新疆石油天然气 ›› 2024, Vol. 20 ›› Issue (3): 64-71.DOI: 10.12388/j.issn.1673-2677.2024.03.008

• 油气开发 • 上一篇    下一篇

二氧化碳在致密储层基质中的作用距离研究

  

  1. 1.中国石油大学(北京)石油工程学院,北京昌平 102249; 2.中国石油集团川庆钻探工程有限公司长庆井下技术作业公司,陕西西安 710018; 3.新疆新易通石油科技有限公司,新疆克拉玛依 834000。
  • 出版日期:2024-09-06 发布日期:2024-09-10
  • 作者简介:牟建业(1975-),2009年毕业于Texas A&M University石油工程专业,博士,教授,目前从事储层改造方面的研究。(Tel)010-89734922(E-mail)moujianye@cup.edu.cn
  • 基金资助:

    1、克拉玛依市科学技术局科研课题“非常规油气藏CO2压裂提高采收率技术研究与应用”(HX20231166);

    2、中国石油集团川庆钻探工程有限公司科研课题CO2与页岩储层及原油作用机理实验测试”(HX20230957)

Research on CO2 Matrix Penetration Distance in Tight Reservoirs

  1. 1.College of Petroleum Engineering,China University of Petroleum (Beijing),Changping 102249,Beijing,China;
    2.Changqing Downhole Service Company,CNPC Chuanqing Drilling Engineering Co.,Ltd.,Xi'an 710016,Shaanxi,China;
    3.Xinjiang Xinyitong Petroleum Technology Co.,Ltd.,Karamay 834000,Xinjiang,China.
  • Online:2024-09-06 Published:2024-09-10

摘要:

摘要:致密油衰竭开采过程中压力、产量下降较快,补充地层能量是提高原油采收率的必要措施。CO2是常用补能介质之一(CO2吞吐、前置蓄能),CO2增产效果与其在储层中的作用距离息息相关,针对该问题从实验和数值模拟两方面开展了CO2在致密储层基质中的作用距离研究。CO2传质包括对流和扩散两种方式,首先采用高温高压反应釜和致密储层岩心进行CO2扩散实验,结合Fick径向扩散模型,测得了CO2在致密岩心中的扩散系数;然后采用CMG软件进行CO2对流、扩散建模,基于模型进行广泛的数值模拟,分析渗透率、扩散系数、驱替时间对CO2作用距离的影响。研究表明,扩散系数与渗透率有关,在目标储层岩心渗透率级别下,扩散系数在10-10~10-8 m2/s范围;CO2作用距离取决于对流和扩散作用,扩散作用对CO2作用距离影响明显,渗透率越低,扩散作用影响越明显,渗透率越高,对流作用越主导;渗透率是CO2在基质中作用距离的决定性因素;CO2在致密储层基质中的作用距离较小,60 d的作用距离不到10 m。

关键词:

致密储层, CO2驱油, 作用距离, 扩散系数, 提高采收率, 数值模拟

Abstract:

During depletion recovery of tight oil,the reservoir pressure and production rate decline rapidly. Energy supplement is a necessary measure to enhance oil recovery. CO2 is a common medium used for energy replenishment (CO2 huff and puff,energy recharging by CO2 prepad). The performance of CO2-assisted enhanced oil recovery (EOR) is highly dependent on the penetration distance. Therefore,the penetration distance of CO2 through the matrix of tight reservoirs was investigated via laboratory experiments and numerical simulation. Mass transfer of CO2 involves both convection and diffusion. Firstly,CO2 diffusion experiments were performed using a high-temperature high-pressure reactor and the cores of a tight formation. Based on the experimental results and Fick's diffusion model,the diffusion coefficient of CO2 was obtained. Next,CMG was used to build a model of CO2 convection and diffusion,and extensive numerical simulations were performed to analyze permeability,considering the effect of diffusion and flooding duration on CO2 penetration distance. The results show that the diffusion coefficient is dependent on permeability. The diffusion coefficient ranges from 10-10 to 10-8 m2/s at the permeability level of the target formation. Diffusion and convention both affect the CO2 penetration distance. Yet,the effects of convection are dominant with higher permeability,while those of diffusion are stronger with lower permeability. Permeability is a decisive factor of the matrix penetration of CO2. The CO2 penetration in tight reservoir matrix is rather low and reaches less than 10 m after 60 days.

Key words:

tight formation, CO2 displacement;penetration distance;diffusion coefficient;enhanced oil recovery(EOR);numerical simulation

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