惠民凹陷西部沙三段三角洲和浊积扇砂体的粒度特征

本文分析了惠民凹陷沙三段三角洲和浊积扇砂体的475块样品,用福克公式计算了它们的粒度参数,并用计算机绘制了概率图、C-M图以及其它图件。综合岩性、沉积构造等资料,总结了三角洲和深水浊积扇亚环境的概率图特征,指出概率图的垂向变化也能反映沉积环境的变迁。根据岩芯观察,解释了三角洲和深水浊积扇 C-M图不同段的沉积环境意义,同时也研究了成岩作用对粒度特征的影响。研究表明,研究区内成岩作用并不显著,粒度资料基本反映了沉积物沉积时的水动力条件和沉积环境。强调指出了使用粒度资料时应综合岩性、电性、沉积构造等多种信息,才能对沉积环境进行正确分析、判断。

GRAIN SIZE FEATURES OF A DELTA AND TURBIDITE FAN AT THIRD MEMBER OF SflAHEJIE FORMATION IN HUIMIN DEPRESSION

On the basis of analyzing 475 samples from Huimin depression, the grain size parameters have been calculated according to Fork Formular. Log-probability plots; C-M diagrams and other type of diagrams have been drawn by computer. The log-probability plot features of different sub-environments for a delta and turbidite fan are summarized. It points out that the vertical evolution of the log-probability plot reflects the change of sedimentary environment. Core analysis indicates that the different fragments in C-M diagram of the delta and turbidite fan represents the different sedimentary sub-environment.The study of diagenesis effecting on the grain size features shows that diagenesis is not obvious in the area. Grain size information can generally reflect the hydrodynamic regime and sedimentary environment of sediments. It is emphasized that grain size data should be used by combination with lithology, electric logging and sendimentary structure to analyze and form an opinion about the sedimentary environments.