“宽频带、宽方位和高密度”陆上三维地震观测系统聚焦分辨率分析

近年来，"两宽一高"——宽频带、宽方位和高密度——三维地震采集技术极大地提升了地震勘探的能力和精度，在岩性油气藏地区取得了明显的应用效果，也对地震采集观测系统设计提出了更高的要求.如何在现有的成本限制和装备条件下，根据具体工区的地质地球物理条件来选择合适的"两宽一高"采集观测参数以实现最佳的勘探效益，已成为当前地震勘探中迫切需要解决的瓶颈问题之一.基于此，本文首先回顾了点绕射聚焦分析的基本原理，随后给出一种新的复杂介质多频率快速聚焦分辨率定量分析方法.基于该理论，我们以一个典型的陆上三维地震勘探采集方案和速度模型为例，系统地研究了"两宽一高"地震资料偏移成像分辨率随着关键采集参数的变化规律，给出了不同条件下分辨率的理论极限值及其所对应的采集参数的临界点值.此外，我们也提出了一种新的采集参数和子波频谱的交汇定量分析方法，进一步阐明了采集参数和子波频谱参数之间的定量关系，为复杂接收激发条件下采集观测系统设计提供了新的理论依据.

Focal beam resolution analysis of wide-band,wide-azimuth and high-density land 3D seismic acquisition geometries

Recent years, the wide-band, wide-azimuth and high-density 3D seismic acquisition technology not only has greatly improved the capability of land seismic exploration, and the accuracy of the complex reservoir identification, but also puts forward higher requirements for the seismic acquisition geometries design to improve the imaging quality while reducing its acquisition cost. However, it is difficult to select the optimal acquisition parameters for a given geological and geophysical condition, cost estimation and equipment level. Based on this, we first review the basic principle of fast multi-frequency focal beams theory, and then present a new quantitative analysis method and process of the imaging resolution and sharpness in a complex medium to select the optimal acquisition scheme from lots of alternatives. Based on a complex velocity model, we take a real land 3D seismic acquisition scheme as an example to study the effects of some key acquisition parameters on the imaging resolution and sharpness, and find their numerical limit. We also draw crossplots of the acquisition parameters and the frequency parameters, which could provide some new ideas for the acquisition geometries designing for the deep-layer seismic imaging with low peak frequency and limited frequency band.