4 results about "Magnetotellurics" patented technology

The invention belongs to the technical field of electromagnetic exploration and numerical simulation. According to the regional decomposition magnetotelluric three-dimensional forward modeling simulation method and system, overlapping DDM is introduced to decompose a large-scale MT problem into a plurality of small sub-domains, so that the calculation complexity is reduced; each small linear system in a sub-domain is solved by using a direct solver, so that the convergence problem of an iterative solver is avoided, an LU decomposition result is repeatedly utilized in a Schwarz iteration process, and the calculation speed is increased; a multi-grid scheme is integrated to accelerate convergence, and a good initial condition is provided through a coarse grid solution, so that the number of iterations is reduced, and the calculation efficiency is further improved; the adaptability of a complex geological structure is enhanced by using an unstructured grid technology, so that the simulation precision is improved; according to the method, the aviation magnetotelluric three-dimensional forward modeling technology which is high in calculation speed and low in memory requirement is developed, and a basis is provided for theoretical research and data three-dimensional inversion of aviation magnetotelluric.

This invention provides a numerical simulation method for magnetotellurics under the Lorentz specification. The Maxwell equations are transformed into a set of governing equations consisting only of vector potentials using the Lorentz specification. A two-dimensional Fourier transform is performed on the quadratic vector potential governing equations in the horizontal direction, converting the three-dimensional governing equations into one-dimensional governing equations, reducing computational load and storage requirements, and improving computational efficiency. The Fourier transform can employ the standard Fourier transform algorithm, the offset sampling Fourier transform algorithm, or the non-uniform sampling Fourier transform algorithm. Then, the one-dimensional equations are solved using the one-dimensional finite element method with quadratic interpolation shape functions, resulting in three pentagonal equation sets, which are then solved using the pursuit method. This invention offers fast computation speed and small memory footprint, providing a new method for efficient and high-precision numerical simulation of large-scale magnetotellurics.

The present invention patent discloses a method for high-order finite element forward modeling of magnetotellurics based on hybrid grids, which specifically relates to the field of geophysical electromagnetic three-dimensional forward modeling. The Delaunay triangulation algorithm is used to divide the earth's surface into triangular grids, and triangular grids are extended on the triangular grids to form triangular prism units; the areas adjacent to the triangular prism units are discretized into tetrahedral units, and the underground electrical model is discretized using the constructed hybrid grid. Finite element unit analysis is performed through high-order shape functions to discretize the magnetotelluric wave equations and form a magnetotelluric high-order finite element system; the hybrid grid finite element system is solved to obtain the magnetotelluric response signal. The technical solution of the present invention solves the problem of increased computational cost caused by the use of traditional unstructured networks in MT forward modeling under high-frequency conditions. The hybrid grid can adapt to complex geoelectric models with strong terrain fluctuations, which requires less computational cost than the use of traditional unstructured units.

The invention discloses a nested finite element magnetotelluric three-dimensional forward modeling method. The method comprises the following steps: constructing a coarse mesh and fine mesh unstructured tetrahedron three-dimensional model; carrying out attribute assignment on the grid material; performing forward modeling calculation on the global coarse mesh model; the coarse grids are de-mapped to the boundaries of the sub-regions; performing forward modeling calculation on the sub-region fine mesh model; and calculating the magnetotelluric response. According to the method, the magnetotelluric response is calculated in two steps through the global coarse mesh and the core region sub-model fine mesh, so that the calculation time and memory consumption are remarkably reduced. The method lays a foundation for improving the magnetotelluric three-dimensional forward and reverse calculation performance, so that the magnetotelluric method can be better applied to the fields of geoscience, mineral exploration and the like.