糜利栋,姜汉桥,李俊键,李涛
MI Lidong,JIANG Hanqiao,LI Junjian,LI Tao

• 1:中国石油大学石油工程教育部重点实验室

摘要(Abstract)：

根据多孔介质中气体分子的扩散形式,结合页岩气储层多尺度分布的结构特点,分析了页岩储集空间中页岩气的扩散机理,包括:有机干酪根中溶解气的扩散和纳米孔隙中游离气的扩散。其中纳米孔隙中游离气的扩散又根据克努森(Kn)数的不同分为Knudsen扩散、Fick扩散和过渡扩散。根据Fick第二定律,建立了干酪根中溶解气扩散模型,给出了纳米孔隙中3种扩散机理扩散系数的计算方法。分析了压缩性对气体平均自由程计算的影响,重点讨论了温度、压力、孔隙直径以及气体压缩性等对纳米孑L隙中扩散机理选择的影响。得出:不同扩散机理的选择对扩散能力的影响不可忽略,实际计算中必须根据Knudsen数,选取相应扩散机理对应的扩散系数。
According the diffusion forms of the gas molecules in the porous media and combining with the structural characteristics of the multi-scale distribution in the shale gas reservoirs,the diffusion mechanisms of the shale gas in the reservoir space are analyzed,including the diffusions of the dissolved gas in the organic kerogen and the free gas in the nano-pores.And moreover,according to the differences of Knudsen number(Kn),the later diffusion is divided into the following three diffusions:Knudsen,Fick diffusion and transitional diffusions.Based on the second Fick's law,the diffusion model of the dissolved gas in the kerogen is established;and furthermore the calculating means of the diffusion coefficients of the aforementioned three kinds of the diffusion mechanisms are presented.The effects of the compressibility of the gas on the calculation of its mean free path are analyzed.And furthermore the effects of the temperature,pressure,pore diameter,gas compressibility and so forth on the selection of the diffusion mechanisms are mainly focused.As a result,the influences of the choice of the different diffusion mechanisms on the diffusion capacity cannot be neglected,in the actual calculation,the diffusion coefficients corresponding to the diffusion mechanisms must be the selected according to Knudsen numbers.

关键词(KeyWords)： 纳米孔隙;干酪根;Knudsen扩散;Fick扩散;过渡扩散
Nano-pore;kerogen;Knudsen diffusion;Fick diffusion;excessive diffusion

Abstract:

Keywords:

基金项目(Foundation): 国家重点技术研究发展计划(973)项目“中国南方海相页岩气高效开发基础研究”(2013CB228000)

作者(Author): 糜利栋,姜汉桥,李俊键,李涛
MI Lidong,JIANG Hanqiao,LI Junjian,LI Tao

参考文献(References)：

• [1]杨庆杰,张恒发,张革,等.页岩气成藏与纳米油气基本理论问题[J].大庆石油地质与开发,2013,32(3):150-156.
• [2]单衍胜,张金川,李晓光,等.辽河东部凸起上古生界海陆过渡相页岩气富集条件[J].大庆石油地质与开发,2012,31(3):12-18.
• [3]关富佳,吴恩江,邱争科,等.页岩气渗流机理对气藏开采的影响[J].大庆石油地质与开发,2011,30(2):80-83.
• [4]曲秀英.扩散系数实验技术研究[J].大庆石油地质与开发,2012,31(4):46-49.
• [5]Javadpour F.Nanopores and apparent permeability of gas flow in mudrocks(shales and siltstone)[J].Journal of Canadian Petroleum Technology,2009,48(8):16-21.
• [6]Vivek S,Settari A.A Pore scale gas flow model for shale gas reservoir[J].SPE 155756,2012.
• [7]李治平,李智锋.页岩气纳米级孔隙渗流动态特征[J].天然气工业,2012,32(4):50-53.
• [8]郭为,熊伟,高树生,等.页岩纳米级孔隙气体流动特征[J].石油钻采工艺,2012,34(6):57-60.
• [9]王瑞.张宁生,刘晓娟,等.页岩气扩散系数和视渗透率的计算与分析[J].西北大学学报:自然科学版,2013,43(1):75-80,88.
• [10]何雪秋,聂百胜.孔隙气体在煤层中的扩散机理[J].中国矿业大学学报,2001,30(1):1-4.
• [11]郭立稳,肖藏岩,刘永新,等.煤孔隙结构对煤层中CO扩散的影响[J].中国矿业大学学报,2007,36(5):636-640.
• [12]Passey Q R,Bohacs K M,Esch W L,et al.From oil-prone source rock to gas-producing shale reservoir—geologic and petrophysical characterization of unconventional shale-gas reservoirs[J].SPE 131350,2010.
• [13]Curtis J B.Fractured shale gas systems[J].AAPG Bulletin,2002,86(11):1921-1938.
• [14]聂百胜,何学秋,王恩元,等.瓦斯气体在煤孔隙中的扩散模式[J].矿业安全与环保,2000,27(5):14-16.
• [15]杨胜来,魏俊之.油层物理学[M].北京:石油工业出版社,2004.