Rayleigh型槽波垂直分量探测的应用研究

Research and application of vertical component detection of Rayleigh wave

在目前的槽波地震勘探中,Love型槽波被广泛应用,从施工和数据处理等环节分析发现,Love型槽波在勘探过程中存在一定的局限性,而Rayleigh型槽波的垂直分量(即z分量)相对于Love型槽波具有一定优势,可以运用于槽波勘探。为了研究Rayleigh型槽波比Love型槽波在勘探中的优越性,利用广义Snell定律并经理论计算证明,Rayleigh型槽波在通常情况下是存在的,基阶Rayleigh型槽波z分量的能量在煤层中央位置最强,且不受接收角度的影响,再通过使用二维数值模拟分析,Rayleigh型槽波在煤层中的传播规律以及能量分布规律,发现基阶的Rayleigh型槽波发育良好,煤层中央位置能量最强,与之前理论分析吻合。最后进行了槽波透射勘探和反射勘探的应用试验,数据处理时运用Rayleigh型槽波的处理方法,取得了良好的探测效果。研究结果表明:Rayleigh型槽波通常都存在,因炸药震源激发的弹性波以P波为主,Rayleigh型槽波z分量能量较Love型槽波更强,所以Rayleigh型槽波更适合槽波勘探,具体表现在勘探施工时相对于Love型槽波具有施工效率高,设备轻便的优势,施工时间可以缩短至之前的1/3甚至1/6;在数据处理阶段免去两分量记录旋转操作,简化了流程提高了处理精度。

Love-type wave is widely used in current in-seam seimic(ISS).From the analysis of construction and data processing,the author finds that Love wave has some limitations in the exploration process,while vertical component(z component)of Rayleigh-type of ISS has certain advantages over Love-type and can be used in ISS.In order to study its feasibility,the generalized Snell’s law was analyzed and proved by theoretical calculation that Rayleigh wave existed under normal circumstances.The energy of z component of fundamental Rayleigh wave is strongest in the central position of coal seam and is not affected by receiving angle.Then,two-dimensional numerical simulation is used to analyze the propagation and energy distribution of Rayleigh wave in coal seam.It is found that the fundamental Rayleigh wave develops well,and the energy in the central position of coal seam is the strongest,which is consistent with the previous theoretical analysis.Finally,the application experiments of channel wave transmission exploration and reflection exploration are carried out.Rayleigh type wave processing method is used in data processing,and good detection results are obtained.The results show that Rayleigh wave usually exists,and because the elastic wave excited by explosive source is mainly P wave and the z component energy of Rayleigh wave is stronger than that of Love wave,Rayleigh wave is more suitable for ISS,which is manifested in the fact that compared with Love wave,Rayleigh wave has the advantages of high construction efficiency,portable equipment and construction time can be reduced to 1/3 or even1/6 of the previous time;In the data processing stage,the rotation operation of two-component records is avoided,which simplifies the process and improves the processing accuracy.