银根盆地苏红图组火山岩特征及其与油气的关系

The Feature of Volcanic Rock of Suhongtu Formation in Yingen Basin and Its Relationship to Oil and Gas

苏红图组火山岩主要出露于银根盆地中央隆起带的南北两侧，通过对野外露头的详细观察及室内的分析研究，认为该火山岩形成于早白垩世中晚期，岩石类型主要为呈熔岩被产出的火山熔岩，包括撖榄粗面玄武岩、橄榄玄武粗安岩、粗安岩等，其次为少量的火山碎屑岩和次火山岩相的辉绿岩，岩石学及岩石化学研究表明，该火山岩为一套钾玄岩系列岩石，这套火山岩的喷发对油气的生成与聚集构成有利条件，首先，火山喷发提供的热能促进了盆地内烃源岩的成熟及向烃类的转化；其次，气孔、溶孔、溶洞、裂缝发育的火山岩可以作为良好的集集层，较厚的玄武岩层的中央相带及层状侵入的辉绿岩可以作为较好的盖层．

The volcanic rock of Suhongtu Formation is mainly exposed on south and north sides of the central uplift in Yingen Basin. According to the detailed field survey and laboratory research of the outcrops, it is held that the volcanic rock was formed in middle to late stage of Early Cretaceous Period. The volcanic rock occurs mainly in lava sheet, including olivine trachybasalt, shoshonite, trachyandesite ect. In addition, the valcanic rock also includes a little pyroclastic rock and diabase of subvolcanic lithofacies. The studies in petrography and petrochemistry show that they belong to shoshonitic series rocks. The eruption of the volcanic rock was favourable to the formation and accumulation of oil and gas. It is because (1) the heat energy provided by the volcanism promoted the maturation of soure rock and its transformation into oil and gas. (2)some volcanic rock with gas holes, dissolved pores and fissures can be acted as good reservoir rock, and the central facies tract of thick basalt layer and layered diabase are good cap rock.