西南石油大学学报(自然科学版)

• 石油与天然气工程 • 上一篇    下一篇

纳米尺度页岩储层的气体流动行为分析

任岚,舒亮,胡永全,赵金洲   

  1. “油气藏地质及开发工程”国家重点实验室西南石油大学,四川成都610500
  • 出版日期:2014-10-01 发布日期:2014-10-01

Analysis of Gas Flow Behavior in Nano-scale Shale Gas Reservoir

Ren Lan, Shu Liang, Hu Yongquan, Zhao Jinzhou   

  1. State Key Laboratory of Oil and Gas Reservoir Geology & Exploitation,Southwest Petroleum University,Chengdu,Sichuan 610500,China
  • Online:2014-10-01 Published:2014-10-01

摘要:

理论分析及矿场实践表明,页岩气藏采用传统渗流模型预测的产量总是比实际产量低,经典的达西渗流定律
不再具有适应性,需要建立能准确描述页岩介质气体流动行为的数学模型。目前针对页岩气藏的渗流模型基本都是
对传统黏性流动的校正或者在黏性流动模型上简单的附加分子流动项,忽略了黏性流与分子流中间流态的问题。考
虑页岩介质中可能存在不同流态,建立了描述页岩气藏的流动分析模型。计算结果表明:页岩储层的孔隙越小、气体
分子摩尔质量越小、地层压力越低,气体流动越倾向表现为微观流态,表观渗透率与达西渗透率的比值越大。模型可
解释页岩气藏生产时实际产量高于达西模型预测产量,该研究对于指导页岩气藏生产具有重要的指导意义。

关键词: 纳米, 表观渗透率, 纳米孔隙, 水力压裂, 黏性流, 分子流, 过渡流

Abstract:

Shale gas reservoir theory and field practices showed that the actual yield is higher than the predicted production
of traditional seepage flow model,and that classic Darcy percolation law cannot fully describe the shale gas flow behavior
of the shale media. Thus a calculation model for accurate description and calculation of gas flow of shale media needs to be
established. Existing shale gas reservoir seepage flow models are the correction to traditional viscous flow by simply attached
molecular flow,which ignored the middle flow state of the molecular flow and viscous flow,especially for characterization
of transition flow. This paper considers different complex flow pattern in shale media to established gas flow analysis model
of describing the shale reservoir. The calculation results show that the smaller the porosity of shale reservoir is,the smaller
the gas molecular molar mass is and the lower formation pressure could be,the easier gas flow shows the micro flow regime,
and the greater the ratio of the apparent permeability to Darcy permeability is. The model reveals the essential reason why the
shale reservoir actual yield is higher than predicted yield of Darcy model,and the research has significant guiding importance
to direct shale gas reservoir production.

Key words: nanometer, apparent permeability, nanopores, hydraulic fracturing, viscous flow, molecular flow, transition flow