巴西桑托斯盆地白垩系湖相藻叠层石礁特征及主控因素分析

Cretaceous Lacustrine Algal Stromatolite Reef Characteristics and Controlling Factors,Santos Basin,Brazil

湖相碳酸盐岩研究正处于不断探索和认识阶段,近年来国内外大量湖相碳酸盐岩储层的发现,使主要借鉴海相碳酸盐岩理论的湖相碳酸盐岩研究得到关注和重视,并取得一定的成果和认识。巴西桑托斯盆地白垩系藻叠层石礁是湖相碳酸盐岩一种特殊的储层类型,对于丰富湖相碳酸盐岩理论具有重要意义。通过对地震剖面的振幅反射结构,钻井岩性剖面,岩芯沉积结构、构造观察,岩芯薄片孔渗及成岩分析,测井曲线反映的沉积物粒序变化及旋回组合特征等现象的综合分析,总结出了白垩系藻叠层石礁的主要特征及主控因素。藻叠层石礁以叠层石为格架,藻类的黏结作用使其成为大面积连片发育的黏结礁,其孔渗发育,是良好的储层。发育和分布主要受物源供给、古隆起、水体变化和藻类改造四种因素的控制。咸水环境下,在远离碎屑物源影响的水下古隆起上,水侵体系域时期,适应环境较强的叠层石繁盛,藻类的黏结作用使其成为具有格架结构的黏结礁,沿巴西桑托斯盆地东部隆起带大面积发育。

The study of lacustrine carbonate is in the stage of continuous exploration and understanding. In recent years, a large number of lacustrine carbonate reservoirs are found in China and abroad. This makes the study of lacus-trine carbonate which learns from the theory of marine carbonate get more concerned and achieved certain results. The Cretaceous lacustrine algal stromatolite reef of Brazil, s Santos Basin is a special type of reservoir. This study enriched lacustrine carbonate theory. Through the seismic reflection structure, and properties of three-dimensional seismic sections ,core deposit structure, containing material, core and thin section diagenetic porosity and permeability analysis, drilling lithological profile, logging curve reflects the change and cycle characteristics graded phenomenon comprehen-sive analysis, summed up the main characteristics and controlling factors of the Cretaceous algal stromatolite reef. Algal stromatolite reefs are stacked by stromatolite and bonded by algae, making large areas of cement reef. The algal stromatolite reef has good porosity and permeability. It is a good reservoir. The development and distribution of algal stromatolite reef are mainly controlled by four factors, including sediment supply, the ancient uplift, water changes and algae development. Algal stromatolite reef developed on the eastern uplift belt with saltwater environment , low debris impaction and transgressive systems tract.