潍北凹陷次级构造带孔三段火山岩油气成藏条件对比研究

潍北凹陷是郯庐断裂带内部典型的走滑拉分盆地，火山岩发育在古近系孔三段。通过对该区火山岩油气藏成藏要素研究，认为孔二中上亚段油页岩和灰质泥岩为主力烃源岩；遭受强烈风化作用的溢流旋回上部亚相为主要储集层，储集空间以裂缝-孔隙型为主；断距较大的反向断块与两套主力烃源岩直接对接，形成良好的圈源配置；断层和风化壳形成的输导网络提供了有利的运移条件；孔二中下亚段暗色泥岩提供了良好的盖层条件。根据潍北凹陷孔三段火山岩油气藏成藏特征，总结出3 种成藏模式，即北部洼陷带近源相控成藏模式、灶户断鼻带断鼻带中源断-相双控成藏模式和南部斜坡带远源断控成藏模式，灶户断鼻带和南部斜坡带是有利成藏区。

Compared research of reservoir-forming condition of Ek3 volcanic rocks in sub-structural belt of Weibei sag

Weibei sag is a typical strike-slip pull-apart basin in Tanlu fault zone. The volcanic rocks mainly distributed at Ek3 of Eogene. Based on the analysis of the reservoir-forming factors of volcanic reservoirs in this area, oil shale and lime mudstone of middle-upper submember of Ek2 were considered to be the chief source rocks. The upper overflow subfacies subjected intense weathering were the main reservoir, and fractured-pore was the main reservoir space. Reverse fault blocks with greater displacement exposed directly to two groups of source rocks and formed a favorable trap-source configuration. Grooming network formed by fault and weathering crust provided favorable migration conditions. Dark mudstone of middle-lower submember of Ek2 provided a favorable cap rock condition. Three kinds of accumulation modes were summarized: Near-source lithofacies controlled accumulation model in northern subsag belt,middle-source fault-lithofacies controlled accumulation model in Zaohu fault zone and far-source faults controlled accumulation model in southern slope zone. Zaohu fault zone and southern slope zone were favorable area of hydrocarbon accumulation.