辽河兴隆台变质岩潜山油气来源及成藏模式

Petroleum Source and Reservoir-forming Mode of Metamorphic Buried Hill of Xinglongtai in Liaohe Depression

在地球化学和石油地质综合分析的基础上,探讨了兴隆台太古宇变质岩潜山油气来源及油气藏形成特征.结果表明,变质岩潜山油气藏序列包括浅层风化壳高压和深层内幕裂缝常压两个成藏系统;两个系统油气性质相同,正常原油饱和烃的质量分数大于75%,异戊间二稀烷烃质量分数低,Pr/Ph(姥鲛烷与植烷的相对丰度比值)在1.0左右,伽玛蜡烷丰度低,规则甾烷呈V形分布,为该区迄今所发现成熟度最高的原油,都来自南侧清水洼陷沙三段成熟度较高的烃源岩;油气运聚成藏时期相近;输导系统和油气聚集控制因素明显不同;油气成藏具有单向油源、复式输导(不整合、断层、内幕裂缝)、双向运移(侧向、垂向)和多期成藏的特征.

The comprehensive analysis of geochemistry and petroleum geology is used to study petroleum source and accumulation characters of Archean metamorphic buried hill of Xinglongtai in the west Sag of Liaohe Depression. The results show that the oil-gas reservoir sequence of the buried hill can be divided into two systems of oil pool formation. One is the high pressure system near the top of the buried hill, the other is the normal pressure system in the inner of the buried hill. The crude oils from two systems have similar geochemical characters, which is characterized by the concentrations of saturated hydrocarbons more than 75 percent, low isoprenoid alkane contents, Pr/Ph around 1.0, paucity of gammacerane,C27, C28. C29 sterane distributed in＂ V＂ shape. They are the highest maturity oils of Xinglongtai and both from the highly mature source rocks of Es3 in Qingshui Subsag. Reservoring period of two systems is very close,however, two systems are distinctly different in system of migration passage and main factors controlling hydrocarbon accumulation. Reservoirforming mode of the buried hill can be characterized by the unidirectional oil-gas source, multiple transportation system （unconformity, fault and fissure in the buried hill）, bidirectional migration （ lateral migration and vertical migration）, multi-period accumulation.