Forward modeling and data inversion for beam propagation in a stratified medium. I: Theory

1992 ◽  
Vol 91 (3) ◽  
pp. 1228-1238 ◽  
Author(s):  
I‐Tai Lu
Keyword(s):  
Beam Propagation ◽  
Forward Modeling ◽  
Stratified Medium ◽  
Data Inversion

Enabling isotropic reflectivity modeling and inversion in anisotropic media

2021 ◽  
Vol 40 (4) ◽  
pp. 267-276
Author(s):  
Peter Mesdag ◽  
Leonardo Quevedo ◽  
Cătălin Tănase
Keyword(s):  
Synthetic Data ◽  
Anisotropic Media ◽  
Forward Modeling ◽  
Seismic Inversion ◽  
Stratified Medium ◽  
Effective Parameters ◽  
Elastic Parameters ◽  
Pp Wave ◽  
Anisotropic Elastic ◽  
And Inversion

Exploration and development of unconventional reservoirs, where fractures and in-situ stresses play a key role, call for improved characterization workflows. Here, we expand on a previously proposed method that makes use of standard isotropic modeling and inversion techniques in anisotropic media. Based on approximations for PP-wave reflection coefficients in orthorhombic media, we build a set of transforms that map the isotropic elastic parameters used in prestack inversion into effective anisotropic elastic parameters. When used in isotropic forward modeling and inversion, these effective parameters accurately mimic the anisotropic reflectivity behavior of the seismic data, thus closing the loop between well-log data and seismic inversion results in the anisotropic case. We show that modeling and inversion of orthorhombic anisotropic media can be achieved by superimposing effective elastic parameters describing the behavior of a horizontally stratified medium and a set of parallel vertical fractures. The process of sequential forward modeling and postinversion analysis is exemplified using synthetic data.

scholarly journals THE ELECTROTOMOGRAPHY SURVEY IN DIFFICULT GEOTECHNOGENIC CONDITIONS AT THE PEACEFUL UNDERGROUND NUCLEAR EXPLOSION "CRYSTAL" SITE

2021 ◽  
Vol 2 (3) ◽  
pp. 61-68
Author(s):  
Alexandr N. Shein ◽  
Svetlana Yu. Artamonova ◽  
Vladimir V. Potapov ◽  
Nickolay O. Kozhevnikov ◽  
Vladislav E. Ushnitskii
Keyword(s):  
Electrical Resistivity ◽  
Carbonate Rocks ◽  
Nuclear Explosion ◽  
Forward Modeling ◽  
Measured Data ◽  
Underground Nuclear Explosion ◽  
Geological Environment ◽  
Two Dimensional ◽  
Data Inversion ◽  
Significant Interference

The paper presents the results of measurements in 2019 by electrotomography at the site of the emplacement hole of the peaceful underground nuclear explosion "Crystal", carried in 1974 at a depth of 98 m in permafrost Cambrian carbonate rocks, and the neighboring forest area. The fence made of metal poles and barbed wire around the site, and the buried fragments of the casing of the emplacement hole create significant interference of measurements. To avoid the electromagnetic noise, the measured data of the apparent electrical resistivity was cleaned manually. Data inversion was performed in the Res2Dinv program. Geoelectric models, namely two-dimensional sections of the upper part of the geological environment to a depth of up to 80 m, were obtained. To verify the models, forward modeling was performed using the ZondRes2D program.

scholarly journals Application of OpenMP to Wireline Triaxial Induction Logging in 1D Layered Anisotropic Medium

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Zhijuan Zhang ◽  
Ning Yuan ◽  
Richard Liu
Keyword(s):  
Real Time ◽  
High Performance ◽  
Data Interpretation ◽  
Forward Modeling ◽  
Computer Hardware ◽  
Time Inversion ◽  
Data Inversion ◽  
Induction Logging ◽  
Anisotropic Formation ◽  
Logging Tool

Efficient and accurate forward modeling of logging tool responses is essential for data inversion in the log data interpretation in both real time and postprocessing. With the aggressive advancement of various high-performance computing techniques and computer hardware technology, it is possible to significantly improve the efficiency of the forward modeling. In this paper, we apply OpenMP to parallelize the simulation of triaxial induction logging tools in 1D multilayered anisotropic formation. The parallel process is explained in detail and numerical examples are presented to demonstrate the effect of the parallel programming. Comparison of the original code and the parallel code shows that the latter is much faster without loss of accuracy, which is very promising for future real-time inversion.

scholarly journals 3D induced-polarization data inversion for complex resistivity

Geophysics ◽  
2011 ◽  
Vol 76 (3) ◽  
pp. F157-F171 ◽  
Author(s):  
Michael Commer ◽  
Gregory A. Newman ◽  
Kenneth H. Williams ◽  
Susan S. Hubbard
Keyword(s):  
Environmental Remediation ◽  
Large Scale ◽  
Forward Modeling ◽  
Induced Polarization ◽  
Inversion Method ◽  
Data Sets ◽  
Inversion Algorithm ◽  
Data Set ◽  
Complex Resistivity ◽  
Data Inversion

The conductive and capacitive material properties of the subsurface can be quantified through the frequency-dependent complex resistivity. However, the routine three-dimensional (3D) interpretation of voluminous induced polarization (IP) data sets still poses a challenge due to large computational demands and solution nonuniqueness. We have developed a flexible methodology for 3D (spectral) IP data inversion. Our inversion algorithm is adapted from a frequency-domain electromagnetic (EM) inversion method primarily developed for large-scale hydrocarbon and geothermal energy exploration purposes. The method has proven to be efficient by implementing the nonlinear conjugate gradient method with hierarchical parallelism and by using an optimal finite-difference forward modeling mesh design scheme. The method allows for a large range of survey scales, providing a tool for both exploration and environmental applications. We experimented with an image focusing technique to improve the poor depth resolution of surface data sets with small survey spreads. The algorithm’s underlying forward modeling operator properly accounts for EM coupling effects; thus, traditionally used EM coupling correction procedures are not needed. The methodology was applied to both synthetic and field data. We tested the benefit of directly inverting EM coupling contaminated data using a synthetic large-scale exploration data set. Afterward, we further tested the monitoring capability of our method by inverting time-lapse data from an environmental remediation experiment near Rifle, Colorado. Similar trends observed in both our solution and another 2D inversion were in accordance with previous findings about the IP effects due to subsurface microbial activity.

scholarly journals Creating realistic models based on combined forward modeling and tomographic inversion of seismic profiling data

Geophysics ◽  
2010 ◽  
Vol 75 (3) ◽  
pp. B115-B136 ◽  
Author(s):  
Ivan Koulakov ◽  
Tatiana Stupina ◽  
Heidrun Kopp
Keyword(s):  
A Priori ◽  
Forward Modeling ◽  
Tomographic Inversion ◽  
Tomographic Images ◽  
Synthetic Model ◽  
Data Inversion ◽  
The Earth ◽  
Velocity Changes ◽  
Priori Information ◽  
Synthetic Models

Amplitudes and shapes of seismic patterns derived from tomographic images often are strongly biased with respect to real structures in the earth. In particular, tomography usually provides continuous velocity distributions, whereas major velocity changes in the earth often occur on first-order interfaces. We propose an approach that constructs a realistic structure of the earth that combines forward modeling and tomographic inversion (FM&TI). Using available a priori information, we first construct a synthetic model with realistic patterns. Then we compute synthetic times and invert them using the same tomographic code and the same parameters as in the case of observed data processing. We compare the reconstruction result with the tomographicimage of observed data inversion. If a discrepancy is observed, we correct the synthetic model and repeat the FM&TI process. After several trials, we obtain similar results of synthetic and observed data inversion. In this case, the derived synthetic model adequately represents the real structure of the earth. In a working scheme of this approach, we three authors used two different synthetic models with a realistic setup. One of us created models, but the other two performed the reconstruction with no knowledge of the models. We discovered that the synthetic models derived by FM&TI were closer to the true model than the tomographic inversion result. Our reconstruction results from modeling marine data acquired in the Musicians Seamount Province in the Pacific Ocean indicate the capacity and limitations of FM&TI.

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