Electromagnetic wave logging detection depth determination method and device, medium and program product

Abstract

The embodiment of the invention discloses an electromagnetic wave logging detection depth determination method and device, a medium and a program product. The method comprises the steps that a conductivity disturbance stratum model under the homogeneous medium background condition is established, a multi-component transmitting and receiving antenna combination mode is simulated, a lower step signal source serves as an excitation source of transient electromagnetic wave logging, and a homogeneous medium transient electromagnetic wave logging response model is determined; according to the electromagnetic wave logging response perturbation model and the uniform medium transient electromagnetic wave logging response model, a sensitivity function of induced electromotive force is determined; determining a radial integral sensitivity function under a cylindrical coordinate system according to the sensitivity function of the induced electromotive force; and determining the detection depth of transient electromagnetic wave logging in the target time range according to the radial integral sensitivity function. According to the scheme, specific analysis can be carried out in combination with instrument parameters and signal definition, the detection performance evaluation problem of time domain signals measured in a well is solved, and the detection depth of transient electromagnetic wave logging equipment is accurately determined.

Description

Technical Field

[0001] This application relates to the field of oil and gas exploration and development technology, and in particular to a method, equipment, medium and program product for determining the depth of electromagnetic wave logging. Background Technology

[0002] The detection performance of electromagnetic wave time-domain signals downhole is constrained by various factors such as measurement time and formation electrical properties. Determining the detection range under different conditions is a prerequisite for well logging data inversion and instrument development. However, there is still a lack of intuitive theoretical support for evaluating the detection characteristics of downhole full-space time-domain signals. Exploring methods to characterize the sensitivity of time-domain signals based on frequency-domain geometric factors (also known as sensitivity functions or response functions) and conducting quantitative analysis of the detection depth of time-domain signals are among the research directions.

[0003] The sensitivity of time-domain electromagnetic fields to geological bodies is related to factors such as electrical properties and measurement time, making it more complex than that of frequency-domain electromagnetic fields. Currently, there is limited research on the sensitivity and detection characteristics of borehole transient electromagnetic logging, and a lack of methods for analyzing the sensitivity of the wellbore surrounding medium and quantitatively evaluating its detection performance. There is an urgent need for systematic research on the ability of the broadband characteristics of time-domain signals to respond to electrical anomalies, providing a basis for the analysis of instrument detection characteristics and information processing. Summary of the Invention

[0004] This application provides a method, device, medium, and program product for determining the detection depth of electromagnetic wave logging, based on the time and space sensitivity of transient electromagnetic waves.

[0005] According to one aspect of this application, a method for determining the depth of electromagnetic wave logging is provided, the method comprising:

[0006] A formation model with conductivity disturbance under uniform medium background conditions is established, and a multi-component transmit and receive antenna combination mode is simulated in the formation model with conductivity disturbance. The lower step signal source is used as the excitation source for transient electromagnetic wave logging, and the transient electromagnetic wave logging response model in uniform medium is determined.

[0007] Based on the electromagnetic wave logging response perturbation model and the homogeneous medium transient electromagnetic wave logging response model, the sensitivity function of the induced electromotive force is determined; wherein, the sensitivity function of the induced electromotive force reflects the degree of influence of the induced electromotive force on the conductivity perturbation in the geology.

[0008] Based on the sensitivity function of induced electromotive force, the radial integral sensitivity function in cylindrical coordinates is determined; whereby the radial integral sensitivity function reflects the degree of influence of the cylindrical variable in the direction perpendicular to the ground on the logging response.

[0009] The detection depth of transient electromagnetic wave logging within the target time range is determined based on the radial integral sensitivity function.

[0010] According to one aspect of this application, an electromagnetic wave logging depth determination device is provided, the device comprising:

[0011] The well logging response calculation module is used to establish a conductivity-perturbed formation model under homogeneous medium background conditions, and to simulate a multi-component transmit-receive antenna combination mode in the conductivity-perturbed formation model. The lower step signal source is used as the excitation source for transient electromagnetic wave logging, and the transient electromagnetic wave logging response model in homogeneous medium is determined.

[0012] The induced electromotive force sensitivity function determination module is used to determine the sensitivity function of the induced electromotive force based on the electromagnetic wave logging response perturbation model and the homogeneous medium transient electromagnetic wave logging response model; wherein, the sensitivity function of the induced electromotive force reflects the degree of influence of the induced electromotive force on the conductivity perturbation in the geology.

[0013] The radial integral sensitivity function determination module is used to determine the radial integral sensitivity function in cylindrical coordinates based on the sensitivity function of the induced electromotive force; wherein, the radial integral sensitivity function reflects the degree of influence of the cylindrical variable in the direction perpendicular to the ground on the logging response;

[0014] The detection depth determination module is used to determine the detection depth of transient electromagnetic wave logging within the target time range based on the radial integral sensitivity function.

[0015] According to another aspect of this application, an electronic device is provided, the electronic device comprising:

[0016] At least one processor; and

[0017] A memory that is communicatively connected to at least one processor; wherein,

[0018] The memory stores a computer program that can be executed by at least one processor, such that the at least one processor is able to execute the electromagnetic wave logging depth determination method of any embodiment of this application.

[0019] According to another aspect of this application, a computer-readable storage medium is provided, which stores computer instructions for causing a processor to execute the electromagnetic wave logging depth determination method of any embodiment of this application.

[0020] According to another aspect of this application, a computer program product is provided, which includes a computer program that, when executed by a processor, implements the electromagnetic wave logging depth determination method of any embodiment of this application.

[0021] The technical solution of this application embodiment establishes a conductivity-perturbed formation model under a uniform medium background condition, and simulates a multi-component transmit-receive antenna combination mode in the conductivity-perturbed formation model. A lower step signal source is used as the excitation source for transient electromagnetic wave logging, and a uniform medium transient electromagnetic wave logging response model is determined. Based on the electromagnetic wave logging response perturbation model and the uniform medium transient electromagnetic wave logging response model, a sensitivity function for the induced electromotive force is determined. The sensitivity function for the induced electromotive force reflects the degree of influence of conductivity perturbation in the geological environment on the induced electromotive force. Based on the sensitivity function for the induced electromotive force, a radial integral sensitivity function in cylindrical coordinates is determined. The radial integral sensitivity function reflects the degree of influence of cylindrical variables in the direction perpendicular to the ground on the logging response. Based on the radial integral sensitivity function, the detection depth of transient electromagnetic wave logging within the target time range is determined. The above scheme, combined with the instrument parameters and signal definitions, provides a specific analysis and solves the problem of evaluating the detection performance of time-domain signals in wells. It accurately determines the detection depth of transient electromagnetic wave logging equipment, provides a theoretical basis for the research and development of transient electromagnetic wave logging instruments, and provides a technical reference for the development of deep-earth and deep-sea oil and gas and residual oil in production wells.

[0022] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this application, nor is it intended to limit the scope of this application. Other features of this application will become readily apparent from the following description. Attached Figure Description

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

[0024] Figure 1 A flowchart of a method for determining the depth of electromagnetic wave well logging provided in this application embodiment;

[0025] Figure 2 A schematic diagram of a formation model with conductivity disturbance under a uniform medium background condition provided in an embodiment of this application;

[0026] Figure 3 A flowchart of a method for determining the depth of electromagnetic wave logging is provided as another embodiment of this application;

[0027] Figure 4 A flowchart of a method for determining the depth of electromagnetic wave logging is provided in another embodiment of this application;

[0028] Figure 5 A flowchart of a method for determining the depth of electromagnetic wave logging is provided in another embodiment of this application;

[0029] Figure 6 A schematic diagram of electromagnetic wave response under nine conditions of a combination of a third transmitting coil and three receiving coils at a fixed time, provided for embodiments of this application;

[0030] Figure 7 This is a schematic diagram of the sensitivity distribution of the magnetic dipole source in the z-direction at different times, provided in an embodiment of this application.

[0031] Figure 8 The time provided for the embodiments of this application is 10. -5 Schematic diagram of logging sensitivity distribution of transient electromagnetic wave components with different source distances at time s;

[0032] Figure 9 The time provided for the embodiments of this application is 10. -3 Schematic diagram of logging sensitivity distribution of multi-component transient electromagnetic waves at different source distances at time s;

[0033] Figure 10 A schematic diagram of the radial sensitivity function of transient electromagnetic wave logging for the zz component provided in this application embodiment;

[0034] Figure 11 This is a schematic diagram of the time-depth double logarithmic distribution of the radial integral sensitivity function for transient electromagnetic wave logging provided in an embodiment of this application.

[0035] Figure 12 A schematic diagram of an electromagnetic wave logging depth determination device provided in this application embodiment;

[0036] Figure 13 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0037] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0038] It should be noted that the terms "first," "second," "third," "fourth," "actual," "preset," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0039] It should be noted that the determination of electromagnetic wave logging depth in this embodiment is performed with the authorization and permission of the target person, and will not be disclosed without the target person's permission, will not infringe on the target person's portrait rights, will not be used for illegal purposes, will not be used for purposes that harm the target's mission interests, will not be used for personalized analysis of the target person or product promotion, and will not affect the target person's normal life.

[0040] Figure 1 This document provides a flowchart of a method for determining the detection depth of electromagnetic wave logging, applicable to situations involving the determination of the detection depth in transient electromagnetic wave logging. This method can be executed by an electromagnetic wave logging depth determination device, which can be implemented in hardware and / or software and can be configured in an electronic device. Figure 1 As shown, the method includes:

[0041] S110. Establish a formation model with conductivity disturbance under uniform medium background conditions, and simulate a multi-component transmit and receive antenna combination mode in the formation model with conductivity disturbance. Use the lower step signal source as the excitation source for transient electromagnetic wave logging, and determine the transient electromagnetic wave logging response model for uniform medium.

[0042] Figure 2This is a schematic diagram illustrating the principle of the transient electromagnetic wave logging sensitivity function used in this invention. A conductivity-perturbed formation model under homogeneous medium background conditions is established. This model is a theoretical formation structure, with the core assumption that the main body of the formation consists of a medium with uniform conductivity distribution, but local areas, due to geological structures (such as fractures, ore bodies, or fluid intrusion) or human activities (such as water injection or thermal extraction), form anomalies with significantly different conductivity from the background. This model quantifies the conductivity difference between the perturbed zone and the background medium (Δσ = σ_perturbed - σ_background), and uses Maxwell's equations for numerical simulation to analyze the electromagnetic field response characteristics. It is widely used in geophysical exploration, groundwater resource assessment, and engineering geological stability monitoring.

[0043] In a conductivity-perturbed stratum model under uniform medium background conditions, a multi-component transmit-receive antenna combination mode is simulated. The lower step current is used as the excitation source T. After the current is turned off, the secondary field is observed through the receiving coil R during the interval of the transmit pulse. Figure 2 For a formation model with conductivity perturbation under a homogeneous background, the source T is located at the origin of the coordinate system, the receiver R is located at point r, and there is a small conductivity perturbation at point r' with internal conductivity σa and volume Va, where σa = δσ + σb, and σb is the conductivity of the homogeneous background formation. Both r and r' are vectors.

[0044] In this context, a transient electromagnetic wave logging response model for homogeneous media can be established, which determines the sensitivity of transient electromagnetic waves to geological layers in homogeneous media. The homogeneous media transient electromagnetic wave logging response model is based on the assumption of uniform formation conductivity and establishes a transient electromagnetic field propagation theoretical framework by solving Maxwell's equations. This model treats the formation as an infinitely extending homogeneous conductive medium. The transient electromagnetic field generated by the transmitting coil diffuses in the medium in the form of eddy currents, and the receiving coil inverts the formation conductivity distribution by measuring the decay characteristics of the secondary field over time. Its core characteristics are: the initial response signal is dominated by the near-field effect of the transmitting source, exhibiting a rapidly decaying early-field characteristic; the later stage mainly reflects deep formation information, exhibiting an exponentially decaying far-field characteristic. This model, through analytical solutions or numerical simulations, can accurately predict the spatiotemporal distribution of the electromagnetic field under different formation resistivity and logging instrument parameters (such as coil spacing and transmission frequency), providing a quantitative theoretical basis for logging data interpretation. In oil and gas exploration and engineering geology applications, this model is an important analytical tool for identifying low-resistivity anomalous layers (such as aquifers) and high-resistivity tight layers. Its theoretical accuracy can reach more than 85% under homogeneous medium conditions.

[0045] S120. Based on the electromagnetic wave logging response perturbation model and the homogeneous medium transient electromagnetic wave logging response model, determine the sensitivity function of the induced electromotive force; wherein, the sensitivity function of the induced electromotive force reflects the degree of influence of the induced electromotive force on the conductivity perturbation in the geology.

[0046] The electromagnetic wave logging response perturbation model is a theoretical framework for analyzing the small perturbations in the electromagnetic field distribution caused by localized conductivity anomalies (such as fractures, mineralized zones, or fluid intrusion zones) under homogeneous medium background conditions. Using homogeneous formations as a baseline, the model quantifies the changes in the secondary field components caused by the anomalies (typically 0.1%–5% of the background field) by solving modified Maxwell equations, and establishes a mapping relationship between the apparent resistivity shift (Δρ) and the geometric parameters and conductivity differences of the perturbation body. The electromagnetic wave logging response perturbation model can reveal the characteristic influence of small-scale anomalies on logging curves (such as phase shift and waveform distortion) and provide theoretical boundary conditions for high-resolution inversion algorithms. Typical applications include thin interlayer identification (accuracy down to the decimeter level) and low-resistivity reservoir fluid property evaluation. The model requires geometric factor correction to eliminate wellbore heterogeneity interference. Practical verification shows that when the conductivity perturbation amplitude is less than 20%, the inversion error can be controlled within 3%.

[0047] The electromagnetic wave logging response perturbation model is the response function of electromagnetic waves when there is disturbance in the geology, while the homogeneous medium transient electromagnetic wave logging response model is the response function of transient electromagnetic waves in a homogeneous medium without disturbance. Based on the electromagnetic wave logging response perturbation model and the homogeneous medium electromagnetic wave logging response model, the sensitivity function of the induced electromotive force can be determined, reflecting the degree of influence of the disturbed geological area on the transient electromagnetic wave response when it is equivalent to an anomaly.

[0048] S130. Based on the sensitivity function of the induced electromotive force, determine the radial integral sensitivity function in the cylindrical coordinate system; wherein, the radial integral sensitivity function reflects the degree of influence of the cylindrical variable in the direction perpendicular to the ground on the logging response.

[0049] For example, the sensitivity function of the induced electromotive force is transformed to a cylindrical coordinate system to determine the radial integral sensitivity function in the cylindrical coordinate system. The sensitivity function of the induced electromotive force includes x, y, z in the world coordinate system and time t. Transformed to cylindrical coordinates, it includes radial distance ρ, azimuth angle φ, vertical height z, and time t. The radial integral sensitivity function reflects the influence of the cylindrical variable in the vertical direction on the logging response, including the radial distance ρ which reflects the depth of exploration.

[0050] S140. Determine the detection depth of transient electromagnetic wave logging within the target time range based on the radial integral sensitivity function.

[0051] For example, the radial integral sensitivity function reflects the sensitivity of transient electromagnetic wave induced electromotive force at a radial distance, which in turn reflects the detection depth. A target time range is fixed in the radial integral sensitivity function, and the detection depth of transient electromagnetic wave logging within that target time range can be calculated based on the radial integral sensitivity function.

[0052] The technical solution of this application embodiment establishes a conductivity-perturbed formation model under a uniform medium background condition, and simulates a multi-component transmit-receive antenna combination mode in the conductivity-perturbed formation model. A lower step signal source is used as the excitation source for transient electromagnetic wave logging, and a uniform medium transient electromagnetic wave logging response model is determined. Based on the electromagnetic wave logging response perturbation model and the uniform medium transient electromagnetic wave logging response model, a sensitivity function for the induced electromotive force is determined. The sensitivity function for the induced electromotive force reflects the degree of influence of conductivity perturbation in the geological environment on the induced electromotive force. Based on the sensitivity function for the induced electromotive force, a radial integral sensitivity function in cylindrical coordinates is determined. The radial integral sensitivity function reflects the degree of influence of cylindrical variables in the direction perpendicular to the ground on the logging response. Based on the radial integral sensitivity function, the detection depth of transient electromagnetic wave logging within the target time range is determined. The above scheme, combined with the instrument parameters and signal definitions, provides a specific analysis and solves the problem of evaluating the detection performance of time-domain signals in wells. It accurately determines the detection depth of transient electromagnetic wave logging equipment, provides a theoretical basis for the research and development of transient electromagnetic wave logging instruments, and provides a technical reference for the development of deep-earth and deep-sea oil and gas and residual oil in production wells.

[0053] Figure 3 This is a flowchart illustrating a method for determining the depth of electromagnetic wave well logging, provided as another embodiment of this application. This embodiment is an optimization based on the above embodiment; schemes not described in detail in this embodiment are found in the above embodiment. Figure 3 As shown, the method in this embodiment of the application specifically includes the following steps:

[0054] S210. Establish a formation model with conductivity disturbance under uniform medium background conditions, and simulate a multi-component transmit and receive antenna combination mode in the formation model with conductivity disturbance. Use the lower step signal source as the excitation source for transient electromagnetic wave logging, and determine the transient electromagnetic wave logging response model for uniform medium.

[0055] S220. Integral representation of electromagnetic wave logging response perturbation model based on Maxwell's equations.

[0056] The integral representation of the electromagnetic wave logging response perturbation model based on Maxwell's equations:

[0057] ;

[0058] In the formula, The vector representing the coordinates from the emission source to the anomalous body. Indicates the electric field part. Indicates the magnetic field part. Let p represent the partial derivative of the magnetic field strength at position r with respect to time at time t. The subscript p indicates the primary field, and the integral term on the right side of the equation represents the secondary field caused by resistivity perturbation. Let Green's functions for the electric field and the magnetic field be represented respectively. This represents the difference in electrical conductivity at coordinate r' between the current and the surrounding environment. t and t' represent time, and v' represents volume. An anomaly is a geological body in geophysical exploration that exhibits geophysical anomalies due to significant differences in its physical properties (such as density, magnetism, and electrical properties) compared to the surrounding medium. These anomalies can be identified using gravity, magnetic, and electrical methods, and their presence typically reflects the distribution characteristics of underground structures or resources. For example, highly conductive ore bodies or low-resistivity fluid intrusion zones significantly alter electromagnetic field responses, making them targets for electrical exploration.

[0059] S230. Using Born's approximation theory, the electric field, internal electric field, and conductivity of the magnetic field model in the integral expression of the electromagnetic wave logging response perturbation model are simplified. Combined with the homogeneous medium transient electromagnetic wave logging response model, the sensitivity function of the induced electromotive force is determined.

[0060] The Born approximation is one of the core theories in quantum mechanics for dealing with particle scattering. Based on perturbation theory, it assumes that the scattering potential energy is much smaller than the incident particle's kinetic energy (i.e., the weak field condition), thus expanding the scattering amplitude into a successive interaction between the incident wave and the potential energy. The Born approximation is mainly applied to the following scenarios: High-energy scattering: such as Coulomb scattering between electrons and atomic nuclei, where the potential energy correction term is negligible; Long-range potential analysis: such as electromagnetic interactions, where asymptoticity satisfies the approximation condition; Experimental verification: verifying the validity of non-relativistic quantum mechanics by comparing theoretical predictions with scattering cross-section data (such as the Rutherford experiment). The limitation of this theory is that it cannot handle strong interactions (such as low-energy neutron scattering) or situations with large potential field depths, requiring the use of fully numerical methods (such as the partial wave method) for correction. An anomalous internal electric field refers to an atypical electric field distribution phenomenon in biological or geological bodies caused by localized abnormalities in conductivity, ion concentration, or structure. An internal electric field refers to the electric field state when an anomalous body reaches electrostatic equilibrium. Conductivity is a physical quantity that measures the ability of a substance to conduct electric current.

[0061] In this embodiment, using Born approximation theory, the anomalous electric field, internal electric field, and conductivity of the magnetic field model in the integral representation of the electromagnetic wave logging response perturbation model are simplified. Combined with the homogeneous medium transient electromagnetic wave logging response model, the sensitivity function of the induced electromotive force is determined, including:

[0062] The anomalous electric field in the magnetic field component of the electromagnetic wave logging response perturbation model is replaced by the background electric field to obtain the simplified magnetic field component.

[0063] The simplified magnetic field component is differentially processed with the transient electromagnetic wave logging response model of the homogeneous medium to obtain the sensitivity function of the induced electromotive force.

[0064] For example, based on the Born approximation, when the volume of the conductivity anomaly approaches infinity, its internal properties can be considered invariant. The conductivity and internal electric field can be treated as constants, and the electric field within the anomaly can be replaced by the background electric field. Specifically, in the integral representation of the electromagnetic wave logging response perturbation model described above, the electric field e(r', t') within the anomaly can be replaced by the background electric field e(r', t'). p (r', t') is used instead. Furthermore, when considering the relative magnitude of sensitivity, parameters such as the number of coil turns and area can be ignored, thus obtaining a simplified magnetic field component. The simplified magnetic field component is then differentially processed with the transient electromagnetic wave logging response model in a uniform medium to obtain the sensitivity function of the induced electromotive force, as follows:

[0065] ;

[0066] In the formula, g h (r, r') is the Green's function of the magnetic field tensor generated by the electric dipole source at r' at r. V (r, r', t) represents the sensitivity of the electromotive force signal at time t to the change in conductivity at position r' when the receiving point position vector is r.

[0067] S240. Based on the sensitivity function of the induced electromotive force, determine the radial integral sensitivity function in the cylindrical coordinate system; wherein, the radial integral sensitivity function reflects the degree of influence of the cylindrical variable in the direction perpendicular to the ground on the logging response.

[0068] S250. Determine the detection depth of transient electromagnetic wave logging within the target time range based on the radial integral sensitivity function.

[0069] This application provides a method for determining the depth of electromagnetic wave logging. It establishes a formation model with conductivity perturbation under a homogeneous medium background, and simulates a multi-component transmit / receive antenna combination mode within this model. A lower step signal source is used as the excitation source for transient electromagnetic wave logging, and a transient electromagnetic wave logging response model for homogeneous medium is determined. An integral representation of the electromagnetic wave logging response perturbation model is established based on Maxwell's equations. Using Born approximation theory, the electric field, internal electric field, and conductivity within the anomalous body of the magnetic field model in the integral representation of the electromagnetic wave logging response perturbation model are simplified. Combined with the homogeneous medium transient electromagnetic wave logging response model, a sensitivity function for the induced electromotive force is determined. Based on the sensitivity function of the induced electromotive force, a radial integral sensitivity function in cylindrical coordinates is determined. Finally, based on the radial integral sensitivity function, the depth of transient electromagnetic wave logging within a target time range is determined. The above scheme simplifies the integral representation of the electromagnetic wave logging response perturbation model based on Born's approximation theory. It then combines the simplified model with the uniform medium plug-variant electromagnetic wave logging response model to determine the sensitivity function of the induced electromotive force, reflecting the sensitivity function of transient electromagnetic waves under small perturbations. This facilitates subsequent accurate analysis and determination of the detection depth based on the sensitivity function.

[0070] Figure 4 This is a flowchart illustrating a method for determining the depth of electromagnetic wave well logging, provided as another embodiment of this application. This embodiment is an optimization based on the above embodiments; schemes not described in detail in this embodiment are found in the above embodiments. Figure 4 As shown, the method in this embodiment of the application specifically includes the following steps:

[0071] S310. Establish a formation model with conductivity disturbance under uniform medium background conditions, and simulate a multi-component transmit and receive antenna combination mode in the formation model with conductivity disturbance. Use the lower step signal source as the excitation source for transient electromagnetic wave logging, and determine the transient electromagnetic wave logging response model for uniform medium.

[0072] S320. Based on the electromagnetic wave logging response perturbation model and the homogeneous medium transient electromagnetic wave logging response model, determine the sensitivity function of the induced electromotive force; wherein, the sensitivity function of the induced electromotive force reflects the degree to which the induced electromotive force is affected by the conductivity perturbation in the geology.

[0073] S330. Integrate the sensitivity function of the induced electromotive force in the direction perpendicular to the ground to obtain a one-dimensional sensitivity function; wherein, the one-dimensional sensitivity function reflects the degree of influence of an infinitesimally small radius column extending in the direction perpendicular to the ground on the logging response.

[0074] In this context, the direction perpendicular to the ground is the z-axis in the world coordinate system. The sensitivity function of the induced electromotive force can be integrated along this direction to obtain a one-dimensional sensitivity function. This sensitivity function reflects the influence of an infinitesimally small radius column extending perpendicular to the ground on the well logging response. Specifically:

[0075] ;

[0076] This represents the sensitivity function of the measurement signal in the xoz plane. This represents the sensitivity function of the measurement signal in the xoy plane. This can be understood as the contribution of an infinitesimally small radius column extending infinitely in the y-direction to the response, while This represents the contribution of an infinitesimally small radius column extending infinitely in the z-direction to the response.

[0077] S340. Transform the one-dimensional sensitivity function to cylindrical coordinates to obtain the planar sensitivity function.

[0078] For example, in cylindrical coordinates, radial distance can reflect the detection depth of transient electromagnetic waves. Therefore, by transforming the one-dimensional sensitivity function to cylindrical coordinates, the relationship between electromagnetic induction and radial distance can be reflected through a planar sensitivity function in cylindrical coordinates, thus reflecting the detection depth of electromagnetic waves. Specifically, the planar sensitivity function obtained by transforming the one-dimensional sensitivity function to cylindrical coordinates takes the following form: The sensitivity function of the measurement signal is reflected in the ρoz plane.

[0079] S350. Determine the radial integral sensitivity function based on the plane sensitivity function.

[0080] For example, the radial integral sensitivity function can be determined based on the planar sensitivity function, which reflects the contribution of an infinitely extending cylinder in a direction perpendicular to the ground.

[0081] In this embodiment of the application, determining the radial integral sensitivity function based on the plane sensitivity function includes:

[0082] Integrating the planar sensitivity function with respect to the variable perpendicular to the ground, we obtain the thin cylindrical sensitivity function.

[0083] The radial integral sensitivity function is obtained by integrating the thin cylindrical sensitivity function over the radial distance variable.

[0084] The process of determining the radial integral sensitivity function based on the planar sensitivity function is as follows: Integrating the planar sensitivity function with respect to the variable perpendicular to the ground surface yields the thin circular surface sensitivity function; integrating the thin cylindrical sensitivity function with respect to the radial distance variable yields the radial integral sensitivity function. Specifically, the planar sensitivity function is... Integrating the variable perpendicular to the ground, we obtain the thin cylindrical sensitivity function, i.e. Let represent the sensitivity function of the measurement signal in the ρ direction, which can be understood as the contribution of an infinitely extending thin cylindrical stratum in the z direction at the ρ coordinate to the response. Integrating the thin cylindrical sensitivity function over the radial distance variable yields the radial integral sensitivity function, i.e. , This represents the contribution of an infinitely extending cylinder with radius ρi in the z-direction to the response. For time-domain electromagnetic logging, this can be used to analyze the detection depth in the logging environment.

[0085] S360. Determine the detection depth of transient electromagnetic wave logging within the target time range based on the radial integral sensitivity function.

[0086] This application provides a method for determining the detection depth of electromagnetic wave logging. The method involves integrating the sensitivity function of the induced electromotive force in a direction perpendicular to the ground to obtain a one-dimensional sensitivity function. This one-dimensional sensitivity function reflects the influence of an infinitesimally small radius column extending infinitely in a direction perpendicular to the ground on the logging response. The one-dimensional sensitivity function is then transformed to a cylindrical coordinate system to obtain a planar sensitivity function. Based on the planar sensitivity function, a radial integral sensitivity function is determined. This method can transform the sensitivity function of electromagnetic induction to a cylindrical coordinate system, reflecting the relationship between electromagnetic induction and radial distance, thereby reflecting the detection depth of electromagnetic waves. This enables accurate detection of the depth, provides theoretical support for the design and optimization of logging instrument parameters, and offers technical reference for the development of transient electromagnetic wave logging instruments.

[0087] Figure 5 This is a flowchart illustrating a method for determining the depth of electromagnetic wave well logging, provided as another embodiment of this application. This embodiment is an optimization based on the above embodiments; schemes not described in detail in this embodiment are found in the above embodiments. Figure 5 As shown, the method in this embodiment of the application specifically includes the following steps:

[0088] S410. Establish a formation model with conductivity disturbance under uniform medium background conditions, and simulate a multi-component transmit and receive antenna combination mode in the formation model with conductivity disturbance. Use the lower step signal source as the excitation source for transient electromagnetic wave logging, and determine the transient electromagnetic wave logging response model for uniform medium.

[0089] S420. Based on the electromagnetic wave logging response perturbation model and the homogeneous medium transient electromagnetic wave logging response model, determine the sensitivity function of the induced electromotive force; wherein, the sensitivity function of the induced electromotive force reflects the degree of influence of the induced electromotive force on the conductivity perturbation in the geology.

[0090] S430. Based on the sensitivity function of the induced electromotive force, determine the radial integral sensitivity function in the cylindrical coordinate system; wherein, the radial integral sensitivity function reflects the degree of influence of the cylindrical variable in the direction perpendicular to the ground on the logging response.

[0091] S440. Determine the relationship between radial distance and time based on the radial integral sensitivity function.

[0092] For example, the relationship between radial distance and time can be determined based on the radial integral sensitivity function, which reflects the contribution of an infinitely extending cylinder with radius ρi in the z-direction to the response. For the radial integral sensitivity function, the range of radial distance variation can be determined for each varying time parameter, and based on this, the relationship between radial distance and time can be determined.

[0093] In this embodiment of the application, determining the relationship between radial distance and time based on the radial integral sensitivity function includes:

[0094] Based on the radial integral sensitivity function, the relationship between the radial integral function value and the radial distance in the cylindrical coordinate system under different target time conditions is determined.

[0095] Different target times are converted into corresponding time-continuous target time ranges, and the relationship between radial distance and time is determined under different radial integral function values.

[0096] Specifically, based on the radial integral sensitivity function, the relationship between the radial integral function value and the radial distance in cylindrical coordinates can be determined under different target time conditions. That is, for different target times, the relationship between the radial integral sensitivity function value and the radial distance at that target time can be determined. Based on this relationship, contour lines with a radial integral sensitivity function value of 0.5 can be defined. This reflects the variation of the radial distance over time when the radial integral sensitivity function is defined as 0.5, corresponding to the corresponding detection depth.

[0097] S450. Based on the relationship between detection depth and time in a double logarithmic coordinate system, determine the relationship between radial distance, time, and conductivity.

[0098] In this embodiment, the contour lines indicate a linear relationship between the detection depth and time in a log-log coordinate system; that is, determining the detection depth at a given moment allows for the calculation of the detection depth over the entire time domain. Combining radial distance, time, and conductivity, the relationship in the log-log coordinate system can be determined as follows:

[0099] In the formula, k is an undetermined coefficient. By simulating the detection depth under different time and conductivity conditions, k=2.76 was obtained through fitting.

[0100] S460. Based on the relationship between radial distance, time, and conductivity, determine the detection depth of transient electromagnetic wave logging under the target conductivity and target time range; wherein, the radial distance obtained by solving is the detection depth.

[0101] For example, based on the above formula, the detection depth of transient electromagnetic wave logging can be determined given a target conductivity and a target time range. For instance, given a target conductivity of 1 S / m and t=10... -6 ~10 -2 The theoretical detection depth ρdoi is approximately between 0.57 and 57 m. The corresponding detection depths for different measurement times under different stratum conductivity conditions can be obtained accordingly.

[0102] This application provides a method for determining the detection depth of electromagnetic wave logging. Based on the radial integral sensitivity function, the relationship between radial distance and time is determined; based on the relationship between detection depth and time in a double logarithmic coordinate system, the relationship between radial distance, time, and conductivity is determined; based on the relationship between radial distance, time, and conductivity, the detection depth of transient electromagnetic wave logging is determined under the condition of target conductivity and target time range; wherein, the obtained radial distance is the detection depth. By transforming the radial integral sensitivity function into the relationship between radial distance, time, and conductivity, the radial distance range, that is, the detection range of electromagnetic waves, can be determined intuitively and accurately under the condition of constant time and conductivity.

[0103] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0104] Step 1: Establish a formation model with small electrical conductivity disturbances under homogeneous medium background conditions;

[0105] Figure 2 This is a schematic diagram illustrating the principle of the transient electromagnetic wave logging sensitivity function used in this invention. The step current is used as the excitation source T. After the current is turned off, the secondary field is observed through the receiving coil R during the interval between transmitted pulses. Figure 2 The background is a homogeneous medium formation model. The source T is located at the origin of the coordinate system, and the receiver R is located at r. There is a small conductivity perturbation at the formation r', and the internal conductivity is σ.a The volume is V a , σ a =δσ+σ b , where σ b The background conductivity is uniform.

[0106] Step 2: Design a multi-component transmit and receive antenna combination mode, determine the lower step signal source as the excitation source for transient electromagnetic wave logging, and derive the calculation formula for transient electromagnetic wave logging response in homogeneous medium.

[0107] Figure 2 The step current T is used as the excitation source. After the current is turned off, the secondary field is observed through the receiving coil R during the interval of the transmitted pulse.

[0108] Step 3 specifically includes the following steps:

[0109] Step 3.1: Establish the electromagnetic field integral equation representation of the micro-winding model based on Maxwell's equations:

[0110] ;

[0111] In the formula, The vector representing the coordinates from the emission source to the anomalous body.

[0112] Step 3.2: When When the minimum value is taken, the electric field e(r', t') inside the anomalous body can be approximated by the background electric field e using the Born approximation theory. p (r', t') replaces, and at the same time, when the abnormal body V a When the voltage is sufficiently low, its conductivity σ a Since the internal electric field e(r', t') can be considered constant, and parameters such as the number of coil turns and area can be ignored when considering the relative magnitude of the sensitivity, the sensitivity function of the measured signal, i.e., the induced electromotive force, can be determined by subtracting the formula for calculating the transient electromagnetic wave logging response in a uniform medium from the second formula in step 3.1.

[0113] ;

[0114] In the formula, The vector representing the coordinates from the emission source to the anomalous body. h (r, r') is the Green's function of the magnetic field tensor generated by the electric dipole source at r' at r. This represents the primary field component of the electric field. Indicates the magnetic field part. It represents the partial derivative of the magnetic field strength at position r with respect to time at time t. S represents conductivity, and t and t' represent time. V(r, r', t) represents the sensitivity of the electromotive force signal at time t to the change in conductivity at the location r' of the anomalous body when the receiving point position vector is r.

[0115] Step 3.3: Construct electrical sensitivity functions for different electrical geometries by integrating the reference geometric factors. First, define the two-dimensional sensitivity function.

[0116] ;

[0117] in, That is , , Let represent the measurement signal sensitivity functions of the xoz and xoy planes, respectively. This can be understood as the contribution of an infinitesimally small radius column extending infinitely in the y-direction to the response, while This represents the contribution of an infinitesimally small radius column extending infinitely in the z-direction to the response. For each... Double numerical integration along the yz and xy directions yields a one-dimensional sensitivity function:

[0118] ;

[0119] in, , Let represent the differential sensitivity functions in the x and z directions, respectively. This can be understood as the contribution of an infinitely extended thin plate at different x-coordinates to the response, while This can be understood as the contribution of an infinitely extended thin plate at different z-coordinates to the response.

[0120] Step 4: Simulate and study the spatial and temporal distribution characteristics of time-domain sensitivity under different time and source distance conditions, and analyze the sensitivity distribution law of transient electromagnetic wave logging signals to different parameters.

[0121] based on By changing the time t and the source distance r, we obtained the sensitivity distribution maps under the conditions of time variation and the source distance variation, respectively.

[0122] Figure 6 This is a schematic diagram of the electromagnetic wave response under nine different combinations of a third transmitting coil and three receiving coils at a fixed time, as provided in the embodiments of this application. Figure 6 In the diagrams, the vertical axis Vzx represents the response produced by the combination of the transmitting coil along the z-direction and the receiving coil along the x-direction. The same applies to the others. Figure 7 This diagram illustrates the sensitivity distribution of the magnetic dipole source in the z-direction at different times, as provided in the embodiments of this application. For the z-component, that is... Figure 7In (g), (h), and (i), the ellipsoids increase in size and change over time. The morphology of the sensitive isosurface remains basically unchanged, but the sensitive range increases. The central depression shown in (i) gradually increases, and the detection range gradually increases. For the zx and zy components, the sensitive range increases over time, while the vertical sensitivity of the two components decreases. That is, at later times, the vertical sensitivity distribution gradually tends to be symmetrical. The time-domain signal sensitivity function changes significantly with time. This is because, as time changes, the induced eddy currents in the formation spread outwards at a relatively fast speed. The distribution of the measurement signal contribution from the receiving coil changes, and the sensitive range spreads from near the wellbore to the formation far from the well. As the spread range continues to expand, the size of the coil system is much smaller than the sensitive area, at which point the influence of the coil system is almost negligible.

[0123] Figure 8 The time provided for the embodiments of this application is 10. -5 A schematic diagram of the logging sensitivity distribution of transient electromagnetic waves with different source distances (zz component) at time s. Figure 9 The time provided for the embodiments of this application is 10. -3 A schematic diagram of the sensitivity distribution of multi-component transient electromagnetic wave logging at different source distances at time s. It can be seen that the distribution of the sensitivity function is affected by the source distance to varying degrees at different times. In the early stages, when the detection range is small, the source distance has a significant impact, while in the later stages, when the detection range is large, the impact is negligible. Furthermore, the azimuth sensitivity of the zx component is only prominent in the early stages and under longer source distance conditions. In transient electromagnetic wave logging, when the source distance itself is small, the distance between the receiving coil and the transmitting coil (i.e., the source distance) has a relatively small impact on the response, allowing for a larger detection range with a smaller source distance. This provides a significant advantage for designing short-sized instruments.

[0124] Step 5: Explore a quantitative characterization method for the radial depth of transient electromagnetic wave logging for the coaxial component, and establish the frequency-time-depth correspondence of transient electromagnetic wave logging. The depth of the signal is quantified by longitudinal and transverse differential and integral geometric factors. Therefore, circumferential integration in cylindrical coordinates yields:

[0125] ;

[0126] In the formula, Represents the radial, circumferential, and longitudinal coordinates in a cylindrical coordinate system, where t represents time. The sensitivity function of the measurement signal in the ρoz plane can be understood as the contribution of the unit loop at point (ρ, z) to the response, corresponding to the induction logging geometric factor. Based on this, the expression for the differential sensitivity function in cylindrical coordinates is given as follows:

[0127] ;

[0128] In the formula, The sensitivity function for the measured signal along the ρ direction can be understood as the contribution of an infinitely extending thin cylindrical stratum along the z direction at the ρ coordinate to the response. Similarly, the radial integral sensitivity function is defined.

[0129] ;

[0130] In the formula, Indicates a radius of ρ i The contribution of an infinitely extending cylinder in the z-direction to the response. For time-domain electromagnetic logging, this can be used to analyze the detection depth in the logging environment.

[0131] Figure 10 A schematic diagram of the radial sensitivity function of transient electromagnetic wave logging for the zz component provided in this application embodiment. Figure 10 (a), (c), and (e) in the text are based on The curves showing the relationship between the sensitivity function values ​​and the radial distance at different times. Figure 10 (b), (d), and (f) are based on The curves showing the relationship between the sensitivity function values ​​and the radial distance at different times reveal significant differences in the magnitude of the sensitivity function distribution at different times. Therefore, coordinates for different intervals are established to simulate the sensitivity function at different times. The figure shows the values ​​at t=10. -6 10 -4 10 -2 The radial differential and integral sensitivity function distributions at time s. It can be seen that when the sensitivity function value is less than 0.5, at t=10... -6 At t=10, the detection range is approximately within 1 m, while at t=10... -2 At time s, the detection range can reach 100 m. If the radial integral sensitivity function is defined as 0.5 as its detection depth, the detection depth is between 0.5 and 50 m within this time range.

[0132] Figure 11 This is a schematic diagram of the time-depth double logarithmic distribution of the radial integral sensitivity function for transient electromagnetic wave logging provided in an embodiment of this application. That is, Figure 10 Convert (b), (d), and (f) to contour lines, and transform the coordinates so that the vertical axis represents time and the horizontal axis represents radial distance. Different contour lines indicate different sensitivity function values, respectively representing time 10. -6 ~10 -4 s, 10 -4 ~10 -2The graph shows the distribution of the integral sensitivity function of s. Contour lines indicating a radial integral sensitivity function of 0.5 are marked in the graph, reflecting the relationship between time and radial distance. As can be seen from the graph, the variation of the sensitivity function is basically consistent across different time periods, but the corresponding detection ranges span approximately one order of magnitude. The detection depth and time exhibit a roughly linear relationship in a logarithmic coordinate system, meaning the contour lines are straight lines. Therefore, once the detection depth at a given moment is determined, the detection depth across the entire time domain can be roughly estimated.

[0133] Combining the relationship between diffusion depth and time and conductivity, taking the logarithm yields...

[0134] ;

[0135] In the formula, k is an undetermined coefficient, representing the relationship between the detection depth and the depth. By simulating the detection depth under different time and conductivity conditions, k=2.76 was obtained through fitting. That is, under the condition of conductivity of 1 S / m, t=10 -6 ~10 -2 s, theoretical detection depth ρ doi The depth is approximately between 0.57 and 57 m. The corresponding detection depth for different measurement times under different stratum conductivity conditions can be obtained accordingly.

[0136] Figure 12 This is a schematic diagram of an electromagnetic wave logging depth determination device provided in an embodiment of this application. This device can execute the electromagnetic wave logging depth determination method provided in any embodiment of this application, and possesses the corresponding functional modules and beneficial effects for executing the method. Figure 12 As shown, the device includes:

[0137] The logging response calculation module 510 is used to establish a conductivity-perturbed formation model under a uniform medium background condition, and to simulate a multi-component transmit-receive antenna combination mode in the conductivity-perturbed formation model. The lower step signal source is used as the excitation source for transient electromagnetic wave logging, and the transient electromagnetic wave logging response model in the uniform medium is determined.

[0138] The induced electromotive force sensitivity function determination module 520 is used to determine the sensitivity function of the induced electromotive force based on the electromagnetic wave logging response perturbation model and the homogeneous medium transient electromagnetic wave logging response model; wherein, the sensitivity function of the induced electromotive force reflects the degree of influence of the induced electromotive force on the conductivity perturbation in the geology.

[0139] The radial integral sensitivity function determination module 530 is used to determine the radial integral sensitivity function in cylindrical coordinates based on the sensitivity function of the induced electromotive force; wherein, the radial integral sensitivity function reflects the degree of influence of the cylindrical variable in the direction perpendicular to the ground on the logging response;

[0140] The detection depth determination module 540 is used to determine the detection depth of transient electromagnetic wave logging within the target time range based on the radial integral sensitivity function.

[0141] In this embodiment, the induced electromotive force sensitivity function determination module 520 determines the sensitivity function of the induced electromotive force based on the electromagnetic wave logging response perturbation model and the homogeneous medium transient electromagnetic wave logging response model, including:

[0142] An integral representation of the electromagnetic wave logging response perturbation model based on Maxwell's equations;

[0143] By using Born's approximation theory, the electric field, internal electric field, and conductivity of the magnetic field model in the integral expression of the electromagnetic wave logging response perturbation model are simplified. Combined with the homogeneous medium transient electromagnetic wave logging response model, the sensitivity function of the induced electromotive force is determined.

[0144] In this embodiment, the induced electromotive force sensitivity function determination module 520 simplifies the anomalous body electric field, internal electric field, and conductivity of the magnetic field model in the integral expression of the electromagnetic wave logging response perturbation model using Born approximation theory. Combined with the homogeneous medium transient electromagnetic wave logging response model, it determines the sensitivity function of the induced electromotive force, including:

[0145] The anomalous electric field in the magnetic field component of the electromagnetic wave logging response perturbation model is replaced by the background electric field to obtain the simplified magnetic field component.

[0146] The simplified magnetic field component is differentially processed with the transient electromagnetic wave logging response model of the homogeneous medium to obtain the sensitivity function of the induced electromotive force.

[0147] In this embodiment, the radial integral sensitivity function determination module 530 determines the radial integral sensitivity function in cylindrical coordinates based on the sensitivity function of the induced electromotive force, including:

[0148] Integrating the sensitivity function of the induced electromotive force in the direction perpendicular to the ground yields a one-dimensional sensitivity function; wherein, the one-dimensional sensitivity function reflects the degree of influence of an infinitesimally small radius column extending infinitely in the direction perpendicular to the ground on the logging response.

[0149] The one-dimensional sensitivity function is transformed to cylindrical coordinates to obtain the planar sensitivity function;

[0150] Based on the plane sensitivity function, determine the radial integral sensitivity function.

[0151] In this embodiment, the radial integral sensitivity function determination module 530 determines the radial integral sensitivity function based on the plane sensitivity function, including:

[0152] Integrating the planar sensitivity function with respect to the variable perpendicular to the ground, we obtain the thin cylindrical sensitivity function.

[0153] The radial integral sensitivity function is obtained by integrating the thin cylindrical sensitivity function over the radial distance variable.

[0154] In this embodiment of the application, the detection depth determination module 540 determines the detection depth of transient electromagnetic wave logging within the target time range based on the radial integral sensitivity function, including:

[0155] The relationship between radial distance and time is determined based on the radial integral sensitivity function;

[0156] Based on the relationship between detection depth and time in a double logarithmic coordinate system, the relationship between radial distance, time, and conductivity is determined;

[0157] Based on the relationship between radial distance, time, and conductivity, the detection depth of transient electromagnetic wave logging is determined under the conditions of target conductivity and target time range; where the radial distance obtained by solving is the detection depth.

[0158] In this embodiment, the detection depth determination module 540 determines the relationship between radial distance and time based on the radial integral sensitivity function, including:

[0159] Based on the radial integral sensitivity function, the relationship between the radial integral function value and the radial distance in the cylindrical coordinate system under different target time conditions is determined.

[0160] Different target times are converted into corresponding time-continuous target time ranges, and the relationship between radial distance and time is determined under different radial integral function values.

[0161] The electromagnetic wave logging depth determination device provided in this application embodiment can execute the electromagnetic wave logging depth determination method provided in any embodiment of this application, and has the corresponding functional modules and beneficial effects of executing the method.

[0162] Figure 13A schematic diagram of an electronic device 10, which can be used to implement embodiments of this application, is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices (such as helmets, glasses, watches, etc.), and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the application described and / or claimed herein.

[0163] like Figure 13 As shown, the electronic device 10 includes at least one processor 11 and a memory, such as a read-only memory (ROM) 12 or a random access memory (RAM) 13, communicatively connected to the at least one processor 11. The memory stores computer programs executable by the at least one processor. The processor 11 can perform various appropriate actions and processes based on the computer program stored in the ROM 12 or loaded from storage unit 18 into the RAM 13. The RAM 13 can also store various programs and data required for the operation of the electronic device 10. The processor 11, ROM 12, and RAM 13 are interconnected via a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0164] Multiple components in electronic device 10 are connected to I / O interface 15, including: input unit 16, such as keyboard, mouse, etc.; output unit 17, such as various types of monitors, speakers, etc.; storage unit 18, such as disk, optical disk, etc.; and communication unit 19, such as network card, modem, radio electromagnetic wave logging depth determination transceiver, etc. Communication unit 19 allows electronic device 10 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0165] Processor 11 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of processor 11 include, but are not limited to, central processing unit (CPU), graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, digital signal processors (DSPs), and any suitable processor, controller, microcontroller, etc. Processor 11 performs the various methods and processes described above, such as electromagnetic wave logging depth determination methods.

[0166] In some embodiments, the electromagnetic wave logging depth determination method can be implemented as a computer program tangibly contained in a computer-readable storage medium, such as storage unit 18. In some embodiments, part or all of the computer program can be loaded and / or installed on electronic device 10 via ROM 12 and / or communication unit 19. When the computer program is loaded into RAM 13 and executed by processor 11, one or more steps of the electromagnetic wave logging depth determination method described above can be performed. Alternatively, in other embodiments, processor 11 can be configured to perform the electromagnetic wave logging depth determination method by any other suitable means (e.g., by means of firmware).

[0167] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), complex programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0168] Computer programs used to implement the methods of this application may be written in any combination of one or more programming languages. These computer programs may be provided to the processor of a general-purpose computer, a special-purpose computer, or other programmable electromagnetic logging depth determination device, such that when executed by the processor, the computer programs cause the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The computer programs may be executed entirely on a machine, partially on a machine, or as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0169] In the context of this application, a computer-readable storage medium can be a tangible medium that may contain or store a computer program for use by or in conjunction with an instruction execution system, apparatus, or device. A computer-readable storage medium can be, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium can be a machine-readable signal medium. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0170] To provide interaction with a user, the systems and techniques described herein can be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the electronic device. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0171] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as data servers), or middleware components (e.g., application servers), or frontend components (e.g., user computers with graphical user interfaces or web browsers through which users can interact with implementations of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., communication networks). Examples of communication networks include local area networks (LANs), wide area networks (WANs), blockchain networks, and the Internet.

[0172] A computing system can include clients and servers. Clients and servers are generally located far apart and typically interact through communication networks. The client-server relationship is created by computer programs running on the respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or cloud host, which is a hosting product within the cloud computing service system to address the shortcomings of traditional physical hosts and VPS services, such as high management difficulty and weak business scalability.

[0173] This invention also provides a computer program product, including a computer program that, when executed by a processor, implements the electromagnetic wave logging depth determination method provided in any embodiment of this application.

[0174] In implementing the computer program product, computer program code for performing the operations of this invention can be written in one or more programming languages ​​or a combination thereof. Programming languages ​​include object-oriented programming languages ​​such as Java, Smalltalk, and C++, as well as conventional procedural programming languages ​​such as C or similar languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or it can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0175] It should be understood that the various forms of processes shown above can be used to rearrange, add, or delete steps. For example, the steps described in this application can be executed in parallel, sequentially, or in different orders, as long as the desired information of the technical solution of this application can be achieved, and this is not limited herein.

[0176] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for determining the depth of electromagnetic wave logging, characterized in that, The method includes: A formation model with conductivity disturbance under uniform medium background conditions is established, and a multi-component transmit and receive antenna combination mode is simulated in the formation model with conductivity disturbance. The lower step signal source is used as the excitation source for transient electromagnetic wave logging, and the transient electromagnetic wave logging response model in uniform medium is determined. Based on the electromagnetic wave logging response perturbation model and the homogeneous medium transient electromagnetic wave logging response model, the sensitivity function of the induced electromotive force is determined; wherein, the sensitivity function of the induced electromotive force reflects the degree of influence of the induced electromotive force on the conductivity perturbation in the geology. Based on the sensitivity function of induced electromotive force, the radial integral sensitivity function in cylindrical coordinates is determined; whereby the radial integral sensitivity function reflects the degree of influence of the cylindrical variable in the direction perpendicular to the ground on the logging response. The detection depth of transient electromagnetic wave logging within the target time range is determined based on the radial integral sensitivity function.

2. The method according to claim 1, characterized in that, Based on the electromagnetic wave logging response perturbation model and the homogeneous medium transient electromagnetic wave logging response model, the sensitivity function of the induced electromotive force is determined, including: An integral representation of the electromagnetic wave logging response perturbation model based on Maxwell's equations; By using Born's approximation theory, the electric field, internal electric field, and conductivity of the magnetic field model in the integral expression of the electromagnetic wave logging response perturbation model are simplified. Combined with the homogeneous medium transient electromagnetic wave logging response model, the sensitivity function of the induced electromotive force is determined.

3. The method according to claim 2, characterized in that, Using Born's approximation theory, the electric field, internal electric field, and conductivity of the magnetic field model in the integral expression of the electromagnetic wave logging response perturbation model are simplified. Combined with the homogeneous medium transient electromagnetic wave logging response model, the sensitivity function of the induced electromotive force is determined, including: The anomalous electric field in the magnetic field component of the electromagnetic wave logging response perturbation model is replaced by the background electric field to obtain the simplified magnetic field component. The simplified magnetic field component is differentially processed with the transient electromagnetic wave logging response model of the homogeneous medium to obtain the sensitivity function of the induced electromotive force.

4. The method according to claim 1, characterized in that, Based on the sensitivity function of the induced electromotive force, the radial integral sensitivity function in cylindrical coordinates is determined, including: Integrating the sensitivity function of the induced electromotive force in the direction perpendicular to the ground yields a one-dimensional sensitivity function; wherein, the one-dimensional sensitivity function reflects the degree of influence of an infinitesimally small radius column extending infinitely in the direction perpendicular to the ground on the logging response. The one-dimensional sensitivity function is transformed to cylindrical coordinates to obtain the planar sensitivity function; Based on the plane sensitivity function, determine the radial integral sensitivity function.

5. The method according to claim 4, characterized in that, Based on the plane sensitivity function, the radial integral sensitivity function is determined, including: Integrating the planar sensitivity function with respect to the variable perpendicular to the ground, we obtain the thin cylindrical sensitivity function. The radial integral sensitivity function is obtained by integrating the thin cylindrical sensitivity function over the radial distance variable.

6. The method according to claim 1, characterized in that, Based on the radial integral sensitivity function, the detection depth of transient electromagnetic wave logging within the target time range is determined, including: The relationship between radial distance and time is determined based on the radial integral sensitivity function; Based on the relationship between detection depth and time in a double logarithmic coordinate system, the relationship between radial distance, time, and conductivity is determined; Based on the relationship between radial distance, time, and conductivity, the detection depth of transient electromagnetic wave logging is determined under the conditions of target conductivity and target time range; where the radial distance obtained by solving is the detection depth.

7. The method according to claim 6, characterized in that, Based on the radial integral sensitivity function, the relationship between radial distance and time is determined, including: Based on the radial integral sensitivity function, the relationship between the radial integral function value and the radial distance in the cylindrical coordinate system under different target time conditions is determined. Different target times are converted into corresponding time-continuous target time ranges, and the relationship between radial distance and time is determined under different radial integral function values.

8. An electronic device, characterized in that, The electronic device includes: At least one processor; and A memory communicatively connected to the at least one processor; wherein, The memory stores a computer program that can be executed by the at least one processor, the computer program being executed by the at least one processor to enable the at least one processor to perform the electromagnetic wave logging depth determination method according to any one of claims 1-7.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that cause a processor to execute the electromagnetic wave logging depth determination method according to any one of claims 1-7.

10. A computer program product, characterized in that, It includes a computer program that, when executed by a processor, implements the electromagnetic wave logging depth determination method as described in any one of claims 1-7.

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