Abundant pyrobitumen related to an abnormal thermal event has been observed in the Ediacaran-lower Cambrian reservoirs of the central Sichuan Basin. Using reflected light microscopy, this study classified reservoir pyrobitumen in the Ediacaran-lower Cambrian into three groups: isotropic, mosaic, and fibrous; the mosaic pyrobitumen was further subdivided into fine-grained, medium-grained, and coarse-grained. Based on organic elemental analysis, carbon isotopic composition, nuclear magnetic resonance, X-ray diffraction, thermogravimetric-mass spectrometry, and fluid inclusion geochemistry, the relationship between the optical texture of pyrobitumen and hydrothermal temperature was determined and the influence of hydrothermal activity on crude oil cracking is discussed. With the exception of the mosaic pyrobitumen (quinoline insoluble matter-enriched tar pad precursor) found in the most porous reservoir zone, the optical texture in the Ediacaran-lower Cambrian reservoirs can be used to trace the hydrothermal activity, which occurred at the end of the Permian and may be related to the Emeishan mantle plume. The hydrothermal fluid may have invaded the strata of the second and fourth members of the Dengying Formation and the Longwangmiao Formation, along deep faults in the Gaoshiti area and migrated laterally to the northeast. The intrusion of the hydrothermal fluid directly promoted the cracking of crude oil in the reservoirs, and this behavior advances the previously accepted cracking time by approximately 60 Ma. The study found that hydrothermal activity promoted the cracking of crude oil in the Ediacaran-lower Cambrian reservoirs, which is a significant recognition for understanding the history of hydrocarbon accumulation in the Sichuan Basin.

在四川盆地中部的埃迪卡拉系-下寒武统储层中观察到了与异常热事件有关的丰富的焦沥青。利用反射光显微镜，本研究将埃迪卡拉纪-下寒武统的储层焦沥青分为三组：各向同性、马赛克和纤维；马赛克焦沥青进一步细分为细粒、中粒和粗粒。基于有机元素分析、碳同位素组成、核磁共振、X射线衍射、热重-质谱和流体包裹体地球化学，确定了焦沥青光学结构与热液温度的关系以及热液活动对原油的影响。石油裂解进行了讨论。除了在最多孔的储层中发现的镶嵌焦沥青（富含喹啉不溶物的焦油垫前体）外，埃迪卡拉纪-下寒武统储层的光学结构可用于追踪热液活动，其发生在二叠纪可能与峨眉山地幔柱有关。热液可能沿高石梯地区深断裂侵入灯二、四段和龙王庙组地层，向东北方向横向运移。热液的侵入直接促进了储层中原油的裂解，这种行为将之前公认的裂解时间提前了约 60 Ma。