摘要
地震波是研究地球内部物质成分和结构最有效的工具之一.鉴于哈密地区油田对砂岩地震波性质研究的需求,本文在室内利用Autolab2000岩石物性测试设备,开展干燥、饱水及饱油条件下,砂岩X、Y、Z三个正交方向的弹性波速测试,得到不同压力下纵横波速随含水饱和度的变化规律,并在不同含水饱和度下分析了动态弹性常数(E和υ).结果表明:(1)波速与压力呈对数关系,相关系数在0.96以上;纵波速度与含水饱和度呈正相关,但随压力的增加,其增加速率会减小;横波速度在低压下基本不受含水饱和度影响,但随压力增加,其与含水饱和度呈负相关.(2)砂岩Z(垂直)方向波速最小;横波各向异性小于纵波;不同压力下,纵横波各向异性都是干燥大于饱油,并皆大于饱水状态.(3)恒定含水饱和度时,杨氏模量和泊松比皆随围压增加而增加,低压下(小于80 MPa,约3 km深度)增加速度快,而高压下(大于80 MPa)增速变缓;相同围压下,泊松比随含水饱和度增加而增加,而杨氏模量则有增有减.
Seismic wave is one of the most effective tools to analyze the inner materials composition and structure of the earth. In view of the need to analyze sandstones＇ seismic properties in Hami＇s oilfields,measurement of elastic wave velocity are taken by applying Auto Lab2000 computer-controlled servo hydraulic triaxial test system in three orthogonal directions X,Y and Z under dry,water saturated and oil saturated environment respectively. Therefore,the alteration regulation of seismic wave velocity with respect to the water saturation are obtained under various pressures. In addition,the dynamic elastic parameters（ E and υ） are analyzed under different water saturation. The results show that both P-and S-wave velocities increase notably with the increasing pressure, which denotes a strong logarithmic relationship and the correlation coefficient is over 0. 96. P-wave velocity increases with the increasing water saturation. However, it slows down with the increasing pressure. S-wave velocity in low pressure is generally not affected by the water saturation,but with the increasing pressure,its velocity decreases dramatically with the increasing water saturation. Besides,the anisotropy of shear wave are smaller than that of compressional wave. Although under various pressures,the seismic anisotropies with different properties show a certain order which is,Adry〉 Aoil saturated〉 Awater saturated. Finally,both Young＇s modulus and Poisson＇s ratio increase with the increasing confining pressures under the same water saturation. When the pressure is less than 80 MPa,the accelerations of elastic parameters increase dramatically,but with the increasing pressure,their accelerations increase slowly. Poisson＇s ratio increases with the increasing water saturation under the same confining pressure,while the variation of Young＇s modulus does not show an obvious variation trend.
出处
《地球物理学进展》
CSCD
北大核心
2017年第3期1034-1042,共9页
Progress in Geophysics
基金
中国地质调查局项目(DD20160060)资助
关键词
哈密地区
砂岩波速
围压
含水饱和度
各向异性
弹性参数
Hami region
sandstones＇ wave velocity
confining pressure
water saturation
anisotropy
elastic parameter
