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Article information
2025 , Volume 30, ¹ 1, p.7-14
Domnikov P.A.
Approximation of a circular induction source by a polygonal frame in electromagnetic logging problems
When using induction logging in horizontal wells, the generator coil of the electromagnetic logging tool is located in a plane perpendicular to the direction of layers with different resistivity. The electromagnetic field excited by the generator coil is three-dimensional in this case. To reduce the computational costs, a method to approximate a loop coil with a vertical square frame was proposed earlier. In this approach, the calculation of a three-dimensional electromagnetic field is performed by solving several axisymmetric (two-dimensional) problems, which significantly reduces computational costs. However, such a replacement of the geometric configuration of the source certainly requires a verification. This article compares the field generated by sources of the regular polygons form containing 3 to 16 segments. To conduct computational experiments, a typical geoelectric model containing a layer of oil-saturated sandstone was used. We use three source current frequencies at 20, 100, and 250 kHz. For a square frame, the error value at a distance of 0.7 m from the center of the loop was less than 0.04 %. When changing the source current frequency and the resistivity of the medium, the error associated with replacing a circular loop with a square frame did not exceed the above values. The provided computational experiments have showed that the choice of a vertical square frame is sufficient in terms of the accuracy of the obtained magnetic field components in the receiver of a logging tool.
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Keywords: electromagnetic field, induction logging, vertical frame source
doi: 10.25743/ICT.2025.30.1.002
Author(s):
Domnikov Petr Alexandrovich
PhD.
Position: Senior Research Scientist
Office: Novosibirsk State Technical University
Address: 630073, Russia, Novosibirsk, 20, prospekt K. Marksa
E-mail: p_domnikov@mail.ru
SPIN-code: 1071-5165 References:
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Bibliography link:
Domnikov P.A. Approximation of a circular induction source by a polygonal frame in electromagnetic logging problems // Computational technologies. 2025. V. 30. ¹ 1. P. 7-14
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