【摘要】 对塔里木盆地古生界海平面变化及沉积相分析、地震反射特征识别及生烃成藏配置关系的综合分析表明,下奥陶统上部—中奥陶统是塔里木盆地海相主力烃源岩。主要依据有:①下奥陶统上部—中奥陶统是塔里木盆地震旦系奥陶系沉积水体最深的层位,沉积有机质相对平均含量最高;②北部坳陷区地震响应表明,下奥陶统上部—中奥陶统下部为一套弱反射或无反射区,具有以泥质岩为主的反射特征,推测为烃源岩,其地震反射特征与下寒武统泥质烃源岩反射特征相似;③海平面变化及沉积相分析表明,下奥陶统上部—中奥陶统烃源岩主要形成于还原环境的饥饿盆地—盆地边缘相环境,据推测分布于整个北部坳陷区;④生烃成藏配置关系分析表明,塔中及塔北隆起的主要海相原生油藏的成藏期为晚海西燕山期,与北部坳陷区下奥陶统上部—中奥陶统烃源岩的生油高峰期吻合,而与下寒武统源岩生油高峰期(晚奥陶世—石炭纪)及上奥陶统源岩生油高峰期(白垩纪以来)不配套;⑤目前在塔中及塔北隆起已发现的油气藏分布特点说明了油气主要来源于北部坳陷盆地相烃源岩分布区。更多还原

【Abstract】 Comprehensive analysis on the sea level changes, sedimentary facies, seismic reflection characteristics, and relationship between hydrocarbon-generation and reservoir formation of the Paleozoic in Tarim Basin shows that the area from the upper of the Lower Ordovician to the Middle Ordovician developed chief marine source rock. The evidences include following aspects: ①The upper of the Lower Ordovician to the Middle Ordovician is the stratum with the deepest sedimentary water in the Sinian to Ordovician of Tarim Basin. The average content of sedimentary total organic carbon (TOC) is the highest. ②The seismic response from the upper of the Lower Ordovician to the lower of the Middle Ordovician in the northern depression of Tarim Basin is characterized by weak or blank reflection and similar to that of the Lower Cambrian mudstone source rock. It is speculated that the stratum is made of source rock. ③The analysis on sea level change and sedimentary facies indicates that the source rocks from the upper of the Lower Ordovician to the Middle Ordovician were mainly formed in starved basin to marginal basin with deoxidization environment. The source rocks may be distributed in all area of the northern depression of Tarim Basin. ④The analysis on relationship between hydrocarbon-generation and reservoir formation shows that the formations of primary oil reservoirs of chief marine in the central and northern uplift of Tarim Basin are in the stage from the Permian to the Cretaceous, which is coupling to the chief oil-generation stage of source rock from the upper of the Lower Ordovician to the Middle Ordovician, but not coupling to the oil-generation stage of source rock of the Lower Cambrian and the Late Ordovician. ⑤The distribution of oil-gas reservoirs discovered in the central and northern uplift of Tarim Basin indicates that oil and gas should be mainly migrated from the distributing region of basin facies’ source rocks in the northern depression.更多还原