渤海南部黄河口凹陷晚期成藏特征及富集模式

摘要

The Huanghekou Sag is one of the major oil-bearing areas in the offshore Bohai Bay Basin and is characterized by late-stage accumulation.The Easy Ro％ model is used to simulate the hydrocarbon generation time of source rocks, showing that the major source rock has matured since 5.1 Ma.The analysis of the migration system reveals that hydrocarbons in the Huanghekou Sag migrate through faults and fractures which are the main pathways.The analysis of reservoir inclusions shows that the main charge time is 5.1 Ma or later.The late-stage accumulation in the Huanghekou Sag is characterized by late quick hydrocarbon generation, late vertical migration through faults, near-source accumulation and late charge.The main factors controlling the hydrocarbon enrichment are the regional reservoir-cap assemblage of the Shahejie Formation and lower member of the Minghuazhen Formation, dominant migration pathways, and traps formed by Neotectonic movement.Paleogene overpressured reservoirs with near source rocks and Neogene shallow water deltaic reservoirs are the most important hydrocarbon accumulation models in the Huanghekou Sag.%黄河口凹陷是渤海海域的主要含油区之一,具有明显的晚期成藏特征.应用Easy R<,o>%模型模拟了烃源岩生烃演化史,结果表明主力烃源岩距今5.1 Ma以来快速成熟;通过断裂分析开展了油气输导体系研究,认为研究区油气运移以断裂输导为主;流体包裹体分析表明油气蘸主成藏期为距今5.1 Ma以来.研究结果表明,晚期快速生烃、晚期垂向断裂输导,近源成藏和晚期充注是黄河口凹陷油气晚期成藏的主要特征.沙河街组和明化镇组下段区域性储盖组合、优势运移通道和新构造作用形成的相关圈闭是控制油气富集的主要因素,古近系近源压控和新近系断控浅水三角洲富集模式是黄河口凹陷最重要的两种油气富集模式.