准噶尔盆地火山岩分类研究与应用

岩石分类一直是人们长期探索的课题。由于油气勘探的需要，针对储层研究的盆地火山岩分类已经成为火成岩研究的重要新方向。在综合分析国内外火山岩分类研究的基础上，根据3条野外剖面和21口钻井岩心岩屑的观察描述、岩石薄片鉴定和化学成分分析等资料，依照结构-成分-成因分类原则，建立了适于储层评价的准噶尔盆地石炭系火山岩及其他岩类的岩性分类体系和识别标准。将本区火山岩划分为火山熔岩、火山碎屑熔岩、火山碎屑岩、沉火山碎屑岩等4大类；同时将盆地内与火山岩共生的其他岩类也进行分类和识别，共划分出8大类45种基本类型。与我国东部的中新生代盆地火山岩不同，本区古生代火山岩普遍遭受较长期风化改造和蚀变作用，常见有绿泥石化、碳酸盐化和黏土矿化。这些蚀变会影响到TAS图解岩性判别的结果，因此笔者探讨了蚀变条件下的岩石识别和定名方法。本文分类体系针对火山岩储层研究，结果显示，基于该分类体系岩性与储集空间的类型及其变化规律呈现明显相关性，不同岩性的储集空间类型、组合方式和发育程度存在差异，由此可指导火山岩油气勘探。

Classification of Volcanogenic Successions and Its Application to Volcanic Reservoir Exploration in the Junggar Basin,NW China

Rock's classification has long been an intriguing task for geologists all over the world. With the development of volcanic reservoir exploration, volcanic classification buried in petroliferous basins has become increasingly needed work recently. Based on comprehensive summarization of the available classification scenarios of volcanic rocks, we proposed a so called structure-composition-origin volcanic classification for the Junggar basin focusing on the volcanic reservoir evaluation and exploration. The related data base includes 3 outcrops of 4.2 km accumulative thickness and 21 wells of 474 m volcanic core sections. Geochemical data and thin sections work have been done on these samples. 8 categories and 45 types are classified for the volcanogenic successions. Volcanic lavas, breccia-bearing lavas, pyroclastic rocks, sedimentary pyroclastic rocks, pyroclastic-bearing sedimentary rocks, hypabyssal rocks and subvolcanic rocks, and platonic rocks are described in detail. Paleozoic volcanic rocks interested have generally been suffered from alterations which can change the petrochemical compositions, and affect the result of the chemical classification using the TAS diagram. Methods were provided for the precise naming of the altered volcanic rocks in the paper. Correlations have been well established between volcanic lithology and reservoir features in the basin. The results would be useful for similar basins concerning volcanic classification and reservoir evaluation and exploration.