摘要
研究含裂缝致密砂岩的AVO响应特征,对致密砂岩储层参数的预测及油气开发具有重要意义。本文基于Biot-Gassmann流体替换理论,利用Thomsen各向异性理论建立含裂缝致密砂岩的等效HTI地震模型,通过分析含裂缝致密砂岩的PP、PS1、PS2波AVO响应特征发现:各向异性与各向同性介质的PP波反射系数在入射角小于10°时无明显差别,入射角大于10°时,不同裂缝密度致密砂岩的反射系数会有明显差异,且随裂缝密度增高而变大;各向异性与各向同性介质的PS波反射系数在入射角为0°、55°时两者几乎无差别;不同裂缝密度时PP波与PS1、PS2波AVA的极性反转位置移动规律不同。
AVO responses in fractured tight sandstone can provide useful evaluation parameters for tight sandstone reservoirs,which are significant to the petroleum production.Based on Biot-Gassmann's fluid substitution,we build horizontal transversely isotropic(HTI)model equivalent to fractured tight sandstone with Thomsen's weak seismic anisotropy theory,and analyze AVO responses of PP-,PS1-and PS2-waves.Within the 10° incidence angle,the PP-wave reflection coefficient difference between the HTI and isotropic media can be ignored.When the incidence angle is over the 10°,this difference in tight sandstones with different fracture density becomes more obvious and increases with the fracture density.At the 0° and 55° incidence angles,the PS-wave reflection coefficient of the HTI media is close to that of the isotropic media.The AVAcurve polarization reversals of the PP-,PS1-and PS2-waves are different at different fracture density.
出处
《石油地球物理勘探》
EI
CSCD
北大核心
2018年第4期798-804,共7页
Oil Geophysical Prospecting
基金
国家自然科学基金项目(41574126
41425017
41604119)
国家科技重大专项"薄层地震波场特征与反演研究"(2016ZX05002-005-008)联合资助
关键词
含裂缝致密砂岩
HTI介质
各向异性参数
裂缝密度
AVO响应
fractured tight sandstone
horizontal transversely isotropic(HTI)medium
anisotropic parameter
fracture density
AVO response
