Monitoring of saturation changes and salt precipitation during CO2 injection using pulsed neutron-gamma logging at the Ketzin pilot site
Monitoring of saturation changes and salt precipitation during CO2 injection using pulsed neutron-gamma logging at the Ketzin pilot site
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DOI：
10.1016/j.ijggc.2014.06.023
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发表时间：
2014-09-01
影响因子：
3.9
通讯作者：
De Lucia, M.
中科院分区：
文献类型：
--
作者：
Baumann, G.;Henninges, J.;De Lucia, M.
在注入CO2期间，需要监测地下饱和度的变化。对于套管井中的测井，只有有限数量的技术，如辐射脉冲中子伽马（PNG）测井是适用的。传统的PNG饱和度模型主要考虑位移过程。但在注入CO2期间，由于盐水和CO2之间的互溶性，预计会发生蒸发和盐沉淀等其他过程。为此目的，扩展的PNG饱和度模型NaCl盐水的开发和应用于时间推移PNG监测数据集从Ketzin网站。结果表明，对于距离注入井较远的观察井，常规驱替饱和度模型有效，平均CO2饱和度低于60%。相比之下，注入井的数据表明，蒸发和盐沉淀都发生了。在这里，最大的CO2饱和度值高达100%是在当地确定的。扩展的饱和度模型的结果表明，干涸的地区，只有CO2和饱和度高达1.4%的岩盐存在，最大的岩盐饱和度高达14.1%发生在附近的盐水水平。在注入井中的岩盐饱和度分布似乎是由与变化的盐水水平，岩性不均匀性，和毛细管效应相关的注入制度的变化控制。PNG监测与扩展饱和度模型相结合，适合于确定二氧化碳储存操作的位移和蒸发/沉淀过程。(C)2014爱思唯尔有限公司版权所有。
During injection of CO2, monitoring of the subsurface saturation changes is required. For well logging in cased boreholes only a limited number of techniques such as radiometric pulsed neutron-gamma (PNG) logging are applicable. The conventional PNG saturation model mainly considers a displacement process. But during CO2 injection additional processes such as evaporation and salt precipitation are expected to occur as a result of the mutual solubility between brine and CO2. For this purpose an extended PNG saturation model for NaCl-brines is developed and applied to a time-lapse PNG monitoring data set from the Ketzin site. The results show that for the observation well further away from the injection well, the conventional displacement saturation model is valid, with average CO2 saturations below 60%. In contrast, the data from the injection well shows that both evaporation and salt precipitation have occurred. Here, the largest CO2 saturations with values up to 100% are determined locally. The results of the extended saturation model indicate that dry-out regions, where only CO2 and halite with saturations up to 1.4% exist, and maximum halite saturations up to 14.1% occur in the vicinity of the brine levels. The halite saturation distribution in the injection well seems to be controlled by changes in the injection regime associated with changing brine levels, lithological heterogeneities, and capillary effects. PNG monitoring in combination with the extended saturation model is suited to determine displacement and evaporation/precipitation processes for CO2 storage operations. (C) 2014 Elsevier Ltd. All rights reserved.