川中震旦系灯影组原生—同层沥青的成因及意义

以往研究认为,四川盆地震旦系灯影组广泛存在的沥青为后生—储层沥青,其来自古油藏裂解,油源为下寒武统泥岩。但近年在四川盆地震旦系灯影组亦发现原生—同层沥青存在,是以上观点无法解释的。通过重新研究四川盆地震旦系灯影组沥青镜下赋存状态、生物标志物及沥青含量分布特征,并结合震旦系灯影组碳酸盐岩无机微量元素等的分析,结果表明沥青确实有来自震旦系灯影组碳酸盐岩生油岩的贡献,且灯影组碳酸盐岩也具备了形成好的生油岩的古沉积环境和保存条件。

Origin and significance of Sinian original and coexist bitumen of central Sichuan Basin

The previous studies indicated that the widespread bitumen of the Sinian Dengying Formation in the central Sichuan Basin were epigenetic reservoir bitumen, which originated from the cracking of oil to gas in paleo oil pools and sourced from the Lower Cambrian mudstones. However, the original coexisting bitumen were also found in the Sinian Dengying Formation in the central Sichuan Basin, which could not be explained by the above opinion. Through the restudy of bitumen occurrence under microscope, biomarker characteristics and bitumen content, combined with the analysis of carbonate inorganic microelement, it was concluded that some of the bitumen came from the carbonate source rocks in the Dengying Formation, and the carbonate rocks in the Dengying Formation were qualified for favorable source rocks in paleo sedimentary environment and preservation condition.