陆上中基性基性熔岩流单元剖面结构相模式初探

熔岩是地层剖面中常见的岩石类型,在我国东部中新生代陆相断坳型含油气盆地中,通常形成良好的油气储层。本文在详细研究山东昌潍坳陷下第三系厚层中基性熔岩流复合体岩心基础上,认识到一个完整的陆上熔岩流单元在剖面上通常具备“五段式”结构,即由下向上依次由A、B、C、D、E岩相段组成。分别建立了原生、风化及沉降3种熔岩流单元相模式,并提出通过绘制气孔含量曲线识别熔岩流复合体中熔岩流单元及单元中各岩相带的方法。从而不仅与传统的“三带”、“四带”认识相比更加先进,而且对火山岩油气储层特征研究、垂向模式建立以及测井资料地质解释等具新的指导意义。

VERTICAL FACIES STRUCTURE MODELS OF SUBAERIAL BASIC AND INTERMEDIATE-BASIC LAVA FLOW UNITS

Lava, which is common in the stratigraphic section, often forms important oiland gas reservoirs in down--faulted petroleum basins in eastern China. Based ondetailed studies of cores from Lower Tertiary lava flows in the Changwei basin,Shangdong Province, vertical facies structure models of "primary", "weathered" and"subsided" lava units are suggested in this paper. Besides, a method for recognizinglava flow units and various lithofacies in the three lava units by constructing afumarolecontent curve is proposed in this paper. These make the lithofacies and"unit" recognization more practicable than the traditional "three--zone model" and"four--zone model", and, thus will be conducive to the study of volcanic reservoirsand establishment of their vertical facies models.