四川盆地震旦系灯影组微生物丘沉积演化特征

微生物丘是四川盆地灯影组的主要油气储集相带。基于岩心与野外露头观测,运用薄片鉴定和X衍射分析等手段,归纳了微生物丘中主要岩石类型和特殊构造。结果表明:微生物丘中的主要岩性包括藻纹层白云岩、藻叠层白云岩、泡沫绵层白云岩、藻凝块白云岩、藻格架白云岩、藻砂屑白云岩、角砾状藻白云岩等,而格架状构造是微生物丘中的重要沉积构造;微生物丘可划分为丘基、丘核、丘坪、丘盖、丘翼5种微相,以海平面变化为主要依据总结出丘基-丘核-丘盖、丘基-丘核-丘坪、丘基-丘核-丘翼3种垂向沉积规律。

SEDIMENTARY AND EVOLUTIONARY CHARACTERISTICS OF SINIAN DENGYING-FORMATION MICROBIAL MOUND IN SICHUAN BASIN

Microbial mound is the principal hydrocarbon accumulation facies-belt in Dengying Formation of Sichuan Basin.Based on the core and outcrop observation,the main types of the rock and special structures in the microbial mound were summarized by means of the thin section identification and X-ray diffraction (XRD).The results show that the main lithologies of the mound include laminite,stromatolite,spongiostromata-type dolomite,thrombolite,cyanobacteria bound-frame dolomite,cyanobacteria related dolomite,cyanobacteria related carbonate breccia,etc.and the frame-like structure is an important sedimentary structure in the microbial mound;the microbial mound can be divided into five microfacieses:mound base,mound core,mound flat,mound cap,mound flank,mainly based on the changes of the sea level,three kinds of the vertical depositional laws were summarized:mound base-mound coremound cap,mound base-mound core-mound flat and mound base-mound core-mound flank.