Papers by Author: Wu Dong

Abstract: In the time spectrum of impulse oxygen activation logging, there will be two peaks which are overlapping when the difference of velocity in oil tubing and casing are very small. Transit time, an important parameter to calculate the velocity of water flow, depends on the foot time of a full peak. So does the computing of velocity and flow volume. Therefore, the separation of the overlapping peak in the time spectrum of impulse oxygen activation logging is the key. A good separation method will increase the precision of flow volume obtained. In this paper, the separation problem of overlapping peak is studied, and an algorithm combining Gaussian function and gray system theory that is used to separate the overlapping peaks in the time spectrum of water flow of pulsed neutron oxygen activation logging is proposed. According to error analysis and rationality test of the case studied, the algorithm shows a high separation precision and its effectiveness in the determination of flow volume, which proves to be a practicable method to separate overlapping peaks in the time spectrum of water flow of oxygen activation logging.

Abstract: In the time spectrum of impulse oxygen activation logging, grave tailed peak occurs when the viscosity of polymer is high and the velocity of the flow is not even. The calculation of transit time, flow velocity as well as flow volume depends on the duration of the oxygen activation peak, so the disposal of the grave tailed peak in the time spectrum of impulse oxygen activation logging is critical. And an effective way to deal with tailed peak will improve the calculation accuracy of transit time and flow velocity. In this paper, the problem of tailed peak is studied, then an algorithm combining Logarithmic transformation and Gaussian function, which is used to deal with tailed peaks in the time spectrum of water flow of pulsed neutron oxygen activation logging, is proposed. Gaussian function is used to describe tailed peaks in the time spectrum of water flow of pulsed neutron oxygen activation logging in the logarithm space. Case analysis shows that the disposal effect of the algorithm is good, effectively eliminating the redundant data of the tailed peak in the flow time spectrum of pulsed neutron oxygen activation logging. The algorithm is a practicable method to deal with the tailed peak in the flow time spectrum of pulsed neutron oxygen activation logging.

Abstract: Many factors may affect array induction log, including skin effect. In this paper, according to relative formula deduced, a correction method of skin effect based on multi-frequency measurement signals is proposed using only the real component. This paper gives apparent conductivities that are from first order derivative correction and second order derivative correction by Chebyshev polynomial fitting method. Compared with measured data calculation, it showed that the correction results from the method above were in good agreement with the data from Express software.