基于地震物理模拟的采集脚印分析  

Analysis of acquisition footprints based on seismic physical simulation

作　　者：熊金良[1] 狄帮让[2] 岳英[1] 魏建新[2] 薛广建[1] 顾培成[2] 

机构地区：[1]大港油田分公司,天津市大港油田公司300280 [2]CNPC物探重点实验室,北京市地球探测与信息技术重点实验室,中国石油大学资源与信息学院

出　　处：《石油地球物理勘探》2006年第5期493-497,共5页Oil Geophysical Prospecting

摘　　要：采集脚印是描述三维地震勘探中的一种地震噪声的新概念,采集脚印的形成机理为:①地面炮点和检波点几何图形离散化分布可造成地下水平层照明强度分布不均匀,并导致CMP面元水平叠加、偏移振幅和相位不均匀;②三维观测模板规律性的纵、横向滚动可造成地下CMP面元属性的周期性变化,从而导致CMP面元水平叠加振幅和相位也呈现周期性变化。文中借助地震物理模拟技术,在三维偏移数据体的时间切片上,观察到了各种特征的采集脚印图像,验证了采集脚印对中、深层地质目标地震成像的影响,并得出以下初步认识:①在微震扰动背景下,采集脚印的振幅水平与背景振幅属于同一数量级,因而可以观测到与理论分析相吻合的各种特征的采集脚印图像;②采集脚印噪声水平对强反射信号影响不大,但它足以影响中、弱反射信号的振幅和相位,从而影响中、深层地质目标的地震成像质量;③在地震物理模拟中,由于地质模型是已知的,所有与地质目标相关的信息都可以正确演示出来,而采集脚印是一种周期性的规则噪声,也可以进行预测、识别,因此地震物理模拟技术是研究采集脚印问题的优势技术。The acquisition footprints is a new conception describing a kind of new seismic noise in 3D seismic exploration, the formed mechanism of which is: discrete distribution of geometrical figure of surface shot points and receiver points results in non-uniform distribution of illumination for horizontal layers, leading to non-uniform distribution of horizontal CMP bin stack, migrated amplitudes and phases; ②regular rolling in in-line and cross-line of 3D surveying template causes periodic change in underground CMP bin attributes, leading to periodic change in amplitudes and phases of horizontal CMP bin stack. By aid of seismic physical simulation technique, the paper observed the acquisition footprints imaging in various characters on time slices of 3D migrated data volume, which proved the influence of acquisition footprints on seismic imaging of middle and deep geologic targets and obtained following preliminary knowledge: under the background of microtremor disturbance, the amplitude level of acquisition footprints is in same rank with the background amplitude, so that can observe the imaging of acquisition footprints in various characters coincident with theoretical analysis; ②the noise level of acquisition footprints has little influence on strong reflection signals, but is strong enough to effect the amplitudes and phases of mid and weak reflection signal, so that can affect the seismic imaging quality of middle and deep geologic targets; ③in seismic physical simulation, because the geologic model is known, all information relative to geologic targets can be correctly displayed, and the acquisition footprints are a kind of periodic and regular noise that can be predicted and identified, so, the seismic physical simulation technique is superior technique in studying the issue of acquisition footprints.

关 键 词：采集脚印 三维观测系统 地震成像 地震物理模拟 面元属性 

分 类 号：TE19[石油与天然气工程—油气勘探]