【摘要】 有效模拟层间多次波是压制层间多次波或分析层间多次波影响的基础.基于点震源的球面波理论,采用反射率法有效模拟了层间多次波.基于三层介质地质模型,利用本文方法模拟了考虑层间多次波条件下地震波传播特征,对多种层间多次波进行了有效识别,验证了方法的有效性.基于实际油田条件研究了煤层产生的多次波对下伏低速气层顶界面的一次波AVO(振幅随偏移距变化)的影响.模型模拟计算结果表明,利用本文研究反射率法可以得到地震波场的完全解,包括地震波在地层中传播时形成的一次波、多次波和转换波信息,层间多次波的存在可以改变目标层的反射波波形特征、地震资料的频谱特征,并影响目标层AVO变化规律,从而很大程度上降低油气藏识别精度,增加钻探风险.更多还原

【Abstract】 The effective simulation of interbed multiples is the base of suppressing or analyzing the impacts of interbed multiples. Based on spherical wave theory of point source, the interbed multiples have been effectively simulated by using the reflectivity method. Given a three-layered geologic model, the propagation characteristic of seismic wave has been simulated with interbed multiples impacts and the different interbed multiples have been identified, which support the validity of the method. For the actual oil field data,the impact of multiples generated by coal beds on the primary wave AVO of top interface of underlying low speed gas sand has been studied. The model simulation shows that the complete solution of the seismic wave field could be obtained by the reflectivity method which includes primary reflection, multiple and converted wave. The existence of interbed multiples can change wave characters of reflection and the frequency spectrum of seismic data, and influence the rule of AVO in target zones, which will reduce the accuracy of reservoir identification to a great extent and increase the risk of exploration drilling.更多还原