青海都兰盐沼区地震采集关键技术研究

A study of the key seismic acquisition technology in the salt marsh area of Dulan,Qinhai province

都兰盐沼区地表覆盖大量盐池、盐湖,近地表结晶互层多而厚,呈现速度反转现象,致使地震资料品质不高。笔者通过对都兰地区近地表介质地震响应特征的深入分析,重点对结晶互层和串珠孔穴进行模拟分析,应用实际地震资料验证了近地表结晶互层的吸收衰减规律。对该区近地表分层、井深设计以及观测系统变观优化技术进行了深入的探讨,取得了相应的采集技术系列,并在实际采集应用中取得了很好的效果,成功地解决了都兰盐沼区地震采集难题。

It is very difficult to conduct seismic acquisition in Dulan,because it has a lot of salt ponds and salt lakes on the surface and extensive thick crystalline interbeds in the near-surface area. In this paper, the authors analyzed in detail the seismic response charac-teristics of the near-surface media in Dulan, with the emphasis placed on the characteristics of crystalline interbedded strata and beaded cavities by means of a model. Through the application of the actual seismic data, it is confirmed that the near-surface absorption decay law of the crystalline interbedded strata is correct. Moreover, the authors investigated the optimization techniques for the acquisition technology series by analyzing the stratification near the surface, and also optimized the depth design and the variable concept of the ob-servation system. As a result, good results in the actual acquisition applications were acquired, and the problems concerning complex salt marsh area acquisition were successfully solved.