用层速度计算砂(泥)岩含量的几种校正方法及其在BY盆地的应用

The methods for interval velocity correction in computing the contents of sandstone or mudstone and their application in BY Basin

中国石油天然气总公司西北石油地质研究所, 兰州 730020

Northwest Institute of Pctroleum Geology, China National Petroleum Corporation, Lanzhou 730020

根据储层研究的需要, 常常要利用地震资料计算主要目的层的层速度, 并将其转换成砂(泥)岩百分含量。在做砂(泥)岩转换前对层速度做一些校正是至关重要的, 其目的是排除那些与砂(泥)岩含量无关的由其它因素造成的层速度的变化, 使算出的层速度值能较真实地反映地层砂(泥)岩含量的多少。本文介绍了对层速度的三种校正方法, 即：地层埋深校正、去异常压实校正和去多种岩性因素的影响。同时剔除了断层阴影带的异常速度值, 并做了层速度的面积平滑。这些方法符合BY盆地的实际情况, 取得了较好的结果。

It is common to calculate the interval velocites of principal objective formations from sesmic data and then change them into percentage contents of sandstone or mudstone. Before the transformation, the corrcctions for the interval velocities are important which eliminate variations of the interval velocitics caused by factors having nothing to do with the contents of sandstonc or mudstone. Three rnethods for interval velocity correction arc introduced. They are: strata depth correction, abnormal compaction correction, and lithological effect elimilation. Meanwhile, the interval velocities at faulted zones are eliminated and areally smoothed. These methods coincide with the actual conditions of BY Basin and a good result is achieved.