松辽盆地北部升平气田营城组火山岩储层特征与成岩演化

对升平气田白垩系营城组火山岩岩石学与物性特征、储集空间类型及其形成和演化等研究结果表明,火山岩岩石类型主要有火山碎屑岩、火山熔岩和沉火山岩,以流纹岩为主,少量英安岩、安山岩。火山岩气藏储集空间以次生溶孔(洞)为主,其次为原生孔隙和裂缝。火山岩的演化过程可划分为前期和后期两个阶段。前期阶段以火山自身活动为主,主要形成气孔和火山角砾间孔为主的原生孔隙;后期阶段包括火山熔岩的冷凝作用与火山岩的后生成岩作用,是火山岩储集空间形成的主要时期。研究区风化剥蚀面、断层与裂缝是天然气成藏的主要运移通道,也是有利的储集空间。

Reservoir characteristics and petrogenesis of volcanic rocks in the Yingcheng Formation of the Shengping gas field, northern Songliao basin

Study of the petrological and physical characteristics, reservoir opening space types and formation and evolution of volcanic rocks in the Cretaceous Yingcheng Formation in the Shengping gas field, Songliao basin, shows that the major volcanic reservoir rocks are lavas, pyroclastic rocks and sedimentary-volcanic rocks, with rhyolite predominating, in addition to small amounts of dacite and andesite. The volcanic gas reservoir spaces are dominated by secondary solution pores (cavities), with subordinate primary pores and fissures. The evolution of the volcanic reservoir rocks involves the early and late phases. The early phase was characterized by volcanic activity, when mainly primary pores including vesicles and pores between volcanic fragments;the late phase included cooling of lavas and epi-petrogenesis of volcanic rocks, which was the main period of formation of volcanic reservoir spaces. The erosion and weathering surfaces as well as faults and fractures in the study area were main conduits for gas migration and also favorable reservoir spaces for gas accumulation.