[0020] The embodiments of the present disclosure further provide a computer readable storage medium, which stores a computer program, and the computer program is executable on a processor to implement the rock physical modeling method with fluid filling in porosity.

[0021] The embodiments of the present disclosure further provide a computer program product, which comprises a computer program, and the computer program is executable on a processor to implement the rock physical modeling method with fluid filling in porosity.

[0022] In the embodiments of the present disclosure, the elastic information of the mixed mineral matrix in the shale oil reservoir is obtained; the elastic information includes the elastic modulus, the bulk modulus and the shear modulus; a mixed mineral matrix model is constructed according to the elastic information of the mixed mineral matrix; the differential equivalent medium method is used to add pore saturated fluid to the mixed mineral matrix to obtain the mixed mineral matrix containing pore saturated fluid, and on the basis of the mixed mineral matrix model, a mixed mineral rock model containing pore saturated fluid is constructed according to the elastic information of the mixed mineral matrix containing pore saturated fluid; the differential equivalent medium method is used to add micro-fracture saturated fluid to the mixed mineral matrix containing pore saturated fluid to obtain the mixed mineral matrix containing pore saturated fluid and micro-fracture saturated fluid, and on the basis of the mixed mineral rock model containing pore saturated fluid, a mixed mineral rock model containing pore saturated fluid and micro-fracture saturated fluid is constructed according to the elastic information of the mixed mineral matrix containing pore saturated fluid and micro-fracture saturated fluid; on the basis of the mixed mineral rock model containing pore saturated fluid and micro-fracture saturated fluid, fracture saturated fluid is added to the mixed mineral matrix containing pore saturated fluid and micro-fracture saturated fluid to calculate the rock elastic characteristics of the mixed mineral matrix containing pore saturated fluid, micro-fracture saturated fluid and fracture saturated fluid; and a rock physics model is obtained according to the rock elastic characteristics. In the above process, the present disclosure considers the multi-pore characteristics and structure of the matrix pores, micro-fractures and natural fractures, and compared with the existing conventional clastic rock physics modeling method which is not applicable to the shale oil reservoir with multiple pore types, the present disclosure gradually adds pore saturated fluid, micro-fracture saturated fluid and fracture saturated fluid to the mixed mineral matrix model, constructs the corresponding rock physics model on the basis of ensuring the diversity of pore types, thereby solving the problem of the difficulty in commonly used rock physics modeling caused by the diversity of pore types, and being conducive to valuable understanding of the reservoir characteristics and percolation mechanism of the rock through the constructed rock physics model. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, brief introductions will be given to the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present disclosure, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings. In the drawings:

[0024] FIG. 1 is a flowchart of a rock physics modeling method of porosity fluid filling in the embodiments of the present disclosure;

[0025] FIG. 2 is a comparison chart of predicted P-wave and S-wave velocities and measured data of well 1 in the embodiments of the present disclosure;

[0026] FIG. 3 is a comparison chart of predicted P-wave and S-wave velocities and measured data of well 2 in the embodiments of the present disclosure;

[0027] Figure 4 is a shale oil reservoir rock property interpretation map in the embodiments of the present disclosure;

[0028] Figures 5(a)-5(c) are plan views of actual shale oil work areas in the embodiments of the present disclosure;

[0029] Figure 6 is a schematic diagram of a porosity fluid-filled rock physics modeling device in the embodiments of the present disclosure. DETAILED DESCRIPTION

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present disclosure clearer, further detailed descriptions of the embodiments of the present disclosure will be given below with reference to the accompanying drawings. Here, the illustrative embodiments of the present disclosure and their descriptions are used to explain the present disclosure but are not limiting to the present disclosure.

[0031] Figure 1 is a flowchart of a porosity fluid-filled rock physics modeling method in the embodiments of the present disclosure, which includes:

[0032] Step 101, obtaining elastic information of a mixed mineral matrix in a shale oil reservoir; the elastic information includes elastic modulus, bulk modulus, and shear modulus;

[0033] Step 102, constructing a mixed mineral matrix model according to the elastic information of the mixed mineral matrix;

[0034] Step 103, adding a pore-saturated fluid to the mixed mineral matrix by using a differential effective medium method to obtain a mixed mineral matrix containing the pore-saturated fluid, and constructing a mixed mineral rock model containing the pore-saturated fluid on the basis of the mixed mineral matrix model and according to the elastic information of the mixed mineral matrix containing the pore-saturated fluid;

[0035] Step 104, adding a micro-fracture-saturated fluid to the mixed mineral matrix containing the pore-saturated fluid by using the differential effective medium method to obtain a mixed mineral matrix containing the pore-saturated fluid and the micro-fracture-saturated fluid, and constructing a mixed mineral rock model containing the pore-saturated fluid and the micro-fracture-saturated fluid on the basis of the mixed mineral rock model containing the pore-saturated fluid and according to the elastic information of the mixed mineral matrix containing the pore-saturated fluid and the micro-fracture-saturated fluid;

[0036] Step 105, adding a fracture-saturated fluid to the mixed mineral matrix containing the pore-saturated fluid and the micro-fracture-saturated fluid to obtain a mixed mineral matrix containing the pore-saturated fluid, the micro-fracture-saturated fluid, and the fracture-saturated fluid, and calculating rock elastic characteristics of the mixed mineral matrix containing the pore-saturated fluid, the micro-fracture-saturated fluid, and the fracture-saturated fluid on the basis of the mixed mineral rock model containing the pore-saturated fluid and the micro-fracture-saturated fluid and according to the elastic information of the mixed mineral matrix containing the pore-saturated fluid, the micro-fracture-saturated fluid, and the fracture-saturated fluid;

[0037] Step 106, obtaining a rock physics model according to the elastic characteristics of the rock.

[0038] In embodiments of the present disclosure, the modeling method can be used for oil and gas reservoir exploration, development and monitoring.

[0039] Each step will be described in detail below.

[0040] In step 101, the elastic information of the mixed mineral matrix in the shale oil reservoir is obtained; the elastic information includes the elastic modulus, the bulk modulus and the shear modulus.

[0041] In specific embodiments, before obtaining the elastic information of the mixed mineral matrix, first, the total porosity, clay content and water saturation data of the shale oil reservoir are obtained by using nuclear magnetic logging, and these three kinds of data are the necessary basic data required for rock physics modeling, and the accuracy of these data directly affects the accuracy of the rock physics model. Then, the content data of quartz, dolomite, calcite, potassium feldspar, sodium feldspar, pyrite and clay minerals in the shale oil reservoir are obtained by using XRD (X-ray diffraction) diffraction experiment. For example, the mineral types of a certain shale oil reservoir are complex, which contains not only common minerals such as quartz, calcite and clay, but also complex minerals such as dolomite, potassium feldspar, sodium feldspar and pyrite. It is difficult to accurately obtain the content of multiple minerals by using conventional methods, so XRD experiment is used to obtain the content. Based on the high-precision element mass fraction obtained by lithology scanning logging, and based on the XRD experimental data as a constraint, the sensitive elements of the minerals (i.e. chemical elements that can specifically reflect the content of a certain mineral) are found, the relationship between the mineral mass fraction and the sensitive element mass fraction is re-established, and then the mineral content is calculated. The content of kerogen (i.e. solid organic matter in sedimentary rocks that is insoluble in conventional organic solvents such as chloroform and benzene) cannot be ignored in rock physics modeling due to the high content of organic matter in the shale oil reservoir. The content of kerogen is calculated according to the △LogR method, so that the influence of kerogen on the elastic parameters is considered in rock physics modeling.

[0042] In step 102, a mixed mineral matrix model is constructed according to the elastic information of the mixed mineral matrix.

[0043] In an embodiment, the mixed mineral matrix model is constructed according to the elastic information of the mixed mineral matrix, including:

[0044] The mixed mineral matrix model is constructed according to the mathematical relationship between the elastic modulus, the bulk modulus and the shear modulus in the elastic information of the mixed mineral matrix.

[0045] In an embodiment, the mathematical relationship between the elastic modulus, the bulk modulus and the shear modulus in the elastic information of the mixed mineral matrix is as follows:

[0046] Wherein, M is the elastic modulus of the mixed mineral matrix; K is the bulk modulus of the mixed mineral matrix; μ is the shear modulus of the mixed mineral matrix; and v is the Poisson's ratio of the mixed mineral matrix.

[0047] In specific embodiments, when obtaining the equivalent elastic modulus of the rock, if the bulk modulus, shear modulus, content and combination details of each mineral component are known, the equivalent elastic modulus can be accurately predicted. If only the elastic modulus and volume content of the constituent components are known, the upper and lower boundaries of the equivalent elastic modulus can be calculated. When the proportions of each component in the whole are known, the equivalent elastic modulus of the rock is usually between the upper and lower boundaries, and the accurate value is different due to the influence of the combination details of each mineral component. When the combination of each mineral component cannot be determined, the H-S bounds (Hashin-Shtrikman Bounds) can be used to determine the acceptable upper and lower bounds of the bulk modulus and shear modulus after the combination of each mineral component.

[0048] In step 103, the differential effective medium method is used to add pore-saturated fluid to the mixed mineral matrix to obtain a mixed mineral matrix containing pore-saturated fluid. Based on the mixed mineral matrix model, a mixed mineral rock model containing pore-saturated fluid is constructed according to the elastic information of the mixed mineral matrix containing pore-saturated fluid.

[0049] In an embodiment, the differential effective medium method is used to add pore-saturated fluid to the mixed mineral matrix to obtain a mixed mineral matrix containing pore-saturated fluid, comprising:

[0050] The mixed mineral matrix is used as the first background medium, and the differential effective medium method is used to add a first inclusion to the first background medium, the first inclusion being pore-saturated fluid (i.e., fluid saturated in pores, such as oil, gas, and water), to obtain a mixed mineral matrix containing pore-saturated fluid.

[0051] In specific embodiments, based on the mixed mineral matrix model, the differential effective medium modeling method is used to add matrix pores and fill them with fluid to establish a mixed mineral rock model containing pore-saturated fluid. The differential effective medium model (DEM) is a model that considers the order of addition, and inclusions are added step by step until the required content. The background medium gradually decreases from 100% content, and the inclusion gradually increases from zero content until the required content of each component is reached. Because DEM considers the order of addition, different background media and different order of addition will have different effects.

[0052] In an embodiment, based on the mixed mineral matrix model, a mixed mineral rock model containing pore-saturated fluid is constructed according to the elastic information of the mixed mineral matrix containing pore-saturated fluid, comprising:

[0053] The mixed mineral rock model containing the pore-saturated fluid is constructed according to the following formula:

[0054] Wherein, φ p is the matrix porosity, which is obtained by using the nuclear magnetic logging method, when φ p = 0, K * and μ * are the bulk modulus K and shear modulus μ of the mixed mineral rock containing the pore-saturated fluid respectively; K f and μ f are the bulk modulus and shear modulus of the first inclusion respectively, P(φ p ) and Q(φ p ) are influence factors related to the aspect ratio of the matrix porosity, which is obtained by observing and counting under a microscope.

[0055] In step 104, the differential equivalent medium method is used to add micro-fracture-saturated fluid (i.e., the fluid (such as oil, gas, and water) saturated in the micro-fracture of the rock) to the mixed mineral matrix containing the pore-saturated fluid, to obtain a mixed mineral matrix containing the pore-saturated fluid and the micro-fracture-saturated fluid. On the basis of the mixed mineral rock model containing the pore-saturated fluid, a mixed mineral rock model containing the pore-saturated fluid and the micro-fracture-saturated fluid is constructed according to the elastic information of the mixed mineral matrix containing the pore-saturated fluid and the micro-fracture-saturated fluid.

[0056] In specific embodiments, the micro-fracture is difficult to identify on the Formation MicroScanner Image (FMI) imaging. For the shale oil tight reservoir, the micro-fracture is an important reservoir space for fluid, and the existing shale oil rock physics modeling method generally does not consider the influence of the micro-fracture. In the embodiments of the present disclosure, the influence of the micro-fracture is fully considered, and the micro-fracture is modeled separately, so as to ensure the accuracy of the overall rock physics model. First, the change amount of the porosity and the aspect ratio under different pressures are obtained by using the rock pressure change experiment, the dry rock skeleton modulus is obtained according to the K-T model and the DEM model, and the porosity is obtained by using the damping least square method. Because the rock matrix porosity of the shale oil tight reservoir is small, the overall change under pressure is weak, and the experiment is difficult to measure, it is considered that the change is caused by the fracture and the micro-fracture, which are the stress-closed pores, and the sum of the porosities of the fracture and the micro-fracture is obtained by inversion. The micro-fracture porosity can be calculated by using the FMI logging data.

[0057] In an embodiment, before the micro-fracture-saturated fluid is added to the mixed mineral matrix containing the pore-saturated fluid by using the differential equivalent medium method, the following steps are included:

[0058] The dry rock skeleton bulk modulus and the dry rock skeleton shear modulus are calculated based on the K-T model.

[0059] According to the rock skeleton volume modulus and the dry rock skeleton shear modulus, a porosity inversion equation is constructed;

[0060] The porosity inversion equation is solved by using a damped least square method to obtain a soft porosity;

[0061] According to the soft porosity and a fracture porosity, a micro-fracture porosity is calculated; the fracture porosity is calculated in advance by using logging data.

[0062] In specific embodiments, the rock pressure variation experiment is used to obtain the variation of porosity under different pressures and the aspect ratio a m According to the K-T model, we have:

[0063] wherein K g is the dry rock skeleton volume modulus; K b is the mixed mineral matrix volume modulus; μ g is the dry rock skeleton shear modulus; K f and μ f are the volume modulus and the shear modulus of the first inclusion respectively, μ b is the mixed mineral matrix shear modulus; m is the group of different pressure experiments, and N is the total number of experiments; T1 is the pore flattening ratio, and P n is the pressure. The equation is an overdetermined equation, and we have:

[0064] The porosity inversion equation is constructed: Ax = b

[0065] The equation Ax = b is solved by using a damped least square method to obtain a soft porosity φ s . Because the rock matrix porosity of the shale oil dense reservoir is small, the overall change under pressure is weak, and the experiment is difficult to measure, it is considered that the change is caused by the stress-closing pores such as fractures and micro-fractures, and the sum of the porosities of the fractures and the micro-fractures is obtained by inversion. The fracture porosity φ f can be calculated by using FMI logging data:

[0066] wherein V i is the volume of different length fractures; V is the total volume of the rock; c i is the fracture length coefficient; d is the wellbore diameter; w i is the fracture width. Then the micro-fracture porosity φ m is: m = φ s - φ f

[0067] In an embodiment, a differential effective medium method is used to add micro-fracture saturated fluid to a mixed mineral matrix saturated with pore fluid to obtain a mixed mineral matrix saturated with pore fluid and micro-fracture saturated fluid, comprising:

[0068] The mixed mineral matrix saturated with pore fluid is taken as a second background medium, and a differential effective medium method is used to add a second inclusion to the second background medium, the second inclusion being micro-fracture saturated fluid, to obtain a mixed mineral matrix saturated with pore fluid and micro-fracture saturated fluid.

[0069] In an embodiment, on the basis of the mixed mineral rock model saturated with pore fluid, a mixed mineral rock model saturated with pore fluid and micro-fracture saturated fluid is constructed according to the elastic information of the mixed mineral matrix saturated with pore fluid and micro-fracture saturated fluid, comprising:

[0070] The mixed mineral matrix saturated with pore fluid and micro-fracture saturated fluid is constructed according to the following formula:

[0071] wherein, φ m is the micro-fracture porosity, when φ m = 0, K ** and μ ** are the bulk modulus K * and shear modulus μ * of the second mixed mineral matrix; K f and μ f are the bulk modulus and shear modulus of the second inclusion; P(φ m ) and Q(φ m ) are influence factors related to the aspect ratio of the micro-fracture, and the aspect ratio of the micro-fracture is obtained by statistical observation under a microscope.

[0072] In step 105, a fracture saturated fluid is added to the mixed mineral matrix saturated with pore fluid and micro-fracture saturated fluid to obtain a mixed mineral matrix saturated with pore fluid, micro-fracture saturated fluid and fracture saturated fluid, and on the basis of the mixed mineral rock model saturated with pore fluid and micro-fracture saturated fluid, the rock elastic characteristics of the mixed mineral matrix saturated with pore fluid, micro-fracture saturated fluid and fracture saturated fluid are calculated according to the elastic information of the mixed mineral matrix saturated with pore fluid, micro-fracture saturated fluid and fracture saturated fluid.

[0073] In the specific embodiment, before determining the rock elastic characteristics of the mixed mineral matrix saturated with the pore fluid, the micro-fracture fluid and the fracture fluid, the rigidity coefficient of the anisotropic rock with the inclined fracture is added, and the influence of different fracture parameters (fracture density, inclination and aspect ratio) on the rock elastic modulus is further analyzed. The simulation results under different fracture parameters are compared by using the logging data, and by adjusting the fracture parameters in sections, the simulation results can be closer to the measured results. The anisotropic Gassmann equation is used to add fluid to the fracture, and the elastic modulus of the mixed mineral matrix saturated with the pore fluid and the micro-fracture fluid is calculated.

[0074] In an embodiment, the fracture saturated fluid is added to the mixed mineral matrix saturated with the pore fluid and the micro-fracture fluid, and the rock elastic characteristics of the mixed mineral matrix saturated with the pore fluid, the micro-fracture fluid and the fracture fluid are calculated, including:

[0075] Obtaining the pore information, the micro-fracture information and the fracture information;

[0076] Based on the bulk modulus and the shear modulus of the mixed mineral matrix saturated with the pore fluid and the micro-fracture fluid, the elastic modulus of the mixed mineral matrix saturated with the pore fluid and the micro-fracture fluid is calculated;

[0077] According to the pore information, the micro-fracture information, the fracture information and the elastic modulus of the mixed mineral matrix saturated with the pore fluid and the micro-fracture fluid, the Gassmann equation is used to determine the rock elastic characteristics of the mixed mineral matrix saturated with the pore fluid, the micro-fracture fluid and the fracture fluid.

[0078] In step 106, the rock physical model is obtained according to the rock elastic characteristics.

[0079] In the specific embodiment, the accuracy of the rock physical model is verified by using the logging measured data, and the range of the elastic parameters corresponding to the high-quality reservoir is obtained by using the rock physical model, and the high-quality reservoir is quantitatively described by combining the elastic parameters of the seismic inversion. The specific example of verifying the accuracy of the rock physical model by using the logging measured data is as follows:

[0080] The shale oil rock physical model established by the present disclosure is verified by using the measured data of the actual drilled well 1 and well 2. FIG. 2 is a comparison diagram of the predicted P-wave and S-wave velocities of well 1 in the embodiment of the present disclosure and the measured data. In FIG. 2, the black curve is the measured P-wave and S-wave velocity curve of the shale oil section of well 1, the red curve is the predicted P-wave and S-wave velocity curve of the rock physical model established by the present disclosure, and the blue curve is the error curve. It can be seen from the comparison that the predicted P-wave and S-wave velocities are highly consistent with the measured velocities, the average prediction error of the P-wave velocity is less than 5%, and the average prediction error of the S-wave velocity is less than 9%, which proves the accuracy of the shale oil reservoir rock physical model established in the embodiment of the present disclosure. In order to further verify the applicability of the present disclosure, the measured data of well 2 is used for verification again. Well 2 is a horizontal well, which is different from the vertical well 1. FIG. 3 is a comparison diagram of the predicted P-wave and S-wave velocities of well 2 in the embodiment of the present disclosure and the measured data. In FIG. 3, the black curve is the measured P-wave and S-wave velocity curve of the horizontal section of well 2, and the red curve is the predicted P-wave and S-wave velocity curve of the established rock physical model. It can be seen from the comparison that there is an obvious deviation between the measured value and the predicted value at the position just entering the horizontal section, which is caused by inaccurate actual measurement. The remaining part of the measured value is highly matched with the predicted value, the average prediction accuracy of the P-wave velocity is 94%, and the average prediction accuracy of the S-wave velocity reaches 90%, which proves that the shale oil reservoir rock physical model is applicable to various well types and ensures the accuracy of the rock physical model.

[0081] FIG. 4 is a rock physical interpretation map of the shale oil reservoir in the embodiment of the present disclosure. FIG. 4 is a rock physical interpretation map constructed based on the shale oil rock physical model established by the present disclosure, wherein the data points are derived from the logging interpretation results of well 1 and well 2, the abscissa is the P-wave impedance, the ordinate is the P-S wave velocity ratio, and the color is the oil saturation. It can be found that the points with good physical properties and high oil saturation are concentrated in the range of P-wave impedance 13500-16000 and P-S wave velocity ratio 1.68-1.78, which provides a quantitative basis for the seismic target prediction of high-quality shale oil reservoirs. The reservoirs in this range are classified. The physical properties and oil content of the type I reservoirs are the best, the P-wave impedance ranges from 13800 to 15200, and the P-S wave velocity ratio is less than 1.72. The physical properties of the type II reservoirs are slightly poor, the P-wave impedance ranges from 14200 to 15800, and the P-S wave velocity ratio ranges from 1.72 to 1.78. The oil content of the type III reservoirs is only better than that of the non-reservoirs, the P-wave impedance ranges from 12500 to 14200, and the P-S wave velocity ratio ranges from 1.73 to 1.78.

[0082] Fig. 5(a)-Fig. 5(c) are plan views of an actual shale oil working area in the embodiment of the present disclosure, quantitative interpretation is performed on the elastic parameter results of the inversion of P-wave impedance (as shown in Fig. 5(a) P-wave impedance inversion plan view of the actual working area) and P-S wave velocity ratio (as shown in Fig. 5(b) P-S wave velocity ratio inversion plan view of the actual working area) of the actual shale oil working area according to the interpretation volume edition, Fig. 5(c) is a classification plan view of the actual working area, which shows the plan distribution range of the Class I, Class II and Class III reservoirs and non-reservoirs in the working area. The oil-bearing property of the shale oil section of well 1 is equivalent to that of well 2, and the physical property is slightly worse than that of well 2. As shown in the classification result of Fig. 5(c), well 1 is a Class II reservoir, and well 2 is a Class I reservoir, which is consistent with the actual understanding, and also illustrates the accuracy of the shale oil rock physics modeling method.

[0083] The embodiment of the present disclosure also provides a device for porosity fluid-filled rock physics modeling, as described in the following embodiment. Since the problem-solving principle of the device is similar to that of the porosity fluid-filled rock physics modeling method, the implementation of the device can be referred to the implementation of the porosity fluid-filled rock physics modeling method, and the repeated parts will not be described herein. It can be understood that the device can include a processor and a memory, wherein the memory stores instructions for executing the porosity fluid-filled rock physics modeling method.

[0084] Fig. 6 is a schematic diagram of the device for porosity fluid-filled rock physics modeling in the embodiment of the present disclosure, which includes:

[0085] The elastic information acquisition module 601 is configured to acquire the elastic information of the mixed mineral matrix in the shale oil reservoir, wherein the elastic information includes the elastic modulus, the bulk modulus and the shear modulus;

[0086] The mixed mineral matrix model construction module 602 is configured to construct a mixed mineral matrix model according to the elastic information of the mixed mineral matrix.

[0087] The mixed mineral rock model with pore-saturated fluid construction module 603 is configured to add a pore-saturated fluid to the mixed mineral matrix by using a differential effective medium method to obtain a mixed mineral matrix with a pore-saturated fluid, and construct a mixed mineral rock model with a pore-saturated fluid based on the mixed mineral matrix model and according to the elastic information of the mixed mineral matrix with the pore-saturated fluid.

[0088] The mixed mineral rock model containing pores saturated with fluid and micro-fracture saturated with fluid is constructed by adding micro-fracture saturated with fluid to the mixed mineral matrix saturated with fluid by using the differential effective medium method, and the mixed mineral rock model containing pores saturated with fluid and micro-fracture saturated with fluid is constructed on the basis of the mixed mineral rock model containing pores saturated with fluid according to the elastic information of the mixed mineral matrix containing pores saturated with fluid and micro-fracture saturated with fluid;

[0089] The rock elastic characteristic calculation module 605 is configured to add fracture saturated fluid to the mixed mineral matrix containing pores saturated with fluid and micro-fracture saturated with fluid on the basis of the mixed mineral rock model containing pores saturated with fluid and micro-fracture saturated with fluid, and calculate the rock elastic characteristic of the mixed mineral matrix containing pores saturated with fluid, micro-fracture saturated with fluid and fracture saturated fluid.

[0090] The rock physical model determination module 606 is configured to obtain the rock physical model according to the rock elastic characteristic.

[0091] In an embodiment, the mixed mineral matrix model construction module 602 is specifically configured to:

[0092] The mixed mineral matrix model is constructed according to the mathematical relationship among the elastic modulus, the bulk modulus and the shear modulus in the elastic information of the mixed mineral matrix.

[0093] In an embodiment, the mathematical relationship among the elastic modulus, the bulk modulus and the shear modulus in the elastic information of the mixed mineral matrix is as follows:

[0094] Wherein, M is the elastic modulus of the mixed mineral matrix; K is the bulk modulus of the mixed mineral matrix; μ is the shear modulus of the mixed mineral matrix; and v is the Poisson's ratio of the mixed mineral matrix.

[0095] In an embodiment, the mixed mineral rock model containing pores saturated with fluid is constructed by the mixed mineral rock model containing pores saturated with fluid construction module 603, and the mixed mineral rock model containing pores saturated with fluid is specifically constructed by:

[0096] The mixed mineral matrix is taken as the first background medium, the first inclusion is added to the first background medium by using the differential effective medium method, the first inclusion is pores saturated with fluid, and the mixed mineral matrix containing pores saturated with fluid is obtained.

[0097] In an embodiment, the mixed mineral rock model containing pores saturated with fluid is constructed by the mixed mineral rock model containing pores saturated with fluid construction module 603, and the mixed mineral rock model containing pores saturated with fluid is specifically constructed by:

[0098] The mixed mineral rock model containing pores saturated with fluid is constructed according to the following formula:

[0099] Wherein, φ pis the matrix porosity, which is obtained by using the nuclear magnetic logging method, when φ p = 0, K * and μ * are the bulk modulus K and shear modulus μ of the mixed mineral matrix saturated with pore fluid, respectively; K f and μ f are the bulk modulus and shear modulus of the first inclusion, respectively, P(φ p ) and Q(φ p ) are influence factors related to the aspect ratio of the matrix porosity, which is obtained by observing and counting under a microscope.

[0100] In an embodiment, the mixed mineral rock model construction module 604 for the mixed mineral matrix saturated with pore fluid and microfracture saturated fluid is specifically configured to:

[0101] The mixed mineral matrix saturated with pore fluid is taken as the second background medium, the differential effective medium method is used to add the second inclusion to the second background medium, the second inclusion is the microfracture saturated fluid, and the mixed mineral matrix saturated with pore fluid and microfracture saturated fluid is obtained.

[0102] In an embodiment, the mixed mineral rock model construction module 604 for the mixed mineral matrix saturated with pore fluid and microfracture saturated fluid is specifically configured to:

[0103] The equivalent medium model of the mixed mineral matrix saturated with pore fluid and microfracture saturated fluid is constructed according to the following formula:

[0104] wherein φ m is the microfracture porosity, when φ m = 0, K ** and μ ** are the bulk modulus K * and shear modulus μ * of the second mixed mineral matrix; K f and μ f are the bulk modulus and shear modulus of the second inclusion, P(φ m ) and Q(φ m ) are influence factors related to the aspect ratio of the microfracture, which is obtained by observing and counting under a microscope.

[0105] In an embodiment, the rock elastic characteristic calculation module 605 is specifically configured to:

[0106] obtain the pore information, the microfracture information and the fracture information;

[0107] calculate the elastic modulus of the mixed mineral matrix saturated with pore fluid and microfracture saturated fluid based on the bulk modulus and shear modulus of the mixed mineral matrix saturated with pore fluid and microfracture saturated fluid.

[0108] According to the porosity information, the micro-fracture information, the fracture information and the elastic modulus of the mixed mineral matrix saturated with the porosity fluid, the micro-fracture fluid, the rock elastic characteristics of the mixed mineral matrix saturated with the porosity fluid, the micro-fracture fluid and the fracture fluid are determined by using the Gassmann equation.

[0109] The embodiment of the present disclosure further provides a computer device, which comprises a memory, a processor and a computer program stored in the memory and capable of running on the processor, and the processor implements the porosity fluid-filled rock physical modeling method when executing the computer program.

[0110] The embodiment of the present disclosure further provides a computer readable storage medium, which stores a computer program, and the computer program is executed by the processor to implement the porosity fluid-filled rock physical modeling method.

[0111] The embodiment of the present disclosure further provides a computer program product, which comprises a computer program, and the computer program is executed by the processor to implement the porosity fluid-filled rock physical modeling method.

[0112] In the embodiments of the present disclosure, the elastic information of the mixed mineral matrix in the shale oil reservoir is obtained; the elastic information includes the elastic modulus, the bulk modulus and the shear modulus; a mixed mineral matrix model is constructed according to the elastic information of the mixed mineral matrix; the differential equivalent medium method is used to add pore saturated fluid to the mixed mineral matrix to obtain the mixed mineral matrix containing pore saturated fluid, and on the basis of the mixed mineral matrix model, a mixed mineral rock model containing pore saturated fluid is constructed according to the elastic information of the mixed mineral matrix containing pore saturated fluid; the differential equivalent medium method is used to add micro-fracture saturated fluid to the mixed mineral matrix containing pore saturated fluid to obtain the mixed mineral matrix containing pore saturated fluid and micro-fracture saturated fluid, and on the basis of the mixed mineral rock model containing pore saturated fluid, a mixed mineral rock model containing pore saturated fluid and micro-fracture saturated fluid is constructed according to the elastic information of the mixed mineral matrix containing pore saturated fluid and micro-fracture saturated fluid; on the basis of the mixed mineral rock model containing pore saturated fluid and micro-fracture saturated fluid, fracture saturated fluid is added to the mixed mineral matrix containing pore saturated fluid and micro-fracture saturated fluid, and the rock elastic characteristics of the mixed mineral matrix containing pore saturated fluid, micro-fracture saturated fluid and fracture saturated fluid are calculated; and a rock physics model is obtained according to the rock elastic characteristics. In the above process, the embodiments of the present disclosure consider the multi-pore characteristics and structure of the matrix pores, micro-fractures and natural fractures, and compared with the existing conventional clastic rock physics modeling method which is not applicable to the shale oil reservoir with multiple pore types, the embodiments of the present disclosure gradually add pore saturated fluid, micro-fracture saturated fluid and fracture saturated fluid to the mixed mineral matrix model, and on the basis of ensuring the diversity of pore types, the corresponding rock physics model is constructed, thereby solving the problem of the difficulty in commonly used rock physics modeling caused by the diversity of pore types.

[0113] Those skilled in the art will understand that the embodiments of the present disclosure can be provided as a method, a system or a computer program product. Therefore, the present disclosure can take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Moreover, the present disclosure can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0114] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks.

[0115] These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the function specified in the flowchart block or blocks.

[0116] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks.

[0117] The specific embodiments described above are examples for implementing the disclosure and the purposes of the disclosure, technical solutions and beneficial effects, and should be understood as merely used to define the scope of the disclosure. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the disclosure should be included in the scope of the disclosure.

Claims

1. A porosity fluid-filled rock physics modeling method, characterized by, The method comprises the following steps: obtaining elastic information of a mixed mineral matrix in a shale oil reservoir; the elastic information comprises an elastic modulus, a bulk modulus and a shear modulus; constructing a mixed mineral matrix model according to the elastic information of the mixed mineral matrix; adding pore-saturated fluid to the mixed mineral matrix by using a differential effective medium method to obtain a mixed mineral matrix containing pore-saturated fluid, and constructing a mixed mineral rock model containing pore-saturated fluid according to the elastic information of the mixed mineral matrix containing pore-saturated fluid on the basis of the mixed mineral matrix model; adding micro-fracture-saturated fluid to the mixed mineral matrix containing pore-saturated fluid by using the differential effective medium method to obtain a mixed mineral matrix containing pore-saturated fluid and micro-fracture-saturated fluid, and constructing a mixed mineral rock model containing pore-saturated fluid and micro-fracture-saturated fluid according to the elastic information of the mixed mineral matrix containing pore-saturated fluid and micro-fracture-saturated fluid on the basis of the mixed mineral rock model containing pore-saturated fluid; adding fracture-saturated fluid to the mixed mineral matrix containing pore-saturated fluid and micro-fracture-saturated fluid to obtain a mixed mineral matrix containing pore-saturated fluid, micro-fracture-saturated fluid and fracture-saturated fluid, and calculating rock elastic characteristics of the mixed mineral matrix containing pore-saturated fluid, micro-fracture-saturated fluid and fracture-saturated fluid according to the elastic information of the mixed mineral matrix containing pore-saturated fluid, micro-fracture-saturated fluid and fracture-saturated fluid on the basis of the mixed mineral rock model containing pore-saturated fluid and micro-fracture-saturated fluid; obtaining a rock physics model according to the rock elastic characteristics.

2. The method of porosity fluid-filled rock physics modeling of claim 1, wherein, According to the elastic information of the mixed mineral matrix, a mixed mineral matrix model is constructed, comprising: According to the mathematical relationship among the elastic modulus, the bulk modulus and the shear modulus in the elastic information of the mixed mineral matrix, the mixed mineral matrix model is constructed.

3. The method of modeling the petrophysics of a porosity fluid-filled rock formation of claim 1, wherein, The differential effective medium method is used to add pore-saturated fluid to the mixed mineral matrix to obtain a mixed mineral matrix containing pore-saturated fluid, comprising: The differential effective medium method is used to add first inclusions to the first background medium, and the first inclusions are pore-saturated fluid, to obtain a mixed mineral matrix containing pore-saturated fluid.

4. The method of porosity fluid-filled rock physics modeling of claim 3, wherein, On the basis of the mixed mineral matrix model, a mixed mineral rock model containing pore-saturated fluid is constructed according to the elastic information of the mixed mineral matrix containing pore-saturated fluid, comprising: A mixed mineral rock model containing pore-saturating fluid is constructed according to the following equation: Where, φ p The matrix porosity is obtained using nuclear magnetic resonance logging. When φ p When K = 0, * and μ * These are the bulk modulus K and shear modulus μ of a mixed mineral matrix containing porous saturated fluid, respectively; K f and μ f These are the bulk modulus and shear modulus of the first inclusion body, P(φ) p ) and Q(φ p The following are the influencing factors related to the aspect ratio of matrix porosity, which were obtained by microscopic observation and statistics of core thin sections.

5. The method of modeling the petrophysics of a porosity fluid-filled rock formation of claim 1, wherein, Before the differential effective medium method is used to add micro-fracture-saturated fluid to the mixed mineral matrix containing pore-saturated fluid, comprising: Based on the K-T model, the dry rock skeleton bulk modulus and the dry rock skeleton shear modulus are calculated; According to the rock skeleton bulk modulus and the dry rock skeleton shear modulus, a porosity inversion equation is constructed; The damping least square method is used to solve the porosity inversion equation to obtain a soft porosity; According to the soft porosity and a fracture porosity, a micro-fracture porosity is calculated; the fracture porosity is calculated in advance by using logging data.

6. The method of modeling the petrophysics of a porosity fluid-filled rock formation of claim 1, wherein, The differential effective medium method is used to add micro-fracture-saturated fluid to the mixed mineral matrix containing pore-saturated fluid to obtain a mixed mineral matrix containing pore-saturated fluid and micro-fracture-saturated fluid, comprising: The differential equivalent medium method is used to add a second inclusion to the second background medium, the second inclusion being a micro-fissure saturated fluid, to obtain a mixed mineral matrix saturated with a pore fluid and a micro-fissure fluid.

7. The method of porosity fluid-filled rock physics modeling of claim 6, wherein, On the basis of the mixed mineral rock model saturated with the pore fluid, the mixed mineral rock model saturated with the pore fluid and the micro-fissure fluid is constructed according to the elastic information of the mixed mineral matrix saturated with the pore fluid and the micro-fissure fluid, including: The equivalent medium model containing pore saturated fluid and microfracture saturated fluid is constructed according to the following formula: Where, φ m For microfracture porosity, when φ m When K = 0, ** and μ ** They are respectively saturated fluid with pores and microcracks. Bulk modulus K of the mixed mineral matrix of the saturated fluid * and shear modulus μ * ; K f and μ f are the bulk modulus and shear modulus of the second inclusion, respectively, P(φ m ) and Q(φ m ) are the influence factors related to the aspect ratio of microfractures, which are obtained by statistical observation under a microscope of the core slice.

8. The method of modeling the petrophysical properties of a porosity fluid-filled rock formation of claim 1, wherein, On the basis of the mixed mineral rock model saturated with the pore fluid and the micro-fissure fluid, the rock elastic characteristics of the mixed mineral matrix saturated with the pore fluid, the micro-fissure fluid and the fissure fluid are calculated according to the elastic information of the mixed mineral matrix saturated with the pore fluid, the micro-fissure fluid and the fissure fluid, including: The pore information, the micro-fissure information and the fissure information are acquired; The elastic modulus of the mixed mineral matrix saturated with the pore fluid and the micro-fissure fluid is calculated based on the bulk modulus and the shear modulus of the mixed mineral matrix saturated with the pore fluid and the micro-fissure fluid; The rock elastic characteristics of the mixed mineral matrix saturated with the pore fluid, the micro-fissure fluid and the fissure fluid are determined by using the Gassmann equation according to the pore information, the micro-fissure information, the fissure information and the elastic modulus of the mixed mineral matrix saturated with the pore fluid and the micro-fissure fluid.

9. A porosity fluid-filled rock physics modeling device, characterized by, including: The elastic information acquisition module is used to acquire the elastic information of the mixed mineral matrix in the shale oil reservoir; the elastic information includes the elastic modulus, the bulk modulus and the shear modulus; The mixed mineral matrix model construction module is used to construct the mixed mineral matrix model according to the elastic information of the mixed mineral matrix; The mixed mineral rock model construction module is used to add the pore saturated fluid to the mixed mineral matrix by using the differential equivalent medium method to obtain the mixed mineral matrix saturated with the pore fluid, and construct the mixed mineral rock model saturated with the pore fluid based on the mixed mineral matrix model and according to the elastic information of the mixed mineral matrix saturated with the pore fluid; The mixed mineral rock model construction module is used to add the micro-fissure saturated fluid to the mixed mineral matrix saturated with the pore fluid by using the differential equivalent medium method to obtain the mixed mineral matrix saturated with the pore fluid and the micro-fissure fluid, and construct the mixed mineral rock model saturated with the pore fluid and the micro-fissure fluid based on the mixed mineral rock model saturated with the pore fluid and according to the elastic information of the mixed mineral matrix saturated with the pore fluid and the micro-fissure fluid; The rock elastic characteristic calculation module is used to add the fissure saturated fluid to the mixed mineral matrix saturated with the pore fluid and the micro-fissure fluid based on the mixed mineral rock model saturated with the pore fluid and the micro-fissure fluid, and calculate the rock elastic characteristics of the mixed mineral matrix saturated with the pore fluid, the micro-fissure fluid and the fissure fluid; The rock physical model determination module is used to obtain the rock physical model according to the rock elastic characteristics.

10. A computer device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor implements the method in any one of claims 1-8 when executing the computer program.

11. A computer readable storage medium, characterized in that, The computer readable storage medium stores a computer program, and the computer program, when executed by a processor, implements the method in any one of claims 1-8.

12. A computer program product, characterised in that, The computer program product comprises a computer program, and the computer program, when executed by a processor, implements the method in any one of claims 1-8.

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