用数字岩心确定低渗透砂岩水锁临界值

发布时间：2018-05-03 16:36

本文选题：低渗透砂岩 + 数字岩心　；参考：《天然气工业》2016年04期

【摘要】：探明水锁内在因素与损害程度之间的联系机制对水锁抑制措施的研发至关重要,但常规的水锁物理实验只能研究宏观水锁损害后的结果,而无法探讨其微观机理。为此,通过高分辨率微CT扫描构建了低渗透砂岩三维数字岩心,并建立了与之等价的孔隙网络模型,利用孔隙级流动模拟开展了由毛细管力控制的虚拟"自吸"实验,探讨了润湿性、含水饱和度、孔喉结构参数等微观内在因素与水锁损害程度的联系机制。结果表明:(1)润湿性从水湿依次过渡到气湿,水锁损害程度逐渐减轻,只要将强水湿毛细管环境转变为弱气湿,就能有效地减轻水锁损害,提高气井产能;(2)初始含水饱和度与束缚水饱和度之间差异越大,水锁损害越严重;(3)水锁损害程度与配位数呈负相关关系,而与孔喉比呈正相关关系;(4)在现有研究条件下,由中等尺寸喉道组成的地层更容易水锁。结论认为,存在一个临界喉道半径使得水锁最为严重。
[Abstract]:It is very important to find out the relationship between the internal factors of water lock and the degree of damage, but the conventional physical experiment of water lock can only study the results of macroscopic water lock damage, but not its microscopic mechanism. Therefore, the 3D digital core of low-permeability sandstone was constructed by high-resolution micro-CT scanning, and the equivalent pore network model was established. The virtual "self-priming" experiment controlled by capillary force was carried out by using pore grade flow simulation. The relationship between wettability, water saturation, pore throat structure parameters and the damage degree of water lock is discussed. The results show that wettability is transferred from moisture to gas in turn, and the damage of water lock is gradually reduced. As long as the environment of strong water and moisture capillary is changed into weak gas and humidity, the damage of water lock can be effectively alleviated. The greater the difference between the initial water saturation and the irreducible water saturation is, the more serious the water lock damage is, and the negative correlation between the water lock damage degree and the coordination number, but the positive correlation between the water lock damage degree and the pore throat ratio. A formation consisting of a medium-sized throat is easier to lock. It is concluded that there is a critical throat radius to make the water lock most serious.
【作者单位】：中国科学院重庆绿色智能技术研究院;"油气藏地质及开发工程"国家重点实验室·西南石油大学;重庆矿产资源开发有限公司;
【基金】：国家青年自然科学基金项目“页岩层理结构对超声波特性的影响研究及应用”(编号:41502287) 重庆市国土局科技计划项目“基于数字岩心技术的页岩含气饱和度评价”(编号:CQGT-KJ-2015018) 中石化地球物理重点实验室开放基金项目“页岩储层微观表征与数字岩石物理实验研究”(编号:33550006-15-FW2099-0015)
【分类号】：TE319

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