一种致密多孔介质的克氏渗透率测试校正方法——以煤岩为例

A Compact Porous Media Klinkenberg Permeability Test Modification Method:A Case Study of Coal-Rock

随着页岩气藏和煤层气藏的深入开发,研究普遍关注气体实验室条件下在岩心微纳流道中的滑脱效应。煤岩的渗透率一般在气测渗透率后,利用Klinkenberg提出的校正方法得到煤岩的克氏渗透率。滑脱效应的校正采用延长低压实验测试段的拟合线,得到克氏渗透率的方法。通过分析煤岩在实验过程中不同回压条件下的流动阶段,研究发现在滑脱流动拟合线延长过程中,流动从滑移流动变化为连续流动的过程中,气测渗透率并不符合滑移流动延长线的变化趋势。研究通过实验以及文献中的数据验证了提出了渗透率校正方法。通过回压校正方法,得到的煤岩的渗透率较常规滑脱校正方法得到的渗透率大,两者的差距在中等渗透率岩心上并不明显,渗透率越小,两者差距越大。

Along with shale gas and CBM reservoirs in-depth exploitation,studies on the slippage effect in core nano-scale flow channel under gas laboratory condition are generally concerned.Commonly after coal-rock permeability perm-plug method determination,using Klinkenberg modification method to modify slippage effect works out Klinkenberg permeability.Through flow stage analysis of coal-rock under laboratory different back-pressure conditions has found that during the slippage flow fitting line extending process,the flow is changed from slippage flow to continuous flow,perm-plug method permeability does not accord with slippage flow extending variation trend.Through experiment and data in references verification,the study has put forward a permeability modification method.Through back-pressure correction,the worked out coal-rock permeability is larger than the result from conventional slippage modification method,the difference is not obvious on medium permeability cores,the smaller the permeability,the larger the difference.