松辽盆地营城组古火山机构的剖析——以东南隆起区三台珍珠岩山为例

Analysis of Ancient Volcanic Edifices of Yingcheng Formation in Songliao Basin——Examples from the Mountain of Perlite in Santai,Southeast Uplift

三台地区下白垩统营城组一段岩石类型有隐爆角砾岩、角砾熔岩、熔结角砾岩、珍珠岩、流纹岩和凝灰岩,所属岩相为火山通道相、侵出相、喷溢相、爆发相。厘定古火山口位置的依据主要是通过分析隐爆角砾岩和珍珠岩的岩性岩相及其分布。整个火山机构划分为中心相组、近源相组和远源相组。中心相组即火山口相,主要包括火山通道相和侵出相,近源相组主要包括喷溢相,远源相组主要包括爆发相。相序(以火山口为基点)为火山通道相隐爆角砾岩亚相—侵出相中带亚相—侵出相内带亚相—喷溢相下部亚相—喷溢相中部亚相—爆发相热碎屑流亚相。近源相组较中心相组储层物性优越。其中喷溢相上部亚相是储层物性最好的岩相带。

The lithological types of the first member of Yingcheng Formation of the Lower Cretaceous in Santai area consist of crypto-explosive breccia, breccia lava, welded breccias, perlite, rhyolite and tuff. Volcanic facies are volcanic conduit facies, extrusive facies, effusive facies and explosive facies. Geological evidence for determination of the position distribution of perlite and rhyolite. Whole volcanic of ancient crater are lithological character,facies and edifice can be subdivided into the central facies,the proximal facies and the distal facies. The central facies, namely as volcanic vent facies, includes volcanic conduit facies and extrusive facies. The proximal facies is effusive facies, the distal facies is explosive facies. Facies-sequence is crypto-explosive breccia subfacies of volcanic conduit facies, middle subfacies of extrusive facies, inner subfacies of extrusive facies, lower subfacies of effusive facies, middle subfacies of effusive facies and pyroclastic flow deposits of explosive facies. The permeability and porosity of the proximal facies is more predominant than the central facies. The upper subfacies of effusive facies is the best reservoir.