双临界DIVA异常速度分析方法及其在储层预测中的应用

Application of Double Critical DIVA Method of Abnormal Velocity Analysis in Reservoir Prediction

层速度是判别地层岩性的一项重要参数,直接利用Dix公式计算地层层速度来判别岩性存在不确定性因素。双临界DIVA方法不需要直接计算地层层速度来进行岩性判别,利用钻井和测井资料得到纯砂岩和纯泥岩的层速度作为背景层速度,再根据地层顶界面实测的均方根速度由逆Dix公式来预测底界面的均方根速度,根据底界面实测均方根速度与预测均方根速度的差值来判别岩性。讨论了Dix公式的应用条件和逆Dix公式进行差异层间速度分析的优点,并且直接利用叠加速度进行双临界差异层间速度分析,应用在浊积砂岩的储层预测中,预测效果非常好,是一种非常有价值的地震勘探方法。

Interval velocity is one of the most important parameters for distinguishing lithology. There are some uncertainty factors to compute interval velocity by using Dix＇s equation to distinguish lithology. Double critical DIVA method predicts formation lithology without computing interval velocity of strata, through drilling and logging data to obtain the velocity of pure sandstone and mudstone as setting interval velocity,according to the measured root mean square （RMS） velocity of the top interface to predict RMS velocity of the bottom interface by using inverse Dix＇s equation. According to the difference between the bottom interface of measured RMS velocity and the predicted RMS velocity predicts lithology. Analysis ap- plication conditions of the Dix＇s equation and advantages to predict reservoir lithology by using inverse Dix＇s s equation for DIVA （Differential Interformational Velocity Analysis） in this paper, use stacking velocity for double critical differential interformational velocity analysis directly. It is applied to predict turbidite sandstone, and the prediction results are identical to drill, ration. which is a very valuable method of seismic exploration.