While-drilling electromagnetic forward modeling simulation system and method for multi-layer non-uniform lossy stratum

Abstract

The invention discloses a while-drilling electromagnetic forward modeling simulation system and method for a multi-layer non-uniform lossy stratum, and belongs to the technical field of while-drilling electromagnetic forward modeling simulation systems. Comprising a stratum parameter modeling module, an excitation source configuration module, an electromagnetic field component calculation module, a data processing optimization module, a simulation result output module, a model verification calibration module and a multi-scene adaptation module. The three-dimensional model of the multi-layer non-uniform lossy stratum is constructed through the stratum parameter modeling module, the physical characteristics of the complex stratum are accurately adapted, and the limitation that a traditional model can only simulate a uniform or simple stratum is solved. The system completely calculates the components of the three directions phi, r and z of the electric field and the components of the three directions r, z and phi of the magnetic field, and the defect that component calculation of a traditional model is not comprehensive is overcome. Through a combination mode of absolute value conversion, natural logarithm conversion and noise reduction processing, the presentation effect of the electromagnetic field data is optimized, interference factors are eliminated, and the data availability is improved.

Description

Technical Field

[0001] This invention relates to the field of drilling electromagnetic forward modeling simulation system technology, specifically to a drilling electromagnetic forward modeling simulation system and method for multi-layer non-uniform lossy formations. Background Technology

[0002] Explanation of relevant terms: Electromagnetic forward modeling during drilling: a technique that uses electromagnetic waves to detect formation characteristics during drilling and processes and analyzes the detected data through forward modeling.

[0003] Multi-layered non-uniform lossy strata: refers to a geological structure composed of multiple strata with different electromagnetic properties (such as conductivity, dielectric constant, etc.) and energy loss.

[0004] In oil and gas field development and geological exploration, electromagnetic detection while drilling (EMD) technology has become one of the core technologies for obtaining formation geological parameters due to its advantages of strong real-time performance and moderate detection depth. The electromagnetic response characteristics of multi-layered, non-uniform, and lossy formations are complex and significantly affected by the spatial distribution differences of formation conductivity, permeability, and dielectric constant, as well as the type of excitation source. It is necessary to accurately simulate the electromagnetic field distribution law through EMD forward modeling.

[0005] Current mainstream drilling electromagnetic forward modeling simulation models (such as drilling electromagnetic forward modeling simulation models based on the finite difference method and drilling electromagnetic forward modeling models based on the method of moments) have many technical bottlenecks: a) Most models are designed only for homogeneous strata or simple two-layer strata, lacking the ability to adapt to multi-layer non-homogeneous lossy strata and failing to reflect the influence of spatial variations in strata parameters on electromagnetic fields. b) The calculation of electromagnetic field components is incomplete, often focusing only on components in a single direction and ignoring the coupling effect between electric and magnetic field components in all directions, resulting in insufficient completeness of simulation results; c) The data processing method is simplistic and does not take into account the large differences in the numerical range of electromagnetic field components, making it difficult to intuitively present the electromagnetic response pattern. d) The model lacks the ability to adapt to multiple excitation sources and cannot meet the requirements for switching excitation methods under different detection scenarios; e) The consistency verification mechanism between simulation results and actual formation electromagnetic response is imperfect, making it difficult to guarantee simulation accuracy.

[0006] Based on this, the present invention designs a drilling electromagnetic forward modeling system and method for multi-layered non-uniform lossy formations to solve the above problems. Summary of the Invention

[0007] To address the aforementioned shortcomings of existing technologies, this invention provides a drilling electromagnetic forward modeling simulation system and method for multi-layered non-uniform lossy formations. This enables accurate and comprehensive simulation of the electromagnetic response characteristics of multi-layered non-uniform lossy formations.

[0008] To achieve the above objectives, the present invention provides the following technical solution: The drilling electromagnetic forward modeling simulation system for multi-layered non-uniform lossy formations includes a formation parameter modeling module, an excitation source configuration module, an electromagnetic field component calculation module, a data processing and optimization module, a simulation result output module, a model verification and calibration module, and a multi-scenario adaptation module. The formation parameter modeling module is used to construct a three-dimensional physical model of multi-layered non-uniform lossy formations. The formation parameter modeling module includes formation structure definition units, electromagnetic parameter assignment units, and mesh generation units. Stratigraphic structure definition unit: Based on actual geological exploration data, define the number of strata, the thickness of each stratum, the boundary of the stratum distribution, and the spatial extension range; Electromagnetic parameter assignment unit: Assign conductivity, magnetic permeability and dielectric constant to each stratum, and establish equivalent formulas for electromagnetic parameters of multi-layer non-uniform lossy strata; Mesh subdivision unit: An adaptive mesh subdivision algorithm is used to spatially discretize the constructed multi-layer stratigraphic model, refine the mesh in key areas, and generate a three-dimensional mesh model of multi-layer non-uniform lossy strata. The excitation source configuration module is used to set the excitation source parameters for electromagnetic detection while drilling. The electromagnetic field component calculation module is used to comprehensively calculate the electric and magnetic field components in all directions in multi-layered non-uniform lossy strata. The electromagnetic field component calculation module includes a control equation establishment unit, a boundary condition setting unit, and a numerical solution unit. Unit for establishing governing equations: Establishing the governing equations for the electromagnetic field distribution; Boundary condition setting unit: Sets the far-field boundary conditions, formation interface boundary conditions, and excitation source boundary conditions of the model; Numerical solution unit: The finite element method is used to discretize and solve the governing equations. The numerical values ​​of the electric field phi direction component, electric field r direction component, electric field z direction component, and magnetic field r direction component, magnetic field z direction component, and magnetic field phi direction component of each grid node in the formation model are obtained through iterative calculation. The data processing optimization module is used to optimize the electromagnetic field component data. The simulation results output module is used to output the original electromagnetic field data, the processed data, and related simulation information; The model validation and calibration module is used to verify the accuracy and reliability of the simulation model. A multi-scenario adaptation module is used to adapt to different formation media scenarios and detection requirements.

[0009] Furthermore, the equivalent formula for electromagnetic parameters is: in, For equivalent electromagnetic parameters, This represents the total number of stratigraphic layers. For the first Layer thickness, For the first Electromagnetic parameters of the formation.

[0010] Furthermore, the excitation source configuration module includes an excitation source type selection unit, an excitation parameter setting unit, and an excitation source location positioning unit; Excitation source type selection unit: provides two core types: current excitation and voltage excitation; Excitation parameter setting unit: For current excitation, set the amplitude of the excitation current; for voltage excitation, set the amplitude of the excitation voltage, and also supports setting the waveform type of the excitation signal; Excitation source location unit: Based on the grid coordinate system of the stratum model, the spatial location of the excitation source in multiple strata is set.

[0011] Furthermore, the data processing optimization module includes an absolute value transformation unit, a natural logarithm transformation unit, and a data noise reduction unit; Absolute value conversion unit: Calculates the absolute values ​​of the electric field components and the magnetic field components in each direction using the absolute value conversion formula. in, These are the original electromagnetic field components. The absolute value after conversion; Natural logarithm transformation unit: Performs natural logarithmic transformation on the electromagnetic field components in each direction after absolute value transformation using the natural logarithm transformation formula: in, The components after transformation by the natural logarithm, It is a very small positive number; Data noise reduction unit: The moving average filtering algorithm is used to perform noise reduction processing on the converted electromagnetic field data.

[0012] Furthermore, the simulation result output module includes a data format conversion unit, a visualization unit, and a data storage unit; Data format conversion unit: converts the raw electromagnetic field component data obtained from numerical solutions and the processed optimized data into a common data format; Visualization unit: Visualizes the original distribution of electric and magnetic field components in each direction, as well as their distribution after absolute value and natural logarithm processing, presenting the spatial variation characteristics of electromagnetic fields in multi-layered non-uniform lossy strata; Data storage unit: Establish a structured database to store key parameters, raw electromagnetic field data, optimized data, and visualization result files during the simulation process, and support data retrieval and retrieval.

[0013] Furthermore, the model verification and calibration module includes a benchmark model establishment unit, a simulation result comparison unit, and a parameter calibration unit; Baseline model building unit: Construct a homogeneous stratigraphic model or a simple two-layer stratigraphic model with known analytical solutions as the baseline model, and set the excitation source parameters and grid subdivision accuracy consistent with the model to be verified; Simulation Result Comparison Unit: This unit quantitatively compares the simulation results of the benchmark model with the corresponding analytical solutions, calculates the mean square error (MSE) and relative error of both, and evaluates the numerical calculation accuracy of the model. Parameter calibration unit: If the comparison result exceeds the preset error threshold, adjust the parameters and re-perform the simulation calculation until the error between the simulation result and the analytical solution meets the preset requirements, and complete the model calibration.

[0014] Furthermore, the multi-scenario adaptation module includes a media type extension unit, a detection parameter adjustment unit, and a scene template storage unit; Medium type extension unit: Supports adding specific media in multi-layer non-uniform lossy strata to simulate complex geological scenarios. By adjusting the spatial distribution range and electromagnetic parameters of the added media, it can be adapted to different detection targets. Detection parameter adjustment unit: Allows users to flexibly adjust the type, parameters and location of the excitation source, change the number of strata, the thickness of each layer and electromagnetic parameters, and quickly build different simulation scenarios; Scene template storage unit: Saves commonly used simulation scenes as templates, which users can directly call and fine-tune.

[0015] Furthermore, the governing equations for the electromagnetic field distribution are: in, For vector magnetic potential, For the Laplace operator, For complex wave number, Angular frequency, The imaginary unit, Permeability, Where is the dielectric constant. For electrical conductivity, denoted as current density.

[0016] To better achieve the objectives of this invention, this invention also provides a drilling electromagnetic forward modeling method for multi-layered non-uniform lossy formations, comprising the following steps: Step 1: System Initialization and Formation Model Construction The simulation model system is started, and the working parameters of each module are initialized. Through the stratigraphic parameter modeling module, actual geological exploration data is input to define the number of layers, thickness of each layer, layer boundaries, and spatial extension range of the multi-layered non-uniform lossy strata. Electrical conductivity, magnetic permeability, and dielectric constant are assigned to each layer to clarify the distribution type of electromagnetic parameters within the same stratum. An adaptive mesh generation algorithm is used to discretize the stratigraphic model, and the mesh is refined in key areas to generate a three-dimensional mesh model of the multi-layered non-uniform lossy strata. Step 2: Configure excitation source parameters; Step 3: Numerical solution of electromagnetic field components The electromagnetic field component calculation module establishes the governing equations for numerical solution of electromagnetic field components based on Maxwell's equations; the far-field absorbing boundary conditions, formation interface boundary conditions, and excitation source boundary conditions of the model are set; the governing equations are discretized using the finite element method, and the formation electromagnetic parameters, excitation source parameters, and boundary conditions are substituted into the equations. The original values ​​of the electric field phi direction component, r direction component, z direction component and magnetic field r direction component, z direction component, phi direction component of each grid node are solved by iterative calculation. Step 4: Simulation data optimization processing The original electromagnetic field component data obtained from the solution is input into the data processing and optimization module. The absolute value of each component data is transformed according to the absolute value transformation formula of the electromagnetic field component. Then, the natural logarithm transformation is performed on the data after the absolute value transformation according to the natural logarithm transformation formula of the electromagnetic field component to compress the numerical range. Finally, the transformed data is denoised by the moving average filtering algorithm to remove random errors and obtain the optimized electromagnetic field data. Step 5: Output and display of simulation results; Step 6: Model validation and calibration; Step 7: Multi-scenario adaptation and expansion; Step 8: Simulation task ends and data is archived.

[0017] Furthermore, steps 2 and 5 through 7 are as follows: Step 2: Configure excitation source parameters Enter the excitation source configuration module and select the excitation source type; set the excitation parameters according to the simulation requirements. If current excitation is selected, set the current amplitude; if voltage excitation is selected, set the voltage amplitude. At the same time, set the waveform type of the excitation signal; based on the coordinate system of the three-dimensional grid model of the stratum, accurately locate the spatial position of the excitation source and complete the deployment of the excitation source. Step 5: Simulation Results Output and Display The simulation results output module converts the original electromagnetic field data and the optimized data into a common format; it visualizes the original distribution and the processed distribution of each electromagnetic field component; and it establishes a structured database to store formation parameters, excitation source parameters, grid parameters, original data, optimized data, and visualization result files, supporting data retrieval and retrieval. Step 6: Model Validation and Calibration Start the model verification and calibration module, construct a benchmark model with known analytical solutions, and set excitation source parameters and mesh generation accuracy consistent with the current simulation model; perform simulation calculations on the benchmark model, compare the simulation results with the analytical solutions, and calculate the mean square error and relative error; if the error exceeds the preset threshold, adjust the parameters and repeat steps 3 to 5 until the error meets the requirements, and complete the model calibration. Step 7: Multi-scenario adaptation and expansion If it is necessary to simulate a formation scenario containing a specific medium, add the corresponding medium through the multi-scenario adaptation module and set its spatial distribution range and electromagnetic parameters; if it is necessary to adjust the detection conditions, the excitation source type, parameters, location or formation structure and electromagnetic parameters can be modified to construct a new simulation scenario; save commonly used scenarios as templates for easy and quick subsequent use; repeat steps 3 to 6 to complete the drilling electromagnetic forward modeling simulation under different scenarios.

[0018] Compared with the prior art, the beneficial effects of this invention are as follows: 1) This invention constructs a three-dimensional model of multi-layer non-uniform lossy strata through the stratum parameter modeling module, supports the setting of uniform, gradual or discrete distribution of electromagnetic parameters, accurately adapts to the physical characteristics of complex strata, and solves the limitation of traditional models that can only simulate uniform or simple strata.

[0019] 2) The present invention system fully calculates the components of the electric field in the three directions of phi, r, and z, and the magnetic field in the three directions of r, z, and phi, fully reflecting the coupling effect and spatial distribution characteristics of the electromagnetic field in multi-layered non-uniform lossy strata, and making up for the shortcomings of the traditional model in terms of incomplete component calculation.

[0020] 3) This invention optimizes the presentation of electromagnetic field data, compresses the numerical range, eliminates interference factors, facilitates intuitive observation of electromagnetic response laws, and improves data usability by combining absolute value transformation, natural logarithm transformation and noise reduction processing.

[0021] 4) The present invention provides an excitation source configuration module, which integrates an excitation source type selection unit, an excitation parameter setting unit, and an excitation source location positioning unit to form a complete customized excitation source configuration scheme.

[0022] 5) The model verification and calibration module constructs a benchmark model of a uniform formation, sets the excitation source parameters and mesh accuracy to be consistent with the current model; after simulating the benchmark model, the results are compared with the analytical solution of the electromagnetic field of the uniform formation, with a mean square error of 3.2%, indicating high simulation accuracy. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0024] Figure 1 This is a system module diagram of the present invention; Figure 2 This is a graph showing the magnitude of the electric field phi directional component under the absolute value and natural logarithm of the result of the electric field phi directional component under the condition of a current of 1A according to the present invention. Figure 3 This is a graph showing the magnitudes of the electric field r-direction components under the absolute value and natural logarithm of the electric field phi-direction component under the condition of a current of 1A according to the present invention. Figure 4 This is a graph showing the magnitude of the electric field z-direction component under the absolute value and natural logarithm of the electric field phi-direction component under the condition of a current of 1A according to the present invention. Figure 5 This is a graph showing the magnitude of the magnetic field r component under the absolute value and natural logarithm of the result of the direction component of the magnetic field r under the condition of a current of 1A according to the present invention. Figure 6 The result of the magnetic field r-direction component under the condition of 1A current in this invention is the absolute value and the magnitude of the natural logarithmic magnetic field z-component. Figure 7 This invention relates to the magnitude of the z-component of the magnetic field under the natural logarithm of the current in the z-direction. Figure 8 This invention relates to the magnitude of the magnetic field phi component under the natural logarithm of the z-direction component of the magnetic field when the current is 1A. Figure 9 This is a diagram showing the magnitudes of the electric field r component under the absolute value and natural logarithm of the z-direction component of the electric field when the voltage is 1V according to the present invention. Figure 10 This is a diagram showing the magnitude of the z-component of the electric field under the absolute value and natural logarithm of the z-direction component of the electric field when the voltage is 1V according to the present invention. Figure 11 This is a diagram showing the magnitudes of the magnetic field phi component under the absolute value and natural logarithm of the electric field z-direction component when the voltage is 1V according to the present invention. Figure 12 This is a diagram showing the magnitudes of the magnetic field phi component under the absolute value and natural logarithm of the electric field phi direction component when the voltage is 1V according to the present invention. Figure 13 This is a diagram showing the magnitudes of the magnetic field r component under the absolute value and natural logarithm of the electric field phi direction component when the voltage is 1V. Figure 14 This is a diagram showing the magnitudes of the magnetic field z-component under the absolute value and natural logarithm of the electric field phi direction component when the voltage is 1V. Figure 15 This is a diagram showing the magnitude of the z-component of the electric field under the absolute value and natural logarithm of the phi-direction component of the electric field under the conditions of adding petroleum, according to the present invention. Figure 16 This is a diagram showing the magnitudes of the electric field phi components under the absolute value and natural logarithm of the electric field phi direction components under the conditions of adding petroleum, according to the present invention. Figure 17 This is a diagram showing the magnitude of the electric field r component under the absolute value and natural logarithm of the electric field phi direction component under the conditions of adding oil according to the present invention; Figure 18 This is a diagram showing the magnitude of the electric field r-direction component under the absolute value and natural logarithm of the electric field r-direction component under the petroleum-adding conditions of the present invention; Figure 19 This is a diagram showing the magnitudes of the magnetic field phi components under the absolute value and natural logarithm of the electric field r-direction component in the oil-addition condition according to the present invention. Figure 20 This is a diagram showing the magnitudes of the magnetic field phi component under the absolute value and natural logarithm of the magnetic field phi direction component under the petroleum conditions of this invention; Figure 21 This is a diagram showing the magnitudes of the magnetic field r component under the absolute value and natural logarithm of the magnetic field phi direction component under the petroleum-adding conditions of this invention; Figure 22 This is a diagram showing the magnitude of the magnetic field z-component under the absolute value and natural logarithm of the magnetic field phi direction component under the petroleum conditions of this invention; Figure 23 This is a flowchart of the method of the present invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0026] Example 1: In some embodiments, please refer to the accompanying drawings. Figures 1-23 The drilling electromagnetic forward modeling simulation system for multi-layered non-uniform lossy formations includes a formation parameter modeling module, an excitation source configuration module, an electromagnetic field component calculation module, a data processing and optimization module, a simulation result output module, a model verification and calibration module, and a multi-scenario adaptation module. Among them, the formation parameter modeling module is used to construct a three-dimensional physical model of multi-layer non-uniform lossy formations. The formation parameter modeling module includes formation structure definition unit, electromagnetic parameter assignment unit and mesh generation unit. Stratigraphic structure definition unit: Based on actual geological exploration data, define the number of strata, the thickness of each stratum, the distribution boundary of the strata and the spatial extension range, clarify the interface position of adjacent strata, and form a multi-layered non-uniform stratigraphic spatial structure framework. Electromagnetic parameter assignment unit: Assigns conductivity values ​​to each formation layer ( ), magnetic permeability ( ) and dielectric constant ( It supports the setting of spatial gradual or discrete distribution of electromagnetic parameters within the same stratum, accurately simulates the non-uniformity and lossy characteristics of the stratum, and establishes equivalent formulas for electromagnetic parameters of multi-layer non-uniform lossy strata by considering the spatial distribution of electromagnetic parameters in each layer. The equivalent formula for the electromagnetic parameters of multi-layered, non-uniform, lossy formations is: in, For equivalent electromagnetic parameters, This represents the total number of stratigraphic layers. For the first Layer thickness, For the first Electromagnetic parameters of the formation; Mesh generation: An adaptive mesh generation algorithm is used to spatially discretize the constructed multi-layered geological model. The mesh is made denser in key areas such as the geological interface with drastic electromagnetic field changes, near the excitation source, and in the detection area, while the mesh is made sparse in areas with gentle electromagnetic field changes, thus balancing simulation accuracy and computational efficiency.

[0027] The excitation source configuration module is used to set the excitation source parameters for electromagnetic detection while drilling. The excitation source configuration module includes an excitation source type selection unit, an excitation parameter setting unit, and an excitation source position positioning unit. Excitation source type selection unit: Provides two core types: current excitation and voltage excitation. Users can select the corresponding excitation method according to simulation requirements to adapt to the working principle of different drilling detection equipment. Excitation parameter setting unit: For current excitation, set the amplitude of the excitation current (e.g., 1A); for voltage excitation, set the amplitude of the excitation voltage (e.g., 1V), and also supports setting the waveform type of the excitation signal (e.g., DC, sine wave). Excitation source location unit: Based on the formation model's grid coordinate system, it accurately sets the spatial location of the excitation source in multiple formations. It can be located inside a certain formation, at the formation interface, or distributed along the drilling trajectory to simulate the deployment scenario of the excitation source in actual drilling exploration.

[0028] The electromagnetic field component calculation module is used to comprehensively calculate the electric and magnetic field components in all directions in multi-layered non-uniform lossy strata. The electromagnetic field component calculation module includes a control equation establishment unit, a boundary condition setting unit, and a numerical solution unit. The governing equation establishment unit: Based on Maxwell's equations and combined with the electromagnetic characteristics of multi-layered non-uniform lossy strata, the governing equations for the electromagnetic field distribution are established, taking into account the influence of the spatial non-uniformity of the strata's conductivity, permeability, and dielectric constant on the electromagnetic field. The governing equations for the electromagnetic field distribution are: in, For vector magnetic potential, For the Laplace operator, For complex wave number, Angular frequency, The imaginary unit, Permeability, Where is the dielectric constant. For electrical conductivity, Current density; Boundary condition setting unit: Sets the far-field boundary conditions, formation interface boundary conditions and excitation source boundary conditions of the model. The far-field boundary adopts the absorbing boundary condition to avoid the interference of electromagnetic wave reflection on the simulation results. The formation interface boundary satisfies the boundary constraints that the tangential component of the electromagnetic field is continuous and the normal component is related to the electromagnetic parameters of the medium. Numerical solution unit: The finite element method is used to discretize and solve the governing equations. The electric field phi direction component of each grid node in the formation model is obtained through iterative calculation. ), electric field r-direction component ( ), z-direction component of electric field ( ) and the magnetic field r-direction component ( ), the z-direction component of the magnetic field ( ), magnetic field phi direction component ( The value of ); The data processing optimization module is used to optimize the electromagnetic field component data. The data processing optimization module includes an absolute value conversion unit, a natural logarithm conversion unit, and a data noise reduction unit. Absolute value conversion unit: for components of electric field in all directions ( , , ) and the components of the magnetic field in each direction ( , , The absolute values ​​are calculated separately using the absolute value conversion formula, eliminating the interference of the positive and negative signs of the components on data observation and analysis, and highlighting the characteristics of numerical magnitude; The formula for converting absolute values ​​is: in, These are the original electromagnetic field components. The absolute value after conversion; Natural logarithm transformation unit: The electromagnetic field component data in each direction after absolute value transformation is transformed by natural logarithm transformation formula to compress the numerical range of the data, making the originally large difference in numerical distribution more reasonable, and making it easier to intuitively observe the spatial variation law of electromagnetic field. The formula for transforming the natural logarithm is: in, The components after transformation by the natural logarithm, It is a very small positive number.

[0029] Data denoising unit: The moving average filtering algorithm is used to denoise the converted electromagnetic field data, eliminate random errors generated during numerical calculation, and retain the true variation trend of electromagnetic field components.

[0030] The simulation result output module is used to output the original electromagnetic field data, the processed data, and related simulation information. The simulation result output module includes a data format conversion unit, a visualization display unit, and a data storage unit. Data format conversion unit: Converts the raw electromagnetic field component data obtained from numerical solution and the processed optimized data into a common data format (such as CSV, TXT) to facilitate subsequent import into data analysis software for further processing; Visualization unit: Through two-dimensional cloud maps, three-dimensional isosurface maps, and cross-sectional distribution maps, the original distribution of electric and magnetic field components in each direction and their distribution after absolute value and natural logarithm processing are displayed intuitively, clearly presenting the spatial variation characteristics of electromagnetic field in multi-layered non-uniform lossy strata. Data storage unit: Establish a structured database to store key parameters (stratum parameters, excitation source parameters, mesh generation parameters), raw electromagnetic field data, optimized data, and visualization result files during the simulation process, supporting rapid data retrieval and access.

[0031] The model verification and calibration module is used to verify the accuracy and reliability of the simulation model. The model verification and calibration module includes a benchmark model establishment unit, a simulation result comparison unit, and a parameter calibration unit. Baseline model building unit: Construct a homogeneous stratigraphic model or a simple two-layer stratigraphic model with known analytical solutions as the baseline model, and set the excitation source parameters and grid subdivision accuracy consistent with the model to be verified; Simulation Result Comparison Unit: This unit quantitatively compares the simulation results of the benchmark model with the corresponding analytical solutions, calculates the mean square error (MSE) and relative error of both, and evaluates the numerical calculation accuracy of the model. Parameter calibration unit: If the comparison result exceeds the preset error threshold, adjust parameters such as mesh density and numerical solution iteration accuracy, and re-perform simulation calculation until the error between the simulation result and the analytical solution meets the preset requirements, thus completing the model calibration.

[0032] The multi-scenario adaptation module is used to adapt to different formation media scenarios and detection requirements. The multi-scenario adaptation module includes a media type extension unit, a detection parameter adjustment unit, and a scenario template storage unit. Medium type extension unit: Supports adding specific media (such as oil) in multi-layer non-uniform lossy formations to simulate complex geological scenarios such as oil-bearing formations. By adjusting the spatial distribution range and electromagnetic parameters of the added media, it can be adapted to different detection targets. Detection parameter adjustment unit: Allows users to flexibly adjust the type, parameters and location of the excitation source, change the number of formation layers, the thickness of each layer and electromagnetic parameters, quickly build different simulation scenarios, and meet diverse drilling electromagnetic detection simulation needs; Scene template storage unit: Saves commonly used simulation scenes (such as different number of layers, layers with specific media, and scenes with different excitation methods) as templates. Users can directly call the templates and make fine adjustments to improve simulation efficiency.

[0033] The system of this invention achieves accurate construction of complex three-dimensional strata models through the stratum parameter modeling module, supporting diverse distribution settings of electromagnetic parameters; the electromagnetic field component calculation module completely solves the components of the electric and magnetic fields in six directions, comprehensively reflecting the coupling effect and spatial distribution characteristics of the electromagnetic fields; the data processing optimization module significantly improves the presentation effect and usability of electromagnetic field data through a combination of absolute value transformation, natural logarithm transformation and noise reduction processing.

[0034] Example 2: A simulation method for a drilling electromagnetic forward modeling system for multi-layered non-uniform lossy formations, comprising the following steps: Step 1: System Initialization and Formation Model Construction Start the simulation model system and initialize the working parameters of each module. Through the stratigraphic parameter modeling module, input actual geological exploration data to define the number of layers, thickness of each layer, layer boundaries, and spatial extension range of multiple non-uniform lossy strata. Assign electrical conductivity, magnetic permeability, and dielectric constant to each stratum, clarifying the distribution type of electromagnetic parameters within the same stratum (uniform, gradual, or discrete). Use an adaptive mesh generation algorithm to discretize the stratigraphic model, refining the mesh in key areas to generate a three-dimensional mesh model of multiple non-uniform lossy strata.

[0035] Step 2: Configure excitation source parameters Enter the excitation source configuration module and select the excitation source type (current excitation or voltage excitation); set the excitation parameters according to the simulation requirements. If current excitation is selected, set the current amplitude (e.g., 1A); if voltage excitation is selected, set the voltage amplitude (e.g., 1V). At the same time, set the waveform type of the excitation signal; based on the coordinate system of the three-dimensional grid model of the stratum, accurately locate the spatial position of the excitation source and complete the deployment of the excitation source.

[0036] Step 3: Numerical solution of electromagnetic field components The electromagnetic field component calculation module establishes the governing equations for numerical solution of electromagnetic field components based on Maxwell's equations. The far-field absorbing boundary conditions, formation interface boundary conditions, and excitation source boundary conditions of the model are set. The governing equations are discretized using the finite element method. The formation electromagnetic parameters, excitation source parameters, and boundary conditions are substituted, and the original values ​​of the electric field phi direction component, r direction component, z direction component and magnetic field r direction component, z direction component, phi direction component of each grid node are solved by iterative calculation.

[0037] Step 4: Simulation data optimization processing The original electromagnetic field component data obtained from the solution is input into the data processing and optimization module. The absolute value of each component data is transformed according to the absolute value transformation formula of the electromagnetic field components. Then, the natural logarithm transformation is performed on the data after the absolute value transformation according to the natural logarithm transformation formula of the electromagnetic field components to compress the numerical range. Finally, the transformed data is denoised by the moving average filtering algorithm to remove random errors and obtain the optimized electromagnetic field data.

[0038] Step 5: Simulation Results Output and Display The simulation results output module converts the original electromagnetic field data and the optimized data into common formats (CSV, TXT); it visualizes the original distribution and the processed distribution of each electromagnetic field component in the form of two-dimensional cloud maps and three-dimensional isosurface maps; it establishes a structured database to store formation parameters, excitation source parameters, grid parameters, original data, optimized data and visualization result files, and supports data retrieval and retrieval.

[0039] Step 6: Model Validation and Calibration Start the model verification and calibration module, construct a benchmark model (uniform formation or simple two-layer formation) with known analytical solutions, and set the excitation source parameters and mesh partitioning accuracy consistent with the current simulation model; perform simulation calculations on the benchmark model, compare the simulation results with the analytical solutions, and calculate the mean square error and relative error; if the error exceeds the preset threshold, adjust the mesh partitioning density, iterative calculation accuracy and other parameters, and repeat steps 3 to 5 until the error meets the requirements, and complete the model calibration.

[0040] Step 7: Multi-scenario adaptation and expansion If you need to simulate a formation scenario containing a specific medium (such as oil), add the corresponding medium through the multi-scenario adaptation module and set its spatial distribution range and electromagnetic parameters. If you need to adjust the detection conditions, you can modify the excitation source type, parameters, location, or formation structure and electromagnetic parameters to construct a new simulation scenario. Save commonly used scenarios as templates for easy and quick use later. Repeat steps 3 to 6 to complete the drilling electromagnetic forward modeling simulation under different scenarios.

[0041] Step 8: Simulation task completion and data archiving Once all the simulation tasks for the preset scenarios are completed, the system outputs a simulation task summary report, which includes key parameters, simulation accuracy, and result file storage paths for each scenario. All simulation data and result files are then categorized and archived, and the working processes of each module are closed, thus completing this numerical simulation of electromagnetic forward modeling during drilling.

[0042] Example 2: Simulation Method Example Step 1: System Initialization and Stratigraphic Model Construction. Start the simulation model system and initialize the working parameters of each module. Using the stratigraphic structure definition unit of the stratigraphic parameter modeling module, input the thickness and stratigraphic boundary information of the three stratigraphic layers; the electromagnetic parameter assignment unit assigns corresponding conductivity, magnetic permeability, and dielectric constant to each stratigraphic layer, setting the conductivity of the second stratigraphic layer to have a linearly gradual distribution; the mesh generation unit adaptively discretizes the stratigraphic model to generate a three-dimensional mesh model.

[0043] Step 2: Excitation source parameter configuration. Enter the excitation source configuration module and select the current excitation type; input the current amplitude of 1A in the excitation parameter setting unit and select the DC waveform; input the coordinates (50m, 50m, 20m) in the three-dimensional grid coordinate system through the excitation source position positioning unit to complete the excitation source deployment.

[0044] Step 3: Numerical Solution of Electromagnetic Field Components. The governing equation establishment unit of the electromagnetic field component calculation module establishes the governing equations for the numerical solution of electromagnetic field components based on Maxwell's equations and combined with the formation electromagnetic parameters; the boundary condition setting unit sets far-field absorbing boundary conditions, and sets boundary conditions at the formation interface where the tangential component of the electromagnetic field is continuous and the normal component matches the medium parameters; the numerical solution unit discretizes the governing equations using the finite element method, substitutes the excitation source current density and boundary conditions, and iteratively calculates the electric field of each grid node. , , and magnetic field , , The original value.

[0045] Step 4: Simulation Data Optimization Processing. The original electromagnetic field component data is input into the data processing and optimization module. The absolute value of each component is calculated according to the absolute value conversion formula of the electromagnetic field components, resulting in... , , , , , Then perform a natural logarithmic transformation according to the formula for the natural logarithmic transformation of electromagnetic field components (taking...). =10 -10 ),get , , , , , Finally, the logarithmically transformed data is denoised using a moving average filtering algorithm to obtain optimized data.

[0046] Step 5: Simulation Results Output and Display. The data format conversion unit of the simulation results output module converts the original data and optimized data into CSV format; the visualization unit generates two-dimensional cloud maps (along the z-axis profile) and three-dimensional isosurface maps for each electromagnetic field component, clearly showing the distribution differences of the electromagnetic field in the three strata; the data storage unit stores the strata parameters, excitation source parameters, grid parameters, original data, optimized data, and visualization result files into the database.

[0047] Step 6: Model Validation and Calibration. The model validation and calibration module constructs a homogeneous formation benchmark model (electrical conductivity 10 S / m, magnetic permeability 4π × 10⁻⁶). -7H / m, dielectric constant 81 Set the excitation source parameters and mesh accuracy to be consistent with the current model; after simulating the benchmark model, compare the results with the analytical solution of the electromagnetic field of the uniform stratum. The mean square error is calculated to be 3.2%, which is less than the preset threshold of 5%, so the model does not need to be calibrated.

[0048] Step 7: Multi-scene adaptation and expansion. This embodiment is for a conventional scenario, requiring no specific media to be added. The existing detection parameters remain unchanged, and no additional scenario construction is performed.

[0049] Step 8: Simulation Task Completion and Data Archiving. The system outputs a simulation task summary report, including information such as the parameters of the three formation layers, the 1A current excitation parameters, the simulation accuracy of 3.2%, and the storage path of the result files; all data and result files are classified and archived, the working processes of each module are closed, and the simulation is completed.

[0050] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A drilling electromagnetic forward modeling simulation system for multi-layered, non-uniform, lossy formations, characterized in that, It includes a formation parameter modeling module, an excitation source configuration module, an electromagnetic field component calculation module, a data processing optimization module, a simulation result output module, a model verification and calibration module, and a multi-scenario adaptation module; The formation parameter modeling module is used to construct a three-dimensional physical model of multi-layered non-uniform lossy formations. The formation parameter modeling module includes formation structure definition units, electromagnetic parameter assignment units, and mesh generation units. Stratigraphic structure definition unit: Based on actual geological exploration data, define the number of strata, the thickness of each stratum, the boundary of the stratum distribution, and the spatial extension range; Electromagnetic parameter assignment unit: Assign conductivity, magnetic permeability and dielectric constant to each stratum, and establish equivalent formulas for electromagnetic parameters of multi-layer non-uniform lossy strata; Mesh subdivision unit: An adaptive mesh subdivision algorithm is used to spatially discretize the constructed multi-layer stratigraphic model, refine the mesh in key areas, and generate a three-dimensional mesh model of multi-layer non-uniform lossy strata. The excitation source configuration module is used to set the excitation source parameters for electromagnetic detection while drilling. The electromagnetic field component calculation module is used to comprehensively calculate the electric and magnetic field components in all directions in multi-layered non-uniform lossy strata. The electromagnetic field component calculation module includes a control equation establishment unit, a boundary condition setting unit, and a numerical solution unit. Unit for establishing governing equations: Establishing the governing equations for the electromagnetic field distribution; Boundary condition setting unit: Sets the far-field boundary conditions, formation interface boundary conditions, and excitation source boundary conditions of the model; Numerical solution unit: The finite element method is used to discretize and solve the governing equations. The numerical values ​​of the electric field phi direction component, electric field r direction component, electric field z direction component, and magnetic field r direction component, magnetic field z direction component, and magnetic field phi direction component of each grid node in the formation model are obtained through iterative calculation. The data processing optimization module is used to optimize the electromagnetic field component data. The simulation result output module is used to output the original electromagnetic field data, the processed data, and related simulation information; The model validation and calibration module is used to verify the accuracy and reliability of the simulation model. A multi-scenario adaptation module is used to adapt to different formation media scenarios and detection requirements.

2. The drilling electromagnetic forward modeling simulation system for multi-layered non-uniform lossy formations according to claim 1, characterized in that, The equivalent formula for electromagnetic parameters is: in, For equivalent electromagnetic parameters, This represents the total number of stratigraphic layers. For the first Layer thickness, For the first Electromagnetic parameters of the formation.

3. The drilling electromagnetic forward modeling simulation system for multi-layered non-uniform lossy formations according to claim 1, characterized in that, The excitation source configuration module includes an excitation source type selection unit, an excitation parameter setting unit, and an excitation source location positioning unit; Excitation source type selection unit: provides two core types: current excitation and voltage excitation; Excitation parameter setting unit: For current excitation, set the amplitude of the excitation current; for voltage excitation, set the amplitude of the excitation voltage, and also supports setting the waveform type of the excitation signal; Excitation source location unit: Based on the grid coordinate system of the stratum model, the spatial location of the excitation source in multiple strata is set.

4. The drilling electromagnetic forward modeling simulation system for multi-layered non-uniform lossy formations according to claim 1, characterized in that, The data processing optimization module includes an absolute value transformation unit, a natural logarithm transformation unit, and a data noise reduction unit; Absolute value conversion unit: Calculates the absolute values ​​of the electric field components and the magnetic field components in each direction using the absolute value conversion formula. in, These are the original electromagnetic field components. The absolute value after conversion; Natural logarithm transformation unit: Performs natural logarithmic transformation on the electromagnetic field components in each direction after absolute value transformation using the natural logarithm transformation formula: in, The components are those transformed by the natural logarithm. It is a very small positive number; Data denoising unit: The moving average filtering algorithm is used to denoise the converted electromagnetic field data.

5. The drilling electromagnetic forward modeling simulation system for multi-layered non-uniform lossy formations according to claim 1, characterized in that, The simulation result output module includes a data format conversion unit, a visualization unit, and a data storage unit; Data format conversion unit: converts the raw electromagnetic field component data obtained from numerical solutions and the processed optimized data into a common data format; Visualization unit: Visualizes the original distribution of electric and magnetic field components in each direction, as well as their distribution after absolute value and natural logarithm processing, presenting the spatial variation characteristics of electromagnetic fields in multi-layered non-uniform lossy strata; Data storage unit: Establish a structured database to store key parameters, raw electromagnetic field data, optimized data, and visualization result files during the simulation process, and support data retrieval and retrieval.

6. The drilling electromagnetic forward modeling simulation system for multi-layered non-uniform lossy formations according to claim 1, characterized in that, The model verification and calibration module includes a benchmark model establishment unit, a simulation result comparison unit, and a parameter calibration unit; Benchmark model building unit: Construct a homogeneous stratigraphic model or a simple two-layer stratigraphic model with known analytical solutions as the benchmark model, and set the excitation source parameters and grid subdivision accuracy consistent with the model to be verified; Simulation Result Comparison Unit: This unit quantitatively compares the simulation results of the benchmark model with the corresponding analytical solutions, calculates the mean square error (MSE) and relative error of both, and evaluates the numerical calculation accuracy of the model. Parameter calibration unit: If the comparison result exceeds the preset error threshold, adjust the parameters and re-perform the simulation calculation until the error between the simulation result and the analytical solution meets the preset requirements, and complete the model calibration.

7. The drilling electromagnetic forward modeling simulation system for multi-layered non-uniform lossy formations according to claim 1, characterized in that, The multi-scenario adaptation module includes a media type extension unit, a detection parameter adjustment unit, and a scene template storage unit; Medium type extension unit: Supports adding specific media in multi-layer non-uniform lossy strata to simulate complex geological scenarios. By adjusting the spatial distribution range and electromagnetic parameters of the added media, it can be adapted to different detection targets. Detection parameter adjustment unit: Allows users to flexibly adjust the type, parameters and location of the excitation source, change the number of strata, the thickness of each layer and electromagnetic parameters, and quickly build different simulation scenarios; Scene template storage unit: Saves commonly used simulation scenes as templates, which users can directly call and fine-tune.

8. The drilling electromagnetic forward modeling simulation system for multi-layered non-uniform lossy formations according to claim 1, characterized in that, The governing equations for the electromagnetic field distribution are: in, For vector magnetic potential, For the Laplace operator, For complex wave number, Angular frequency, The imaginary unit, Permeability, Where is the dielectric constant. For electrical conductivity, denoted as current density.

9. A method for a drilling electromagnetic forward modeling simulation system for multi-layered non-uniform lossy formations according to any one of claims 1 to 8, characterized in that, Includes the following steps: Step 1: System Initialization and Formation Model Construction The simulation model system is started, and the working parameters of each module are initialized. Through the stratigraphic parameter modeling module, actual geological exploration data is input to define the number of layers, thickness of each layer, layer boundaries, and spatial extension range of the multi-layered non-uniform lossy strata. Electrical conductivity, magnetic permeability, and dielectric constant are assigned to each layer to clarify the distribution type of electromagnetic parameters within the same stratum. An adaptive mesh generation algorithm is used to discretize the stratigraphic model, and the mesh is refined in key areas to generate a three-dimensional mesh model of the multi-layered non-uniform lossy strata. Step 2: Configure excitation source parameters; Step 3: Numerical solution of electromagnetic field components The electromagnetic field component calculation module establishes the governing equations for numerical solution of electromagnetic field components based on Maxwell's equations; the far-field absorbing boundary conditions, formation interface boundary conditions, and excitation source boundary conditions of the model are set; the governing equations are discretized using the finite element method, and the formation electromagnetic parameters, excitation source parameters, and boundary conditions are substituted into the equations. The original values ​​of the electric field phi direction component, r direction component, z direction component and magnetic field r direction component, z direction component, phi direction component of each grid node are solved by iterative calculation. Step 4: Simulation data optimization processing The original electromagnetic field component data obtained from the solution is input into the data processing and optimization module. The absolute value of each component data is transformed according to the absolute value transformation formula of the electromagnetic field component. Then, the natural logarithm transformation is performed on the data after the absolute value transformation according to the natural logarithm transformation formula of the electromagnetic field component to compress the numerical range. Finally, the transformed data is denoised by the moving average filtering algorithm to remove random errors and obtain the optimized electromagnetic field data. Step 5: Output and display of simulation results; Step 6: Model validation and calibration; Step 7: Multi-scenario adaptation and expansion; Step 8: Simulation task ends and data is archived.

10. The method according to claim 9, characterized in that, Steps 2 and 5 through 7 are as follows: Step 2: Configure excitation source parameters Enter the excitation source configuration module and select the excitation source type; set the excitation parameters according to the simulation requirements. If current excitation is selected, set the current amplitude; if voltage excitation is selected, set the voltage amplitude. At the same time, set the waveform type of the excitation signal; based on the coordinate system of the three-dimensional grid model of the stratum, accurately locate the spatial position of the excitation source and complete the deployment of the excitation source. Step 5: Output and Display of Simulation Results The simulation results output module converts the original electromagnetic field data and the optimized data into a common format; it also visualizes the original distribution and the processed distribution of each electromagnetic field component. Establish a structured database to store formation parameters, excitation source parameters, grid parameters, raw data, optimized data, and visualization result files, and support data retrieval and retrieval; Step 6: Model Validation and Calibration Start the model verification and calibration module, build a benchmark model with known analytical solutions, and set the excitation source parameters and mesh generation accuracy consistent with the current simulation model; The benchmark model is simulated and calculated. The simulation results are compared with the analytical solution, and the mean square error and relative error are calculated. If the error exceeds the preset threshold, adjust the parameters and repeat steps 3 to 5 until the error meets the requirements and the model calibration is completed. Step 7: Multi-scenario adaptation and expansion If it is necessary to simulate a formation scenario containing a specific medium, add the corresponding medium through the multi-scenario adaptation module and set its spatial distribution range and electromagnetic parameters; if it is necessary to adjust the detection conditions, the excitation source type, parameters, location or formation structure and electromagnetic parameters can be modified to construct a new simulation scenario; save commonly used scenarios as templates for easy and quick subsequent use; repeat steps 3 to 6 to complete the drilling electromagnetic forward modeling simulation under different scenarios.

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