灰岩裸露区地震激发机理研究

Study on shooting mechanism of seismic waves in limestone-exposed area

地震激发因素选择是影响地震资料品质的一个重要环节。地震激发机理研究表明,灰岩裸露区炸药激发的地震波能量很弱,已经成为制约灰岩地震勘探的瓶颈。为此,本文从研究灰岩区地震激发机理着手,分析了爆炸激发地震的主要因素,并相应地开展了数值模拟、现场试验及物理模拟,得出了一些结论:改善灰岩等坚硬地层的激发条件,应增加爆炸冲量及对灰岩的作用时间;选择合理的几何耦合系数,增加低爆速的药量,在炮孔中充填介质且保证在井孔封闭良好时进行激发。

The selection of seismic shooting factors is an important link affecting seismic data quality. The study of seismic shooting mechanism showed that the weak seismic energy by dynamite shooting in limestone-exposed area has become bottleneck restraining seismic exploration in that area. For that reason,starting from the studying seismic shooting mechanism in limestone area,the paper analyzed the main factors of seismic waves shot by explosion and developed numeric simulation,in-site experiment and physical simulation correspondingly,which gained following conclusions:it should increase explosion impulse and acting time on limestone to improve the shooting condition in rigid bed such as limestone; selecting reasonable geometric coupling coefficient,increasing charge size with low explosive speed,using filling medium in shot-well and ensuring good closed borehole to implement explosion.