海底电缆地震中二次定位法的探讨

Discussion on secondary positioning in OBC survey

长安大学应用地球物理研究所, 陕西西安 710054

Research Institute of Applied Geophysics, Changan University, Xi'an 710054, China

在海底电缆地震勘探时,拖放的电缆往往不能下沉在设计位置。随着海底地震勘探的应用与发展,对资料精度的要求有所提高,必须对检波器电缆进行准确的定位。为此,利用地震采集到的直达波初至信息进行事后二次定位的问题,从方法上做了一些探讨。分析了空间三线交汇法的适用性和准确性,提出了近正四面体的选择原则和评价标准。模型实验证明,此方法具有一定的可行性和可靠性。

The cable used in OBC survey is sometimes incapable of sinking to the design position. With increasingly wide application of seabed seismic exploration, accuracy requirements on data have increased which requires precisely positioning for cables of geophones. In this paper the author discussed issues of secondary positioning with first arrival of direct waves. Based on an analysis of the applicability and accuracy of space three-line inter-junction, the paper proposes some rules for selection and evaluation of near regular tetrahedrons. The feasibility and reliability of these rules was demonstrated with model experiments.