Porosity fluid filled rock physical modeling method and device

Abstract

The invention discloses a porosity fluid filled rock physical modeling method and device, and the method comprises the steps: building a mixed mineral matrix model according to the elastic information of a mixed mineral matrix; adopting a differential equivalent 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; adopting a differential equivalent 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 the pore saturated fluid and the micro-fracture saturated fluid; adding crack saturated fluid into a mixed mineral matrix containing pore saturated fluid and micro-crack saturated fluid, and calculating corresponding rock elastic characteristics; and obtaining a rock physical model according to the rock elastic characteristics. According to the method, the problem that common rock physical modeling is difficult due to various pore types can be solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil and gas exploration, and particularly relates to a porosity fluid filling rock physics modeling method and device. BACKGROUND

[0002] Shale oil reservoirs are usually low-porosity and low-permeability tight reservoirs. Due to the characteristics of rich organic matter and multiple mineral components in shale oil reservoirs, the relationship between reservoir evaluation parameters and seismic elastic parameters is not clear, which leads to great difficulty in predicting favorable reservoirs. Rock physics modeling plays an important role in seismic wave propagation, seismic data interpretation, reservoir prediction, fluid identification and the like. Rock physics modeling is a bridge between physical parameters such as porosity, fluid saturation, 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 more and more attention and has become a very active research field. The invention patent CN117458519A discloses a rock physics modeling method and device for fractured-porous reservoirs, which comprises: obtaining rock attribute information of the fractured-porous reservoir, wherein the rock attribute information includes mineral component information, fluid component 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 by using a modified linear slip model to obtain a saturated rock model. However, the conventional rock physics modeling method does not consider different pore types, and cannot solve the problem of rock physics modeling difficulty caused by the diversity of pore types. SUMMARY

[0003] The present application provides a porosity fluid filling rock physics modeling method to solve the problem of common rock physics modeling difficulty caused by the diversity of pore types. The method comprises:

[0004] Obtaining elastic information of a mixed mineral matrix in a shale oil reservoir; the elastic information includes elastic modulus, bulk modulus and shear modulus;

[0005] Constructing a mixed mineral matrix model according to the elastic information of the mixed mineral matrix;

[0006] A pore-saturated fluid was added to a mixed mineral matrix using the differential equivalent medium method 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 was constructed according to the elastic information of the mixed mineral matrix containing pore-saturated fluid.

[0007] The differential equivalent medium method was used to add microfracture saturated fluid to a mixed mineral matrix containing pore saturated fluid, resulting in a mixed mineral matrix containing both pore saturated fluid and microfracture saturated fluid. Based on the mixed mineral rock model containing pore saturated fluid, and according to the elastic information of the mixed mineral matrix containing both pore saturated fluid and microfracture saturated fluid, a mixed mineral rock model containing both pore saturated fluid and microfracture saturated fluid was constructed.

[0008] Based on a mixed mineral rock model containing pore-saturated fluid and microfracture-saturated fluid, fracture-saturated fluid is added to the mixed mineral matrix containing pore-saturated fluid and microfracture-saturated fluid, and the rock elastic characteristics of the mixed mineral matrix containing pore-saturated fluid, microfracture-saturated fluid and fracture-saturated fluid are calculated.

[0009] A rock physics model is obtained based on the elastic characteristics of the rock.

[0010] This invention also provides a rock physics modeling device for pore fluid filling, which solves the problem of difficulties in commonly used rock physics modeling caused by the diversity of pore types. The device includes:

[0011] The elasticity information acquisition module is used to acquire elasticity information of the mixed mineral matrix in shale oil reservoirs; the elasticity information includes elastic modulus, bulk modulus and shear modulus;

[0012] The mixed mineral matrix model building module is used to build a mixed mineral matrix model based on the elasticity information of the mixed mineral matrix.

[0013] A module for constructing a mixed mineral rock model containing pore-saturated fluid is used to add pore-saturated fluid to a mixed mineral matrix using the differential equivalent medium method 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.

[0014] A module for constructing a mixed mineral rock model containing pore-saturated fluid and microfracture-saturated fluid is used to add microfracture-saturated fluid to a mixed mineral matrix containing pore-saturated fluid using the differential equivalent medium method, thereby obtaining a mixed mineral matrix containing both pore-saturated fluid and microfracture-saturated fluid. Based on the mixed mineral rock model containing pore-saturated fluid, and according to the elastic information of the mixed mineral matrix containing both pore-saturated fluid and microfracture-saturated fluid, a mixed mineral rock model containing both pore-saturated fluid and microfracture-saturated fluid is constructed.

[0015] The rock elasticity characteristic calculation module is used to calculate the rock elasticity characteristics of the mixed mineral matrix containing pore saturated fluid, microfracture saturated fluid, and fracture saturated fluid, based on a mixed mineral rock model containing pore saturated fluid and microfracture saturated fluid.

[0016] The rock physics model determination module is used to obtain a rock physics model based on the elastic characteristics of the rock.

[0017] This invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the above-described rock physics modeling method for pore fluid filling.

[0018] This invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described rock physics modeling method for porosity fluid filling.

[0019] This invention also provides a computer program product, which includes a computer program that, when executed by a processor, implements the above-described rock physics modeling method for filling porosity fluids.

[0020] In this embodiment of the invention, elastic information of the mixed mineral matrix in a shale oil reservoir is obtained; the elastic information includes elastic modulus, bulk modulus, and shear modulus; a mixed mineral matrix model is constructed based on the elastic information of the mixed mineral matrix; pore-saturated fluid is added to the mixed mineral matrix using the differential equivalent medium method 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; microfracture saturated fluid is added to the mixed mineral matrix containing pore-saturated fluid using the differential equivalent medium method to obtain a mixed mineral matrix containing pore-saturated fluid. A mixed mineral matrix containing pore-saturated fluid and microfracture-saturated fluid is constructed based on a mixed mineral rock model containing pore-saturated fluid and microfracture-saturated fluid, according to the elastic information of the mixed mineral matrix containing pore-saturated fluid and microfracture-saturated fluid. Based on the mixed mineral rock model containing pore-saturated fluid and microfracture-saturated fluid, fracture-saturated fluid is added to the mixed mineral matrix containing pore-saturated fluid and microfracture-saturated fluid, and the rock elastic characteristics of the mixed mineral matrix containing pore-saturated fluid, microfracture-saturated fluid, and fracture-saturated fluid are calculated. A rock physical model is obtained based on the rock elastic characteristics. In the above process, the embodiments of the present invention take into account the multi-pore characteristics and structure of matrix pores, microfractures, and natural fractures. Compared with the existing conventional clastic rock physical modeling methods, which are not suitable for shale oil reservoirs with multiple pore types, the embodiments of the present invention gradually add pore saturated fluids, microfracture saturated fluids, and fracture saturated fluids to the mixed mineral matrix model. On the basis of ensuring the diversity of pore types, a corresponding rock physical model is constructed, thereby solving the problem of the difficulty of commonly used rock physical modeling caused by the diversity of pore types. It is beneficial to gain valuable insights into the reservoir characteristics and seepage mechanism of rocks through the constructed rock physical model. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0022] Figure 1 This is a flowchart of a rock physics modeling method for filling porosity fluid in an embodiment of the present invention;

[0023] Figure 2 This is a comparison chart of the predicted P-wave and S-wave velocities and the measured data in Well 1 according to an embodiment of the present invention;

[0024] Figure 3This is a comparison chart of the predicted P-wave and S-wave velocities and the measured data in Well 2 according to an embodiment of the present invention;

[0025] Figure 4 This is a map showing the petrophysical interpretation of shale oil reservoirs in an embodiment of the present invention.

[0026] Figure 5 This is a plan view of an actual shale oil production area in an embodiment of the present invention;

[0027] Figure 6 This is a schematic diagram of a rock physics modeling device filled with porosity fluid in an embodiment of the present invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Here, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0029] Figure 1 This is a flowchart of a rock physics modeling method for porosity fluid filling according to an embodiment of the present invention. The method includes:

[0030] Step 101: 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;

[0031] Step 102: Construct a mixed mineral matrix model based on the elasticity information of the mixed mineral matrix;

[0032] Step 103: Using the differential equivalent medium method, pore-saturated fluid is added 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.

[0033] Step 104: Using the differential equivalent medium method, microfracture saturated fluid is added to the mixed mineral matrix containing pore saturated fluid to obtain a mixed mineral matrix containing both pore saturated fluid and microfracture saturated fluid. Based on the mixed mineral rock model containing pore saturated fluid, and according to the elastic information of the mixed mineral matrix containing both pore saturated fluid and microfracture saturated fluid, a mixed mineral rock model containing both pore saturated fluid and microfracture saturated fluid is constructed.

[0034] Step 105: Add fracture saturated fluid to the mixed mineral matrix containing pore saturated fluid and microfracture saturated fluid to obtain a mixed mineral matrix containing pore saturated fluid, microfracture saturated fluid, and fracture saturated fluid. Based on the mixed mineral rock model containing pore saturated fluid and microfracture saturated fluid, calculate the rock elastic characteristics of the mixed mineral matrix containing pore saturated fluid, microfracture saturated fluid, and fracture saturated fluid according to the elastic information of the mixed mineral matrix.

[0035] Step 106: Obtain the rock physical model based on the rock elastic characteristics.

[0036] Each step is explained in detail below.

[0037] In step 101, the elastic information of the mixed mineral matrix in the shale oil reservoir is obtained; the elastic information includes elastic modulus, bulk modulus and shear modulus.

[0038] In a specific embodiment, before obtaining the elasticity information of the mixed mineral matrix, firstly, nuclear magnetic resonance logging is used to obtain data on the total porosity, clay content, and water saturation of the shale oil reservoir. These three types of data are essential basic data required for rock physics modeling, and their accuracy directly affects the accuracy of the rock physics model. Then, XRD (X-ray diffraction) experiments are used to obtain data on the content of quartz, dolomite, calcite, potassium feldspar, sodium feldspar, pyrite, and clay minerals in the shale oil reservoir. For example, a certain shale oil reservoir has a complex mineral composition, containing 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 using conventional methods, so XRD experiments are used to obtain them. Based on the high-precision elemental mass fractions obtained from lithological scanning logging and constrained by XRD experimental data, sensitive elements of the minerals are identified, and the relationship between mineral mass fractions and sensitive element mass fractions is re-established, thereby calculating the mineral content. Shale oil reservoirs have high organic matter content, and the influence of kerogen on elastic parameters cannot be ignored when rock physics modeling. The kerogen content is calculated using the ΔLogR method, so that the influence of kerogen on elastic parameters can be considered in rock physics modeling.

[0039] In step 102, a mixed mineral matrix model is constructed based on the elasticity information of the mixed mineral matrix.

[0040] In one embodiment, a mixed mineral matrix model is constructed based on the elasticity information of the mixed mineral matrix, including:

[0041] Based on the mathematical relationships between the elastic modulus, bulk modulus, and shear modulus in the elastic information of the mixed mineral matrix, a mixed mineral matrix model is constructed.

[0042] In one embodiment, the mathematical relationships between the elastic modulus, bulk modulus, and shear modulus in the elastic information of the mixed mineral matrix are as follows:

[0043]

[0044]

[0045] Where 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 ν is the Poisson's ratio of the mixed mineral matrix.

[0046] In a specific embodiment, when obtaining the equivalent elastic modulus of a rock, if the bulk modulus, shear modulus, content, and combination details of each mineral component are known, its equivalent elastic modulus can be accurately predicted. If only the elastic modulus and volume content of the constituent components are known, then the upper and lower boundaries of the equivalent elastic modulus can be calculated. When the proportion of each component in the rock is known, its equivalent elastic modulus is usually between the upper and lower boundaries, and its precise value varies depending on the combination details of each mineral component. When the combination of each mineral component is unclear, the HS boundary can be used to determine the acceptable upper and lower boundaries of the bulk modulus and shear modulus after the combination of each mineral component.

[0047] In step 103, a pore-saturated fluid is added to the mixed mineral matrix using the differential equivalent medium method 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.

[0048] In one embodiment, a differential equivalent medium method is used to add a pore-saturated fluid to a mixed mineral matrix to obtain a mixed mineral matrix containing the pore-saturated fluid, comprising:

[0049] Using a mixed mineral matrix as the first background medium, a first inclusion is added to the first background medium using the differential equivalent medium method. The first inclusion is a pore-saturated fluid, resulting in a mixed mineral matrix containing pore-saturated fluid.

[0050] In a specific embodiment, based on the mixed mineral matrix model, a differential equivalent medium modeling method is used to add matrix pores and fill them with fluid, establishing a mixed mineral rock model containing pore-saturated fluid. The differential equivalent medium model (DEM) is a model that considers the order of addition, gradually adding inclusions until the desired content is reached. The background medium gradually decreases in content from 100%, while the inclusions gradually increase from zero content until the required component contents are achieved. Because the DEM considers the order of addition, different choices of background medium and addition order will have different effects.

[0051] In one 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, including:

[0052] Construct a mixed mineral rock model containing pore-saturated fluid using the following formula:

[0053]

[0054] Where, φ p The matrix porosity is obtained using nuclear magnetic resonance logging. When φ p When K = 0, * and μ * The bulk modulus K and shear modulus μ of a mixed mineral rock containing pore-saturated fluid are respectively. 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.

[0055] In step 104, a microfracture saturated fluid is added to a mixed mineral matrix containing pore saturated fluid using the differential equivalent medium method, resulting in a mixed mineral matrix containing both pore saturated fluid and microfracture saturated fluid. Based on the mixed mineral rock model containing pore saturated fluid, a mixed mineral rock model containing both pore saturated fluid and microfracture saturated fluid is constructed according to the elastic information of the mixed mineral matrix.

[0056] In specific embodiments, microfractures are difficult to identify in FMI (Formation MicroScanner Image) imaging. For tight shale oil reservoirs, microfractures are important fluid storage spaces, and existing shale oil rock physics modeling methods generally do not consider the influence of microfractures. In this embodiment of the invention, the influence of microfractures is fully considered, and microfractures are modeled separately to ensure the accuracy of the overall rock physics model. First, the change in porosity and aspect ratio under different pressures are obtained using rock pressure change experiments. The dry rock skeleton modulus is calculated based on the KT model and DEM model, and the porosity is obtained using the damped least squares method. Because the pore size of the rock matrix in tight shale oil reservoirs is small, the overall change under pressure is weak and difficult to measure experimentally. It is assumed that the changes are caused by fractures and microfractures, which are easily closed under stress. The inversion yields the sum of the porosity of fractures and microfractures. The porosity of microfractures can be calculated using FMI logging data.

[0057] In one embodiment, before adding microfracture saturated fluid to a mixed mineral matrix containing porous saturated fluid using a differential equivalent medium method, the method includes:

[0058] Based on the KT model, the bulk modulus and shear modulus of the dry rock skeleton were calculated.

[0059] Based on the bulk modulus of the rock skeleton and the shear modulus of the dry rock skeleton, a porosity inversion equation is constructed.

[0060] The porosity inversion equation is solved using the damped least squares method to obtain the soft porosity;

[0061] Microfracture porosity is calculated based on soft porosity and fracture porosity; the fracture porosity is pre-calculated using well logging data.

[0062] In a specific embodiment, rock pressure variation experiments were used to obtain the change in porosity under different pressures. and aspect ratio a m According to the KT model:

[0063]

[0064] Among them, K g K represents the bulk modulus of the dry rock skeleton. b Bulk modulus of mixed mineral matrix; μ g K represents the shear modulus of the dry rock skeleton. f and μ f These are the bulk modulus and shear modulus of the first inclusion body, μ, respectively. b is the shear modulus of the mixed mineral matrix; m is the group of different pressure experiments; N is the total number of experiments; T1 is the porosity; P n For pressure. This equation is an overdetermined equation, let:

[0065]

[0066] Construct the porosity inversion equation:

[0067] Ax = b

[0068] The soft porosity φ is obtained by solving the equation Ax = b using the damped least squares method. s Because the rock matrix of tight shale oil reservoirs has small pores, the overall change under pressure is weak and difficult to measure experimentally. It is believed that the changes are caused by fractures and microfractures, which are easily closed under stress. The inversion yields the sum of the porosity of fractures and microfractures. The fracture porosity φ can be calculated using FMI logging data. f :

[0069]

[0070] Among them, V i V represents the volume of cracks of different lengths; C represents the total volume of the rock; V represents the volume of the cracks of different lengths. i d is the fracture length coefficient; d is the wellbore diameter; w i Let φ be the crack width. Then the microcrack porosity φ is... m for:

[0071] φ m =φ s -φ f

[0072] In one embodiment, a microfracture saturated fluid is added to a mixed mineral matrix containing pore saturated fluid using a differential equivalent medium method to obtain a mixed mineral matrix containing both pore saturated fluid and microfracture saturated fluid, comprising:

[0073] Using a mixed mineral matrix containing porous saturated fluid as a second background medium, a second inclusion is added to the second background medium using the differential equivalent medium method. The second inclusion is microfracture saturated fluid, resulting in a mixed mineral matrix containing porous saturated fluid and microfracture saturated fluid.

[0074] In one embodiment, based on a mixed mineral rock model containing pore-saturated fluid, and according to the elastic information of the mixed mineral matrix containing pore-saturated fluid and microfracture-saturated fluid, a mixed mineral rock model containing pore-saturated fluid and microfracture-saturated fluid is constructed, including:

[0075] Construct equivalent medium models for saturated fluids with pores and saturated fluids with microfractures using the following formula:

[0076]

[0077] Where, φ m For microfracture porosity, when φ m When K = 0, ** and μ ** The bulk modulus K of the second mixed mineral matrix * and shear modulus μ * ;K f and μ f Let P(φ) be the bulk modulus and shear modulus of the second inclusion body. m ) and Q(φ m The aspect ratio of microfractures is an influencing factor related to the aspect ratio of microfractures. The aspect ratio of microfractures is obtained by statistical observation under a microscope of core thin sections.

[0078] In step 105, fracture saturated fluid is added to the mixed mineral matrix containing pore saturated fluid and microfracture saturated fluid to obtain a mixed mineral matrix containing pore saturated fluid, microfracture saturated fluid, and fracture saturated fluid. Based on the mixed mineral rock model containing pore saturated fluid and microfracture saturated fluid, the rock elastic characteristics of the mixed mineral matrix containing pore saturated fluid, microfracture saturated fluid, and fracture saturated fluid are calculated according to the elastic information of the mixed mineral matrix.

[0079] In a specific embodiment, before determining the rock elastic characteristics of a mixed mineral matrix containing pore-saturated fluid, microfracture-saturated fluid, and fracture-saturated fluid, it is necessary to incorporate the stiffness coefficient of anisotropic rocks with inclined fractures. Based on this, the influence of different fracture parameters (fracture density, dip angle, and aspect ratio) on the rock elastic modulus is further analyzed. By comparing simulation results under different fracture parameters using well logging data, and by adjusting the fracture parameters in segments, the simulation results can be made closer to the measured results. The anisotropic Gassmann equation is used to add fluid to the fractures, and the elastic modulus of the mixed mineral matrix containing pore-saturated fluid and microfracture-saturated fluid is calculated.

[0080] In one embodiment, adding fracture saturated fluid to a mixed mineral matrix containing pore-saturated fluid and microfracture-saturated fluid, and calculating the rock elastic characteristics of the mixed mineral matrix containing pore-saturated fluid, microfracture-saturated fluid, and fracture saturated fluid, includes:

[0081] Acquire pore information, microcrack information, and fracture information;

[0082] Based on the bulk modulus and shear modulus of the mixed mineral matrix containing pore-saturated fluid and microfracture-saturated fluid, calculate the elastic modulus of the mixed mineral matrix containing pore-saturated fluid and microfracture-saturated fluid.

[0083] Based on pore information, microfracture information, fracture information, and the elastic modulus of the mixed mineral matrix containing pore-saturated fluid and microfracture-saturated fluid, the Gassmann equation is used to determine the rock elastic characteristics of the mixed mineral matrix containing pore-saturated fluid, microfracture-saturated fluid, and fracture-saturated fluid.

[0084] In step 106, a rock physical model is obtained based on the rock elastic characteristics.

[0085] In a specific embodiment, well logging data is used to verify the accuracy of the rock physics model. Then, the range of elastic parameters corresponding to high-quality reservoirs is obtained using the rock physics model, and the elastic parameters obtained from seismic inversion are combined to quantitatively characterize the high-quality reservoirs. A specific example of using well logging data to verify the accuracy of the rock physics model is as follows:

[0086] The accuracy of the shale oil rock physics model established in this invention was verified using actual measured data from wells 1 and 2. Figure 2 This is a comparison chart of the predicted P-wave and S-wave velocities and the measured data in well 1 according to an embodiment of the present invention. Figure 2 The black curve represents the measured P-wave and S-wave velocity curves of the shale oil section in Well 1, the red curve represents the predicted P-wave and S-wave velocity curves of the rock physics model established in this invention, and the blue curve represents the error curve. The comparison shows that the predicted P-wave and S-wave velocities in this embodiment are highly consistent with the measured velocities, with an average P-wave velocity prediction error of less than 5% and an average S-wave velocity prediction error of less than 9%, proving the accuracy of the shale oil reservoir rock physics model established in this embodiment. To further verify the applicability of this invention, measured data from Well 2 were used for further validation. Well 2 is a horizontal well, unlike Well 1 which is a vertical well. Figure 3 This is a comparison chart of the predicted P-wave and S-wave velocities and the measured data in Well 2 according to an embodiment of the present invention. Figure 3 The black curve represents the measured P-wave and S-wave velocity curves in the horizontal section of Well 2, while the red curve represents the predicted P-wave and S-wave velocity curves from the established rock physics model. The comparison shows a significant deviation between the measured and predicted values ​​at the very beginning of the horizontal section, due to inaccurate actual measurements. For the remaining portion, the measured and predicted values ​​show a high degree of agreement, with an average P-wave velocity prediction accuracy of 94% and an average S-wave velocity prediction accuracy of 90%. This demonstrates that the shale oil reservoir rock physics model is applicable to various well types while maintaining its accuracy.

[0087] Figure 4 This is a map showing the petrophysical interpretation of shale oil reservoirs in an embodiment of the present invention. Figure 4 This is a quantitative interpretation graph for shale oil based on the rock physics model established in this invention. The data points are derived from the logging interpretation results of Well 1 and Well 2. The horizontal axis represents P-wave impedance, the vertical axis represents the P-wave / S-wave velocity ratio, and the color represents oil saturation. It can be observed that points with better physical properties and higher oil saturation are concentrated in the range of P-wave impedance (13500–16000) and P-wave / S-wave velocity ratio (1.68–1.78), which provides a quantitative basis for seismic target prediction of high-quality shale oil reservoirs. The reservoirs within this range are further classified as follows: Class I reservoirs have the best physical properties and oil-bearing properties, with a P-wave impedance range of 13800–15200 and a P-wave / S-wave velocity ratio of less than 1.72; Class II reservoirs have slightly worse physical properties, with a P-wave impedance range of 14200–15800 and a P-wave / S-wave velocity ratio range of 1.72–1.78; Class III reservoirs have oil-bearing properties that are only better than non-reservoirs, with a P-wave impedance range of 12500–14200 and a P-wave / S-wave velocity ratio range of 1.73–1.78.

[0088] Figure 5 This is a plan view of an actual shale oilfield in an embodiment of the present invention. Based on the interpretation scale, the longitudinal wave impedance of the actual shale oilfield is inverted (e.g., ...).Figure 5 (a) The actual working area longitudinal wave impedance inversion plan view is shown) and the longitudinal and transverse wave velocity ratio (as shown in the figure). Figure 5 (b) The inversion planar diagram showing the ratio of longitudinal and transverse wave velocities in the actual work area is used to quantitatively interpret the elastic parameter results. Figure 5 (c) The actual work area classification plan shows the planar distribution range of Class I, II, and III reservoirs and non-reservoirs in this work area. The oil-bearing capacity of the shale oil section in Well 1 is comparable to that of Well 2, but its physical properties are slightly worse. Figure 5 The classification results (c) show that Well 1 is a Class II reservoir and Well 2 is a Class I reservoir, which is consistent with the actual understanding and also demonstrates the accuracy of the rock physics modeling method for shale oil.

[0089] This invention also provides a rock physics modeling device for porosity fluid filling, as described in the following embodiments. Since the principle by which this device solves the problem is similar to that of the rock physics modeling method for porosity fluid filling, the implementation of this device can refer to the implementation of the rock physics modeling method for porosity fluid filling; repeated details will not be elaborated further. Figure 6 This is a schematic diagram of a rock physics modeling device for filling porosity fluid according to an embodiment of the present invention. The device includes:

[0090] The elastic information acquisition module 601 is used to acquire the elastic information of the mixed mineral matrix in shale oil reservoirs; the elastic information includes elastic modulus, bulk modulus and shear modulus;

[0091] The mixed mineral matrix model construction module 602 is used to construct a mixed mineral matrix model based on the elasticity information of the mixed mineral matrix.

[0092] The mixed mineral rock model construction module 603 is used to add pore saturated fluid to the mixed mineral matrix using the differential equivalent medium method 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.

[0093] The module 604 for constructing a mixed mineral rock model containing pore saturated fluid and microfracture saturated fluid is used to add microfracture saturated fluid to a mixed mineral matrix containing pore saturated fluid using the differential equivalent medium method, thereby obtaining a mixed mineral matrix containing pore saturated fluid and microfracture saturated fluid. Based on the mixed mineral rock model containing pore saturated fluid, and according to the elastic information of the mixed mineral matrix containing pore saturated fluid and microfracture saturated fluid, a mixed mineral rock model containing pore saturated fluid and microfracture saturated fluid is constructed.

[0094] The rock elasticity characteristic calculation module 605 is used to add fracture saturated fluid to the mixed mineral matrix containing pore saturated fluid and microfracture saturated fluid based on the mixed mineral rock model containing pore saturated fluid and microfracture saturated fluid, and calculate the rock elasticity characteristics of the mixed mineral matrix containing pore saturated fluid, microfracture saturated fluid and fracture saturated fluid.

[0095] Rock physical model determination module 606 is used to obtain a rock physical model based on the elastic characteristics of the rock.

[0096] In one embodiment, the mixed mineral matrix model construction module 602 is specifically used for:

[0097] Based on the mathematical relationships between the elastic modulus, bulk modulus, and shear modulus in the elastic information of the mixed mineral matrix, a mixed mineral matrix model is constructed.

[0098] In one embodiment, the mathematical relationships between the elastic modulus, bulk modulus, and shear modulus in the elastic information of the mixed mineral matrix are as follows:

[0099]

[0100] Where 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 ν is the Poisson's ratio of the mixed mineral matrix.

[0101] In one embodiment, the mixed mineral rock model construction module 603 containing pore-saturated fluid is specifically used for:

[0102] Using a mixed mineral matrix as the first background medium, a first inclusion is added to the first background medium using the differential equivalent medium method. The first inclusion is a pore-saturated fluid, resulting in a mixed mineral matrix containing pore-saturated fluid.

[0103] In one embodiment, the mixed mineral rock model construction module 603 containing pore-saturated fluid is specifically used for:

[0104] Construct a mixed mineral rock model containing pore-saturated fluid using the following formula:

[0105]

[0106] 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 fThese 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.

[0107] In one embodiment, the mixed mineral rock model construction module 604, containing pore-saturated fluid and microfracture-saturated fluid, is specifically used for:

[0108] Using a mixed mineral matrix containing porous saturated fluid as a second background medium, a second inclusion is added to the second background medium using the differential equivalent medium method. The second inclusion is microfracture saturated fluid, resulting in a mixed mineral matrix containing porous saturated fluid and microfracture saturated fluid.

[0109] In one embodiment, the mixed mineral rock model construction module 604, containing pore-saturated fluid and microfracture-saturated fluid, is specifically used for:

[0110] Construct equivalent medium models for saturated fluids with pores and saturated fluids with microfractures using the following formula:

[0111]

[0112]

[0113] Where, φ m For microfracture porosity, when φ m When K = 0, ** and μ ** The bulk modulus K of the second mixed mineral matrix * and shear modulus μ * ;K f and μ f Let P(φ) be the bulk modulus and shear modulus of the second inclusion body. m ) and Q(φ m The aspect ratio of microfractures is an influencing factor related to the aspect ratio of microfractures. The aspect ratio of microfractures is obtained by statistical observation under a microscope of core thin sections.

[0114] In one embodiment, the rock elastic characteristic calculation module 605 is specifically used for:

[0115] Acquire pore information, microcrack information, and fracture information;

[0116] Based on the bulk modulus and shear modulus of the mixed mineral matrix containing pore-saturated fluid and microfracture-saturated fluid, calculate the elastic modulus of the mixed mineral matrix containing pore-saturated fluid and microfracture-saturated fluid.

[0117] Based on pore information, microfracture information, fracture information, and the elastic modulus of the mixed mineral matrix containing pore-saturated fluid and microfracture-saturated fluid, the Gassmann equation is used to determine the rock elastic characteristics of the mixed mineral matrix containing pore-saturated fluid, microfracture-saturated fluid, and fracture-saturated fluid.

[0118] This invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the above-described rock physics modeling method for pore fluid filling.

[0119] This invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described rock physics modeling method for porosity fluid filling.

[0120] This invention also provides a computer program product, which includes a computer program that, when executed by a processor, implements the above-described rock physics modeling method for filling porosity fluids.

[0121] In this embodiment of the invention, elastic information of the mixed mineral matrix in a shale oil reservoir is obtained; the elastic information includes elastic modulus, bulk modulus, and shear modulus; a mixed mineral matrix model is constructed based on the elastic information of the mixed mineral matrix; pore-saturated fluid is added to the mixed mineral matrix using the differential equivalent medium method 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; microfracture saturated fluid is added to the mixed mineral matrix containing pore-saturated fluid using the differential equivalent medium method to obtain a mixed mineral matrix containing pore-saturated fluid. A mixed mineral matrix containing pore-saturated fluids and microfracture-saturated fluids is constructed. Based on a mixed mineral rock model containing pore-saturated fluids, a mixed mineral rock model containing pore-saturated fluids and microfracture-saturated fluids is built according to the elastic information of the mixed mineral matrix containing pore-saturated fluids and microfracture-saturated fluids. Based on this mixed mineral rock model containing pore-saturated fluids and microfracture-saturated fluids, fracture-saturated fluids are added to the mixed mineral matrix, and the rock elastic characteristics of the mixed mineral matrix containing pore-saturated fluids, microfracture-saturated fluids, and fracture-saturated fluids are calculated. A rock physical model is obtained based on these rock elastic characteristics. In the above process, this embodiment of the invention considers the multi-dimensional pore characteristics and structure of matrix pores, microfractures, and natural fractures. Compared with existing conventional clastic rock physical modeling methods that are not suitable for shale oil reservoirs with multiple pore types, this embodiment of the invention gradually adds pore-saturated fluids, microfracture-saturated fluids, and fracture-saturated fluids to the mixed mineral matrix model. While ensuring the diversity of pore types, a corresponding rock physical model is constructed, thereby solving the problem of difficulties in commonly used rock physical modeling due to the diversity of pore types.

[0122] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied 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.

[0123] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0124] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0125] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0126] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A rock physics modeling method for porous fluid filling, characterized in that, include: Obtain elastic information of the mixed mineral matrix in shale oil reservoirs; elastic information includes elastic modulus, bulk modulus, and shear modulus; A model of the mixed mineral matrix is ​​constructed based on the elasticity information of the mixed mineral matrix; A pore-saturated fluid was added to a mixed mineral matrix using the differential equivalent medium method 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 was constructed according to the elastic information of the mixed mineral matrix containing pore-saturated fluid. The differential equivalent medium method was used to add microfracture saturated fluid to a mixed mineral matrix containing pore saturated fluid, resulting in a mixed mineral matrix containing both pore saturated fluid and microfracture saturated fluid. Based on the mixed mineral rock model containing pore saturated fluid, and according to the elastic information of the mixed mineral matrix containing both pore saturated fluid and microfracture saturated fluid, a mixed mineral rock model containing both pore saturated fluid and microfracture saturated fluid was constructed. Add fracture saturated fluid to a mixed mineral matrix containing pore saturated fluid and microfracture saturated fluid to obtain a mixed mineral matrix containing pore saturated fluid, microfracture saturated fluid, and fracture saturated fluid. Based on the mixed mineral rock model containing pore saturated fluid and microfracture saturated fluid, calculate the rock elastic characteristics of the mixed mineral matrix containing pore saturated fluid, microfracture saturated fluid, and fracture saturated fluid according to the elastic information of the mixed mineral matrix. A rock physics model is obtained based on the elastic characteristics of the rock.

2. The rock physics modeling method for porosity fluid filling as described in claim 1, characterized in that, Based on the elasticity information of the mixed mineral matrix, a mixed mineral matrix model is constructed, including: Based on the mathematical relationships between the elastic modulus, bulk modulus, and shear modulus in the elastic information of the mixed mineral matrix, a mixed mineral matrix model is constructed.

3. The rock physics modeling method for porosity fluid filling as described in claim 1, characterized in that, A pore-saturated fluid was added to a mixed mineral matrix using the differential equivalent medium method to obtain a mixed mineral matrix containing pore-saturated fluid, including: Using a mixed mineral matrix as the first background medium, a first inclusion is added to the first background medium using the differential equivalent medium method. The first inclusion is a pore-saturated fluid, resulting in a mixed mineral matrix containing pore-saturated fluid.

4. The rock physics modeling method for porosity fluid filling as described in claim 3, characterized in that, Based on the mixed mineral matrix model, and using the elastic information of the mixed mineral matrix containing pore-saturated fluid, a mixed mineral rock model containing pore-saturated fluid is constructed, including: Construct a mixed mineral rock model containing pore-saturated fluid using the following formula: 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 rock physics modeling method for porosity fluid filling as described in claim 1, characterized in that, Before adding microfractured saturated fluid to a mixed mineral matrix containing porous saturated fluid using the differential equivalent medium method, the following steps are included: Based on the KT model, the bulk modulus and shear modulus of the dry rock skeleton were calculated. Based on the bulk modulus of the rock skeleton and the shear modulus of the dry rock skeleton, a porosity inversion equation is constructed. The porosity inversion equation is solved using the damped least squares method to obtain the soft porosity; Microfracture porosity is calculated based on soft porosity and fracture porosity; the fracture porosity is pre-calculated using well logging data.

6. The rock physics modeling method for porosity fluid filling as described in claim 1, characterized in that, A differential equivalent medium method was used to add microfracture saturated fluid to a mixed mineral matrix containing porous saturated fluid, resulting in a mixed mineral matrix containing both porous saturated fluid and microfracture saturated fluid, comprising: Using a mixed mineral matrix containing porous saturated fluid as a second background medium, a second inclusion is added to the second background medium using the differential equivalent medium method. The second inclusion is microfracture saturated fluid, resulting in a mixed mineral matrix containing porous saturated fluid and microfracture saturated fluid.

7. The rock physics modeling method for porosity fluid filling as described in claim 6, characterized in that, Based on the mixed mineral-rock model containing pore-saturated fluid, and according to the elastic information of the mixed mineral matrix containing pore-saturated fluid and microfracture-saturated fluid, a mixed mineral-rock model containing pore-saturated fluid and microfracture-saturated fluid is constructed, including: Construct equivalent medium models for saturated fluids with pores and saturated fluids with microfractures using the following formula: Where, φ m For microfracture porosity, when φ m When K = 0, ** and μ ** The bulk modulus K of the mixed mineral matrix containing pore-saturated fluid and microfracture-saturated fluid, respectively. * and shear modulus μ * ;K f and μ f These are the bulk modulus and shear modulus of the second inclusion body, respectively, P(φ m ) and Q(φ m The figures () represent the influencing factors related to the aspect ratio of microfractures, which were obtained from microscopic observation and statistics of core thin sections.

8. The rock physics modeling method for porosity fluid filling as described in claim 1, characterized in that, Based on a mixed mineral rock model containing pore-saturated fluids and microfracture-saturated fluids, and using the elastic information of the mixed mineral matrix containing pore-saturated fluids, microfracture-saturated fluids, and fracture-saturated fluids, the rock elastic characteristics of the mixed mineral matrix containing pore-saturated fluids, microfracture-saturated fluids, and fracture-saturated fluids are calculated, including: Acquire pore information, microcrack information, and fracture information; Based on the bulk modulus and shear modulus of the mixed mineral matrix containing pore-saturated fluid and microfracture-saturated fluid, calculate the elastic modulus of the mixed mineral matrix containing pore-saturated fluid and microfracture-saturated fluid. Based on pore information, microfracture information, fracture information, and the elastic modulus of the mixed mineral matrix containing pore-saturated fluid and microfracture-saturated fluid, the Gassmann equation is used to determine the rock elastic characteristics of the mixed mineral matrix containing pore-saturated fluid, microfracture-saturated fluid, and fracture-saturated fluid.

9. A rock physics modeling device filled with porosity fluid, characterized in that, include: The elasticity information acquisition module is used to acquire elasticity information of the mixed mineral matrix in shale oil reservoirs; the elasticity information includes elastic modulus, bulk modulus and shear modulus; The mixed mineral matrix model building module is used to build a mixed mineral matrix model based on the elasticity information of the mixed mineral matrix. A module for constructing a mixed mineral rock model containing pore-saturated fluid is used to add pore-saturated fluid to a mixed mineral matrix using the differential equivalent medium method 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. A module for constructing a mixed mineral rock model containing pore-saturated fluid and microfracture-saturated fluid is used to add microfracture-saturated fluid to a mixed mineral matrix containing pore-saturated fluid using the differential equivalent medium method, thereby obtaining a mixed mineral matrix containing both pore-saturated fluid and microfracture-saturated fluid. Based on the mixed mineral rock model containing pore-saturated fluid, and according to the elastic information of the mixed mineral matrix containing both pore-saturated fluid and microfracture-saturated fluid, a mixed mineral rock model containing both pore-saturated fluid and microfracture-saturated fluid is constructed. The rock elasticity characteristic calculation module is used to calculate the rock elasticity characteristics of the mixed mineral matrix containing pore saturated fluid, microfracture saturated fluid, and fracture saturated fluid, based on a mixed mineral rock model containing pore saturated fluid and microfracture saturated fluid. The rock physics model determination module is used to obtain a rock physics model based on the elastic characteristics of the rock.

10. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method of any one of claims 1 to 8.

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

12. A computer program product, characterized in that, The computer program product includes a computer program that, when executed by a processor, implements the method of any one of claims 1 to 8.

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