准噶尔盆地西缘车排子凸起石炭系火山岩储层成因

通过岩心观察、薄片鉴定、元素测试、物性分析等技术手段,对准噶尔西缘车排子凸起石炭系火山岩岩性、岩相、储集空间类型、物性特征及储层成因进行详细研究。结果表明:石炭系火山岩以玄武岩、安山岩、玄武安山岩等火山熔岩和中基性火山角砾岩、凝灰岩等火山碎屑岩为主;火山岩储层储集空间主要为次生溶蚀孔隙和裂缝,属于低孔-特低渗储层;石炭系火山岩储层的形成经历了复杂的演化过程,火山岩先后经历了冷凝固结、构造抬升、表生风化淋滤、埋藏流体充填、溶蚀等后期改造作用;火山岩储集性能呈现先提高后降低再提高的演化过程。

Genesis of Carboniferous volcanic reservoirs in Chepaizi salient in western margin of Junggar Basin

Carboniferous volcanic rock is an important reservoir type in Chepaizi salient, western margin of Junggar Basin. Based on the results of core observation, thin section identification, element test and physical property analysis, this study analyzed the lithology, lithofacies, reservoir space types, physical property and genesis of the Carboniferous volcanic rocks. The results reveal that Carboniferous volcanic rocks are dominated by volcanic lava (including basalt, andesite, and basaltic andesite) and pyroclastic rocks (including intermediate-basic volcanic breccias and tuff).The volcanic rocks are low porosity and ultra-low permeability reservoirs, with main reservoir space of secondary dissolved pore and fracture. The Carboniferous volcanic rocks have undergone intense reformation at late stage, including condensation consolidation, tectonic uplifting, weathering leaching, and cavity filling and dissolution. The quality of volcanic reservoirs is changed accordingly:first improved by tectonic uplifting or weathering leaching, then deteriorated by cavity filling, and finally improved by dissolution.