川东北地区长兴组-飞仙关组固体沥青的形貌特征与成因分析

Morphology and genesis of the solid bitumen from the Changxing Formation-Feixianguan Formation in northeastern Sichuan

利用扫描电镜观察川东北某地区上二叠统、下三叠统储层固体沥青时,发现固体沥青与显微镜下的无定形、它形充填构造不同,按其外形可分为皮壳状、葡萄状、瘤状、蠕虫状和柿饼状5种类型。其中皮壳状、葡萄状沥青分布在飞仙关组,瘤状、蠕虫状和柿饼状沥青分布在长兴组。根据固体沥青内部鳞片状结构和球粒中间相结构推测其已达高演化阶段。

The SEM examination of the solid bitumen from the Upper Permian to the Lower Triassic reservoirs in northeastern Sichuan shows the morphological features of the solid bitumen including crustiform,botryoidal,nodular,vermiform and dried persimmons-like features,of which the crustiform and botryoidal solid bitumen is dispersed in the Triassic reservoirs,while the nodular,vermiform and dried persimmons-like solid bitumen occurs in the Permian reservoirs.The differences in occurrence represent distinct genesis and evolutionary phases of the bitumen.It is inferred from the scaly textures and pelleted mesophase textures that the bitumen has entered into high-grade evolutionary stages.