CN113504571A - Polarization equivalent ring device of multiphase conductive medium and design method - Google Patents
Polarization equivalent ring device of multiphase conductive medium and design method Download PDFInfo
- Publication number
- CN113504571A CN113504571A CN202110835063.9A CN202110835063A CN113504571A CN 113504571 A CN113504571 A CN 113504571A CN 202110835063 A CN202110835063 A CN 202110835063A CN 113504571 A CN113504571 A CN 113504571A
- Authority
- CN
- China
- Prior art keywords
- polarization
- conductive medium
- branch
- multiphase
- induction
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
- G01V3/08—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices
- G01V3/10—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
- G01V3/38—Processing data, e.g. for analysis, for interpretation, for correction
Abstract
The invention relates to a polarization equivalent ring device of a multiphase conductive medium and a design method thereof, wherein the polarization equivalent ring device is formed by connecting an RC circuit and a coil in parallel, wherein the RC circuit comprises 1 induction branch and a plurality of polarization branches. The number of the polarization branches is equal to the number of the conductive media. The induction branch comprises 1 induction resistor, and each polarization branch comprises 1 polarization resistor and 1 polarization capacitor. And calculating the conductivity of the surrounding rock of the medium to be equivalent and the conductivity, the polarizability and the time constant of each phase medium based on the GEMTIP model. Determining the resistance value of the induction resistor according to the conductivity of the surrounding rock; and calculating the resistance capacitance value of the corresponding polarization branch according to the conductivity, the polarizability and the time constant of each phase medium. The coil is wound by adopting a thin conducting wire. The invention aims to simulate the induction-polarization characteristics of a multiphase conductive medium through a polarization equivalent ring device and reflect the law of induction-polarization effect of an underground medium under magnetic field excitation.
Description
Technical Field
The invention relates to the field of geophysical exploration, in particular to a polarization equivalent ring device of a multiphase conductive medium and a design method.
Background
In the field of geophysical exploration, the detection of deep metal ores is a major future development trend. When the electromagnetic detection method is adopted, an external alternating electromagnetic field causes induction effect and polarization effect in the underground polymetallic ore body. Wherein the polymetallic ore is more sensitive to polarization effects than resistivity information.
CN102096113A discloses a time domain ground-air electromagnetic detection system and a calibration method, which adopts a closed abnormal loop induction signal recording device to realize the test and calibration of the detection system. However, the abnormal ring structure adopted by the method is simple and is equivalent to a series connection of a resistor and an inductor, and only induction current and induction voltage can be recorded and the induction effect can be simulated. And the actual valuable target bodies (such as metal ores and the like) are sensitive to the polarization effect, the requirement for geophysical exploration cannot be met by simply researching the induction effect, and the complex characteristic of a multiphase polarization medium is ignored.
CN112666618A discloses a geometric-physical multi-feature parameter extraction method for a multiphase medium, which is used for extracting polarization parameters according to a quantum particle swarm optimization algorithm based on a generalized equivalent polarization (GEMTIP) model of an underground multiphase medium. The method applies the generalized equivalent polarization model to the inversion of the polarization effect, but due to factors such as instrument equipment and environmental interference, the numerical simulation result in actual work is difficult to correspond to the measured data one by one.
At present, researches aiming at the induction effect and the polarization effect mainly comprise forward and backward numerical calculation and field engineering detection, and how to establish a relationship between the forward and backward numerical calculation and the field engineering detection is urgent to solve. Therefore, a new device and a new method are needed to be provided to realize the simulation of the induction-polarization characteristics of the multiphase conductive medium, so as to reflect the law of the induction-polarization effect of the underground medium under the excitation of the magnetic field, and combine the numerical simulation and the experimental verification.
Disclosure of Invention
The present invention is directed to overcoming the above-mentioned disadvantages and problems of the prior art, and providing a polarization equivalent loop device and design method for a multi-phase conductive medium.
The present invention is achieved in such a way that,
a polarized equivalent loop device of a multiphase conductive medium, the device comprising:
a polarization equivalent ring device of a multi-phase conductive medium is formed by connecting an RC circuit and a coil in parallel, wherein the RC circuit comprises 1 induction branch and a plurality of polarization branches, the induction branch is connected with the polarization branches in parallel, the plurality of polarization branches are connected in parallel, and the number of the polarization branches is equal to that of the conductive medium and corresponds to that of the conductive medium one by one; the induction branch comprises 1 resistor, each polarization branch is formed by connecting 1 resistor and 1 capacitor in series, the resistor and the capacitor of the RC circuit adopt a precision resistor and a precision capacitor, the coil is wound by a thin wire, and the resistance value of the coil is at least 10 times smaller than that of the induction branch; the coil is used for receiving the excitation of an external time-varying magnetic field and generating induced electromotive force, and current is generated in the induction branch and the polarization branch, wherein the resistance value of the coil can be ignored; when the polarization equivalent ring device is applied with a time-varying electromagnetic field, the current of the induction branch reflects the induction characteristic of the multiphase conductive medium, the current of each polarization branch reflects the polarization characteristic of the corresponding conductive medium, and the sum of the currents of all the polarization branches reflects the polarization characteristic of the multiphase conductive medium.
A method of designing a poled equivalent ring device for a multiphase conductive medium, the method comprising:
1) consulting geological data, determining the number and size of phases of the multiphase conductive medium to be equivalent, and calculating the conductivity sigma of the surrounding rock based on a generalized equivalent polarization model (GEMTIP) of the multiphase conductive medium0And the conductivity σ of each phase of the conductive mediumlPolarizability etalAnd time constant τl；
2) Neglecting the resistance value of the coil, and calculating the inductance L of the coil based on the size of the multiphase conductive medium;
3) the number of polarization branches of the polarization equivalent ring device is equal to the number of phases of the multiphase conductive medium, and the polarization equivalent ring device is used for controlling the polarization equivalent ring device to be equal to the number of phases of the multiphase conductive medium according to the conductivity sigma of the surrounding rock0Calculating resistance R of induction branch of polarization equivalent ring device0According to the conductivity σ of each phase of the conductive mediumlPolarizability etalAnd time constant τlAnd calculating the resistance R in the corresponding polarization branchlAnd a capacitor Cl；
4) Connecting an RC circuit formed by connecting an induction branch and a polarization branch in parallel with a coil in parallel to form a calibrated polarization equivalent ring, and calculating an admittance G of the polarization equivalent ring and the integral polarizability eta of the multi-phase conductive medium;
5) and applying a time-varying electromagnetic field to the polarization equivalent ring device, and analyzing the induced polarization characteristic of the multiphase conductive medium to be equivalent by acquiring the current of each branch of the RC circuit.
Further, the conductivity sigma of the surrounding rock in the step 1)0And the conductivity σ of each phase of the conductive mediumlPolarizability etalAnd time constant τlCalculated by the following formula:
wherein, the total N-phase conductive medium is rho according to GEMTIP model0The direct current conductivity of the medium to be equivalent; the parameters of each phase of conductive medium respectively comprise: rholIs the resistivity tensor of the l-th phase of the conductive medium, flIs the volume fraction, alpha, of the conductive medium of the l-th phaselIs the surface polarization coefficient of the l-phase conductive medium, alIs the radius of the l-th phase conductive medium.
Further, the size of the multiphase conductive medium in step 2) is related to the coil inductance L as follows:
wherein, the multiphase conductive medium is in the shape of a square thin plate, D is the side length of the multiphase conductive medium, r is the thickness of the multiphase conductive medium, and mu0Is a vacuum magnetic permeability.
Further, the resistance R of the sensing branch in the step 3)0And a resistance R in each polarization branchlAnd a capacitor ClThe calculation method of (2) is as follows:
wherein beta is a geometric parameter of the earth, and the numerical value is usually 1-10; if the number of polarization branches is N, then RlIs the resistance of the first polarized branch, ClThe capacitance of the l polarized branch.
Further, the admittance G of the polarization equivalent ring and the overall polarizability η of the subsurface medium in step 4) are respectively calculated by:
wherein i is an imaginary number, ω is an angular frequency, R0Is a resistance of the sensing branch, ClThe capacitance of the l polarized branch.
Compared with the prior art, the invention has the beneficial effects that:
the invention provides an equivalent circuit model of a multiphase conductive medium, which analyzes the induction characteristic and the polarization characteristic of the multiphase conductive medium in a circuit form, receives the excitation of an external magnetic field through a coil, verifies and simulates the law of induction-polarization effect of the underground medium under the excitation of the magnetic field, and combines numerical simulation and experimental verification.
Drawings
FIG. 1 is a flow diagram of a design of a polarized equivalent loop arrangement of a multiphase conductive medium;
fig. 2 is a block diagram of a polarized equivalent loop arrangement of a multi-phase conductive medium.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The invention designs a polarization equivalent ring device according to a generalized equivalent polarization (GEMTIP) model based on a multiphase conductive medium, establishes an equivalent relation between physical parameters of the medium to be equivalent and resistance capacitance in the polarization equivalent ring device, calculates admittance of the polarization equivalent ring device and integral polarization rate of the multiphase conductive medium, analyzes induction-polarization characteristics of the multiphase conductive medium through current of each branch circuit excited by an external time-varying electromagnetic field of an acquisition device, compares the induction-polarization characteristics with a forward result of the multiphase conductive medium, and verifies the accuracy of the device, wherein a flow chart is shown in figure 1.
The invention is realized by a polarized equivalent ring device of a multiphase conductive medium, as shown in fig. 2, the device comprises:
the circuit is formed by connecting an RC circuit and a coil in parallel, wherein the RC circuit comprises 1 induction branch and a plurality of polarization branches, and the number of the polarization branches is equal to the number of phases of a conductive medium and corresponds to the number of the conductive medium one by one; the induction branch comprises 1 induction resistor, each polarization branch is formed by connecting 1 polarization resistor and 1 polarization capacitor in series, the resistor and the capacitor of the RC circuit adopt a precision resistor and a precision capacitor, the coil is wound by a thin wire, the resistance value of the coil is at least 10 times smaller than that of the induction branch, and the resistance of the coil can be ignored; the coil is used for receiving the excitation of an external time-varying magnetic field and generating induced electromotive force, and current is generated in the induction branch and the polarization branch, wherein the resistance value of the coil can be ignored; when the polarization equivalent ring device is applied with a time-varying electromagnetic field, the current of the induction branch reflects the induction characteristic of the multiphase conductive medium, the current of each polarization branch reflects the polarization characteristic of the corresponding conductive medium, and the sum of the currents of all the polarization branches reflects the polarization characteristic of the multiphase conductive medium.
A method of designing a poled equivalent ring device for a multiphase conductive medium, the method comprising:
1) consulting geological data, determining the number and size of phases of the multiphase conductive medium to be equivalent, and calculating the conductivity sigma of the surrounding rock based on a generalized equivalent polarization (GEMTIP) model of the multiphase conductive medium0And the conductivity σ of each phase of the conductive mediumlPolarizability etalAnd time constant τlThe formula is as follows:
wherein, the total N-phase conductive medium is rho according to GEMTIP model0The direct current conductivity of the medium to be equivalent; the parameters of each phase of conductive medium respectively comprise: rholIs the resistivity tensor of the l-th phase of the conductive medium, flIs the volume fraction, alpha, of the conductive medium of the l-th phaselIs the surface polarization coefficient of the l-phase conductive medium, alIs the radius of the l-th phase conductive medium.
2) Neglecting the resistance value of the coil, setting the multiphase conductive medium to be in the shape of a square thin plate, D to be the side length of the multiphase conductive medium, r to be the thickness of the multiphase conductive medium, mu0For the vacuum permeability, the coil inductance L is calculated based on the dimensions of the multiphase conductive medium:
3) the number of polarization branches of the polarization equivalent ring device is equal to the number of phases of the multiphase conductive medium, and the polarization equivalent ring device is used for controlling the polarization equivalent ring device to be equal to the number of phases of the multiphase conductive medium according to the conductivity sigma of the surrounding rock0Calculating resistance R of induction branch of polarization equivalent ring device0According toConductivity σ of each phase of conductive mediumlPolarizability etalAnd time constant τlAnd calculating the resistance R in the corresponding polarization branchlAnd a capacitor ClThe calculation method is as follows:
wherein beta is a geometric parameter of the earth, and the numerical value is usually 1-10; if the number of polarization branches is N, then RlIs the resistance of the first polarized branch, ClThe capacitance of the l polarized branch.
4) Connecting an RC circuit formed by connecting an induction branch and a polarization branch in parallel with a coil in parallel, namely a calibrated polarization equivalent ring, and calculating an admittance G of the polarization equivalent ring and the integral polarizability eta of the multi-phase conductive medium:
where i is an imaginary number and ω is an angular frequency.
5) And applying a time-varying electromagnetic field to the polarization equivalent ring device, and analyzing the induced polarization characteristic of the multiphase conductive medium to be equivalent by acquiring the current of each branch of the RC circuit.
Claims (6)
1. A polarization equivalent ring device of a multi-phase conductive medium is characterized in that the device is formed by connecting an RC circuit and a coil in parallel, wherein the RC circuit comprises 1 induction branch and a plurality of polarization branches, the induction branch is connected with the polarization branches in parallel, the plurality of polarization branches are connected in parallel, and the number of the polarization branches is equal to that of the conductive medium and corresponds to that of the conductive medium one by one; the induction branch comprises 1 resistor, each polarization branch is formed by connecting 1 resistor and 1 capacitor in series, the coil is wound by a thin wire, and the resistance value of the coil is at least 10 times smaller than that of the induction branch; the coil is used for receiving the excitation of an external time-varying magnetic field and generating induced electromotive force, and current is generated in the induction branch and the polarization branch.
2. A method of designing a polar equivalent ring arrangement of a multiphase conductive medium in accordance with claim 1, the method comprising:
1) consulting geological data, determining the number and size of phases of the multiphase conductive medium to be equivalent, and calculating the conductivity sigma of the surrounding rock based on the generalized equivalent polarization model of the multiphase conductive medium0And the conductivity σ of each phase of the conductive mediumlPolarizability etalAnd time constant τl；
2) Neglecting the resistance value of the coil, and calculating the inductance L of the coil based on the size of the multiphase conductive medium;
3) the number of polarization branches of the polarization equivalent ring device is equal to the number of phases of the multiphase conductive medium, and the polarization equivalent ring device is used for controlling the polarization equivalent ring device to be equal to the number of phases of the multiphase conductive medium according to the conductivity sigma of the surrounding rock0Calculating resistance R of induction branch of polarization equivalent ring device0According to the conductivity σ of each phase of the conductive mediumlPolarizability etalAnd time constant τlAnd calculating the resistance R in the corresponding polarization branchlAnd a capacitor Cl；
4) Connecting an RC circuit formed by connecting an induction branch and a polarization branch in parallel with a coil in parallel to form a calibrated polarization equivalent ring, and calculating an admittance G of the polarization equivalent ring and the integral polarizability eta of the multi-phase conductive medium;
5) and applying a time-varying electromagnetic field to the polarization equivalent ring device, and analyzing the induced polarization characteristic of the multiphase conductive medium to be equivalent by acquiring the current of each branch of the RC circuit.
3. The method according to claim 2, wherein the conductivity σ of the surrounding rock in step 1) is0And the conductivity σ of each phase of the conductive mediumlPolarizability etalAnd time constant τlCalculated by the following formula:
wherein, the total N-phase conductive medium is rho according to GEMTIP model0The direct current conductivity of the medium to be equivalent; the parameters of each phase of conductive medium respectively comprise: rholIs the resistivity tensor of the l-th phase of the conductive medium, flIs the volume fraction, alpha, of the conductive medium of the l-th phaselIs the surface polarization coefficient of the l-phase conductive medium, alIs the radius of the l-th phase conductive medium.
4. Method according to claim 2, characterized in that the dimensions of the multiphase conductive medium in step 2) are related to the coil inductance L as follows:
wherein, the multiphase conductive medium is in the shape of a square thin plate, D is the side length of the multiphase conductive medium, r is the thickness of the multiphase conductive medium, and mu0Is a vacuum magnetic permeability.
5. Method according to claim 2, characterized in that the resistance R of the sensing branch in step 3) is0And a resistance R in each polarization branchlAnd a capacitor ClThe calculation method of (2) is as follows:
wherein beta is a geometric parameter of the earth, and the numerical value is usually 1-10; if the number of polarization branches is N, then RlIs the resistance of the first polarized branch, ClThe capacitance of the l polarized branch.
6. The method of claim 2, wherein the admittance G of the polarization equivalent ring and the overall polarizability η of the subsurface medium in step 4) are each calculated by:
wherein i is an imaginary number, ω is an angular frequency, R0Is a resistance of the sensing branch, ClThe capacitance of the l polarized branch.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110835063.9A CN113504571B (en) | 2021-07-23 | 2021-07-23 | Polarization equivalent ring device of multiphase conductive medium and design method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110835063.9A CN113504571B (en) | 2021-07-23 | 2021-07-23 | Polarization equivalent ring device of multiphase conductive medium and design method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113504571A true CN113504571A (en) | 2021-10-15 |
| CN113504571B CN113504571B (en) | 2022-05-03 |
Family
ID=78014341
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110835063.9A Active CN113504571B (en) | 2021-07-23 | 2021-07-23 | Polarization equivalent ring device of multiphase conductive medium and design method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113504571B (en) |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20070061080A1 (en) * | 2005-07-22 | 2007-03-15 | Zhdanov Michael S | Geophysical technique for mineral exploration and discrimination based on electromagnetic methods and associated systems |
| US20140254317A1 (en) * | 2013-03-05 | 2014-09-11 | Arthur Thompson | Correlation Techniques for Passive Electroseismic and Seismoelectric Surveying |
| CN105676295A (en) * | 2016-01-30 | 2016-06-15 | 吉林大学 | SQUID-based magnetic source induced polarization-induction combined detection system and method |
| US20170023694A1 (en) * | 2015-07-23 | 2017-01-26 | Advanced Electromagnetic Technologies | Apparatus for airborne and ground electromagnetic prospecting and method thereof |
| CN109061751A (en) * | 2018-06-20 | 2018-12-21 | 西安石油大学 | The apparent conductivity calculation method of multilayer dielectricity |
| CN112166330A (en) * | 2019-01-23 | 2021-01-01 | 株式会社Lg化学 | Battery management apparatus, battery management method, and battery pack |
| CN112683965A (en) * | 2020-12-03 | 2021-04-20 | 华北电力大学 | Composite material dielectric constant calculation method and system |
| CN112698410A (en) * | 2020-12-16 | 2021-04-23 | 吉林大学 | Induction-polarization symbiotic time domain electromagnetic detection method for electric source double-phase conductive medium |
-
2021
- 2021-07-23 CN CN202110835063.9A patent/CN113504571B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20070061080A1 (en) * | 2005-07-22 | 2007-03-15 | Zhdanov Michael S | Geophysical technique for mineral exploration and discrimination based on electromagnetic methods and associated systems |
| US20140254317A1 (en) * | 2013-03-05 | 2014-09-11 | Arthur Thompson | Correlation Techniques for Passive Electroseismic and Seismoelectric Surveying |
| US20170023694A1 (en) * | 2015-07-23 | 2017-01-26 | Advanced Electromagnetic Technologies | Apparatus for airborne and ground electromagnetic prospecting and method thereof |
| CN105676295A (en) * | 2016-01-30 | 2016-06-15 | 吉林大学 | SQUID-based magnetic source induced polarization-induction combined detection system and method |
| CN109061751A (en) * | 2018-06-20 | 2018-12-21 | 西安石油大学 | The apparent conductivity calculation method of multilayer dielectricity |
| CN112166330A (en) * | 2019-01-23 | 2021-01-01 | 株式会社Lg化学 | Battery management apparatus, battery management method, and battery pack |
| CN112683965A (en) * | 2020-12-03 | 2021-04-20 | 华北电力大学 | Composite material dielectric constant calculation method and system |
| CN112698410A (en) * | 2020-12-16 | 2021-04-23 | 吉林大学 | Induction-polarization symbiotic time domain electromagnetic detection method for electric source double-phase conductive medium |
Non-Patent Citations (3)
| Title |
|---|
| VLADIMIR BURTMAN ET AL.: "Induced polarization effect in reservoir rocks and its modeling based on generalized effective-medium theory", 《RESOURCE-EFFICIENT TECHNOLOGIES》 * |
| 张锐锋等: "时频电磁法时域激电参数提取与应用", 《石油地球物理勘探》 * |
| 昌彦君等: "等效介质理论激电模型频率相关系数的影响因素", 《石油地球物理勘探》 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113504571B (en) | 2022-05-03 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Kratzer et al. | Induced polarization in airborne EM | |
| US3967190A (en) | Method using induced polarization for ore discrimination in disseminated earth deposits | |
| CA2257748C (en) | Method and apparatus for evaluating the resistivity of invaded formations at high apparent dip angle | |
| Walsh et al. | Practical limitations and applications of short dead time surface NMR | |
| EP2352041A1 (en) | Method for quantitatively separating the effects of electromagnetic induction and induced polarization | |
| Yu et al. | Break-point diagnosis of grounding grids using transient electromagnetic apparent resistivity imaging | |
| CN111058834B (en) | Anisotropic stratum dip angle determining method based on transient multicomponent induction logging | |
| Lin et al. | A discussion of 2D induced polarization effects in airborne electromagnetic and inversion with a robust 1D laterally constrained inversion scheme | |
| CN112698410B (en) | Induction-polarization symbiotic time domain electromagnetic detection method for electric source double-phase conductive medium | |
| Smith et al. | The moments of the impulse response: A new paradigm for the interpretation of transient electromagnetic data | |
| West et al. | The borehole transient electromagnetic response of a three-dimensional fracture zone in a conductive half-space | |
| CN113504571B (en) | Polarization equivalent ring device of multiphase conductive medium and design method | |
| Davis et al. | Measuring AEM waveforms with a ground loop | |
| Zhang et al. | Borehole electrical resistivity modeling using neural networks | |
| CN111188611A (en) | Cased well deconvolution resistivity processing method | |
| Kozhevnikov | Testing TEM systems using a large horizontal loop conductor | |
| CN105137495B (en) | A kind of method and system of oil and gas detection | |
| Malecki et al. | A new method for absolute underground positioning based on transient electromagnetics | |
| Lee et al. | Transient electromagnetic response of a halfspace with exponential conductivity profile and its applications to salinity mapping | |
| Ji et al. | Excitation process under the ramp-step waveform of inductive source-induced polarization method | |
| Persova et al. | Numerical scheme for modelling the electromagnetic field in airborne electromagnetic survey taking into account follow currents in transmitter loop | |
| Xiao et al. | Helicopter TEM parameters analysis and system optimization based on time constant | |
| US6449561B1 (en) | Induction logging | |
| Zhang et al. | Determining bed boundaries from inversion of EM logging data using general measures of model structure and data misfit | |
| Kozhevnikov et al. | Aftereffects in the transient electromagnetic method: inductively induced polarization |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |