Optimization for Emission Frequency of Oceanic Impulse Sound Source Logging

Abstract

Gao, X.; Zhu, J.; Fu, H., and Hao, X., 2020. Optimization for emission frequency of oceanic impulse sound source logging. In: Liu, X. and Zhao, L. (eds.), Today's Modern Coastal Society: Technical and Sociological Aspects of Coastal Research. Journal of Coastal Research, Special Issue No. 111, pp. 124–129. Coconut Creek (Florida), ISSN 0749-0208.In the exploration and development of offshore oilfields, the requirements for the detection distance and accuracy of underground geological structures are increasing day by day. When the traditional acoustic logging technology is used in oceanic logging, the formation structure is complex, and the reflected signal is very weak, which makes it difficult to extract the reflected signal and accurately identify the reflector orientation. The plasma impulse sound source is used as the emission source of the technology of ocean exploration while drilling, which has the characteristics of high power, wide frequency band, energy accumulation, and controllable and repeatable excitation, which can not only enhance the detection distance of traditional acoustic logging, but also detect the geological structure, fracture types, and strike around the well. In this article, sound depth detection technology is applied to study the selection of the dominant emission frequency band of the stimulated sound source based on the establishment of the geological interface depth detection model with different borehole diameter parameters. The results show that: when the well diameter is 0.1524, 0.2159, 0.2445, and 0.3112 m, 5, 3.8–4.2, 3.5–4, and 3 kHz are selected as the dominant excitation frequency bands, and the detection distance can reach tens of meters or even hundreds of meters. This research provides a reference for the subsequent application of impulse source in offshore logging.