高陡逆掩推覆构造地区地震观测系统研究

Study of seismic layout in areas with steep nappe structures

中国石油集团地球物理勘探局 河北涿州072751

Geophysical Exploration Bureau of CNPC, Zhuozhou 072751,China

复杂高陡逆掩构造地区由于地表及地下构造均复杂,若采用同一种观测系统施工,难以适应构造多变的情况,甚至不能获得目的层的反射资料。针对不同的地质情况和表层结构,应进行分段观测系统设计。对激发效果差的山地地段,则采用将炮点和检波点向相反方向移动、将山体区的炮点移动至平坦地段,保持地震反射资料CMP位置不变的观测方式。本方法在塔里木盆地秋里塔格地区应用,明显地提高了资料信噪比和生产效率,采集的地震资料可以较好地用于地质解释.

Owing to the surface and subsurface structures are complicated in areas of complex steep overthrust structures, acquisition with a common seismic layout is impracticable to the structural variations, and even cannot obtain desired data. To cope with different geological structures and surface conditions, a varied seismic layout is used. In mountanious regions, shots and receivers are moved in opposite direction with CMP position keeping unchanged, making the shot points move to flat zone possible. Application of this method in Queletage, Tarim Basin has yielded a great improvement in S/N ratio of seismic data and production efficiency. The resulted seismic data can readily be used in geological interpretation.