CN113219542A - Frequency domain electromagnetic inversion method based on improved damped least square method - Google Patents

Frequency domain electromagnetic inversion method based on improved damped least square method Download PDF

Info

Publication number
CN113219542A
CN113219542A CN202110421513.XA CN202110421513A CN113219542A CN 113219542 A CN113219542 A CN 113219542A CN 202110421513 A CN202110421513 A CN 202110421513A CN 113219542 A CN113219542 A CN 113219542A
Authority
CN
China
Prior art keywords
parameter
magnitude
order
frequency domain
iteration
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
Application number
CN202110421513.XA
Other languages
Chinese (zh)
Other versions
CN113219542B (en
Inventor
卞雷祥
钟名尤
冷伟峰
李恒锐
高飞
崔陈丽
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nanjing University of Science and Technology
Original Assignee
Nanjing University of Science and Technology
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Nanjing University of Science and Technology filed Critical Nanjing University of Science and Technology
Priority to CN202110421513.XA priority Critical patent/CN113219542B/en
Publication of CN113219542A publication Critical patent/CN113219542A/en
Application granted granted Critical
Publication of CN113219542B publication Critical patent/CN113219542B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01VGEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V3/00Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
    • G01V3/38Processing data, e.g. for analysis, for interpretation, for correction

Abstract

The invention discloses a frequency domain electromagnetic inversion method based on an improved damping least square method, which is characterized in that the action of correction quantity on thickness parameters in each iteration is enhanced by adjusting the magnitude of each element of a Jacobian matrix in the iteration process, so that each parameter to be solved is converged near a preset model true value. The method improves the accuracy of the frequency domain electromagnetic inversion result.

Description

Frequency domain electromagnetic inversion method based on improved damped least square method
Technical Field
The invention belongs to a geophysical inversion technology, and particularly relates to a frequency domain electromagnetic inversion method based on an improved damped least square method.
Background
The frequency domain electromagnetic detection method is a mature geophysical exploration method, has the characteristics of non-plunging property, high resolution and the like, and is widely applied to the aspects of underground mineral deposit exploration, archaeological vestige excavation range defining, underground water exploration, urban underground supply and drainage pipeline detection, urban underground space exploration and the like. The problem of reconstructing the model from observed data by calculating the mathematical physical model parameters by a suitable method is the inverse problem, which is essentially an optimization problem. The frequency domain electromagnetic inversion problem is nonlinear, that is, there is no linear relation between the observation data and the model parameter to be solved, the nonlinear problem is generally approximately linearized, and the model parameter is solved by a linear inversion algorithm. The most common linear inversion algorithms such as conjugate gradient method and damped least square method have good effect in the field of frequency domain electromagnetic inversion.
The damped least squares algorithm was proposed by Marquardt in 1963, and is therefore also called a marquinter algorithm, mainly to solve the problem that the convergence of the traditional least squares algorithm is unstable. The method is effective in solving the frequency domain electromagnetic detection problem by applying the damped least square inversion algorithm, and the classical frequency domain electromagnetic detection instrument GEM-2 is integrated with the damped least square inversion algorithm for data processing and interpretation. In recent years, during inversion calculation and data interpretation, some improvements are made on a damped least square algorithm according to the characteristics of the algorithm and specific measurement area conditions, wherein transverse constraints and longitudinal constraints are most commonly added into an objective function, so that the transition of calculation results of adjacent measurement points is smoother and more practical. These methods blur the thickness information of subsurface anomalies in order to smooth the inversion results.
For underground space exploration, the purpose is to find out the depth information of an underground building body and the electromagnetic parameters of each medium layer, and the thickness of different medium layers is often the most important information. When the parameters to be solved simultaneously include the electromagnetic parameters and the thickness parameters of the underground medium layer, the correction quantity of the thickness parameters is very small in the iterative calculation process due to the fact that the electromagnetic parameters and the thickness parameters have large numerical difference, so that the thickness parameters cannot be accurately converged to the vicinity of the preset model true value, and accuracy of detection results is affected.
Disclosure of Invention
The invention aims to provide a frequency domain electromagnetic inversion method based on an improved damped least square method.
The technical scheme for realizing the purpose of the invention is as follows: a frequency domain electromagnetic inversion method based on an improved damping least square method comprises the following specific steps:
step 1: measuring a measured area by using a frequency domain electromagnetic detecting instrument, acquiring secondary field signals generated by an underground medium layer at different excitation frequencies as observation data, and determining an inversion target function according to the observation data;
step 2: setting an iteration initial value, a maximum allowable error, an initial damping factor and a maximum iteration number of inversion calculation, and calculating an initial Jacobian matrix according to the iteration initial value;
and 3, step 3: taking the numerical value of the 1 st row element in the initial Jacobian matrix as a reference, comparing the data of the rest rows with the numerical value of the 1 st row element to obtain the order of magnitude of each parameter to be solved,
and 4, step 4: adjusting the magnitude of each parameter in the iteration initial value according to the calculated magnitude of each parameter needing to be adjusted;
and 5, step 5: recalculating the Jacobian matrix;
and 6, step 6: solving an equation:
(Jk TJkkI)δk=-Jk T·gk
wherein JkIs the Jacobian matrix, λ, during the kth iterationkIs damping factor of kth, I is unit diagonal matrix, deltakCorrection amount of model parameter for k time, gkIs the k-th residual vector;
and 7, step 7: iteratively correcting the model parameters and simultaneously calculating the current nonlinear factor;
and 8, step 8: judging whether the iteration times reach the maximum iteration times or whether the current residual vector is smaller than the maximum allowable error, if so, performing the step 9, otherwise, adjusting a damping factor according to the value of the current nonlinear factor, and jumping to the step 5;
step 9: and taking the currently obtained model parameters as results, and restoring the order of magnitude of the results according to the calculated order of magnitude of adjustment required by each parameter.
Preferably, the inverted objective function is determined from the observation data
Figure BDA0003027998880000021
Comprises the following steps:
Figure BDA0003027998880000022
wherein M represents the number of observed data, fm(x) Is the forward response function at the mth frequency, dmFor electromagnetic observation data corresponding to the mth frequency point, F is a frequency domain electromagnetic method positive operator of the uniform layered medium, and x is a model parameter to be solved, called a parameter vector:
x=[x1,x2,x3,...,x3N-1]T
=[σ1,σ2,...σN,μ1,...,μN,h1,...hN-1]T
wherein sigmaiDenotes the conductivity, μ, of the i-th layer mediumiDenotes the permeability, h, of the i-th layer mediumiThe thickness of the ith layer of medium is shown, and N represents the number of layers of the underground medium layer.
Preferably, the initial Jacobian matrix is:
Figure BDA0003027998880000031
in the formula (f)mIs a forward response function at the mth frequency, wherein M is more than or equal to 1 and less than or equal to M, xjJ is more than or equal to 1 and less than or equal to 3N-1;
preferably, the order of magnitude that each parameter needs to be adjusted includes an order of magnitude that the conductivity parameter to be solved needs to be adjusted, an order of magnitude that the permeability parameter to be solved needs to be adjusted, and an order of magnitude that the thickness parameter to be solved needs to be adjusted.
Preferably, the order of magnitude of the adjustment required is:
nc=[nc1,...nci,...,ncN]
ns=[ns1,...nsi,...,nsN]
nh=[nh1,...nhi,...,nhN-1]
the subscript i represents the ith layer of medium, nc represents the order of magnitude that the conductivity parameter sigma to be solved needs to be adjusted, ns represents the order of magnitude that the permeability parameter mu to be solved needs to be adjusted, nh represents the order of magnitude that the thickness parameter h to be solved needs to be adjusted, wherein l is less than or equal to i and less than or equal to N;
the order of magnitude adjusting method comprises the following steps:
Figure BDA0003027998880000032
wherein j is more than 1 and is not more than N;
Figure BDA0003027998880000033
wherein j is more than N and less than or equal to 2N;
Figure BDA0003027998880000041
wherein J is more than 2N and less than or equal to 3N-1, J0(1) is the 1 st column element in the initial Jacobian matrix, J0And (j) is the j-th column element in the initial Jacobian matrix.
Preferably, according to the calculated order of magnitude that each parameter needs to be adjusted, a specific method for adjusting the order of magnitude of each parameter in the iteration initial value is as follows:
Figure BDA0003027998880000042
wherein sigmaiRepresenting electricity of the i-th layer mediumConductivity, μiDenotes the permeability, h, of the i-th layer mediumiRepresents the thickness of the ith layer of medium, and has 1-N, nciRepresenting the conductivity parameter σ to be solvediOrder of magnitude of adjustment, nsiRepresenting the permeability parameter mu to be solvediThe order of magnitude of the adjustment, nhiRepresenting the thickness parameter h to be solvediThe order of magnitude of the adjustment required;
preferably, the specific method for iteratively correcting the model parameters comprises the following steps:
x(k+1)=x(k)k
current non-linearity factor r(k)The method specifically comprises the following steps:
Figure BDA0003027998880000043
wherein
Figure BDA0003027998880000044
In the formula (I), the compound is shown in the specification,
Figure BDA0003027998880000045
is the value of the objective function for the kth iteration, JkIs the Jacobian matrix, λ, during the kth iterationkIs damping factor of kth, I is unit diagonal matrix, deltakCorrection amount of model parameter for k time, gkIs the k-th residual vector;
preferably, according to the current non-linearity factor r(k)Is used for adjusting the damping factor lambdakThe specific method comprises the following steps:
if r is(k)< 0.25, then λk+1=10λkIf 0.25 < r(k)< 0.75, then λk+1=λkIf 0.75 < r(k)Then λk+1=0.1λk
Compared with the prior art, the invention has the following remarkable advantages: by adjusting the magnitude of each element of the Jacobian matrix in the iterative process, the electromagnetic parameters and the thickness parameters with larger numerical value difference can be converged near the true value, and the accuracy of the inversion result is improved; the thickness is used as an important parameter for underground space detection, the accuracy of an inversion result of the parameter is improved, and the drawing imaging of an underground space structure is facilitated.
Drawings
FIG. 1 is a flow chart of a frequency domain electromagnetic inversion method based on an improved damped least squares method.
Fig. 2 is a result obtained by inversion calculation using a classical damped least squares algorithm, wherein the abscissa is the depth of the dielectric layer, and the ordinate is the conductivity of the dielectric at the corresponding depth.
Fig. 3 is a result obtained by inversion calculation using a classical damped least squares algorithm, where the abscissa is the depth of the dielectric layer and the ordinate is the magnetic permeability of the dielectric at the corresponding depth.
Fig. 4 is a result obtained by inversion calculation using an improved damped least squares algorithm, where the abscissa is the depth of the dielectric layer and the ordinate is the conductivity of the dielectric at the corresponding depth.
Fig. 5 is a result obtained by performing inversion calculation using an improved damped least squares algorithm, where the abscissa is the depth of the dielectric layer, and the ordinate is the magnetic permeability of the dielectric at the corresponding depth.
Detailed Description
As shown in fig. 1, a frequency domain electromagnetic inversion method based on an improved damped least square method enhances the effect of a correction amount on a thickness parameter during each iteration by adjusting the magnitude of each element of a jacobian matrix in the iteration process, so that each parameter to be solved converges to a vicinity of a preset model true value, thereby improving the accuracy of a frequency domain electromagnetic inversion result, and specifically comprises the following steps:
step 1: measuring the measured area by using a frequency domain electromagnetic detecting instrument, acquiring secondary field signals generated by the underground medium layer at different excitation frequencies, and taking the secondary field signals as observation data d obtained by an experimental instrumentobsBased on the observed data dobsDetermining an inverted objective function:
Figure BDA0003027998880000051
wherein M represents the number of observed data, fm(x) Is the forward response function at the mth frequency, dmFor electromagnetic observation data corresponding to the mth frequency point, F is a frequency domain electromagnetic method positive operator of the uniform layered medium, and x is a model parameter to be solved, called a parameter vector:
x=[x1,x2,x3,...,x3N-1]T
=[σ1,σ2,...σN,μ1,...,μN,h1,...hN-1]T
wherein sigmaiDenotes the conductivity, μ, of the i-th layer mediumiDenotes the permeability, h, of the i-th layer mediumiThe thickness of the ith layer of medium is shown, N is the number of layers of the underground medium layer, and the total number of the parameters is 3N-1 by considering the parameters of the conductivity, the permeability and the thickness of the underground medium layer.
Step 2: setting an initial iteration value x of inversion calculation(0)I.e. the parameter vector of the model, where the superscript (0) represents the initial iteration calculation, the maximum allowable error epsilon, the initial damping factor lambda are set0And a maximum number of iterations n;
according to the initial value x of the iteration(0)Computing an initial Jacobian matrix J0
Figure BDA0003027998880000061
And 3, step 3: with an initial Jacobian matrix J0The numerical value of the 1 st row element is taken as a reference, and the data of the rest rows and J0Comparing 1 to obtain the order of magnitude that each parameter to be solved needs to be adjusted, representing the order of magnitude that the conductivity parameter sigma to be solved needs to be adjusted by nc, representing the order of magnitude that the permeability parameter mu to be solved needs to be adjusted, and representing the order of magnitude that the thickness parameter h to be solved needs to be adjusted by nh;
because the convergence conditions of the parameters in the iterative process are different, the electromagnetic parameters and the thickness parameters of different dielectric layers need to be adjusted in different orders of magnitude, namely
nc=[nc1,...nci,...,ncN]
ns=[ns1,...nsi,...,nsN]
nh=[nh1,...nhi,...,nhN-1]
Wherein subscript i represents the ith layer of media;
the order of magnitude adjusting method comprises the following steps:
Figure BDA0003027998880000062
wherein j is more than 1 and is not more than N;
Figure BDA0003027998880000063
wherein j is more than N and less than or equal to 2N;
Figure BDA0003027998880000064
wherein j is more than 2N and less than or equal to 3N-1.
Storing the obtained nc, ns and nh as fixed values in an inversion calculation program;
and 4, step 4: according to the calculated nc, ns and nh, adjusting the magnitude of each parameter in the iteration initial value, namely adjusting the magnitude of each parameter in the iteration initial value
Figure BDA0003027998880000071
Simultaneously adjusting the magnitude of each parameter in the forward calculation function, namely, in the process of calculating the forward calculation function F, adjusting the conductivity parameter sigma of the ith layer of mediumiMultiplication by
Figure BDA0003027998880000072
Power of the magnetic permeability muiMultiplication by
Figure BDA0003027998880000073
Power, thickness parameter h for i-th layer mediumiMultiplication by
Figure BDA0003027998880000074
The power;
and 5, step 5: recalculating Jacobian matrix Jk
Figure BDA0003027998880000075
Computing residual vector gk
gk=dobs-F(x(k))
The subscript k represents the kth calculation, and the superscript k represents the parameter vector obtained by the kth updating;
and 6, step 6: solving equations
(Jk TJkkI)δk=-Jk T·gk
And 7, step 7: model parameter correction by iteration
x(k+1)=x(k)k
Simultaneously calculating the current non-linear factor r(k)
Figure BDA0003027998880000076
Wherein
Figure BDA0003027998880000077
And 8, step 8: judging whether the iteration number k reaches the maximum iteration number n or not, or judging whether the current residual vector g reaches the maximum iteration number n or notkWhether or not it is less than the maximum allowable errorThe difference epsilon, if yes, step 9 is carried out, otherwise, the current nonlinear factor r is used as the basis(k)Is used for adjusting the damping factor lambdakIf r is(k)< 0.25, then λk+1=10λkIf 0.25 < r(k)< 0.75, then λk+1=λkIf 0.75 < r(k)Then λk+1=0.1λkAnd jumping to the step 5;
step 9: with x(k+1)As a result of the iteration, x is recovered according to the calculated nc, ns and nh(k+1)Of order of magnitude, i.e.
x(k+1)=[σ1·nc1,...,σN·ncN,μ1·ns1,...,μN·nsN,h1·nh1,...,hN-1·nhN-1]
Outputting final model parameters in an inversion procedure
Figure BDA00030279988800000810
Figure BDA00030279988800000811
After k times of iterative computation, the conductivity, permeability and thickness parameters of the underground medium layer to be solved are corrected, and the actual conditions of the measuring area are better met.
The invention adopts an improved damping least square inversion algorithm to adjust the magnitude of each element in the Jacobian matrix so as to enhance the correction quantity delta in each iteration processkFor thickness parameter hiThe specific improvement method comprises the following steps:
will iterate the initial value x(0)Conductivity parameter σ of the intermediate layeriMultiplication by
Figure BDA00030279988800000812
Power, permeability parameter μiMultiplication by
Figure BDA0003027998880000081
Thickness parameter hiMultiplication by
Figure BDA0003027998880000082
Wherein nci、nsi、nhiEach integer is greater than 0, and i is 1, 2,. N;
in order to balance the results of the frequency domain response, correspondingly, in the calculation of the forward function F, the conductivity parameter σ for the i-th layer mediumiMultiplication by
Figure BDA0003027998880000083
Power of the magnetic permeability muiMultiplication by
Figure BDA0003027998880000084
Power, thickness parameter h for i-th layer mediumiMultiplication by
Figure BDA0003027998880000085
The power;
the adjusted iteration initial value x(0)Substituting into a classical damped least square algorithm for calculation to obtain an inversion result x;
conducting inversion calculation to obtain conductivity parameter sigma of each layer in parameter vector xiMultiplication by
Figure BDA0003027998880000086
Permeability parameter muiMultiplication by
Figure BDA0003027998880000087
Thickness parameter hiRiding device
Figure BDA0003027998880000088
And output as a final result.
The idea of adjusting the magnitude of each element in the Jacobian matrix is to perform the electromagnetic inversion process in the whole frequency domain only once initially, and the adjusted magnitude cannot change along with the change of the iteration times in the continuous iteration process.
Examples
Taking a single-point model of three layers of media as an example, the accuracy of the improved inversion algorithm is verified through simulation calculation, wherein table 1 shows the electromagnetic parameters and the thickness parameters of the preset single-point model. The parameters in table 1 are used as the true values of the model, and the error of the inversion results before and after the improvement of the algorithm is compared.
TABLE 1 Preset electromagnetic and thickness parameters of Single Point model
Figure BDA0003027998880000089
Fig. 2 and 3 are inversion results obtained using a classical damped least squares algorithm. From the results shown in the figure, the calculated conductivity, permeability and thickness of the dielectric layer have larger deviation from the true value of the preset model. The relative error between the conductivity of the second layer medium and the true value reaches 44%, and the magnetic conductivity inversion result of the second and third layers media deviates from the preset true value of the model seriously; in addition, the thickness inversion result of the second layer is 4.99m, which is 2.5 times of the true value, and the inversion result is basically the same as the set initial iteration value, which indicates that the thickness inversion result stays near the initial iteration value without accurate convergence. From the overall result, the classical damped least square algorithm has the problems that the correction quantity of the thickness result is too small to be converged near the true value of the preset model in the frequency domain electromagnetic inversion calculation, and the deviation of the electromagnetic parameter inversion result of a part of the dielectric layer is large.
Fig. 4 and 5 are inversion results obtained by using the modified damped least squares algorithm. As can be seen from the results shown in the figure, the inversion result is basically consistent with the true value of the preset model, the maximum error is the conductivity result of the second layer of medium, the relative error is about 9.6%, the relative error of the permeability result of the second layer of medium is about 8.72%, and the relative error of the inversion result of the electromagnetic parameters is greatly reduced compared with the result obtained by adopting the classical damped least square algorithm; in addition, the thickness inversion result of each dielectric layer is basically consistent with the preset model parameters, the error is very small, and the inversion result can be obviously improved by adopting the improved damped least square algorithm.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and all equivalent modifications made within the spirit and principle of the present invention are included in the scope of the present invention.

Claims (8)

1. A frequency domain electromagnetic inversion method based on an improved damping least square method is characterized by comprising the following specific steps:
step 1: measuring a measured area by using a frequency domain electromagnetic detecting instrument, acquiring secondary field signals generated by an underground medium layer at different excitation frequencies as observation data, and determining an inversion target function according to the observation data;
step 2: setting an iteration initial value, a maximum allowable error, an initial damping factor and a maximum iteration number of inversion calculation, and calculating an initial Jacobian matrix according to the iteration initial value;
and 3, step 3: taking the numerical value of the 1 st row element in the initial Jacobian matrix as a reference, and comparing the data of the rest rows with the numerical value of the 1 st row element to obtain the order of magnitude of each parameter to be solved, which needs to be adjusted;
and 4, step 4: adjusting the magnitude of each parameter in the iteration initial value according to the calculated magnitude of each parameter needing to be adjusted;
and 5, step 5: recalculating the Jacobian matrix;
and 6, step 6: solving an equation:
(Jk TJkkI)δk=-Jk T·gk
wherein JkIs the Jacobian matrix, λ, during the kth iterationkIs damping factor of kth, I is unit diagonal matrix, deltakCorrection amount of model parameter for k time, gkIs the k-th residual vector;
and 7, step 7: iteratively correcting the model parameters and simultaneously calculating the current nonlinear factor;
and 8, step 8: judging whether the iteration times reach the maximum iteration times or whether the current residual vector is smaller than the maximum allowable error, if so, performing the step 9, otherwise, adjusting a damping factor according to the value of the current nonlinear factor, and jumping to the step 5;
step 9: and taking the currently obtained model parameters as results, and restoring the order of magnitude of the results according to the calculated order of magnitude of adjustment required by each parameter.
2. The method of claim 1, wherein the inverted objective function is determined from observation data
Figure FDA0003027998870000011
Comprises the following steps:
Figure FDA0003027998870000012
wherein M represents the number of observed data, fm(x) Is the forward response function at the mth frequency, dmFor electromagnetic observation data corresponding to the mth frequency point, F is a frequency domain electromagnetic method positive operator of the uniform layered medium, and x is a model parameter to be solved, called a parameter vector:
x=[x1,x2,x3,…,x3N-1]T
=[σ1,σ2,…σN,μ1,…,μN,h1,…hN-1]T
wherein sigmaiDenotes the conductivity, μ, of the i-th layer mediumiDenotes the permeability, h, of the i-th layer mediumiThe thickness of the ith layer of medium is shown, N represents the number of layers of the underground medium layer, and i is more than or equal to 1 and less than or equal to N.
3. The method of claim 1, wherein the initial Jacobian matrix J is used as a basis for frequency domain electromagnetic inversion based on the modified damped least squares method0Comprises the following steps:
Figure FDA0003027998870000021
in the formula (f)mIs a forward response function at the mth frequency, wherein M is more than or equal to 1 and less than or equal to M, xjJ is more than or equal to 1 and less than or equal to 3N-1.
4. The method for frequency domain electromagnetic inversion based on the improved damped least squares method as claimed in claim 1, wherein the order of magnitude that each parameter needs to be adjusted includes an order of magnitude that a conductivity parameter to be solved needs to be adjusted, an order of magnitude that a permeability parameter to be solved needs to be adjusted, and an order of magnitude that a thickness parameter to be solved needs to be adjusted.
5. The frequency domain electromagnetic inversion method based on the improved damped least squares method as claimed in claim 1, wherein the required adjustment orders of magnitude are respectively:
nc=[nc1,…nci,…,ncN]
ns=[ns1,…nsi,…,nsN]
nh=[nh1,…nhi,…,nhN-1]
the subscript i represents the ith layer of medium, nc represents the order of magnitude that the conductivity parameter sigma to be solved needs to be adjusted, ns represents the order of magnitude that the permeability parameter mu to be solved needs to be adjusted, and nh represents the order of magnitude that the thickness parameter h to be solved needs to be adjusted;
the order of magnitude adjusting method comprises the following steps:
Figure FDA0003027998870000022
wherein 1< j is not more than N;
Figure FDA0003027998870000031
wherein N < j is less than or equal to 2N;
Figure FDA0003027998870000032
wherein 2N is<j≤3N-1,J0(1) is the 1 st column element in the initial Jacobian matrix, J0And (j) is the j-th column element in the initial Jacobian matrix.
6. The frequency domain electromagnetic inversion method based on the improved damped least squares method as claimed in claim 1, wherein the specific method for adjusting the magnitude of each parameter in the initial iteration value according to the calculated magnitude of each parameter to be adjusted is as follows:
Figure FDA0003027998870000033
wherein sigmaiDenotes the conductivity, μ, of the i-th layer mediumiDenotes the permeability, h, of the i-th layer mediumiRepresents the thickness of the ith layer of medium, and has 1-N, nciRepresenting the conductivity parameter σ to be solvediOrder of magnitude of adjustment, nsiRepresenting the permeability parameter mu to be solvediThe order of magnitude of the adjustment, nhiRepresenting the thickness parameter h to be solvediThe order of magnitude of the adjustment is required.
7. The frequency domain electromagnetic inversion method based on the improved damped least squares method as claimed in claim 1, wherein the specific method for model parameter modification by iteration is:
x(k+1)=x(k)k
current non-linearity factor r(k)The method specifically comprises the following steps:
Figure FDA0003027998870000034
wherein
Figure FDA0003027998870000035
In the formula (I), the compound is shown in the specification,
Figure FDA0003027998870000036
is the value of the objective function for the kth iteration, JkIs the Jacobian matrix, λ, during the kth iterationkIs damping factor of kth, I is unit diagonal matrix, deltakCorrection amount of model parameter for k time, gkIs the k-th residual vector;
8. the method for frequency domain electromagnetic inversion based on the improved damped least squares method as claimed in claim 1, wherein the current non-linear factor r is determined according to(k)Is used for adjusting the damping factor lambdakThe specific method comprises the following steps:
if r is(k)<0.25, then lambdak+1=10λkIf 0.25<r(k)<0.75, then lambdak+1=λkIf 0.75<r(k)Then λk+1=0.1λk
CN202110421513.XA 2021-04-20 2021-04-20 Frequency domain electromagnetic inversion method based on improved damped least square method Active CN113219542B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110421513.XA CN113219542B (en) 2021-04-20 2021-04-20 Frequency domain electromagnetic inversion method based on improved damped least square method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110421513.XA CN113219542B (en) 2021-04-20 2021-04-20 Frequency domain electromagnetic inversion method based on improved damped least square method

Publications (2)

Publication Number Publication Date
CN113219542A true CN113219542A (en) 2021-08-06
CN113219542B CN113219542B (en) 2022-06-28

Family

ID=77087945

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110421513.XA Active CN113219542B (en) 2021-04-20 2021-04-20 Frequency domain electromagnetic inversion method based on improved damped least square method

Country Status (1)

Country Link
CN (1) CN113219542B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114089430A (en) * 2021-11-10 2022-02-25 南京理工大学 Underground target detection multi-source data joint inversion method

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140207379A1 (en) * 2013-01-17 2014-07-24 Pgs Geophysical As Uncertainty-based frequency-selected inversion of electromagnetic geophysical data
US20180364390A1 (en) * 2017-06-16 2018-12-20 Pgs Geophysical As Electromagnetic Data Inversion
CN109597136A (en) * 2018-11-27 2019-04-09 中煤科工集团西安研究院有限公司 A kind of mine total space transient electromagnetic data processing method
CN110618453A (en) * 2019-08-07 2019-12-27 成都理工大学 Wave impedance inversion method based on improved damping least square method
CN111103627A (en) * 2020-01-14 2020-05-05 桂林理工大学 Two-dimensional inversion method and device for electric field data by magnetotelluric (TM) polarization mode

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140207379A1 (en) * 2013-01-17 2014-07-24 Pgs Geophysical As Uncertainty-based frequency-selected inversion of electromagnetic geophysical data
US20180364390A1 (en) * 2017-06-16 2018-12-20 Pgs Geophysical As Electromagnetic Data Inversion
CN109597136A (en) * 2018-11-27 2019-04-09 中煤科工集团西安研究院有限公司 A kind of mine total space transient electromagnetic data processing method
CN110618453A (en) * 2019-08-07 2019-12-27 成都理工大学 Wave impedance inversion method based on improved damping least square method
CN111103627A (en) * 2020-01-14 2020-05-05 桂林理工大学 Two-dimensional inversion method and device for electric field data by magnetotelluric (TM) polarization mode

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114089430A (en) * 2021-11-10 2022-02-25 南京理工大学 Underground target detection multi-source data joint inversion method
CN114089430B (en) * 2021-11-10 2024-05-03 南京理工大学 Underground target detection multi-source data joint inversion method

Also Published As

Publication number Publication date
CN113219542B (en) 2022-06-28

Similar Documents

Publication Publication Date Title
CN111323830B (en) Joint inversion method based on magnetotelluric and direct-current resistivity data
CN110618453B (en) Wave impedance inversion method based on improved damping least square method
CN112733449B (en) CNN well-seismic joint inversion method, CNN well-seismic joint inversion system, CNN well-seismic joint inversion storage medium, CNN well-seismic joint inversion equipment and CNN well-seismic joint inversion application
CN108019206B (en) With boring electromagnetic wave resistivity instrument Range Extension method under a kind of high-k
CN106483559B (en) A kind of construction method of subsurface velocity model
CN113219542B (en) Frequency domain electromagnetic inversion method based on improved damped least square method
CN114381737B (en) Output debugging and optimizing method for multi-set constant potential impressed current cathodic protection system
CN113204054A (en) Self-adaptive wide-area electromagnetic method induced polarization information extraction method based on reinforcement learning
CN111045076A (en) Multi-mode Rayleigh wave frequency dispersion curve parallel joint inversion method
CN107256316B (en) Artificial intelligence electromagnetic logging inversion method based on high-speed forward result training
CN113486591B (en) Gravity multi-parameter data density weighted inversion method for convolutional neural network result
CN112882114B (en) Complex-geology-oriented transient electromagnetic self-adaptive transverse constraint inversion method
CN111965712B (en) Method for correcting static effect of controllable source audio magnetotelluric method
Dudzik et al. Analysis of the error generated by the voltage output accelerometer using the optimal structure of an artificial neural network
CN111025388B (en) Multi-wave combined prestack waveform inversion method
CN116992754A (en) Rapid inversion method for logging while drilling data based on transfer learning
CN111241460A (en) Complex compact reservoir porosity calculation method
CN110646707A (en) Grounding grid fault diagnosis method based on micro-processing method and particle swarm optimization
CN115128700A (en) Gravity-magnetic three-dimensional joint inversion method and system based on gramian constraint
CN111310251B (en) High-precision structure reliability analysis method based on three-weighted response surface
CN114675337A (en) Underground depth sounding method based on multi-turn coil and transient electromagnetic method
CN111428190A (en) Real-time hybrid simulation self-adaptive compensation method based on frequency domain evaluation index
CN114706127A (en) Rayleigh wave waveform inversion imaging method
SG182447A1 (en) Improved method for determining the magnetisation of the hull of a ship, and associated device
CN114329970A (en) Gradient correction method based on single-well dynamic sensitivity area

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
CB03 Change of inventor or designer information
CB03 Change of inventor or designer information

Inventor after: Bian Leixiang

Inventor after: Zhong Mingyou

Inventor after: Cui Chenli

Inventor before: Bian Leixiang

Inventor before: Zhong Mingyou

Inventor before: Leng Weifeng

Inventor before: Li Hengrui

Inventor before: Gao Fei

Inventor before: Cui Chenli

GR01 Patent grant
GR01 Patent grant