Large-scale 3D inversion of marine magnetotelluric data: Case study from the Gemini prospect, Gulf of Mexico

Geophysics ◽  
2011 ◽  
Vol 76 (1) ◽  
pp. F77-F87 ◽  
Author(s):  
Michael S. Zhdanov ◽  
Le Wan ◽  
Alexander Gribenko ◽  
Martin Čuma ◽  
Kerry Key ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Large Scale ◽  
Three Dimensional ◽  
Integral Equation Method ◽  
Computer Code ◽  
Hydrocarbon Exploration ◽  
Parallel Computer ◽  
3D Inversion ◽  
Magnetotelluric Data ◽  
Geoelectrical Structures

Three-dimensional magnetotelluric (MT) inversion is an emerging technique for offshore hydrocarbon exploration. We have developed a new approach to the 3D inversion of MT data, based on the integral equation method. The Tikhonov regularization and physical constraint have been used to obtain a stable and reasonable solution of the inverse problem. The method is implemented in a fully parallel computer code. We have applied the developed method and software for the inversion of marine MT data collected by the Scripps Institution of Oceanography (SIO) in the Gemini prospect, Gulf of Mexico. The inversion domain was discretized into 1.6 million cells. It took nine hours to complete 51 iterations on the 832-processor cluster with a final misfit between the observed and predicted data of 6.2%. The inversion results reveal a resistive salt structure, which is confirmed by a comparison with the seismic data. These inversion results demonstrate that resistive geoelectrical structures like salt domes can be mapped with reasonable accuracy using the 3D inversion of marine MT data.

Experience of using three-dimensional inversion for the large volume of magnetotelluric data

2019 ◽  
pp. 84-87
Author(s):  
S. V. Zaytsev
Keyword(s):  
Computer Technology ◽  
Large Volume ◽  
High Performance ◽  
Three Dimensional ◽  
Hydrocarbon Exploration ◽  
Huge Amount ◽  
3D Inversion ◽  
Magnetotelluric Data ◽  
Geophysical Field ◽  
Wide Range

When switching to 3D inversion of MT data, the requirement for computer technology is significantly increased. In this paper we will discuss a few examples of 3D inversion of electromagnetic geophysical field data with the usage of “Lomonosov” supercomputer and show its effectiveness on several geological objects. Each object is associated with a variety of problems: from search for shallow ore to regional hydrocarbon exploration. But all these objects contain a large volume of measurements obtaining qualitative results for which requires a huge amount of time. So that the use of 3D inversion with a high-performance computational complex makes it possible to obtain a qualitative result of solving a wide range of problems.

Three-dimensional large-eddy motions and fine-scale activity in a plane turbulent wake

1990 ◽  
Vol 210 ◽  
pp. 371-414 ◽  
Author(s):  
J. A. Ferré ◽  
J. C. Mumford ◽  
A. M. Savill ◽  
Francesc Giralt
Keyword(s):  
Large Scale ◽  
Statistical Tests ◽  
Three Dimensional ◽  
Computer Code ◽  
Horseshoe Vortex ◽  
Turbulence Energy ◽  
Similar Data ◽  
Fine Scale ◽  
Horseshoe Vortices ◽  
Far Wake

A pattern recognition technique has been applied to simultaneously sampled multipoint hot-wire anemometry data obtained in the far wake of a circular cylinder. Data from both the streamwise fluctuating velocity field and the temperature field have been analysed employing a computer code that uses a correlation approach to automatically detect and ensemble average flow patterns and patterns for mean-square fluctuations. Statistical tests then allow the significance and contribution to the turbulence intensity of the detected structures to be evaluated. This procedure has been used to infer the three-dimensional topology of the double-roller eddies previously identified in the far-wake region and to relate these to the motions responsible for entrainment. It appears that the two types of motion are not independent, but are linked together, forming parts of horseshoe vortex structures which account for at least 40% of the total turbulence energy. These structures originate near the centre of the flow, may extend across the centreline and typically occur in groups of about three. The resulting picture of the flow dynamics is related to the conclusions drawn from similar data by other workers and a possible regeneration mechanism is presented. The addition to the code of a fine-scale activity indicator, the choice of which is discussed in some detail, has allowed the relationship between these energetic large-scale motions and smaller eddies to be investigated. It seems that the most intense fine-scale activity is associated with the vortical cores of the double-roller eddies. It is shown that this observation is consistent with the concepts of ‘isotropy’ and ‘spotiness’ of the dissipative scales. It also suggests that the horseshoe vortices loose energy both to their own secondary instabilities and to smaller scales resulting from the breakup of other highly strained large eddies.

scholarly journals Electric Propulsion Plume Simulations Using Parallel Computer

2007 ◽  
Vol 15 (2) ◽  
pp. 83-94 ◽  
Author(s):  
Joseph Wang ◽  
Yong Cao ◽  
Raed Kafafy ◽  
Viktor Decyk
Keyword(s):  
Electric Propulsion ◽  
Large Scale ◽  
Three Dimensional ◽  
Particle Simulation ◽  
Parallel Computer ◽  
Solar Array ◽  
Electron Mass ◽  
Ion Thruster ◽  
Particle In Cell ◽  
Pic Code

A parallel, three-dimensional electrostatic PIC code is developed for large-scale electric propulsion simulations using parallel supercomputers. This code uses a newly developed immersed-finite-element particle-in-cell (IFE-PIC) algorithm designed to handle complex boundary conditions accurately while maintaining the computational speed of the standard PIC code. Domain decomposition is used in both field solve and particle push to divide the computation among processors. Two simulations studies are presented to demonstrate the capability of the code. The first is a full particle simulation of near-thruster plume using real ion to electron mass ratio. The second is a high-resolution simulation of multiple ion thruster plume interactions for a realistic spacecraft using a domain enclosing the entire solar array panel. Performance benchmarks show that the IFE-PIC achieves a high parallel efficiency of ≥ 90%

Parallel Algorithm for DC Resistivity Method Based on CUDA-Enabled GPU

2013 ◽  
Vol 765-767 ◽  
pp. 1752-1756 ◽  
Author(s):  
Tuo Wang ◽  
Rui Chen
Keyword(s):  
Computer Architecture ◽  
Large Scale ◽  
Graphic Processing Unit ◽  
Three Dimensional ◽  
Parallel Computer ◽  
Processing Unit ◽  
The Finite Element Method ◽  
Electrical Method ◽  
Resistivity Method ◽  
Electrical Prospecting

During the electrical prospecting, the three-dimensional forward problem has been the hot topic in the research of DC electrical method. When the forward computation results are solved through the finite element method and the finite difference method, a large-scale sparse linear equation set should be obtained, moreover the computation in the solution of large-scale linear algebraic equation sets are very heavy. If we adopt serial computation, the computing efficiency is very low, which greatly affects the application efficiency. With the increasing maturation of the parallel computer architecture, the Graphic Processing Unit (GPU) parallel computing modeling can apply in this field to enable the efficiency of the three-dimensional forward modeling to be significantly improved.

Integral Equation Method via Domain Decomposition and Collocation for Scattering Problems

1995 ◽  
Vol 62 (1) ◽  
pp. 186-192 ◽  
Author(s):  
Xiaogang Zeng ◽  
Fang Zhao
Keyword(s):  
Domain Decomposition ◽  
Large Scale ◽  
Three Dimensional ◽  
Integral Equation Method ◽  
Computational Effort ◽  
Boundary Integral ◽  
Infinite Domain ◽  
Scattering Problems ◽  
Exterior Region ◽  
Plane Incident Wave

In this paper an exterior domain decomposition (DD) method based on the boundary element (BE) formulation for the solutions of two or three-dimensional time-harmonic scattering problems in acoustic media is described. It is known that the requirement of large memory and intensive computation has been one of the major obstacles for solving large scale high-frequency acoustic systems using the traditional nonlocal BE formulations due to the fully populated resultant matrix generated from the BE discretization. The essence of this study is to decouple, through DD of the problem-defined exterior region, the original problem into arbitrary subproblems with data sharing only at the interfaces. By decomposing the exterior infinite domain into appropriate number of infinite subdomains, this method not only ensures the validity of the formulation for all frequencies but also leads to a diagonalized, blockwise-banded system of discretized equations, for which the solution requires only O(N) multiplications, where N is the number of unknowns on the scatterer surface. The size of an individual submatrix that is associated with a subdomain may be determined by the user, and may be selected such that the restriction due to the memory limitation of a given computer may be accommodated. In addition, the method may suit for parallel processing since the data associated with each subdomain (impedance matrices, load vectors, etc.) may be generated in parallel, and the communication needed will be only for the interface values. Most significantly, unlike the existing boundary integral-based formulations valid for all frequencies, our method avoids the use of both the hypersingular operators and the double integrals, therefore reducing the computational effort. Numerical experiments have been conducted for rigid cylindrical scatterers subjected to a plane incident wave. The results have demonstrated the accuracy of the method for wave numbers ranging from 0 to 30, both directly on the scatterer and in the far-field, and have confirmed that the procedure is valid for critical frequencies.

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