塔里木盆地原油中芳基类异戊二烯烃的检出及其地质意义

研究表明。沉积有机质中芳基类异戊二烯烃化合物是光合绿硫细菌Chlorobiaceae 的成岩转变产物。指示源岩形成于水体分层的强还原环境。塔里木 盆地台盆区海相原油中普遍检出含量丰富的C:o-C23系列芳基类异戊二烯烃化合物.原油沥青质裂解产物也显示出绿硫细菌来源的典型标志:co-C,烷基苯系物中具有高丰度四甲基苯异常分布特征。这些特征揭示塔里木 盆地台盆区海相主力油气源岩除了目前所认识的、以上升洋流模式为主导形成的中、上奥陶统台缘斜坡灰泥丘相沉积外。至少还存在一套水体分层厌氧沉积模式下发育的重要烃源岩

Aryl-Isoprenoids in Crude Oil and Its Implication in Geological Exploration

Investigations of aryl-isoprenoids in sedimentary organic matter suggest that these compounds are the diagenetic productsof certain precursors from photosynthetic green sulphur bacteria Chlorobiaceae,indicating that its source rock was formed in anintense reductive environment.Marine oils from the tableland-basin region in Tarim basin generally contain abundant aryl-isoprenoids with the carbon number range of C]o~C23 The pyrolytic products of the bitumen fraction in the oils are also characterized by a typical sulphur bacteria origin,i.e.,an abnormal enrichment of tetra-methyl benezenes in the C2~C5 alkylbenzene fraction. These data indicate that the major marine oil and gas were originated at least from one set of the importantsource rocks developed in a water-layered anaerobic sedimentary environment in the tableland-basin region of Tarim basin,iraddition to the consensus that they were derived from the Upper-Mid Ordovician sedimentary rocks with clay -mottar dome faciescontrolled by the upwelling ocean current in an incline at the platform margin.