地震地层学盆地分析与储层+特性401-410.docVIP

石油地质学翻译作业 061103班 吴泽 学号：20091001592 页码 401-410页 P(lithologyn| ATR) = Posterior probability densityfunction (PDF). P(ATR | lithologyn) = The conditional probability of having a set of seismic inversion attributes ATR given a certain lithology and P(ATR) = ΣP(lithology)P(ATR | lithology). P（岩性n| ATR）=较晚的概率密度函数（PDF）。 P（ATR | 岩性n）=有一组地震反演属性ATR给定一个特定的岩性和P（ATR）=ΣP（岩性）P（ATR |岩性）条件概率。 Bayes rule provides a means to combine the probabilistic a-priori knowledge with information contained in theobserved data to update the prior model. Noise in the data has a tremendous effect on the uncertainties in the inversion solution (Buland and Omre 2003). 贝叶斯规则相结合的概率为先验知识和观测数据中包含的信息来更新现有的模型相结合提供了一种方法。数据中噪声的不确定性对反演有巨大的影响（布兰多2003）。 The cascaded two-step elastic inversion performs an elastic inversion of the seismic data to obtain P- and S-impedance models (Saltzer et al. 2005). And these impedances are in the second step inverted into lithology (or Volume of Shale) and a porosity component. Information on the expected fill, faults and stratigraphic horizons are taken into account during the modelling. The specific rock physical model is used to transform the impedances into V Shale and porosity estimates. The effect of sand (large aspect ratio) and clay pores (smaller aspect ratio) on the rock elastic moduli are computed based on differential effective media theory. The sand is dry and the clay pores are brine filled. Gassmann fluid substitution serves to calculate the bulk modulus of the saturated sand. Explicit non-linear relationships between clay content, porosity and water saturation are exploited. A Bayesian approach is applied to the constraints, with estimates of the data noise and a-priori model parameters to deduce the most likely model. By incorporating the model and data covariances, it is possible to estimate the combined uncertainty of the data error and a-priori model uncertainty in the inversion solution. Thus it calculates a posterior covariance (Saltzer et al. 2005). 串