【摘要】 检波器-大地耦合系统处于地震数据采集的最前端,是地震采集中的基本问题."耦合是指两个系统之间的相互作用.检波器和大地的耦合是影响能量转换的重要因素之一,取决于两者之间接触的牢固程度,以及检波器的重量和接触面积等;该耦合系统中存在着自然谐振并有滤波效应"(R.E.Sheriff).多年来,对耦合响应的研究主要集中在理论研究以及检波器耦合效果对比两个方面,并以感性描述、现象罗列居多.笔者在研究过程中设计了检波器-大地耦合响应的测定方法,并实际测量了检波器-大地耦合响应.结果表明,检波器-大地耦合响应可以用"单自由度有阻尼的自由振动系统"来描述,涉及到"固有频率"以及"阻尼比"两个参数,并可用参数扫描法对其振动模态进行参数识别.当检波器埋置效果差时,耦合响应使得地震子波相位增加,分辨率降低;高频成分增加,信噪比降低(主要在高频端).根据测得的耦合响应对检波器接收到的数据进行"耦合反褶积",将地震数据"还原为"地表下数十厘米处的介质振动,从而消除耦合响应,可以增强地震信号的"保真度",提高信噪比与分辨率.由于地表介质的多变性,每一个检波器对应的耦合响应均不同,同一检波器组合中多个检波器的耦合响应存在一定差异;其中只要有一个检波器埋置差,其整体的耦合效果就会显著变差;因为耦合响应对地震数据的影响非常深刻并难以忽略,所以合成地震记录时也应该考虑耦合响应的影响.更多还原

【Abstract】 The coupling between the ground and geophone is an important factor in seismic acquisition.In this paper,we conducted a test to determine the practical effect of the coupling,which show that geophone-ground coupling effect can be described as a single-degree-of-freedom damped free vibration system with two main parameters: equivalent frequency and equivalent damping.The parameters of vibration mode could be identified using a least squares method.When the coupling effect becomes worse,the seismic data may show more high-frequency components.In addition our results prove that the anti-coupling deconvolution can largely eliminate the coupling effect and enhance the fidelity of the seismic signal.The importance of the practical effects of coupling means that it should be taken into account when making a synthetic seismogram.更多还原