祁连山山地地震勘探激发方法

针对祁连山山地地形起伏剧烈,地下岩性变化快,各种原生和次生噪声十分发育,原始资料信噪比较低等特点,通过理论研究和实际资料分析,本文提出以下提高激发效果的适用措施:①横向上选点激发,如在岩性相同区选择低缓平坦处激发、老地层出露区避开地面断层区段、在岩性接触面附近尽量不设激发点、避开巨厚第四系砾石及干燥冲沟分布区等;②纵向上选择在强波阻抗界面下激发,可有效地降低干扰、增强有效波能量;③采用相对较小的激发药量,降低源致线性噪声和次生噪声强度。将这些措施应用于实际复杂山地地震数据采集,明显地改善了地震资料的品质。

Seismic source optimization in Qilian Mountain area

The surface as well as the near surface lithology in Qilian Mountainous area varies roughly.Seismic source in this kind of area often generates low signal to noise ratio data due to strong primary and secondary noises during seismic data acquisition.According to theoretical study and practical analysis,we propose the following applicable measures to improve seismic source: ① optimizing shot location in the horizontal direction such as putting shot points in low lying and flat site in the same lithology area,avoiding shot points on ground fault zone in the strata exposed area,laying shot points away from old fault area and thick gravel and dry gullies of the Quaternary,etc.;② Shooting under the strong wave impedance interface,which can effectively reduce interference and enhance the effective energy;③ Small charges can reduce linear noise and secondary noise.Our field practices show that these measures applied in complex Qilian mountainous area improve greatly the seismic data quality.