摘要
Hydrocarbon exploration interests have renewed the need for developing new sub basalt imaging techniques. One of the most important problems encountered today is seismic imaging below basalt. In recent years, this problem appears to have been overcome partly by using long offset seismic data. However near offset data are yet to be fully utilised due to the complex waveform caused by the surface as well as internal heterogeneity of the basalts. The near normal incidence data, which influence the sub-basalt imaging, are highly useful to understand the internal structure within a basalt layer. The use of converted waves for such targets has been proposed as an alternative in a rather homogeneous basalt layer. With a few synthetic modelling exercises here we highlight the practical difficulties in dealing with more realistic and heterogeneous basalt flow. Full waveform seismograms are computed to understand the effects of intra-trappean sediments on the seismic data. A case study from the Deccan Traps of India is presented in this paper. First, we discuss the effects of intercalated sediments on the overall seismic image. Later, the sonic log data from the field are used to compute the full wave-field response using the reflectivity method and compared with the field data. The feasibility of using mode converted waves （P to S and vice-versa at the top and bottom basalt interfaces） for sub-basalt imaging in Kutch region is discussed through a series of velocity-depth profiles. By comparing with the field data we demonstrate that the effects of multiple thin layering within the basalt can strongly deteriorate the image we seek to interpret and exploit.
烃探索兴趣为开发新潜水艇暗岩成像技术更新了需要。今天遇到的最重要的问题之一是在暗岩下面的地震成像。在最近的年里，这个问题看起来被长使用部分克服了抵消地震数据。然而近的偏移量数据充分还有待于由于表面以及暗岩的内部异质引起的复杂波形被利用。近正常的发生数据，影响亚暗岩成像，是高度有用的在暗岩层以内理解内部结构。为如此的目标的变换波浪的使用在相当同类的暗岩层作为一种选择被建议了。与合成建模这里行使的一些，我们在处理更多的现实主义、异构的暗岩流动加亮实际困难。完整的波形震动图被计算在地震数据上理解 intra-trappean 沉积的效果。从印度的 Deccan 陷井的案例研究在这篇论文被介绍。首先，我们在全面地震图象上讨论设置的沉积的效果。后来，来自这个领域的声音的木头数据被用来用反射率方法并且与领域数据相比计算完整的波浪地反应。使用模式的可行性变换了波浪(在顶和底部暗岩接口的到 S 并且反过来的 P ) 因为在 Kutch 区域的亚暗岩成像通过一系列速度深度侧面被讨论。由与领域数据作比较，我们证明在暗岩罐头以内的多重薄 layering 的效果强烈败坏我们寻求解释并且利用的图象。
