CAJ | 학술논문

地震信号在传播过程中受到近地表和深地层吸收衰减的影响，能量变弱，高频成分衰减比低频成分更为严重，接收与识别反射系数较小或高频的弱反射信号是高密度地震勘探的瓶颈问题。笔者通过建立典型的粘弹性地质模型，分析了弱反射信号与近地表、震源主频、炮检距以及与深地层的关系，得出以下认识：在近地表吸收衰减严重的低噪比地区，由于截止频率的存在，高密度采集的宽频优势难以体现；良好的激发条件对提高弱反射信号能量、拓宽频带作用较大；中小炮检距是弱反射信号有效反射系数较好的区域，是提取弱反射信号的最佳区域。
지진신호재전파과정중수도근지표화심지층흡수쇠감적영향，능량변약，고빈성분쇠감비저빈성분경위엄중，접수여식별반사계수교소혹고빈적약반사신호시고밀도지진감탐적병경문제。필자통과건립전형적점탄성지질모형，분석료약반사신호여근지표、진원주빈、포검거이급여심지층적관계，득출이하인식：재근지표흡수쇠감엄중적저조비지구，유우절지빈솔적존재，고밀도채집적관빈우세난이체현；량호적격발조건대제고약반사신호능량、탁관빈대작용교대；중소포검거시약반사신호유효반사계수교호적구역，시제취약반사신호적최가구역。
The seismic signal received by sensors is very weak because the energy is absorbed and attenuated by subsurface and deep layer during signal propagating. The high frequency component was much more seriously absorbed and attenuated than low frequency component. The key issues for high density seismic acquisition are to receive and identify low reflection coefficient or high frequency weak signal. In this paper, the relationship of weak signal to subsurface, dominant frequency, offset and deep target layer was analyzed based on a typical elastic-viscoelastic earth model. The results show that it is very difficult to give expression to the advantages of broad band frequency in high density seismic acquisition in the area with strong subsurface attenuation and low S/N ratio due to the existence of the cut off frequency. Good condition excitation can improve weak signal energy and give more contribution to broaden frequency band. The effective reflection coefficient can be better presented in small and middle receiver-source offset and can be well extracted.