琼东南盆地深水区源—储共控的天然气成藏模式

琼东南盆地深水区天然气成藏过程复杂。通过开展区域构造—沉积演化、烃源岩—储层识别评价及油气运聚等多方法的综合性研究，明确了中央拗陷天然气来源、优势成藏组合及区带。研究表明，崖城组三角洲的发育规模及古地貌控制了煤系和陆源海相烃源岩的分布，形成了生气为主、油气兼生的渐新统陆源海相烃源岩；受早渐新世三角州分布、中中新世以来沉积充填速率及水深变化的控制，预测中央坳陷南斜坡及松南低凸起区优质烃源岩规模更大，且储层在相同的海拔深度条件下，相比北部陡坡带势能较低，油气输导能力更佳。深水区崖城组优质海相烃源岩、大型三角州砂岩输导体及低流体势区的耦合分布控制了天然气初次运移的优势方向，中央坳陷南部斜坡及低凸起是下一步大中型气田的突破方向。

Natural Gas Accumulation Model Controlled Jointly by Source andReservoir in Deep Water Area of Qiongdongnan Basin

The processes of natural gas accumulation in the deep water area of the Qiongdongnan Basin are complex. Through the comprehensive study of regional tectonic-sedimentary evolution, source-reservoir identification and evaluation, as well as hydrocarbon accumulation, the sources, dominant plays and zones of natural gas in the central depression are identified. The study shows that the development scale and paleo-geomorphology of the Oligocene delta controled the distribution of coal-series and terrestrial marine source rocks, and then formed the Oligocene terrestrial marine source rock which mainly generated natural gas but could also generate oil; Controlled by the distribution of early Oligocene delta, sedimentary filling rate and water depth since the Middle Miocene, it is predicted that the scale of high-quality source rocks in the south slope and Songnan low uplift area of the central depression is larger, its potential energy of reservoirs is lower than that of the northern steep slope zone at the same altitude depth, and the oil and gas transport capacity is better. The distribution of high-quality marine source rocks, large reservoirs and low-fluid potential areas controls the dominant migration of natural gas in deep waters, thereby southern slope of the central depression and the low convex are the potential breakthrough targets of large and medium-sized gas fields.