摘要
我国的油气田多为薄层或薄互层类型,薄互层调谐效应使AVO的变化规律发生了改变,从而影响了AVO技术的应用。针对这一问题,根据实际薄互层气藏的岩石物理参数和地质条件,设计了系列薄互层气藏地质模型,分析了薄互层调谐效应对AVO的影响。首先,对未考虑调谐效应的双层地质模型和根据测井资料合成的地震角道集的AVO曲线变化规律进行了分析,结果表明,2种情况下的AVO呈现完全不同的变化规律。然后利用实际的储层和盖层数据,建立了由不同厚度薄层组成的系列薄互层地质模型,分别合成了地震角道集,绘制了不同厚度薄层砂泥岩界面的AVO曲线,对AVO与地层厚度之间的关系进行了讨论。结果表明,当薄层厚度大于1/8波长时,薄层调谐效应会使地震反射振幅相对变大或变小,但AVO的变化规律相一致；当薄层厚度小于1/16波长时,薄层调谐效应则会导致AVO的变化规律发生反转。
Most oil/gas fields in China are thin beds or thin interbeds. The thin interbed tuning effect makes the changing rules of AVO alter,affecting the application of AVO.Based on physical parame- ters of rocks and geological conditions of actual thin interbed gas reservoir,a series of geological models for this reservoir are de- signed to analyze the affection rules of thin interhed tuning effect on AVO.First,the changing rule of AVO curves from double-lay- er geologic model without considering tuning effect and from the seismic angle trace assemblage formed by logging data are ana- lyzed.The results show completely different changing rules of AVO in this two situations;Then,the actual reservoir and cap rock data is used to establish a series of thin interbed geologic mod- el consisted of thin beds different in thickness,to synthesize seis- mic angle trace assemblage,and to draw AVO curves of interfaces of thin sandy shale beds with different thickness.The relationship between AVO and layer thickness is discussed.The results show that 1) when the thin bed thickness is more than 1/8λ.the thin in- terbed tuning effect may make the seismic reflection amplitude be- come either bigger or smaller,but the changing tendency of AVO keeps the same;2) when the thin bed thickness is less than 1/16λ,the thin interbed tuning effect may cause the changing rule of AVO to be reversed.
出处
《石油物探》
EI
CSCD
2006年第6期570-573,共4页
Geophysical Prospecting For Petroleum
基金
国家自然科学基金项目(40574048)
国家高技术研究发展计划(863)(2003AA602110-2)资助。
关键词
薄互层
调谐效应
地质模型
地震模拟
角道集
薄层厚度
AVO分析
thin interbed
tuning effect
geologic model
seismic modeling
angle gather
thin bed thickness
AVO analysis
