大庆火山岩孔隙结构及气水渗流特征

THE PORE STRUCTURE AND THE PROPERTIES OF WATER-GAS FLOWING THROUGH POROUS MEDIA IN A VOLCANIC ROCK IN DAQING

利用CT成像、恒速压汞、核磁共振、铸体薄片等实验技术,对大庆火山岩岩石的孔隙结构和气水渗流特征进行了分类研究。研究表明:大庆火山岩孔隙结构复杂,喉道细小,孔隙易被喉道控制,喉道大小决定储层的渗透性,储集空间可以分为孔隙型、裂缝型、致密型三种类型,不同孔隙类型岩样的储集空间、气水渗流特征明显。大庆火山岩残余水饱和度较高,气水渗流显著特征是裂缝型岩样两相渗流区间小,但在高含水饱和度下,气相仍具备一定的渗流能力,表明裂缝具有较好的导流能力,孔隙型岩样两相渗流区间较大,在残余水饱和度下,气相相对渗透率较高,储渗物性较好;随含水饱和度的增加,两种类型的岩样气相相对渗透率下降均比较快。

By means of such advanced experimental techniques and integrated analysis methods as CT imaging, NMR etc,the authors of the paper study the pore structure and properties of gas-water flow in volcanic core. The pore structure of volcanic rock in Daqing is complex, the throat is small and the pore is easy to be restricted by the throat, the throat′s size decides the permeability of the formation, the reservoir space can be classified into three types: pore, fracture and the tight. In different pore structure, there are different reservoir space and properties of gas-water flow. The residual water saturation of volcanic rock in Daqing is high and the obvious and properties of gas-water flow is that the fracture core′s two phase flow area is small in fracture core, but the gas also has flow ability under high water saturation, so, the fracture has good flow conductivity. The pore core′s two phase flow area is big, the gas phase permeability is high under residual water saturation, the reservoir-physical property is good, both the two kinds of core′s gas phase permeability decrease quickly as water saturation′s increase.