用层速度计算泥岩比值的方法

ESTIMATION OF SAND-SHALE RATIO FROM INTERVAL VELOCITIES

南海地调指挥部综合研究大队

本文介绍一种根据钻井中已知岩性和相应的声速测井求得的层速度,用概率论中的具叶斯公式算出不同井深各层速度值对应的泥岩比值的方法。当井的数量较多时,每一个泥岩比值所对应的层速度随深度的变化,就呈现出明显的规律性。这就是泥岩比值的层速度概率分布图。根据此图画出等间隔泥岩比值的层速度曲线,就可用作以地震勘探资料求得的层速度来计算泥岩比值的量板。

Based on the known interval velocities obtained from the lithologic log and sonic log, this paper presents a way of estimating the sand-shale ratio corresponding to the interval velocity at different well depths by using the Bayes formula of the probability theory. While the number of well increases, the regularity of the interval velocity varied with depth corresponding to the sand-shale ratio will speak for itself. This can be seen in the diagram of probability distribution of interval velocities related to the sand-shale ratio. Therefore, the interval velocity curves drawn by equal sand-shale ratio from the diagram mentioned above, could thus be used as the template to estimate the sand-shale ratio by comparing it with the interval velocity curves obtained from seismic data.