DAS directional sensitivity in surface seismic surveys using straight and helically wound cables

The application of distributed acoustic sensing (DAS) technology in China is currently focused on borehole seismic surveys, while its utilization in surface seismic exploration remains relatively limited. This study presents surface seismic acquisition experiments conducted using both straight fiber-optic cables and helically wound cables (HWCs). Through comparative analysis, the directional sensitivity issues of DAS in surface seismic exploration and their underlying causes are elucidated, and the effectiveness of HWC technology in mitigating these problems is validated. First, the basic method for DAS surface seismic acquisition is introduced, and a theoretical analysis of its directional sensitivity is performed. The basic principles by which HWC mitigates the directional sensitivity problem of DAS are also presented. Second, through comparative analysis of data acquired from straight-cable, HWC, and geophone surface seismic experiments, the capability of HWC to mitigate the directional sensitivity issue of DAS is verified, and the receiving characteristics of HWC under varying channel spacings are analyzed. Finally, drawing upon production experience, the critical issues for the widespread application of DAS technology in surface seismic exploration are discussed from the perspectives of coupling conditions and signal fidelity. The practice and analysis presented in this study demonstrate that HWC-DAS technology possesses broad application prospects and great potential in surface seismic exploration, and is an effective means to support efficient acquisition and high-precision seismic exploration.