计算物理 ›› 2014, Vol. 31 ›› Issue (6): 681-689.

• 论文 • 上一篇    下一篇

注气驱替煤层气数值模拟

吴金涛1, 侯健1, 陆雪皎1, 于波2   

  1. 1. 中国石油大学(华东)石油工程学院, 山东 青岛 266580;
    2. 中国石油大学(华东)理学院, 山东 青岛 266580
  • 收稿日期:2013-11-18 修回日期:2014-04-09 出版日期:2014-11-25 发布日期:2014-11-25
  • 通讯作者: 侯健(1972-),男,四川营山,教授,博士,从事油藏数值模拟、三次采油及油藏工程方案设计研究
  • 作者简介:吴金涛(1988-),男,山东邹城,硕士生,主要从事油气渗流理论与应用研究,E-mail:wjtwave@gmail.com
  • 基金资助:
    山东省自然科学杰出青年基金(JQ201115);新世纪优秀人才支持计划(NCET-11-0734);中央高校基本科研业务费专项资金(13CX05007A);中国石油大学(华东)自主创新科研计划(13CX06031A);中国石油科技创新基金(2012D-5006-0207)资助

Numerical Simulation of Coalbed Methane Displacement with Gas Injection

WU Jintao1, HOU Jian1, LU Xuejiao1, YU Bo2   

  1. 1. College of Petroleum Engineering,China University of Petroleum, Qingdao 266580, China;
    2. College of Science,China University of Petroleum, Qingdao 266580, China
  • Received:2013-11-18 Revised:2014-04-09 Online:2014-11-25 Published:2014-11-25

摘要: 建立一种注气驱替煤层气的双重介质数学模型,考虑注气驱替煤层气中多组分气体渗流、吸附/解吸、扩散及孔隙度和渗透率敏感性等多物理场的耦合,用有限差分方法对数学模型数值求解,并验证模型的有效性.通过实例模拟,对比分析注入CO2、N2和70%N2+30%CO2提高采收率、产出组分动态及储层物性.计算表明:注入CO2、N2及其混合气体均能显著提高煤层气藏采收率,提高程度可达28%以上;N2在注入后迅速突破产出,而CO2突破时间较晚;注气后基质的收缩/膨胀效应在孔隙度和渗透率敏感性中起主导作用,CO2吸附造成孔隙度和渗透率减小,而N2吸附将增大孔隙度和渗透率.

关键词: 煤层气, 注气, 数学模型, 数值模拟

Abstract: A double medium mathematical model for coalbed methane displacement with gas injection is established. Multi-physics coupling process containing Darcy flow,adsorption/desorption and diffusion of multiple component gas and variation of porosity and permeability is involved. The model is solved numerically with finite difference method and validity of the model is verified. In example simulation calculations,improved recovery,evolution of produced gas composition and variation of coal seam properties under injection of CO2、N2and 70% N2+ 30% CO2 are contrastively analyzed. It indicates that injections of CO2、N2and their mixed gas are able to improve coalbed methane recovery significantly by a degree over 28 %. N2 breaks through rapidly after injected,while CO2 occurs in production well later. Shrinkage /swell effect plays a dominant role in variation of porosity and permeability after gas injection.Adsorption of CO2 reduces porosity and permeability,while adsorption of N2 leads their increase.

Key words: coalbed methane, gas injection, mathematical model, numerical simulation

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