scholarly journals A Uniform Linear Multi-Coil Array-Based Borehole Transient Electromagnetic System for Non-Destructive Evaluations of Downhole Casings

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2707 ◽  
Author(s):  
Bo Dang ◽  
Ling Yang ◽  
Changzan Liu ◽  
Yahong Zheng ◽  
Hui Li ◽  
...  
Keyword(s):  
Eddy Current ◽  
Field Experiments ◽  
Signal To Noise Ratio ◽  
Minimum Variance ◽  
Observation Time ◽  
Oil Well ◽  
Electromagnetic System ◽  
Coil Array ◽  
Transient Electromagnetic ◽  
Nondestructive Evaluations

Borehole transient electromagnetic (TEM) techniques have been proven to be efficient for nondestructive evaluations (NDEs) of metal casings using eddy-current properties. However, physical limitations and bad borehole conditions restrict the use of eddy-current sensors, which makes downhole casing inspections very different from those of conventional NDE systems. In this paper, we present a uniform linear multi-coil array-based borehole TEM system for NDEs of downhole casings. On the basis of the borehole TEM signal model, a numerical multi-coil array approach using the Gauss–Legendre quadrature is derived. The TEM response can be divided into two independent parts related to the transmitting-receiving distance (TRD) and the observation time and casing thickness. Using this property, the signal received by the multi-coil array is weighted to cancel the influence of the TRDs of the different array elements to obtain the optimal response according to the linearly constrained minimum variance criterion, which can be shown to be identical to that of achieving the maximum signal-to-noise ratio. The effectiveness of the proposed method was verified by applying the uniform linear multi-coil array to a borehole TEM system for NDEs of oil-well casings. Field experiments were conducted, and the results demonstrate the effectiveness of the proposed method.

Weak Transient Electromagnetic Radiation Signal Detection Method Considering the New Watershed Image Segmentation Algorithm

2019 ◽  
Vol 34 (03) ◽  
pp. 2054009
Author(s):  
Wenjun Huo ◽  
Peng Chu ◽  
Kai Wang ◽  
Liangting Fu ◽  
Zhigang Niu ◽  
...  
Keyword(s):  
Electromagnetic Radiation ◽  
Cross Correlation ◽  
Detection Efficiency ◽  
Signal To Noise Ratio ◽  
Estimation Method ◽  
Detection Methods ◽  
Signal To Noise ◽  
Long Distance ◽  
Transient Electromagnetic ◽  
Noise Ratio

In order to study the detection methods of weak transient electromagnetic radiation signals, a detection algorithm integrating generalized cross-correlation and chaotic sequence prediction is proposed in this paper. Based on the dual-antenna test and cross-correlation information estimation method, the detection of aperiodic weak discharge signals under low signal-to-noise ratio is transformed into the estimation of periodic delay parameters, and the noise is reduced at the same time. The feasibility of this method is verified by simulation and experimental analysis. The results show that under the condition of low signal-to-noise ratio, the integrated method can effectively suppress the influence of 10 noise disturbances. It has a high detection probability for weak transient electromagnetic radiation signals, and needs fewer pulse accumulation times, which improves the detection efficiency and is more suitable for long-distance detection of weak electromagnetic radiation sources.

Influences of the Earth’s Magnetic Field on the Transient Electromagnetic Process in the Geoelectric Field: an Experimental Study

2021 ◽  
Vol 62 (12) ◽  
pp. 1430-1439
Author(s):  
V.S. Mogilatov ◽  
V.V. Potapov ◽  
A.N. Shein ◽  
V.A. Gur’ev
Keyword(s):  
Magnetic Field ◽  
Hall Effect ◽  
Field Experiments ◽  
Geoelectric Field ◽  
Earth’S Magnetic Field ◽  
Electromagnetic Process ◽  
Transient Electromagnetic ◽  
Schematic Layout ◽  
Earth's Magnetic Field ◽  
Tem Method

Abstract —A mathematical model of the influence of the Earth’s magnetic field (the Hall effect) on results of the controlled source transient electromagnetic (TEM) method has been elaborated. For identification of this effect, we propose a schematic layout of the experimental grounded system with a pulsed loop source and signals recording by radial receive lines equally spaced relative to the loop. The 2018–2019 special field experiments were conducted in the Tatar region of the West Siberian Lowland with an aim to estimate the Hall effect contributions to the TEM method. To detect the Hall effect, transient electromagnetic responses were measured mainly by four receive lines radiating from a 500×500 m square loop. Analysis of the TEM results processing aimed at improving the signal quality and reducing the interference revealed a great similarity in signals from the radial lines, which is theoretically possible only under the Hall effect. Comparison of the field signals with the theoretical ones enabled estimation of the components caused by the Hall effect, in particular, conductivity at ~0.002 S/m.

scholarly journals Detectability of Delamination in Concrete Structure Using Active Infrared Thermography in Terms of Signal-to-Noise Ratio

2018 ◽  
Vol 8 (10) ◽  
pp. 1986 ◽  
Author(s):  
Jungwon Huh ◽  
Van Mac ◽  
Quang Tran ◽  
Ki-Yeol Lee ◽  
Jong-In Lee ◽  
...  
Keyword(s):  
Concrete Structure ◽  
Signal To Noise Ratio ◽  
High Reliability ◽  
Heating Time ◽  
Observation Time ◽  
Percentage Error ◽  
Heating Regime ◽  
Signal To Noise ◽  
Noise Ratio ◽  
Whole Life Cycle

Detecting subsurface delamination is a difficult and vital task to maintain the durability and serviceability of concrete structure for its whole life cycle. The aim of this work was to obtain better knowledge of the effect of depth, heating time, and rebar on the detectability capacity of delamination. Experimental tests were carried out on a concrete specimen in the laboratory using Long Pulsed Thermography (LPT). Six halogen lamps and a long wavelength infrared camera with a focal plane array of 640 × 480 pixels were used as the heat source and infrared detector, respectively. The study focused on the embedded imitation delaminations with the size of 10 cm × 10 cm × 1 cm, located at depths varying from 1 to 8 cm. The signal-to-noise ratio (SNR) was applied as a criterion to assess the detectability of delamination. The results of this study indicate that as the provided heating time climbed, the SNR increased, and the defect could be identified more clearly. On the other hand, when using the same heating regime, a shallow delamination displayed a higher SNR than a deeper one. The moderate fall of the SNR in the case of imitating defect located below reinforced steel was also observed. The absolute contrast was monitored to determine the observation time, and the nondimensional prefactor k was empirically proposed to predict the depth of delamination. The mean absolute percentage error (MAPE) was used to quantitatively evaluate the difference between forecasted and real depth, which evaluation confirmed the high reliability of the estimated value of the prefactor k.

Rapid Mapping of Hydrological Systems in Tanzania Using a Towed Transient Electromagnetic System

Ground Water ◽  
2021 ◽  
Author(s):  
Denys Grombacher ◽  
Pradip Kumar Maurya ◽  
Johan Christensen Lind ◽  
John Lane ◽  
Esben Auken
Keyword(s):  
Electromagnetic System ◽  
Rapid Mapping ◽  
Transient Electromagnetic

Drone-borne transient electromagnetic system and its application in UXO detection

2018 ◽  
Author(s):  
Zhi-peng Qi ◽  
Xiu Li ◽  
He Li ◽  
Ying-ying Zhang ◽  
Jianmei Zhou
Keyword(s):  
Electromagnetic System ◽  
Transient Electromagnetic

Reducing Motion-Induced Noise With Mechanically Resonant Coil Sensor in a Rigid Helicopter Transient Electromagnetic System

2020 ◽  
Vol 67 (3) ◽  
pp. 2391-2401
Author(s):  
Fei Liu ◽  
Jun Lin ◽  
Yanzhang Wang ◽  
Shilong Wang ◽  
Quan Xu ◽  
...  
Keyword(s):  
Electromagnetic System ◽  
Transient Electromagnetic

Newmont Transient Electromagnetic System

1980 ◽  
Vol 11 (1-2) ◽  
pp. 47-51 ◽  
Author(s):  
G. O. Dickson ◽  
G. W. Boyd
Keyword(s):  
Electromagnetic System ◽  
Transient Electromagnetic

Remote Control Technology in Intelligent Oil-Well Based on Acoustic Wave

2013 ◽  
Vol 706-708 ◽  
pp. 912-915
Author(s):  
Yan Song Wang ◽  
Lei Chen ◽  
Shi Qiang Zu ◽  
Bao Hui Zhang ◽  
Gang Wu ◽  
...  
Keyword(s):  
Control System ◽  
Remote Control ◽  
Acoustic Wave ◽  
Field Experiments ◽  
Oil Well ◽  
Control Technology ◽  
Acoustic Source ◽  
Reliable Communication ◽  
Remote Control System ◽  
Underground Equipment

In this paper, we investigate an acoustic remote control technology through the annulus channel in an oil-well. To establish a reliable communication, we first evaluated the acoustic charateristic of the aunnulus channel through field experiments. Then, a remote control system was implemented with a ground equipment serving as an acoustic source, and an underground equipment used as a receiver. A demonstrative experiment, in which we succeded in remoting an intelligent valve over 1257 m, has been presented to verify the proposed technology.

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