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1

An improved local phase variation attribute and its application in channels detection

Shi Lei, Liu Junzhou, Liu Lanfeng, Wang Tieyi, Su Yuxin

Acta Geophysica

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2020

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Vol. 68, no. 2

357--364

EN

Instantaneous phase is a commonly used attribute for structural and stratigraphic feature characterization. The conventional calculation method is to construct the complex-valued seismic trace, then get the ratio of the imaginary part to the real part and fnally compute the antitangent of the ratio as the instantaneous phase attribute. In this way, the phase result at one time sample point is the total phase rotation from the beginning of the trace to this point, which means the traditional instantaneous phase is cumulative. Furthermore, the phase obtained by arctangent is usually entangled, which makes it more difcult to apply to seismic interpretation. To address the two issues above, we proposed a new way to calculate the improved local phase variation attributes. Firstly, we calculate traditional instantaneous phase and unwrap it. Then we set a time window on the unwrapped phase to compute the local phase variation by using some diference methods. Finally, we slide the time window on the whole trace to obtain the fnal phase variation attributes. This strategy turns the whole cumulative value into local variational value, which makes the obtained local phase variation nearly zero in the continuous region but changed greatly at the interface or the abnormal structure areas. Tested by the numerical model and the real data, the proposed attributes have a good application efect in channel detection, which provides a train of thought to seismic structure interpretation with phase attributes.

2

Multi sparsity based spectral attributes for discontinuity detection

Wang Tieyi, Yuan Sanyi, Yang Shan, Liu Bingyang, Wang Shangxu

Acta Geophysica

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2019

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Vol. 67, no. 4

1059--1069

EN

Structural and stratigraphic discontinuities, such as faults and channels, generally contribute to the construction of traps and reservoirs. Spectral decomposition can utilize the sensitivities of different frequency components to different geological conditions to identify these geological anomalies. The sparse inverse spectral decomposition (SISD) involves a sparse constraint of time–frequency spectra, and one critical parameter is the sparsity which determines the time–frequency resolution. A small sparsity gives a low temporal resolution result that cannot be used for thin-bed detection. Conversely, a large sparsity provides a high-resolution result, but it may lose weak refection signals. The complex geological conditions in the subsurface will lead to some difficulties in detecting the discontinuities by using the SISD method with a fixed sparsity. To address this issue, we propose multi-sparsity-based spectral attributes by fusing the amplitude spectra results of three different sparsities to detect subsurface discontinuities. Compared with the fixed sparsity, the multi-sparsity-based spectral attributes can detect more geological details and highlight geological edges more clearly. The application on a 3D real data with an area of 230 km2 from deep formation in Northwest China exhibits its effectiveness in discontinuity detection. The proposed method can detect the weak or small hidden geological details more and better than the fixed sparsity method, suggesting that it may serve as a future tool for detecting the distribution of geological abnormalities in subsurface.

3

The amplitude-frequency measurement in non-destructive testing using the eddy current method

Kondej A., Szczepański A.

Welding Technology Review

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2018

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R. 90, nr 11

12--15

EN

The paper describes a miniaturized device that records changes in voltage amplitude and signal frequency. After applying the measuring probe to the surface of the tested material, the voltage and frequency amplitude changes. In a place free from defects and nonconformities values of voltage amplitude and frequency are taken as reference values, with which the results obtained during further tests are compared. A clear change in the value of any of the parameters indicates a change in the condition of the tested material. Registration of two parameters with different sensitivity for selected factors allows for a more accurate analysis of the condition of the tested material. The miniaturized device can works in manual measurement mode or in automatic mode, it can be used in defectoscopy, structure and thickness measurements.

4

Automatyczne stanowisko do badań nieniszczących metodą prądów wirowych

Kondej A., Baranowski M., Niedźwiedzki K., Jończyk S., Szczepański A.

Inżynieria Powierzchni

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2014

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nr 1

57--62

PL

W Instytucie Mechaniki Precyzyjnej zostało opracowane i wykonane stacjonarne stanowisko automatyczne do badań nieniszczących metodą prądów wirowych – AutoWIR-S1. Stanowisko przeznaczone jest do prowadzenia badań ukierunkowanych na wykrywanie wad i nieciągłości materiału, wykrywanie zmian strukturalnych oraz pomiar grubości warstw i powłok. Ma ono charakter uniwersalny, dzięki czemu mogą być badane próbki o zróżnicowanym kształcie i wymiarach (koła zębate, płyty, pierścienie, tuleje itp.). W artykule omówiono podstawowe zagadnienia dotyczące metody prądów wirowych. Przedstawiono budowę i zasadę działania stanowiska automatycznego. Opisano możliwości jego zastosowania oraz podano przykłady wykonywanych badań nieniszczących.

EN

The automatic stationary stand for non-destructive eddy current testing – AutoWIR-S1 – was developed and manufactured in the Institute of Precision Mechanics. The stand is designed to conduct a measurements directed at detection of material defects and discontinuities, detection of structural changes, measuring the thickness of layers and coatings. Developed stand is universal, so that samples of different shapes and sizes (gears, sheets, rings, bushings, etc.) can be tested. This paper describes basic issues concerning the eddy current method. The design and the principle of operation of the automatic stand was presented. There has been described the applicability of the stand, and examples of non-destructive testing were shown.