九台营城煤矿区珍珠岩特征、成因及储层地质意义

九台营城煤矿区珍珠岩类型多样、种类繁多:按珍珠岩成分和组构可分为强蚀变珍珠岩、流纹构造珍珠岩、流纹构造与珍珠构造互层珍珠岩、含斑晶珍珠岩和硅化珍珠岩;根据珍珠岩蚀变阶段和蚀变产物又可分为未蚀变(正常)珍珠岩、弱蒙脱石化珍珠岩、强蒙脱石化珍珠岩和硅化-蒙脱石化珍珠岩。本区珍珠岩为熔岩喷出地表后,直接进入水中,发生塑状玻璃的水化作用冷凝固结形成。其蚀变过程是在碱性水介质参与下完成的。本区珍珠岩具有随蚀变程度加强而储集性能大大降低的特征。

Perlite in Yingcheng Coal Mine,Jiutai: Characteristics, Formation and Reservoir Significance

Different types of perlite have been found in the Yingcheng coal mine,Jiutai.Based on the composition and structure,perlite in the mine can be classified as strong altered,rhyolitic structure,rhyolitic and pearl structure interbedded,porphyroblast containing and silicated perlites.According to their altered stages and products,perlite in the mine can also be classified as unaltered(normal),weak montmorillonitized,strong montmorillonitized and silicified-montmorillonitized perlites.The formation processes of the perlite in the area could be suggested as the followings: after being exhausted on the surface,the lava falls into water directly,where it was condensed and consolidated because of plastic glass hydration.And its alteration process was promoted by the presence of the alkaline aqueous medium.The perlite in the area is of characteristics of decreasing reservoir significance with increasing alteration.