新疆哈密地区砂岩地震波速的实验研究及其对特殊地质填图物性工作的启示

THE EXPERIMENTAL RESEARCH OF SEISMIC WAVE VELOCITY OF SANDSTONES IN HAMI,XINJIANG AND THE ENLIGHTMENT TO THE WORK OF PROPERTY ON SPECIAL GEOLOGICAL MAPPING

本文在特殊地质填图的过程中研究了哈密地区砂岩的地震波速,利用ZBL-U520非金属超声检测仪和Autolab2000多功能岩石物性设备,在0~200 MPa(约0~7000 m地下深度)下研究了密度、孔隙度和压力三个因素对砂岩地震波速的影响。研究发现:砂岩的波速与密度呈正相关关系,但与孔隙度呈负相关关系;纵波与密度和孔隙度的线性关系好于横波;波速与压力呈对数关系。此外,本文还分析了ZBL-U520与Autolab2000两种仪器测试方法的适用性。最后针对地质填图的特点给出建议:在特殊地质填图中,不仅要按照规范采集标本,测试其在常温常压下的岩石波速,还应该适当考察不同地层压力状态下的速度特征,才能更全面地认识填图区地震波的性质。

The seismic wave velocity of sandstones in Hami in the process of special geological mapping isstudied in this article. The effects of density, porosity and pressure on seismic wave velocity under different pressure （0 ？ 200 MPa） are analyzed by applying ZBL-U520 nonmetal ultrasonic detector and AutoLab 2000 computer-controlled servo hydraulic triaxial test system. The results show that wave velocity and density are positively correlated , but there is a negative correlation between wave velocity and porosity. The degree of linear relationship between density or porosity and P-wave is higher than that of S-wave. Both P- and S-wave velocities of sandstones in Hami area increase notably with the increasing pressure which denotes a strong logarithmic relationship. Besides,the adaptability of test methods of ZBL-U520 nonmetal ultrasonic detector and AutoLab 2000 computer-controlled servo hydraulic triaxial test system are analyzed. In conclusion , in respect of geological mapping it is suggested that not only should we collect samples to test the seismic wave velocity of rocks at normal temperatures and pressure , but also we should analyze the seismic wave characteristics under different formation pressure to comprehensively understand the seismic properties in special geological mapping.