Abstract:Energy distribution of transmitted compression wave at seafloor has an influence upon exploration scheme design and data processing.As for this issue,this paper discusses variation characteristics of transmitted wave energy of 6 types of seafloor with different lithologies(silt,tuff,powder-grained sandstone,coarse-grained sandstone,limestone and granite) with respect to the incident angle,which is based on theories like coefficients of liquid-solid interface and energy function.The situations of transmitted wave energy distribution turn out with great differences in terms of different seafloors and the same conditions of acquisition: 1) For sea-floor of silt,it is beneficial for transmitted compression wave exploration when incident angle does not go over the critical angle(49°),otherwise transmitted converted-wave exploration is more effective.2) For sea-floor of tuff,it is beneficial for transmitted compression wave exploration when incident angle is not bigger than 65°,while transmitted converted-wave exploration is more effective when incident angle is between 40° and 80°.3) For sea-floor of powder-grained sandstone and coarse-grained sandstone,it is beneficial for transmitted compression wave exploration when incident angle does not go over the critical angle(powder-grained sandstone 61°,coarse-grained sandstone 55°).4) For sea-floor of limestone and granite,10%~30% of the energy is distributed to transmitted compression wave when incident angle is smaller than the first critical angle(limestone 14°,granite 18°),while transmitted converted wave takes nearly 40% of the energy when incident angle is between the first and the second critical angle(limestone 28°,granite 34°).The transmitted wave disappears after the second critical angle.This type of seafloor is not beneficial for exploration.
杨正华, 朱光明, 袁伟. 六种岩性海底地震波透射能量AVA特征研究[J]. 石油地球物理勘探, 2011, 46(4): 501-505.
Yang Zheng-hua, Zhu Guang-ming, Yuan Wei. A research on AVA characteristics of seismic transmission energy at seafloor of six lithologies. OGP, 2011, 46(4): 501-505.