右江盆地晚古生代白云岩与层序地层的关系及其储集性

Research on relationship of Late Palaeozoic dolomite to sequence evolution and reservoir characteristics of dolomite in Youjiang Basin, Guangxi

以广西右江盆地晚古生代白云岩为研究对象,详细研究了白云岩在剖面上的分布与产出的形态,归纳起来包括5种类型:(1)与硅质岩互层;(2)与灰质泥岩互层;(3)与灰黑色中层含光壳节石的微晶灰岩互层;(4)与灰白色厚层块状生物屑灰岩互层;(5)与厚层块状灰质白云岩、白云质灰岩互层。在此基础上讨论了白云岩的分布与层序地层学的关系,即与LST有关的白云岩主要为一套角砾状白云岩;与TST有关的白云岩主要为薄层状的硅质粉—细晶白云岩或细晶白云岩;与HST有关的白云岩主要为厚层块状中—粗晶白云岩或含残余生物屑结构白云岩。进而研究了白云岩的储集性,讨论了不同类型的白云岩和不同体系域内的白云岩的储集性。这为全面研究白云岩储层提供了基础资料。

Taking the dolomite of Late Palaeozoic Era in Youjiang Basin as example, this paper researches in detail the distribution and shapes of the dolomite in profiles which include five types: (1) siliceous dolomite and interbeded silica rock; (2) dolomite and interbeded calcareous mudstone; (3) ataxitic dolomite and interbeded shelly microcrystallite limestone; (4) dolomite and interbeded biologic limestone; (5) dolomite and interbeded dolomitized limestone. The paper also discusses the relationship of dolomite distribution to sequence evolution that is the petrology feature of dolomite in different system tracts and studies the reservoir characteristics of different types of dolomite and dolomite in difference system tracts.