Perfectly matched layer method in the finite-difference time-domain and frequency-domain calculations

2007 ◽  
Vol 244 (10) ◽  
pp. 3506-3514 ◽  
Author(s):  
D. M. Shyroki ◽  
A. V. Lavrinenko
Keyword(s):  
Finite Difference ◽  
Frequency Domain ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Perfectly Matched Layer ◽  
Layer Method ◽  
Difference Time

scholarly journals 2D Multitransient Electromagnetic Response Modeling of South China Shale Gas Earth Model Using an Approximation of Finite Difference Time Domain with Uniaxial Perfectly Matched Layer

2016 ◽  
Vol 2016 ◽  
pp. 1-20 ◽  
Author(s):  
Olalekan Fayemi ◽  
Qingyun Di
Keyword(s):  
Finite Difference ◽  
Impulse Response ◽  
South China ◽  
Shale Gas ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Perfectly Matched Layer ◽  
Electromagnetic Response ◽  
Earth Model ◽  
Difference Time

In this study, we introduced multitransient electromagnetic (MTEM) method as an effective tool for shale gas exploration. We combined the uniaxial perfectly matched layer (UPML) equation with the first derivative diffusion equation to solve for a finite difference time domain (FDTD) UPML equation, which was discretized to form an algorithm for 3D modeling of earth impulse response and used in modeling MTEM response over 2D South China shale gas model. We started with stepwise demonstration of the UPML and the FDTD algorithm as an effective tool. Subsequently, quantitative study on the convergence of MTEM earth impulse response was performed using different grid setup over a uniform earth material. This illustrates that accurate results can be obtained for specified range of offset. Furthermore, synthetic responses were generated for a set of geological scenarios. Lastly, the FDTD algorithm was used to model the MTEM response over a 2D shale gas earth model from South China using a PRBS source. The obtained apparent resistivity section from the MTEM response showed a similar geological setup with the modeled 2D South China shale gas section. This study confirmed the competence of MTEM method as an effective tool for unconventional shale gas prospecting and exploitation.

3D marine magnetotelluric modeling and inversion with the finite-difference time-domain method

Geophysics ◽  
2014 ◽  
Vol 79 (6) ◽  
pp. E269-E286 ◽  
Author(s):  
Sébastien de la Kethulle de Ryhove ◽  
Rune Mittet
Keyword(s):  
Finite Difference ◽  
Frequency Domain ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Linear Equations ◽  
Time Domain Method ◽  
Domain Method ◽  
Frequency Domain Methods ◽  
Starting Point ◽  
Difference Time

Frequency-domain methods, which are typically applied to 3D magnetotelluric (MT) modeling, require solving a system of linear equations for every frequency of interest. This is memory and computationally intensive. We developed a finite-difference time-domain algorithm to perform 3D MT modeling in a marine environment in which Maxwell’s equations are solved in a so-called fictitious-wave domain. Boundary conditions are efficiently treated via convolutional perfectly matched layers, for which we evaluated optimized parameter values obtained by testing over a large number of models. In comparison to the typically applied frequency-domain methods, two advantages of the finite-difference time-domain method are (1) that it is an explicit, low-memory method that entirely avoids the solution of systems of linear equations and (2) that it allows the computation of the electromagnetic field unknowns at all frequencies of interest in a single simulation. We derive a design criterion for vertical node spacing in a nonuniform grid using dispersion analysis as a starting point. Modeling results obtained using our finite-difference time-domain algorithm are compared with results obtained using an integral equation method. The agreement was found to be very good. We also discuss a real data inversion example in which MT modeling was done with our algorithm.

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