北部湾盆地涠西南凹陷流沙港组隐蔽油气藏油源及成藏特征

Oil Sources of Concealed Reservoirs in Liushagang Formation of the Weixinan Sag and Accumulation Feature,Beibuwan Basin

运用生物标志化合物参数及同位素资料,综合划分北部湾盆地涠西南凹陷原油成因类型和烃源岩供烃组合,认为涠西南凹陷原油可划分为三大类,流沙港组烃源岩在剖面上可划分出2个供烃组合。在此基础上进行油—源精细对比,明确涠西南凹陷流沙港组一段、二段隐蔽油气藏原油的来源,它们分别来自流沙港组烃源岩的不同供烃组合。与此同时,根据隐蔽圈闭与烃源岩的接触关系,提出流沙港组发育有"类构造"和"类岩性"2种独特的隐蔽油气藏成藏模式,二者具有不同成藏特征及成藏主控因素。流沙港组一段、二段隐蔽油气藏在烃源岩、输导体系及成藏模式等方面存在差异。

Based on biomarker parameters and carbon isotopes,three types of oils and two settings of hydrocarbonsourced groups in the Liushagang Formation are classified. According to oiltosource correlation, the oil sources of the concealed reservoirs in the first and the second members of Liushagang Formation of the Weixinan sag are determined. They are generated from different hydrocarbonsourced groups. Based on contacting relationship between concealed traps and source rocks, two patterns of oil entrapments for different reservoirs,i, e parastructural and paralithologcal reservoirs. Two types of reservoirs have different accumulation features and controlling factors. For the concealed reservoirs in the first and the second mem- ber of Liushagang Formation,it is different in source rock,conducting system and oil filling pattern.