四川盆地震旦系灯影组表生岩溶作用研究

四川盆地灯影组是中国最为古老的海相碳酸盐岩沉积地层,也是年代最老的含气储集层之一,灯影组在漫长的地质历史时期中经历过多期次的岩溶作用改造,而表生岩溶作用是其中最为重要的一种。本文以野外露头以及钻井岩心样品的宏观、微观特征为基础,以不同结构组分进行微区取样的多参数实验分析方法为辅助手段,对灯影组白云岩表生岩溶作用进行了研究。灯影组表生岩溶作用主要发育在三个层位,即灯四段顶部,灯二段顶部以及灯二段中、下部。其中桐湾Ⅰ幕和桐湾Ⅱ幕构造运动是造成灯二段顶部以及灯四段顶部表生岩溶作用的主控因素,而灯二段早、中期的表生岩溶作用主要受气候等原因引起的大规模海平面升降所控制。

Supergene karstification in the Sinian Dengying Formation, Sichuan Basin

The Sinian Dengying Formation strata in the Sichuan Basin are interpreted to be the oldest marine carbonate strata and gas reservoirs in China. In the last geologic periods, the Dengying Formation underwent multiple phases of karstification, of which the supergene karstification have played an important part in the formation of the excellent reservoir rocks in the Formation. Therefore, the emphasis in the present paper is placed on the supergene karstification in the Sinian Dengying Formation on the basis of macroscopic and microscopic features, and multi-parameter experimental analysis of samples from the field outcrops and drilled cores in the Sichuan Basin. The supergene karstification occurs dominantly in three horizons, including the topmost parts of the 4th member and the 2nd member, and lower and middle parts of the 2nd member of the Dengying Formation. The tectonic movements during the Tongwan I and II episodes are believed to be the main controlling factors for the supergene karstification in the topmost parts of the 4th member and 2nd member of the Dengying Formation. The supergene karstification in the lower and middle parts of the 2nd member of the Dengying Formation is mostly constrained by the large-scale sea level changes caused by climatic variations..