渗流气体滑脱现象与渗透率变化的关系  

GAS SLIPPAGE PHENOMENON AND CHANGE OF PERMEABILITY WHEN GAS FLOWES IN TIGHT POROUS MEDIA

作　　者：陈代珣[1] 

机构地区：[1]西南石油学院工业自动化系,南充637001

出　　处：《力学学报》2002年第1期96-100,共5页Chinese Journal of Theoretical and Applied Mechanics

基　　金：中国石油天然气总公司九五科技攻关项目资助(960501)~~

摘　　要：气体在致密多孔介质中低速渗流时存在着因气体分子碰撞岩壁而引起的滑脱现象，它由介质的孔隙结构和气体分子的平均自由程共同决定．该现象使气测渗透率大于孔隙介质的绝对渗透率．介质中气体的低速渗流为黏滞流与滑脱流组成，各自所占比例与气体分子按自由程的分布有关．理论计算得到了低速气体渗流的气测渗透率Ｋｇ与绝对渗透率Ｋ０比值的关系式。The collinsion occured between gas molecules and pore walls causes the gas slippage phenomenon when gas flowes at low velocity in tight porous media. The phenomenon depends on the constructure of the porous media and mean free path of gas molecules. It results in that gas permeability is larger than absolute permeability of porous media and causes deviating off Darcy's law in low pressure. The gas flow quantity is governed by weighted addition of viscous flow and slippage flow. The distribution according to free path of gas moleculars dominated the weighting factor. Using capillary tube model, the gas flow rate equation is obtained and the relative expression of gas permibility Kg and absolute permibility Ko of porous media is determined. The experiments of gas flow through sandstone cores at certain net confining pressure △pw are made. The experimental results show consistent with theory analysis.

关 键 词：气体渗流 滑脱现象 渗透率 致密多孔介质 气体分子 自由程分布 毛管束模型 气体流体力学 

分 类 号：O357.3[理学—流体力学]