摘要
针对碳酸盐岩酸化过程中存在的酸蚀蚓孔扩展问题,建立了一种适用于径向的达西尺度和孔隙尺度的双重尺度模型,并利用该模型研究了径向上酸蚀溶解的形态特征和主要影响因素,分析了蚓孔形成的条件。结果表明:新建模型与前人的实验结果非常吻合,能够用于研究径向蚓孔扩展;注入速度越大或扩散系数越小时,对流作用起主导作用,易于形成均一溶蚀;扩散系数越大或注入速度越小时,扩散作用起主导作用,易于形成面溶蚀;蚓孔是在对流作用与扩散作用相当的条件下形成的,它既能提供足够高的渗透率,又能最大限度地降低酸液用量;当扩散作用过大时,靠近井筒的一定区域内容易形成面溶蚀,在此区域外形成蚓孔突破;非均质程度存在一最优值,小于该值时,随着非均质程度的增强,蚓孔密度和突破体积均呈下降趋势,大于该值时,蚓孔密度和突破体积对非均质程度不敏感。
In response to the questions of wormholing during carbonate acidizing,this paper derives a radial two-cale continuum model based on former researches,and studies the dissolving pattern and the effect of some key factors on it,and gets the conditions of the occurrence of wormholes.The results show that;the conclusions got from the models accord well with the experiments conducted by former researchers perfectly;with the rise of diffusion efficiency and decrease of injection rate,the diffusion effect becomes stronger relatively and it is easier to form face dissolution;with the decrease of diffusion efficiency and increase of injection rate,the convection effect becomes more apparent relatively,and it is easier to form uniform dissolution;the wormhole,which can provide adequate permeability and minimize the injection volume of acid at most,is formed when the effect of convection and diffusion is equivalent;the magnitude of heterogeneity has an optimal value,below which the wormhole density and breakthrough volume decrease under more heterogeneity,above which the wormhole density and breakthrough volume become insensitive to the heterogeneity.
出处
《油气地质与采收率》
CAS
CSCD
北大核心
2012年第2期106-110,118,共5页
Petroleum Geology and Recovery Efficiency
基金
国家科技重大专项子课题"酸液滤失模式和蚓孔发育模拟模型研究"(2008ZX05017-003-02-01HZ)
关键词
碳酸盐岩
酸化
蚓孔
径向模型
突破体积
非均质程度
carbonate
acidizing
wormhole
radial model
breakthrough volume
heterogeneity
