珠江口盆地番禺4洼新近系油气成藏条件及成藏模式

Accumulation conditions and modes of Neogene hydrocarbons in Panyu 4 Sag,Pearl River Mouth Basin

为深入剖析珠江口盆地番禺4洼这一小型富洼油气成藏机理,结合油气成藏条件与特征的分析,充分利用地震资料及钻井资料,建立了番禺4洼独特的油气成藏模式。研究结果表明,番禺4洼油气成藏条件优越,生烃量大,发育文二段至文五段等4套烃源岩系,但以文三段和文四段为主力烃源岩层,烃源岩分布面积广且垂向叠合性好;珠江组上段、下段发育2套优质储盖组合,输导介质多样;油气纵向分布层系多,以珠江组最为富集,横向上主要分布在缓坡带和陡坡带,以构造型油气藏为主。番禺4洼新近系油气成藏模式包括源-断耦合成藏模式和源-面-断立体成藏模式,两者在油气成藏机理上存在较大差异。

In order to deeply analyze the hydrocarbon accumulation mechanism of Panyu 4 Sag low-lying area of Pearl River Mouth Basin,combined with the analysis of hydrocarbon accumulation conditions and characteristics,and making full use of seismic data and drilling data,the unique hydrocarbon accumulation model of Panyu 4 Sag is established.The results show that Panyu 4 Sag has favorable hydrocarbon accumulation conditions and large hydrocarbon generation.Four sets of source rock series,including WC2-WC5,are developed.However,WC3 and WC4 are the main source rocks with wide distribution area and good vertical superposition;Two sets of high-quality reservoir cap rock assemblages are developed in the upper and lower members of Zhujiang Formation,with various transport media;Oil and gas are mainly distributed in the gentle slope zone and steep slope zone,mainly in structural reservoirs.The Neogene hydrocarbon accumulation models in Panyu 4 Sag include the source fault-coupling accumulation model and the source surface fault three-dimensional accumulation model,which are quite different in hydrocarbon accumulation mechanism.