松辽盆地断陷期火山岩典型地震相的地质解译

以松辽盆地营城组和火石岭组火山岩为例，对火山岩地震相类型及其可能地质解释进行分析。依据外形和内部结构可将地震相划分为4类：丘状/透镜状—亚平行反射（Ⅰ类）、板状/席状/盾状—平行/亚平行反射（Ⅱ类）、穹窿状/丘状—空白/杂乱反射（Ⅲ类）和蘑菇状—杂乱反射（Ⅳ类）。Ⅰ类对应流纹质或玄武质岩石，对应岩相多是喷溢相和爆发相互层，富含气孔、粒间孔和裂缝，多为中孔隙度，发育多层有利储层，火山口—近火山口相带的储层厚度大、远源相带厚度小。Ⅱ类对应基性熔岩或酸性碎屑岩，对应的岩相多是喷溢相夹爆发相，富含气孔、粒间孔和裂缝，多为高孔隙度，发育多层有利储层，从火山口—近火山口相带到远源相带的储层厚度变化小。Ⅲ类对应英安岩或粗安岩，对应的岩相多是侵出相或喷溢相，富含裂缝，多为中低孔隙度，仅在顶部发育一层有利储层，火山口—近火山口相带的储层厚度大、远源相带厚度小。Ⅳ类对应流纹质凝灰岩、流纹岩或粗面岩，对应的岩相多是爆发相和喷溢相互层，富含气孔、溶蚀孔和裂缝，可能为中高孔隙度，发育多层有利储层，火山口—近火山口相带的储层厚度大、远源相带厚度小。

Geological significances of typical seismic facies of volcanic rocks of the rifted period in Songliao Basin,NE China

Based on seismic and borehole data,we discuss typical facies types and geological significances of volcanic rocks of Yingcheng Formation and Huo-shiling Formation in Songliao Basin.The seismic facies can be divided into 4 types:moundy/lenticular shape-subparallel (M/L-SP),platy/sheet/shield shape-parallel/subparallel (P/S/Sh-P/SP),dome/moundy shape-vacant/disordered (D/M-V/D),and mushroom shape-disordered (M-D).The M/L-SP is correlated to rhyolitic or basaltic rocks,and corresponds to interbedding effusive facies and eruptive facies.This type facies has middle-good porosity,abundant vesicles,intergranular pores,and fractures,and favorable reservoirs might probably be developed,which are thick in the center of seismic facies unit and are thin in the distal part.The P/S/Sh-P/SP is correlated to basaltic lava or rhyolitic pyroclastic rocks,and corresponds to effusive facies interbedded with eruptive facies.With good-excellent porosity,abundant vesicles,intergranular pores,and fractures,several thick favorable reservoirs might be developed.The D/M-V/D is correlated to dacite or trachyandensite,and corresponds to intrusive facies and effusive facies.With fair-good porosity and abundant fractures,only one reservoir might probably be developed.The M-D is correlated to rhyolitic tuff,rhyolite or trachyandensite,and corresponds to interbedding eruptive facies and effusive facies.With good-fair porosity,abundant vesicles,dissolution pores,and fractures,several favorable reservoirs might be developed.