摘要
岩心气测渗透率具有较强的压力依赖性,该现象在1941年被L.J.Klinjenberg所发现,在传统渗流力学中称作滑脱效应或Klinenberg效应。从对气测岩心渗透率流程和计算公式分析入手,依据气体地下渗流力学原理,研究认为,由于气体滑脱要求岩心孔隙中存在着无穷大的剪切应力,这实际上是不可能的。因此滑脱效应不具有发生的条件。气测渗透率偏高和对压力依赖性的原因,主要是在计算气测渗透率时气体黏度选用为定值所造成的。由于实验中测试都是在低压下进行的,低压气体黏度对压力十分敏感。因此在测试过程中气体黏度随压力而变化,但在计算渗透率时却只用一个气体黏度值,这就出现了上述现象。同时通过分析,认为气测渗透率还与边界层的存在、气体高速非达西渗流有关。因此正确认识气测渗透偏高和压力依赖性的原因有助于理解气体渗流机理和气测渗透率实验方法的改进。
Permeability measured by the perm-plug method has strong dependence on the pressure,which was observed by L.J.Klinkenberg in 1941 and was called slippage effect or Klinkenberg effect.Based on the procedures and calculating formula of the perm-plug method,and subsurface gas flow mechanics,this paper discovered that gas slippage would never be expected to happen unless there was infinite share stress,which was proved practically impossible.Therefore,the premise for slippage effect was at least deniable.The main reason for the relatively high perm-plug measured permeability and its great dependence on pressure was that a fixed value was used as gas viscosity.All measurements were performed under low-pressure environment,where gas viscosity was very sensitive to pressure changes.The contradictory of actual varying viscosity and used fix value results in so-called slippage effect.In addition,analysis of this paper also found out that the measured permeability was related to the existing of boundary layer and gas non-Darcy flow.In a word,to have a correct understanding of the relationship between perm-plug measured permeability and pressure will be helpful for comprehending well the gas flow mechanics and improving experimental methods on permeability measurement.
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2007年第10期85-87,共3页
Natural Gas Industry
关键词
岩石
渗透率
滑脱
效应
气体
非达西流
rock,permeability,slippage,effect,gas,non-Darcy flow
