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Well logging technology is of great significance to oil production. A new lateral resistivity logging-while-drilling (LWD) method applied in oil-based drilling fluid condition is proposed in this paper by combining capacitive coupling with inductive coupling principle. By using a new logging model, the ineffectiveness of the conventional resistivity LWD methods in oil-based drilling fluid is overcome...
In tunnel advanced detection, it will use FEM and physical experiment to simulate the anomalous characteristics of the new DC resistivity method of focus-current. Firstly, the principle and electrode arrangement will be introduced in the paper. Secondly, it makes an analog calculation to several relatively typical geoelectric models which apply the finite element method with solving anomalous potential...
Electrical impedance tomography (EIT) is a technique for reconstructing conductivity of an inhomogeneous medium by injecting currents at the boundary of an object and measuring the resulting changes in voltage. The SNR of acquisitive data and the reconstructed image quality of EIT system are directly determined by current drive patterns. In this paper, eight current drive patterns with the same boundary...
A simple analog instrumentation for electrical impedance tomography is developed and calibrated using the practical phantoms. A constant current injector consisting of a modified Howland voltage controlled current source fed by a voltage controlled oscillator is developed to inject a constant current to the phantom boundary. An instrumentation amplifier, 50 Hz notch filter and a narrow band pass filter...
An electrical impedance tomography (EIT) method is considered in which 32 electrodes are placed around the thorax, currents are injected, and voltages are measured to reconstruct a cross-sectional image of resistivity. The authors solve the forward problem using the finite-element method (FEM). The number of elements determines the spatial resolution of the resistivity image. An adaptive current-injection...
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