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CN-121997586-A - Electromagnetic forward modeling system and method while drilling for multilayer non-uniform lossy stratum

CN121997586ACN 121997586 ACN121997586 ACN 121997586ACN-121997586-A

Abstract

The invention discloses an electromagnetic forward modeling system and method while drilling for a multilayer non-uniform lossy stratum, belonging to the technical field of electromagnetic forward modeling systems while drilling, the system comprises 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. According to the invention, the three-dimensional model of the multilayer heterogeneous lossy stratum is constructed through the stratum parameter modeling module, the physical characteristics of the complex stratum are accurately adapted, and the limitation that the traditional model can only simulate a uniform stratum or a simple stratum is solved. The system completely calculates components of the electric field phi, r and z and the magnetic field r, z and phi, and overcomes the defect of incomplete calculation of the components of the traditional model. The presentation effect of electromagnetic field data is optimized, interference factors are eliminated, and the usability of the data is improved by the combination mode of absolute value conversion, natural logarithmic conversion and noise reduction.

Inventors

  • WU YUE
  • HU KAI

Assignees

  • 西华大学

Dates

Publication Date
20260508
Application Date
20260122

Claims (10)

  1. 1. The system is characterized by 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 stratum parameter modeling module is used for constructing a three-dimensional physical model of the multilayer non-uniform lossy stratum and comprises a stratum structure definition unit, an electromagnetic parameter assignment unit and a grid subdivision unit; The stratum structure definition unit is used for defining the layer number, the thickness of each layer, the distribution boundary of the layer and the space extension range of the stratum according to actual geological exploration data; an electromagnetic parameter assignment unit for assigning conductivity, magnetic conductivity and dielectric constant to each stratum and establishing an electromagnetic parameter equivalent formula of the multi-layer non-uniform lossy stratum; The grid subdivision unit is used for carrying out space discretization on the constructed multi-layer stratum model by adopting a self-adaptive grid subdivision algorithm, encrypting grids in a key area and generating a three-dimensional grid model of the multi-layer non-uniform lossy stratum; The excitation source configuration module is used for setting excitation source parameters of electromagnetic detection while drilling; The electromagnetic field component calculation module is used for comprehensively calculating components in all directions of an electric field and a magnetic field in the multilayer non-uniform and lossy stratum and comprises a control equation establishment unit, a boundary condition setting unit and a numerical value solving unit; a control equation establishing unit for establishing a control equation of electromagnetic field distribution; The boundary condition setting unit is used for setting far-field boundary conditions, stratum interface boundary conditions and excitation source boundary conditions of the model; The numerical value solving unit is used for carrying out discrete solving on the control equation by adopting a finite element method, and obtaining the numerical values of an electric field phi direction component, an electric field r direction component, an electric field z direction component, a magnetic field r direction component, a magnetic field z direction component and a magnetic field phi direction component of each grid node in the stratum model through iterative calculation; the data processing optimization module is used for performing optimization processing on the electromagnetic field component data; The simulation result output module is used for outputting the original electromagnetic field data, the processed data and the related simulation information; The model verification and calibration module is used for verifying the accuracy and the reliability of the simulation model; And the multi-scene adapting module is used for adapting different stratum medium scenes and detection requirements.
  2. 2. The electromagnetic forward modeling system for a multi-layer heterogeneous lossy formation while drilling of claim 1, wherein the electromagnetic parameter equivalent formula is: Wherein, the As the equivalent electromagnetic parameter, the electromagnetic parameter, For the total number of layers of the formation, Is the first The thickness of the layer, Is the first Layer formation electromagnetic parameters.
  3. 3. The electromagnetic forward modeling system while drilling for the multilayer non-uniform and lossy formation according to claim 1, wherein the excitation source configuration module comprises an excitation source type selection unit, an excitation parameter setting unit and an excitation source position positioning unit; the excitation source type selection unit is used for providing two core types of current excitation and voltage excitation; The excitation parameter setting unit is used for setting the amplitude of excitation current for current excitation, setting the amplitude of excitation voltage for voltage excitation and supporting waveform type setting of excitation signals; And the excitation source position positioning unit is used for setting the spatial position of the excitation source in the multi-layer stratum based on a grid coordinate system of the stratum model.
  4. 4. The electromagnetic forward modeling system while drilling for a multi-layer heterogeneous lossy formation according to claim 1, wherein the data processing optimization module comprises an absolute value conversion unit, a natural logarithm conversion unit and a data noise reduction unit; The absolute value conversion unit is used for respectively calculating the absolute values of the electric field component and the magnetic field component according to an absolute value conversion formula: Wherein, the As an original electromagnetic field component, Is the absolute value after conversion; The natural logarithm conversion unit is used for carrying out natural logarithm conversion on the component data of each direction of the electromagnetic field after the absolute value conversion through a natural logarithm conversion formula: Wherein, the As a component after the natural logarithmic conversion, Is an extremely small positive number; And the data noise reduction unit is used for carrying out noise reduction treatment on the converted electromagnetic field data by adopting a moving average filtering algorithm.
  5. 5. The electromagnetic forward modeling system while drilling for the multilayer non-uniform and lossy stratum according to claim 1, wherein the simulation result output module comprises a data format conversion unit, a visual display unit and a data storage unit; the data format conversion unit is used for converting the original electromagnetic field component data obtained by numerical solution and the processed optimized data into a universal data format; The visual display unit is used for visually displaying the original distribution of components in all directions of an electric field and a magnetic field and the distribution situation after absolute value and natural logarithm treatment, and presenting the spatial variation characteristics of an electromagnetic field in a plurality of layers of non-uniform and consumable stratum; And the data storage unit is used for establishing a structured database, storing key parameters, original electromagnetic field data, optimized data and visualized result files in the simulation process, and supporting the retrieval and the calling of the data.
  6. 6. The electromagnetic forward modeling system while drilling for the multilayer non-uniform and lossy formation according to claim 1, wherein the model verification and calibration module comprises a reference model establishment unit, a simulation result comparison unit and a parameter calibration unit; The reference model establishing unit is used for establishing a uniform stratum model or a simple two-layer stratum model of a known analytic solution as a reference model and setting excitation source parameters and mesh subdivision precision consistent with the model to be verified; The simulation result comparison unit is used for quantitatively comparing the simulation result of the reference model with the corresponding analytic solution, calculating the mean square error MSE and the relative error of the simulation result and the analytic solution, and evaluating the numerical calculation precision of the model; And the parameter calibration unit is used for carrying out simulation calculation again after the parameters are adjusted if the comparison result exceeds the preset error threshold value until the errors of the simulation result and the analysis solution meet the preset requirement, and completing the model calibration.
  7. 7. The electromagnetic forward modeling system while drilling for the multilayer non-uniform and lossy formation according to claim 1, wherein the multi-scene adaptation module comprises a medium type expansion unit, a detection parameter adjustment unit and a scene template storage unit; The medium type expansion unit supports adding specific mediums into the multilayer heterogeneous lossy stratum, simulates a complex geological scene, and adapts to different detection targets by adjusting the spatial distribution range and electromagnetic parameters of the added mediums; The detection parameter adjusting unit allows a user to flexibly adjust the type, the parameters and the position of the excitation source, changes the layer number of the stratum, the thickness of each layer and the electromagnetic parameters, and rapidly builds different simulation scenes; and the scene template storage unit is used for storing the common simulation scene as a template, and a user can directly call the template and perform fine adjustment.
  8. 8. The electromagnetic forward modeling system while drilling for a multi-layer non-uniform and lossy formation according to claim 1, wherein the electromagnetic field distribution control equation is: Wherein, the In the form of a vector magnetic potential, In order for the laplace operator to be useful, In order to obtain the number of complex waves, In order to be of an angular frequency, In units of imaginary numbers, In order to be of magnetic permeability, For the dielectric constant of the material to be a dielectric constant, In order to be of electrical conductivity, Is the current density.
  9. 9. A method of an electromagnetic forward modeling system while drilling for a multi-layer non-uniform and lossy formation according to any one of claims 1 to 8, comprising the steps of: Step 1, system initialization and stratum model construction The method comprises the steps of starting a simulation model system, initializing working parameters of each module, inputting actual geological exploration data through a stratum parameter modeling module, defining the number of layers, thickness of each layer, layer boundary and space extension range of a plurality of layers of non-uniform and lossy strata, assigning conductivity, permeability and dielectric constant to each layer of strata, and determining the distribution type of electromagnetic parameters in the same stratum; step 2, configuring excitation source parameters; Step 3, electromagnetic field component numerical solution The control equation is discretized by adopting a finite element method, and is substituted into stratum electromagnetic parameters, excitation source parameters and boundary conditions, and the original values of an electric field phi direction component, an r direction component, a z direction component, a magnetic field r direction component, a z direction component and a phi direction component of each grid node are solved through iterative calculation; step 4, optimizing the simulation data The method comprises the steps of obtaining original electromagnetic field component data, transmitting the original electromagnetic field component data obtained by solving to a data processing optimization module, carrying out absolute value conversion on each component data according to an absolute value conversion formula of the electromagnetic field component, carrying out natural logarithmic conversion on the data after the absolute value conversion according to a natural logarithmic conversion formula of the electromagnetic field component, compressing a numerical range, and finally carrying out noise reduction on the data after the conversion through a moving average filtering algorithm, eliminating random errors and obtaining optimized electromagnetic field data; Step 5, outputting and displaying simulation results; Step 6, model verification and calibration; step 7, multi-scene adaptation and expansion; and 8, finishing the simulation task and archiving the data.
  10. 10. The method according to claim 9, wherein the steps 2 and 5 to 7 are specifically: step 2, configuring excitation source parameters Setting excitation parameters according to simulation requirements, setting current amplitude values if current excitation is selected, setting voltage amplitude values if voltage excitation is selected, and setting waveform types of excitation signals simultaneously; step 5, outputting and displaying simulation results The method comprises the steps of receiving electromagnetic field components, converting the electromagnetic field components into original electromagnetic field data and optimized data into universal formats through a simulation result output module, visually displaying the original distribution and the processed distribution of the electromagnetic field components, establishing a structured database, storing stratum parameters, excitation source parameters, grid parameters, original data, optimized data and visual result files, and supporting data retrieval and calling; Step 6, model verification and calibration Starting a model verification and calibration module, constructing a reference model of a known analytic solution, setting excitation source parameters and mesh subdivision precision consistent with the current simulation model, performing simulation calculation on the reference model, comparing a simulation result with the analytic solution, and calculating a mean square error and a relative error; step 7, multiple scene adaptation and expansion If the stratum scene containing the specific medium needs to be simulated, the corresponding medium is added through the multi-scene adaptation module, the spatial distribution range and electromagnetic parameters of the stratum scene are set, if the detection conditions need to be adjusted, the type, the parameters and the position of an excitation source or the stratum structure and the electromagnetic parameters can be modified, a new simulation scene is built, the common scene is saved as a template, the subsequent quick calling is facilitated, and the steps 3 to 6 are repeated to complete the electromagnetic forward simulation while drilling under different scenes.

Description

Electromagnetic forward modeling system and method while drilling for multilayer non-uniform lossy stratum Technical Field The invention relates to the technical field of electromagnetic forward modeling while drilling systems, in particular to an electromagnetic forward modeling while drilling system and method for a multi-layer non-uniform lossy stratum. Background Interpretation of related terms: Electromagnetic forward modeling detection while drilling, namely, in the drilling process, the electromagnetic wave is utilized to detect the stratum characteristics, and the detection data is processed and analyzed by a forward modeling method. Multilayer inhomogeneous lossy formations, meaning geological structures composed of layers of formations of different electromagnetic properties (e.g., conductivity, dielectric constant, etc.) and having energy losses. In the development of oil and gas fields and the geological exploration process, the electromagnetic detection while drilling technology is one of core technologies for acquiring stratum geological parameters by virtue of the advantages of strong instantaneity and moderate detection depth. The electromagnetic response characteristics of the multilayer inhomogeneous lossy stratum are complex, the electromagnetic response characteristics are obviously influenced by the spatial distribution differences of the conductivity, the permeability and the dielectric constant of the stratum and the type of an excitation source, and the electromagnetic field distribution rule of the multilayer inhomogeneous lossy stratum needs to be accurately simulated through an electromagnetic forward simulation model while drilling. There are a number of technical bottlenecks in current mainstream electromagnetic forward simulation models while drilling (e.g., electromagnetic forward simulation models while drilling based on finite difference method, electromagnetic forward simulation models while drilling based on moment method): a) Most models are designed only for uniform stratum or simple two-layer stratum, lack of adaptive capacity for multiple layers of non-uniform lossy stratum, and cannot reflect influence of stratum parameter spatial variation on electromagnetic fields; b) The electromagnetic field component is not fully calculated, only a single direction component is usually focused, and the coupling effect of the electric field and the magnetic field component in each direction is ignored, so that the completeness of a simulation result is insufficient; c) The data processing mode is single, the optimization processing is not carried out aiming at the characteristic of large difference of the numerical range of electromagnetic field components, and the electromagnetic response rule is difficult to intuitively present; d) The model lacks the adaptive capacity of multiple excitation sources, and cannot meet the excitation mode switching requirements under different detection scenes; e) The consistency verification mechanism of the simulation result and the actual stratum electromagnetic response is imperfect, so that the simulation precision is difficult to guarantee. Based on the method, the invention designs an electromagnetic forward modeling system and method while drilling for a plurality of layers of non-uniform and lossy strata so as to solve the problems. Disclosure of Invention Aiming at the defects existing in the prior art, the invention provides an electromagnetic forward modeling system and method while drilling for a plurality of layers of non-uniform and lossy stratum. The method realizes accurate and comprehensive simulation of electromagnetic response characteristics of the multilayer heterogeneous lossy stratum. In order to achieve the above purpose, the invention is realized by the following technical scheme: The system comprises 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 stratum parameter modeling module is used for constructing a three-dimensional physical model of the multilayer non-uniform lossy stratum and comprises a stratum structure definition unit, an electromagnetic parameter assignment unit and a grid subdivision unit; The stratum structure definition unit is used for defining the layer number, the thickness of each layer, the distribution boundary of the layer and the space extension range of the stratum according to actual geological exploration data; an electromagnetic parameter assignment unit for assigning conductivity, magnetic conductivity and dielectric constant to each stratum and establishing an electromagnetic parameter equivalent formula of the multi-layer non-uniform lossy stratum; The grid subdivision unit is used for carrying out space discretization on the constructed multi-layer st