哈密地区砂岩地震波速的实验研究

摘要

岩石的地震波速是区域构造研究和浅部地震勘探的基础.哈密地区是我国重要的产油区域之一,但目前仍缺少地震波速方面的基础资料.这是在实验室条件下模拟了深层环境,分析了四组哈密地区砂岩样品的波速与压力之间的关系.结果表明:随着压力增加,砂岩样品的纵横波速度以对数关系增加;砂岩的孔隙度影响波速的变化速率;砂岩地震波速的滞后效应主要表现为:在相同压力下,降压过程中的波速大于升压过程中的波速;高压下的波速接近于用空间平均模型计算的理论波速.实验所得的波速数据与哈密地区的测井数据解释相吻合,其可以作为判断油层、水层和干层的辅助条件.%Seismic velocity of rocks have a wide range of applications in regional tectonic research and shallow seismic exploration.Hami region is one of the important production bases for oil and gas in China,but there is no data of seismic velocity.Deep environment is simulated in laboratory and the change rule of P-and S-wave velocity which come from four groups of sandstones in Hami is studied in this paper.The result shows that the P-wave and S-wave velocity increase (or decrease) with the pressure at the logarithmic rule.The porosity of sandstone affect the rate and size of increased wave velocity.The lag effect of sandstone's wave velocity mainly in the procession that wave velocity of decompression is greater than boost when they are under the same pressure.The wave velocity with high pressure is closed to the theoretical wave velocity of space averaging models.Wave velocity data measured by experiment is consistent with the log data in Hami.Therefore it can be used as the auxiliary condition to define oil layer,water layer and dry layer.