According to the concept of "petroleum accumulation system" , in combination with source rocks, source-reservoir relationship, reservoir characteristics and accumulation mechanism, we recognized two Mesozoic petroleum accumulation systems in the southern Ordos Basin,I. E. near-source system and far-source system. The near-source accumulation system is dominated by Hthologic traps,and features in short migration distance,abnormal pressure as major driving force of migration, and implicit carrier system. Hydrocarbon accumulation in the near-source system is mainly controlled by high-quality source rocks and reservoirs as well as favorable structural setting,and the pattern of hydrocarbon accumulation can be described as "near-source and facies-control". The far-source system is dominated structural traps and structural-lithologic traps,and is characterized by long migration distance, buoyancy as the major driving force of migration and source rock-rooted faults containing the major carrier system. Hydrocarbon accumulation in the far-source system is mainly controlled by source rock-rooted faults , local structures and high-quality sandstone reservoirs, and the pattern of oil accumulation can be described as "far-source and fault-control". The source rock-reservoir relationship in the near-source system has a "sandwich-like" structure. The synchronism of peak hydrocarbon generation with hydrocarbon accumulation provides favorable condilions for widespread and large-scale hydrocarbon charging and accumulation near source rocks. The near-source systems are the priority of future exploration, and the top-ranking play fairways in the CH9-CH8-CH7 near-source systems are the important exploration targets for large- and medium-sized oil and gas fields.%在典型油藏解剖的基础上,根据油气成藏体系概念和划分原则,结合烃源岩、源-储组合样式、油藏特征和成藏机制等,将鄂南地区中生界划分为近源成藏体系和远源成藏体系两类.前者油藏类型以岩性油藏为主,具有“近源成藏”特征,运移距离短,运移动力主要为异常压力,隐性输导,油气富集主控因素为优质烃源岩、有利储集体和构造背景,油气富集模式可概括为“近源相控”；后者油藏类型以构造、构造-岩性生油藏为主,具有“远源成藏”特征,运移距离长,运移主要动力为浮力,输导体系以通源断裂为主,油气富集主控因素为通源断裂、局部构造和有利砂体,富集模式可概括为“远源断控”.近源成藏体系源储空间呈“三明治”结构,直接大面积接触,具有“近水楼台”成藏优势,生烃高峰期与关键成藏期一致,油气就近大面积充注成藏,是下一步勘探首选领域.其中,长9-长8-长7近源成藏体系Ⅰ类富集有利区是大中型油气田重要的勘探方向.
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