中文摘要：

分析中国中低丰度油气资源大型化成藏的条件与分布特征。成藏要素的大型化发育与规模变化是油气大型化成藏的物质基础,决定了油气藏分布的区域性;海相烃源灶内分散液态烃裂解规模生气与煤系烃源灶抬升期规模排气是大型化成藏的重要条件,决定了烃源灶整体进入主生气阶段的规模性;体积流和扩散流是大型化成藏的主要运聚机制,保证了烃源输入的充分性;薄饼式、似层状和集群式成藏是大型化成藏的主要形式,保证了成藏的规模性。中低丰度油气资源成藏分布有近源性、成藏组合有主体性、成藏时机有晚期性、成藏类型有单一性特点。海相克拉通盆地古隆起围斜区、陆内坳陷盆地广大斜坡低部位—坳陷区以及前陆盆地缓翼斜坡区等是油气大型化成藏的主要部位,表现为大面积和大范围成藏两种类型。中国中低丰度油气资源大型化成藏认识的提出,提升了叠合盆地中深层和坳陷盆地斜坡低部位—坳陷区油气资源发现潜力,规模扩大了勘探范围,实现了油气勘探＂由局部二级构造带向以主力烃源灶为中心的全盆地＂和＂由中浅层向深层、超深层＂的推进发展。

英文摘要：

This paper analyzes the large-scale accumulation conditions and distribution characteristics of medium-low abundance hydrocarbon resources in China.Large-scale development of accumulation elements and their change in scale are the material basis of large scale oil and gas accumulation,determining the regional nature of oil and gas distribution.Liquid hydrocarbon dispersed in marine source rocks being cracked to form a large volume of gas and coal measure source rocks expelling gas during uplift are two important factors for the formation of large-scale hydrocarbon accumulation,which control the scale of source rocks that enter the main gas-generating stage.Volume flow and diffusive flow are the main migration-accumulation mechanism for the large-scale hydrocarbon accumulation,which ensures the sufficiency of hydrocarbon supply.Pancake,layer-like,and cluster are three main accumulation forms of large-scale hydrocarbon accumulation,which ensure the scale of hydrocarbon accumulation.Middle to low abundance hydrocarbon resources are characterized by near-source distribution,main-body play,late accumulation stage and single accumulation type.The periclinal area of palaeo-highs in marine craton basins,the lower slopes and sags in an intra-continental depression basin,and the gentle slopes of foreland basins are the most likely areas for the development of large-scale hydrocarbon accumulation,and they have two types of accumulation,large area and large scope.The proposal of the large-scale accumulation of middle to low abundance hydrocarbon resources in China improves the hydrocarbon discovering potential in middle to deep layers of superimposed basins and in the lower slopes and sags in depression basins,enlarges the exploration scale,and extends the hydrocarbon exploration from local second-order structure zones to the whole basin with the main source rock as the center,and from middle layers to deep,even super-deep,layers.