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地球科学(中国地质大学学报) 2016
从含油气检测来洞悉琼东南盆地东部发育始新统烃源岩的可能性
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Abstract:
目前普遍认为琼东南盆地天然气来源于渐新统和中新统海相煤型烃源岩,对于始新统偏I型干酪根烃源岩的存在尚不明确,因此确定始新统烃源岩生烃可能性及其分布将为下一步勘探提供重要依据.琼东南盆地东部45块样品的流体包裹体系统测试分析以及天然气和轻烃地球化学特征分析结果表明,盆地东部气藏以油型气及油型-煤型混合气为特征,至少有4期天然气充注,其中第1期天然气充注与始新统烃源岩生排烃有关.由此认为,琼东南盆地东部可能发育始新统偏I型干酪根烃源岩,主要分布于松南-宝岛-长昌凹陷以及北礁凹陷.
It is generally held that most gas in Qiongdongnan basin, the South China Sea, is coal type gas and comes from the Oligocene and Miocene marine source rocks, while the existence of Eocene source rocks is uncertain. Determining Eocene source rocks will provide significant foundation for oil and gas exploration. The systematical analysis of fluid inclusions of 45 samples and geochemical characteristics of gas and light hydrocarbons indicate that most of the gas is oil type gas and oil coal gas with 4 gas charging episodes. The first gas charging episode probably comes from Eocene source rocks in eastern of Qiongdongnan basin, the South China Sea. The results indicate that it probably develops kerogen type I of Eocene source, distributed in Songnan Baodao Changchang depression and Beijiao depression of Qiongdongnan basin, the South China Sea, which can be regarded as advantage exploration targets