A Robust Mode-Matching Algorithm for the Analysis of Triaxial Well-Logging Tools in Anisotropic Geophysical Formations

Rosa, Guilherme S.; Bergmann, J.R.; Teixeira, Fernando L.

doi:10.1109/tgrs.2016.2646839

Cited by 27 publications

(35 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For sources with non-zero span along the axial direction (such as tilted-coil antennas that are described in Section 3.5.4), vertical mode expansion described in [6,8,27,46] (where both sources and radial discontinuities are matched over a constant radial plane) appears an appropriate way to model the problem. In [147][148][149] we demonstrate a way to compute the contribution of general and non-zero span sources using the axial mode-matching. To use this method; that is described in detail in Section 3.5.6; we need to consider the existence of general modal excitation coefficients, which may leads toĀ…”

Section: A Wave Equation In Cylindrical Coordinatesmentioning

confidence: 99%

Pseudo-Analytical Modeling for Electromagnetic Well-Logging Tools in Complex Geophysical Formations

Rosa¹

View full text Add to dashboard Cite

Section: A Wave Equation In Cylindrical Coordinatesmentioning

confidence: 99%

Pseudo-Analytical Modeling for Electromagnetic Well-Logging Tools in Complex Geophysical Formations

Rosa¹

View full text Add to dashboard Cite

“…A brief theoretical background of the formulation will be presented in this section. More mathematical details can be found in [16].…”

Section: Pseudo-analytical Formulationmentioning

confidence: 99%

“…The radially-dependent coefficients in (1) are given by a linear combination of first kind Hankel and Bessel function of integer order n , as given in [15], [16]. The transversal field components can be expressed as a combination of the axial ones using well-known relations for cylindrical coordinates [13].…”

Section: A Electromagnetic Fields Along Radial Stratificationsmentioning

confidence: 99%

“…where , We are able to obtain analytical results for the above coupling integral as in [16], [22], [26].…”

Section: B Electromagnetic Fields Along Axial Stratificationsmentioning

confidence: 99%

“…As a further simplification, we can show that our initial series solution in (17) and (18) reduces to a cosine series for positive integer n as shown in [16].…”

Section: Mode Excitation From a Tca Sourcementioning

confidence: 99%

See 2 more Smart Citations

Pseudo-Analytical Modeling of Tilted-Coil Antennas in Anisotropic Geophysical Formations

Rosa

Bergmann

Teixeira

2017

J. Microw. Optoelectron. Electromagn. Appl.

Self Cite

View full text Add to dashboard Cite

Abstract-In this paper we present an efficient mode-matching technique to analyze tilted-coil antennas in anisotropic geophysical formations. In this problem, a number of coil antennas with arbitrary relative tilt angle with respect to the symmetry axis are used to radiate electromagnetic fields in a cylindrically layered medium comprised of a metallic mandrel, a borehole, and a surrounding layered Earth formation. This configuration corresponds to that of directional well-logging tools used in oil and gas exploration. Our technique combines closed-form solutions for the Maxwell's Equations in uniaxially anisotropic and radiallystratified cylindrical coordinates with the generalized scattering matrix (GSM) at each axial discontinuity based on the modematching technique. The field from the transmitter tilted-coil source is represented by a set of modal coefficients which, after computation using GSM matrices, are used to compute the transimpedances. We present validation results which show that our technique can efficiently model directional well-logging tools used for oil and gas exploration.Index Terms-Anisotropic media, mode matching methods, stratified media, well logging tools. I. INTRODUCTIONLogging-while-drilling (LWD) and measurement-while-drilling (MWD) tools are frequently used to evaluate hydrocarbon reservoirs. The complex geophysical formations present in this type of problem can be successfully modeled using numerical techniques such as finite-differences (FD), finite elements (FE) and finite volumes (FV) [1]- [5]. However, these brute-force techniques suffer from relatively high cost in terms of both computer memory and CPU time. Bearing in mind that oil exploration usually employs LWD tools comprised of coil antennas wrapped around a metallic mandrel inside a borehole, as illustrated in Fig. 1, a series of practical scenarios can be properly approximate as a radially-stratified medium [6]. In this case, efficient algorithms based on pseudoanalytical methods [6]-[10] are good alternatives to model these geometries and provide efficient inversion algorithms designed to estimate the Earth formation properties given the tool responses.More complicated geometries including inhomogeneities in the Earth formation along both radial and axial directions can be accounted by using the numerical mode-matching (NMM), which may be seen In this work, we employ an axial mode-matching combining attractive features of the early described pseudo-analytical techniques, to obtain a flexible technique for analyzing directional welllogging tools in anisotropic formations which can be easily extended to model wells with curvature. II. PSEUDO-ANALYTICAL FORMULATIONThe geometry shown in Fig. 1 Journal of Microwaves, Optoelectronics and Electromagnetic Applications, Vol. 16,No. 1, March A. Electromagnetic Fields Along Radial StratificationsThe forward propagating axial fields can be written in a compact fashion asThe modal propagation constant in the z direction is , .In order to simplify the notation, we will tempor...

show abstract

A mode-matching solution for the study of cylindrical waveguide bifurcation via closed-form coupling integrals

Lima

Rosa

Bergmann

2020

AEU - International Journal of Electronics and Communications

View full text Add to dashboard Cite

A Robust Mode-Matching Algorithm for the Analysis of Triaxial Well-Logging Tools in Anisotropic Geophysical Formations

Cited by 27 publications

References 34 publications

Pseudo-Analytical Modeling for Electromagnetic Well-Logging Tools in Complex Geophysical Formations

Pseudo-Analytical Modeling for Electromagnetic Well-Logging Tools in Complex Geophysical Formations

Pseudo-Analytical Modeling of Tilted-Coil Antennas in Anisotropic Geophysical Formations

A mode-matching solution for the study of cylindrical waveguide bifurcation via closed-form coupling integrals

Contact Info

Product

Resources

About