升平气田下白垩统营城组火山岩的岩性学与岩相学、火山活动机制等研究结果显示,火山岩岩石类型主要为火山碎屑岩和火山熔岩,少量火山碎屑熔岩、沉火山碎屑岩、火山碎屑沉积岩和次火山岩。熔岩以流纹岩为主,少量英安岩。营城组重点含气层段营三段可划分为4个火山喷发-喷溢旋回。火山活动以喷发频率高和喷发迅速、间隔时间短和冷凝迅速、较强烈的中心式爆发与较宁静的裂隙武溢流喷发交替为特征。可识别出火山爆发相、火山溢流相、火山侵出相、火山通道相和火山沉积相5个相和溅落熔岩、火山碎屑岩、熔岩、火山重力流、火山颈和次火山岩6个亚相。高产气流井主要位于火山爆发相以及爆发相与溢流相互层地带。火山岩的储集性能主要受岩性、岩相、火山岩厚度及其空间分布特征的控制,其次受火山活动特点、古地貌、成岩作用与构造作用的影响。
Study on lithology and petrography of volcanics and mechanism of volcanic activities in the Lower Cretaceous Yingcheng Formation of the Shengping gas field in the Songliao Basin, indicates that rock types are mainly pyroclastics and lava, with minor pyroclastic lavas, sedimentary pyroclastic rocks, pyroclastic sedimentary rocks and sub-volcanic rocks. Lavas are dominated by rhyolite with minor dacite. Four volcanic eruption-effusion cycles can be recognized in the third member, the major gas-bearing interval, of Yingcheng Formation. The volcanic activities are characterized by alternation of relatively quiet fissure effusion with relatively strong central eruption that features in high frequency, rapid eruptions, short intermittence, and quick condensation and consolidation. Five lithofacies ( explosive, effusive, extrusive, volcanic conduit and volcanic-sedimentary facies) and six sub-facies ( splash fall lava, pyroclastic,lava flow, volcanic gravity flow, volcanic neck and sub-volcanic) can be recognized. Wells with high gas flow rate are mainly located in areas with the volcanic explosive facies or interbeded explosive facies and effusive facies. The volcanic reservoir quality is mainly controlled by lithology, lithofacies, thickness and spatial distribution of volcanic rocks, followed by the characteristics of volcanic activity, paleogeomorphology,diagenesis and tectonic action.