The cross-gradients joint inversion technique has been applied to multiple geophysical data with a significant improvement on compatibility, but its numerical implementation for practical use is rarely discussed in th...The cross-gradients joint inversion technique has been applied to multiple geophysical data with a significant improvement on compatibility, but its numerical implementation for practical use is rarely discussed in the literature. We present a MATLAB-based three-dimensional cross-gradients joint inversion program with application to gravity and magnetic data. The input and output information was examined with care to create a rational, independent design of a graphical user interface (GUI) and computing kernel. For 3D visualization and data file operations, UBC-GIF tools are invoked using a series of I/O functions. Some key issues regarding the iterative joint inversion algorithm are also discussed: for instance, the forward difference of cross gradients, and matrix pseudo inverse computation. A synthetic example is employed to illustrate the whole process. Joint and separate inversions can be performed flexibly by switching the inversion mode. The resulting density model and susceptibility model demonstrate the correctness of the proposed program.展开更多
In order to effectively solve the low precision problem of the single gravity density inversion and the magnetic susceptibility inversion,and the limitation of the gravity?magnetic joint inversion method based on the ...In order to effectively solve the low precision problem of the single gravity density inversion and the magnetic susceptibility inversion,and the limitation of the gravity?magnetic joint inversion method based on the petrophysical parameter constraint,this paper studies the three-dimensional gravity?magnetic cross-gradient joint inversion based on the structural coupling and the fast optimization algorithm.Based on the forward and inversion modeling of three-dimensional gravity density and three-dimensional magnetic susceptibility using the same underground grid,along with cross-gradient coupling as the structural cons train t,we propose a new gravit y?magnetic joint inversion objective function including the data fitting term,the total variation regularization constraint term and the crossgradient term induced by the structural coupling?The depth weighted constraint and the data weighting constraint are included into the objective function,which requires different physical property models to minimize their respective data residuals.At the same time,the cross-gradient term tends to zero,so that the structure of the gravity and magne ic models tends to be consistent.In realization,we address a fast and efficient gradient algorithm to iteratively solve the objective function.We apply this new joint inversion algorithm to the 3D gravity-magnetic model inversion test and compare it with the results of a single inversion algorithm.The experimental tests of synthetic data indicate that the gravity-magnetic cross-gradient joint inversion method can effectively improve the accuracy of the anomaly position and numerical accuracy of the inverted anomaly physical parameters compared with the single physical inversion method.展开更多
The gravity and magnetic data can be adopted to interpret the internal structure of the Earth.To improve the calculation efficiency during the inversion process and the accuracy and reliability of the reconstructed ph...The gravity and magnetic data can be adopted to interpret the internal structure of the Earth.To improve the calculation efficiency during the inversion process and the accuracy and reliability of the reconstructed physical property models,the triple strategy is adopted in this paper to develop a fast cross-gradient joint inversion for gravity and magnetic data.The cross-gradient constraint contains solving the gradients of the physical property models and performing the cross-product calculation of their gradients.The sparse matrices are first obtained by calculating the gradients of the physical property models derived from the first-order finite difference.Then,the triple method is applied to optimize the storages and the calculations related to the gradients of the physical property models.Therefore,the storage compression amount of the calculations related to the gradients of the physical property models and the cross-gradient constraint are reduced to one-fold of the number of grid cells at least,and the compression ratio increases with the increase of the number of grid cells.The test results from the synthetic data and field data prove that the structural coupling is achieved by using the fast cross-gradient joint inversion method to effectively reduce the multiplicity of solutions and improve the computing efficiency.展开更多
文摘The cross-gradients joint inversion technique has been applied to multiple geophysical data with a significant improvement on compatibility, but its numerical implementation for practical use is rarely discussed in the literature. We present a MATLAB-based three-dimensional cross-gradients joint inversion program with application to gravity and magnetic data. The input and output information was examined with care to create a rational, independent design of a graphical user interface (GUI) and computing kernel. For 3D visualization and data file operations, UBC-GIF tools are invoked using a series of I/O functions. Some key issues regarding the iterative joint inversion algorithm are also discussed: for instance, the forward difference of cross gradients, and matrix pseudo inverse computation. A synthetic example is employed to illustrate the whole process. Joint and separate inversions can be performed flexibly by switching the inversion mode. The resulting density model and susceptibility model demonstrate the correctness of the proposed program.
基金We would like to thank reviewers very much for their valuable comments and suggestions.The research is supported by National Key R&D Program of the Minis try of Science and Technology of China with the Project“Integration Platform Construction for Joint Inversion and Interpretation of Integrated Geophysics(Grant No.2018YFC0603500)”National Natural Science Foundation of China under grant number 91630202.
文摘In order to effectively solve the low precision problem of the single gravity density inversion and the magnetic susceptibility inversion,and the limitation of the gravity?magnetic joint inversion method based on the petrophysical parameter constraint,this paper studies the three-dimensional gravity?magnetic cross-gradient joint inversion based on the structural coupling and the fast optimization algorithm.Based on the forward and inversion modeling of three-dimensional gravity density and three-dimensional magnetic susceptibility using the same underground grid,along with cross-gradient coupling as the structural cons train t,we propose a new gravit y?magnetic joint inversion objective function including the data fitting term,the total variation regularization constraint term and the crossgradient term induced by the structural coupling?The depth weighted constraint and the data weighting constraint are included into the objective function,which requires different physical property models to minimize their respective data residuals.At the same time,the cross-gradient term tends to zero,so that the structure of the gravity and magne ic models tends to be consistent.In realization,we address a fast and efficient gradient algorithm to iteratively solve the objective function.We apply this new joint inversion algorithm to the 3D gravity-magnetic model inversion test and compare it with the results of a single inversion algorithm.The experimental tests of synthetic data indicate that the gravity-magnetic cross-gradient joint inversion method can effectively improve the accuracy of the anomaly position and numerical accuracy of the inverted anomaly physical parameters compared with the single physical inversion method.
基金supported by the National Key Research and Development Program(Grant No.2021YFA0716100)the National Key Research and Development Program of China Project(Grant No.2018YFC0603502)Henan Youth Science Fund Program(Grant No.212300410105).
文摘The gravity and magnetic data can be adopted to interpret the internal structure of the Earth.To improve the calculation efficiency during the inversion process and the accuracy and reliability of the reconstructed physical property models,the triple strategy is adopted in this paper to develop a fast cross-gradient joint inversion for gravity and magnetic data.The cross-gradient constraint contains solving the gradients of the physical property models and performing the cross-product calculation of their gradients.The sparse matrices are first obtained by calculating the gradients of the physical property models derived from the first-order finite difference.Then,the triple method is applied to optimize the storages and the calculations related to the gradients of the physical property models.Therefore,the storage compression amount of the calculations related to the gradients of the physical property models and the cross-gradient constraint are reduced to one-fold of the number of grid cells at least,and the compression ratio increases with the increase of the number of grid cells.The test results from the synthetic data and field data prove that the structural coupling is achieved by using the fast cross-gradient joint inversion method to effectively reduce the multiplicity of solutions and improve the computing efficiency.
