Reduction of noise in electrical field measurements

An electromagnetic measurement, noise technology, applied in the field of noise influence, can solve the problem of response pollution and so on

Inactive Publication Date: 2009-08-12
MTEM LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Especially when measurements are performed near railways, elevated power lines, and electrical machinery, the measured response may be contaminated due to ground electrical noise
This can be a significant problem where very sensitive measurements are required

Method used

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  • Reduction of noise in electrical field measurements
  • Reduction of noise in electrical field measurements
  • Reduction of noise in electrical field measurements

Examples

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Embodiment Construction

[0021] figure 2 An MTEM system is shown with a grounded bipolar current source with electrodes A and B, a voltage receiver with grounded electrodes C and D, and calibration electrodes E and F. Ideally, current electrodes A and B and receiver electrodes C and D are placed along the same straight line, but in practice obstacles such as roads, buildings etc. often force deviations. Therefore, if figure 2 As shown, receiver electrodes C and D may be slightly offset from the axis of the source, and therefore cannot measure accurate in-line voltages. In practice, the effect of offset can be included in the processing of the data, but for clarity, in the illustrations below, the measured voltage vs I (t) considered to be on the same straight line.

[0022] The linear voltage signal measured between receiver electrodes C and D at time t vs I (t) by random noise na I (t) and regular noise np I (t) Contamination, where I represents on a straight line. The noise in the higher fr...

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PUM

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Abstract

A method for removing cultural noise from a measurement of the field generated by an electromagnetic source, such as a current bi-pole or a magnetic loop source, the method comprising: simultaneously measuring the electromagnetic signal at a field measurement position and a calibration position close to the field measurement position, but in a null field of the source; using the field measurement and the calibration measurement to compute a filter that estimates the component of the field measurement that is correlated with cultural noise; convolving the computed filter with the calibration measurement to yield the estimated cultural noise component, and subtracting that component from the field measurement.

Description

technical field [0001] The present invention relates to techniques for reducing noise in electromagnetic field measurements. In particular, the present invention relates to techniques for reducing the effects of noise in multi-channel transient electromagnetic (MTEM) measurements. Background of the invention [0002] Porous rocks are filled with fluid. These fluids may be water, gas or oil or a mixture of all three. Electricity in the Earth is determined by the electrical resistance of these rocks, which is affected by the fluids they fill. For example, a porous rock filled with brine has a much lower electrical resistance than the same rock filled with hydrocarbons. Hydrocarbons can be detected by measuring the electrical resistance of geological formations. Thus, electrical resistance measurements can be performed during the exploration phase to detect hydrocarbons prior to drilling. [0003] Various techniques are known for measuring the electrical resistance of geol...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01V3/12
CPCG01V3/02
Inventor A·齐奥尔科夫斯基R·卡森
Owner MTEM LTD
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