松辽盆地中生代火山岩油气藏特征

松辽盆地中生代火山岩油气藏主要形成于晚侏罗-早白垩世火山-沉积序列中。在火山-断陷成盆期,深湖相泥质岩与火山岩呈现垂向或侧向的接触关系,是火山岩油气藏形成的主要因素。火山岩储层岩石类型主要包括熔岩类、火山碎屑岩类。火山岩储层主要发育在溢流相,尤其是溢流相顶底部的气孔带是最为有利的储集相带。火山岩储集空间可分为原生孔隙、次生孔隙和裂缝3种类型。区内火山岩油气藏主要受NNE向和近EW向两组区域大断裂控制,大多分布在区域性断裂活动带、基底隆起或构造带上。

CHARACTERISTICS OF MESOZOIC VOLCANIC RESERVOIRS IN SONGLIAO BASIN

The Mesozoic volcanic reservoirs in Songliao basin formed in the Late Jurassic to Early Cretaceous volcanic-sedimentary sequences. The vertical or lateral contacts between the deep lacustrine argillaceous rocks and volcanic rocks are the key factors of the formation of volcanic reservoirs during the volcanic-fault depression period—basin forming. Rock types of volcanic reservoirs include mainly lava and pyroclastic rock.The major volcanic reservoirs are mainly in the effusive facies, and the best reservoir belts are in the gas cavity belts on top and at base of the effusive facies. The reservoir spaces can be divided into primary pores, secondary pores and fissures. The volcanic reservoirs are mainly controlled by both NNE and nearly EW regional faults, most of them occur in active regional fault zones, basement uplifts or tectonic zones.