南黄海盆地南部坳陷三叠纪以来的构造演化与油气成藏

目前已在陆上苏北盆地发现多个中古生界气田，但在其东侧的南黄海盆地南部坳陷一直没有获得勘探突破。为了寻找后备油气基地，利用2Dmove软件对研究区内典型地震剖面进行了平衡剖面分析，恢复了三叠纪以来的构造演化过程，在此基础上分析了三叠系油气成藏条件，总结出了有利成藏模式。结果表明:南部坳陷三叠纪以来共经历了4期构造演化过程；研究区东部三叠系烃源岩仅发生过一次生烃，而中西部可能存在二次生烃；古近纪Ed-Es阶段构造活动剧烈，是所有圈闭的最终定型期，同时也是早期所形成油气藏的强烈破坏时期；综合油气成藏条件分析认为研究区主要存在3种有利油气成藏模式。研究认为，南黄海盆地南部坳陷的三叠系油气成藏规律主要受构造演化所控制，研究区东部和中西部发育不同的油气成藏模式。

Tectonic Evolution and Hydrocarbon Accumulation Since Triassic of the Southern Depression in South Yellow Sea Basin

At present several gas fields have been discovered in the Mesozoic-Paleozoic of the Subei Basin,but exploration has not got breakthrough in the southern depression of the South Yellow Sea Basin which is located to the east of Subei Basin.In order to open up the hydrocarbon reserve,we have conducted balanced cross-section analysis of typical seismic section in the study area using 2Dmove software and recovered the tectonic evolution since Triassic.On this basis,we have analyzed hydrocarbon accumulation conditions and concluded the favorable accumulation models.The studying area has undergone four stages of basin evolution since Triassic.Triassic source rocks only experienced one hydrocarbon generation in eastern part of the study area,while the source rocks may experience secondary hydrocarbon generation in the mid-west part.Tectonic activity was intense in Ed-Es stage of Paleogene when all the traps fell into final pattern and reservoirs formed in the early stage were strongly destroyed.By the analysis of Triassic hydrocarbon accumulation in the Southern Depression,we proposed three accumulation models.Through the above research we know that hydrocarbon accumulation of Triassic in Southern Depression of the South Yellow Sea Basin is mainly controlled by the tectonic evolution.Accumulation models in the eastern part of the study area were different from those in the mid-west part.