成岩作用与砂层(岩)孔隙的演化

DIAGENESIS IN RELATION TO EVOLUTION OF PORES IN SANDSTONE

朱国华

Zhu Guohua

本文论述了鄂尔多斯盆地南部的主力油层(侏罗纪延安统延砂层组)在成岩过程中的孔隙演化史。作者认为:1.成岩作用改造砂层（岩）的过程,也是改造砂层（岩）中孔隙的过程,砂层（岩）中孔隙的演化史是原生孔隙不断消失和次生孔隙不断形成和消失的过程。2.石英砂屑岩（Quartz arenite）的孔隙度降低,主要是成岩期自生矿物在砂岩孔隙中的沉淀作用造成的;含柔性碎屑组分多的砂屑岩,其孔隙度的降低主要是成岩期的压实作用造成的。

In Maling oilfield and its vicinity,the process of pore evolution in Yan-10 sandstones of Jurassic during diagenesis is discussed in this paper.The main conclusion proposed are as follows:1)The pore evolution is in fact a process of gradual substitution of secondary pores for the primary ones;2)The decrease of porosity in quartz arenites is mainly due to the precipitation of authigenic minerals in the sandstone pores during diagenesis;while the decrease of porosity in arenites with more flexible component is mainly caused by compaction during diagenesis;3)The secondary solution pore mainly developed after its diagenetic stage by dissolution and kaolinization in arenite which is abundant in feldspar.This process is likely to be related to the decarboxylation of organic matter in interbedded coal seams and carbonaceous shales by thermalizatin;4)The clastic constituents of sandstone controlled by source materal distinctly affect the development of pores.Therefore,the primary and secondary pores in sandstones favourable can be predicted on the basis of finding out the source material of sediments;5)Diagenesis obviously affects on the texture and the uniformity of pores in sandstones.

10.11743/ogg19820301