垦西油田馆陶组河流沉积高分辨率层序地层研究

河流相地层沉积环境特殊,难于用传统的地震层序分析方法来进行层序划分与解释,Cross分析基准面与成因地层形成的过程响应原理,是利用高分辨率地层方法来研究河流地层的理论基础。高分辨率等时地层对比的关键是不同级别基准面旋回的识别。利用岩芯资料及其沉积标志,分析沉积微相类型及组合关系,可识别短期基准面旋回。在建立测井曲线响应模板的基础上,根据短期旋回的叠加样式,可识别中期基准面旋回。把基准面旋回转换点作为高分辨率等时地层对比的优选位置,进行连井剖面地层对比,建立河流地层高分辨率地层格架。以基准面旋回变化特征为研究对象,分析了河流相地层发育的过程演化规律及其沉积相横向迁移、纵向组合叠加关系与基准面旋回变化之间的藕合。通过深入研究,认为馆陶组地层形成的环境区别于传统的模式所指的环境,在分析了古典模式的基础上,指出了本区河流地层模型的独特之处。

High Resolution Stratigraphy Study on Fluvial Deposit of Guantao Formation in Kenxi Oil Field

It is difficult to divide and interpret the fluvial strata because its depositional environment is very special compared with others. The response principle between base level cycle and genetic strata developed by Cross is regarded as the basic theory for high-resolution stratigraphy applications in fluvial strata. The key of high resolution isochronostratigraphic correlation is to identify multi-level base cycles. Short-term base level cycles can be identified by sedimentary microfacies, analysis on the well profiles and the well profile themselves.The mid-term base level cycles also can be identified by stacking patterns of short-term cycles on the base of log curves facies model. Taken the turnround point of base-level cycle as optimal positions in the connected wells' profile isochro nostratigraphic correlation,the high resolution sequence stratigraghic framwork can be established. The paperhas analyzed the evolution principle of fluvial strata and the coupling between base level and sedimentary lateral migration,vetical stacking from the view of base level variation on the established frame work,and pointed out that the environment model is finally different from the classical one .