ݺ�躣�����Դ����������Ȼ�������ݻ�ģʽ

莺歌海盆地存在中新统和渐新统两套重要烃源岩。其中，中新统海相烃源岩有机质丰度中等、成烃母质以陆源高等植物为主又有浮游植物的贡献，被认为是区内底辟浅层气田的主要烃源岩。盆地内高的地温条件和中新统源岩富含偏腐殖混合型－腐殖型有机质决定了其以生气为主的特点，通过热模拟实验并结合已知气田天然气主要成分的共生关系、分布特征和地质条件，深入探讨了该区烃气、氮气和二氧化碳等生成的先后顺序及其相互关系，建立了中新统烃源岩天然气生成演化模式，以期为本区的天然气勘探提供有价值的地球化学信息。

Characteristics of Hydrocarbon Source Rocks and Generation & Evolution Model of Natural Gas in Yinggehai Basin

There are two series of hydrocarbon so urce rocks,i.e.Miocene and Oligocene source rocks,in Yinggehai Basin.The Miocene marine source rocks are considered to be the major ones of the diapiric shallow gas fields in the basin owing to their medium abundance organic matters and the kerogen's being mainly derived from terrigenous high plants and partially from phytoplanktons.The character of mainly generating gas in Miocene is determined b y the high geothermal gradient of the basin and by the source rocks rich in the organic matters of tendency humic mixture type and humic type.Through thermal s imulation experiments and in combination with the distribution characteristics a nd geological conditions of the gas fields found and with the paragenetic relati on of the key components of natural gas in the fields,the gengeration periods an d interrelation among hydrocarbon gas,carbon dioxide and nitrogen were profoundl y investigated and a generation & evolution model of the natural gas originated from the Miocene hydrocarbon source rocks was set up so as to provide some valua ble geochemical data for natural gas exploration in the basin.