While-drilling azimuth electromagnetic wave resistivity imaging feature extraction method

Abstract

The invention discloses a while-drilling azimuth electromagnetic wave resistivity imaging feature extraction method, and the method comprises the following steps: selecting a proper dual-tree complexwavelet filter combination for the multi-scale decomposition of azimuth resistivity imaging; determining an optimal scale during the multi-scale decomposition, carrying out the analysis and comparisonof low-frequency band and high-frequency subbands at different scales after decomposition, and selecting the imaging at a scale with the optimal resolution for application; and carrying out the reconstruction of azimuth resistivity imaging. The method makes the most of the approximate translation invariance and direction selectivity of dual-tree complex wavelet transform, and achieves the dual-tree complex wavelet transform of the while-drilling azimuth electromagnetic wave resistivity imaging. The method reduces or eliminates the impact on the imaging from the interference noise. The methodcan achieve the enhancement of the texture or edge of imaging in some directions, and the detailed feature information of imaging is obtained. The method highlights the stratum boundary or crack edgeinformation reflected by imaging. The method keeps the general picture information and vibration information of imaging. The method is higher in adaptability, and needs less manual intervention.

Description

technical field [0001] The invention belongs to the fields of drilling, logging and directional well engineering, and in particular relates to a feature extraction method of azimuth electromagnetic wave resistivity imaging while drilling. Background technique [0002] Nowadays, horizontal wells and extended-reach well development technologies are commonly used in oilfields to increase production capacity. During the construction of extended-reach wells and horizontal wells, azimuth electromagnetic resistivity logging tools are needed for steering drilling, and azimuth electromagnetic resistivity logging while drilling is used The instrument can reduce production risk and cost, detect undrilled formation boundaries and increase the rate of reservoir drilling. During the rotation measurement process, the azimuth electromagnetic wave resistivity logging tool while drilling can measure and image the resistivity distribution of surrounding rock in multiple sectors around the well...

AI Technical Summary

Problems solved by technology

However, the resistivity imaging around the borehole mainly depends on the attenuation signals of electromagnetic waves in different directions measured by the receiving antenna. Due to the imperfection of the antenna system, the interference of the transmission channel and the limitation of the size of the instrument, the useful electromagnetic wave signal is collected, transmitted, and processed. There will be noise interference in every link

Especially when the interference noise of different frequencies is superimposed on the useful electromagnetic wave signal, it will not only destroy the correlation of the internal structure, texture, content, etc. It is more difficult to identify and analyze the reflected formation or fracture boundary

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