准噶尔盆地西北缘火山岩岩石学与孔隙特征及演化模式研究

Lithology,Porosity Characteristics and Evolution Model of Volcanic Rocks in Northwest Junggar Basin

对研究区火山岩岩性特征、储集空间类型、孔隙演化特征及其主要影响因素进行了深入分析,研究了区内6种火山岩的岩性特征及4个亚类储集空间的发育特征,深入分析了区内主要的火山岩储层如安山岩、玄武岩、火山角砾岩和凝灰岩等的孔隙演化过程及其控制因素。认为火山岩原生孔隙因连通性差而不能形成有效储层,而经过后期改造作用,尤其是溶蚀作用和构造运动将大大改善火山岩的储集性能而成为有效储层。在上述研究的基础上,将火山岩储集空间的演化过程分为火山岩的形成阶段、风化剥蚀淋滤阶段、埋藏和构造作用阶段、溶蚀改造作用阶段和油气聚集成藏阶段5个阶段,并以安山岩和玄武岩为例,建立了火山岩储层的孔隙演化模式。

This paper studied the lithologic characteristics, porosity and its evaluation, forming mechanisms of six kinds of volcanic rocks, and analyzed the evaluation history and the key factors about the main volcanic reservoirs, including andesite, basalt and tuff, etc. It is concluded that the volcanic rocks itself could not become reservoirs unless being reformed by erosion and tectonic movement. The evolution history of the volcanic rocks goes through five stages, the forming stage, the weathering and leaching stage, the burial and tectonic-reforming stage, the erosion stage and the oil and gas accumulation stage. Finally, the model of porosity evolution was set up with andesite and basalt as examples.