摘要
地震波在地下介质传播时流体对波的传播有很大影响,利用孔隙介质中的平面波反射系数可以较好的进行描述。本次研究采用基于渐近分析理论的法向反射系数渐近方程,通过建立上层饱和含油、下层饱和含气和上层饱和含气、下层饱和含油的砂岩可渗透孔隙介质模型,开展反射系数频散特征研究,对比分析基于等效介质、孔隙介质和渐近分析三种理论在饱含油气可渗透分界面上法向反射系数频散特征,并对比分析基于孔隙介质和渐近分析理论的反射系数频散对渗透率的敏感性。研究表明:在地震频带(0~100 Hz)内,该反射系数渐近方程在上层饱和含气、下层饱和含油可渗透界面上反射系数增加15%,变化明显;当渗透率从低渗透率到高渗透率时,其反射系数增加12%,也有明显变化。从而可以用来识别上层饱和含气、下层饱和含油可渗透界面。因此,基于孔隙介质渐近分析的反射系数方法可用于研究饱含油气可渗透界面上反射系数频散特征,从而为油气识别提供了很好的理论和依据。
When seismic wave propagates in underground medium,fluid has a great influence on wave propagation.The reflection coefficient of plane wave in porous medium can be used for a better description of the process.Asymptotic equation of normal reflection coefficient based on the asymptotic analysis theory is used to study the dispersion characteristics of reflection coefficient by establishing the permeable porous media models of sandstone with upper saturated oil,lower saturated gas and upper saturated gas and lower saturated oil.Based on comparative analysis of equivalent medium,porous medium and asymptotic medium,the dispersion characteristics of normal reflection coefficient of three theories on permeable interface of saturated oil and gas are studied,and the sensitivity of reflection coefficient dispersion to permeability based on porous media and asymptotic analysis theory is compared and analyzed.It is showed that the method of asymptotic equation of reflection coefficient effectively reflect the dispersion characteristics of reflection coefficient on permeable interface in seismic frequency band(0-100 Hz),and presents good sensitivity to permeability. In the seismic frequency band(0-100 Hz),the reflection coefficient of the asymptotic equation increases by 15% on the permeable interface between the upper layer and the lower layer,and changes obviously.When the permeability changes from low permeability to high one,the reflection coefficient also increases by 12%.Thus,the reflection coefficient can be used to identify the permeable interface between the upper layer and the lower layer. It proves that the reflection coefficient method based on the asymptotic analysis of porous media can be used to study the dispersion characteristics of reflection coefficient on permeable interface of saturated oil and gas and provid evidence and basis for oil & gas identification.
作者
刘春成
李勇
牛聪
陈力鑫
黄饶
黄成龙
Liu ChunCheng;Li Yong;Niu Cong;Chen LiXinHuang Rao;Huang Chenglong(CNOOC Research Institute Co.Ltd.,Beijing 100027,China;College of Geophysics,Chengdu University of Technology,Chengdu,Sichuan 610059,China)
出处
《矿物岩石》
CAS
CSCD
北大核心
2019年第4期109-114,共6页
Mineralogy and Petrology
基金
国家科技重大专项(2016ZX05026001-004)
2018国家级大学生创新创业训练计划项目(201810616045X)
关键词
法向反射系数
法向透射系数
弹性孔隙介质
可渗透界面
渐近分析
normal reflection coefficient
normal transmission coefficient
elastic porous media
permeable interface
asymptotic analysis
