陆家堡凹陷白垩系下统火成岩储层特征及成藏模式

辽河外围盆地陆家堡凹陷中生代火成岩油藏主要分布在早白垩世火山沉积序列中,火成岩岩石类型主要包括火山熔岩、火山碎屑熔岩、火山碎屑岩、沉火山碎屑岩和浅成侵入岩等五大类岩性,有利储层主要发育在火山通道相隐爆角砾岩亚相、喷溢相上部亚相、爆发相空落亚相及侵入相浅成侵入亚相等岩相带,含油火成岩储层储集空间多为孔隙-裂缝组合型。九佛堂期为凹陷快速断陷期,该时期欠补偿沉积的深湖-半深湖相泥质岩及油页岩,是火成岩油藏形成的资源基础。火成岩油藏受烃源岩供给、构造应力作用、火山机构特征、岩浆活动时期等多个因素控制。依据火成岩油藏赋存层位及储层岩石类型,将区内火成岩油藏划分为九佛堂组侵入岩油藏、九佛堂组火山碎屑岩油藏及义县组火成岩油藏等三种类型,并建立相应的成藏模式。

Igneous rock reservoir characteristics and accumulation pattern of lower Cretaceous in Lujiapu depression

Mesozoic igneous reservoirs in Lujiapu depression of Liaohe peripheral basin are mainly distributed in the early cretaceous volcanic sedimentary sequence.The igneous rock types mainly include five kinds of lithology,namely volcanic lava,volcanic clastic lava,pyroclastic rocks,pyroclastic rock,and hypabyssal intrusive rocks.Favorable reservoirs are mainly developed in facies belts,such as cryptoexplosive breccia subfacies,the upper subfacies of eruption phase,eruption phase empty fall subfacies and intrusive facies hypabyssal intrusive belt.The reservoir space with igneous reservoir is more of pore-fracture combination.Jiufotang formation was at rapid fault depression period,and the argillaceous rock of under-compensation deposition during the period of deep lake-half deep lacustrine and oil shale,acting as the resource basis of the igneous reservoirs formation.Igneous reservoirs are controlled by the supply of hydrocarbon source rock,tectonic stress action,and volcanic mechanism characteristics.According to occurrence horizon of igneous rock reservoir and the reservoir rock types,the igneous rock reservoirs can be divided into three types,intrusive rock reservoir of Jiufotang formation,volcanic clastic rock reservoirs of Jiufotang formation and igneous reservoir of Yixian formation,and the corresponding accumulation models have been established.