Научная статья на тему 'Algorithm for inversion of resistivity logging-while-drilling data in 2D pixel-based model'

Algorithm for inversion of resistivity logging-while-drilling data in 2D pixel-based model Текст научной статьи по специальности «Медицинские технологии»

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Текст научной работы на тему «Algorithm for inversion of resistivity logging-while-drilling data in 2D pixel-based model»

Section 6

INVERSE PROBLEMS

On the stability of determining the position and shape of local acoustic inhomogeneities when solving

an inverse problem using the BaL algorithm

A. B. Bakushinsky1,2, A. S. Leonov3

1Research Center Computer Science and Control of RAS, Institute for Systems Analysis

2Mari State University

3National Nuclear Research University 'MEPHI', Moscow

Email: asleonov@mephi.ru

DOI 10.24412/cl-35065-2021-1-01-87

In [1], the so-called BAL algorithm is proposed for stable solvng of the 3D scalar inverse problem of acous-

tic sounding of an inhomogeneous medium. The data for the solution is the complex amplitude of the wave

field measured in a layer outside the region of inhomogeneities. The inverse problem is reduced to solving 1D

Fredholm integral equations of the first kind, to the subsequent calculation of the complex amplitude in the

region of inhomogeneity, and then to finding the required sound velocity field in this region. The algorithm

allows solving the 3D inverse problem on a PC of average performance for sufficiently fine 3D grids in tens of

seconds. Now we present the numerical study of the stability of determining the position and shape of local

inhomogeneities using the BAL algorithm in the case of many such inclusions with different geometries.

This work was supported by the Russian Science Foundation (project 20-11-20085) (first author) and the Programm

of Competitiveness Increase of the National Research Nuclear University MEPhI (Moscow Engineering Physics Institute);

contract no. 02.a03.21.0005, 27.08.2013 (second author).

References

1. Bakushinskii, A.B., Leonov, A.S. Numerical solution of an inverse multifrequency problem in scalar acoustics.

Comput. Math. and Math. Phys. 2020. V.60. P. 987�999.

Algorithm for inversion of resistivity logging-while-drilling data in 2D pixel-based model

A. V. Bondarenko, D. Yu. Kushnir, N. N. Velker and G. V. Dyatlov

Baker Hughes

Email: alexey.bondarenko@bakerhughes.com

DOI 10.24412/cl-35065-2021-1-01-88

Multi-frequency and multi-component extra-deep azimuthal resistivity measurements with depth of in-

vestigation a few tens of meters provide advanced possibilities for mapping of complex reservoir structures.

Inversion of the induction measurements set becomes an important technical problem. We present a regular-

ized Levenberg � Marquardt algorithm for inversion of resistivity measurements in a 2D environment model

with pixel-based resistivity distribution. The cornerstone of the approach is an efficient parallel algorithm for

computation of resistivity tool signals and its derivatives with respect to the pixel conductivities using volume

integral equation method. Numerical tests of the suggested approach demonstrate its feasibility for near real

time inversion.

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