珠三坳陷成岩作用与油气聚集

Diagenesis and Hydrocarbon Accumulation in Zhu Ⅲ Depression,Pearl River Mouth Basin

采用岩石学、矿物学、Ｘ射线衍射分析技术、有机包裹体以及地球化学等方法对珠三坳陷成岩作用与油气聚集规律进行研究，认为珠三坳陷的成岩作用阶段处于早成岩期和晚成岩期Ａ、Ｂ亚期，坳陷内两个主力成油（气）凹陷具有不同的成岩史，其次生孔隙发育带的形成机理也不同，油气的分布与伊蒙泥层粘土矿物转化带关系密切。珠海组砂岩石英次生加大边的形成对坳陷内油气聚集起控制作用。

The diagenesis and hydrocarbon accumulation was studied by ways of petrology.mineralogy,X-ray diffraction analysis,organic inclusion and geochemistry in Zhu ⅢDepression,Pearl River Mouth Basin.It is suggested that the diagenetic stages are the early diagenesis and subphase A, B of late diagenesis.There aer different diagenetic history and genetic mechanism of secondary pore development zone in two major source sags of the depression.The hydrocarbon distribution is correlated with the illite/smectite mixed layer clay mineral conversion zone.The hydrocarbon accumulation of wenchang A Sag is in the first and second clay mineral conversion zone,and over the first clay mineral conversion zone in Wenchang B Sag.The organic inclusions were formed in the diagenetic process.which contained rich information such as the generation,evolution and migration of oil/gas as well as reservoir and so on.By studying the organic inclusions in Zhu Ⅲ Depression,it was learned about the type,distribution,homogenization temperature,the number of times oil/gas migration and composition in the inclusions as well as the organic inclusion is correlated with the diagenesis.There are two migrations of oil and gas in Wenchand A Sag.The second time is the main period of oil and gas migration .There is only one peak of oil and gas migration in Wenchang B Sag.The secondary quartz in the sandstone from Zhuhai Formation controls the hydrocarbon accumulation.