Connate water salinity is a vital property of the reservoir and its influence on the displacement efficiency cannot be overemphasised. Despite the numerous analytical literatures on the dispersion behaviour of CO2 in CH4 at different parametric conditions, studies have so far been limited to systematic effects of the process while parameters such as connate water salinity of the reservoir has not been given much attention and this could redefine the CO2-CH4 interactions in the reservoir. This study aims to experimentally determine the effect of connate water salinity on the dispersion coefficient in consolidated porous media under reservoir conditions. A laboratory core flooding experiment depicting the detailed process of the CO2-CH4 displacement using Grey Berea sandstone core sample at a temperature of 50°C and at a pressure of 1300 psig was carried out to determine the optimum injection rate, from 0.2-0.5 ml/min, for the experimentation based on dispersion coefficients and methane recovery in the horizontal orientation. This was established to be 0.3 ml/min. At the same conditions, the effects of connate water saturation of 10% and a salinity of 0 (distilled water), 5, and 10% wt. with a CO2 injection rate of 0.3 ml/min on the dispersion coefficients was investigated. The results from the core flooding process indicated that the dispersion coefficient decreases with increasing salinity, hence the higher the density of the immobile phase (connate water) the lower the dispersion of CO2 into CH4. This is a significant finding given that the inclusion of the connate water and its salinity have an effect on the mixing of the gases in the core sample and should be given importance and included during simulation studies for field scale applications of Enhanced Gas Recovery (EGR). This is the first experimental investigation into the relationship between the connate water salinity and the dispersion coefficient in consolidated porous media. Keywords: Enhanced Gas Recovery; Dispersion Coefficient; Connate water Salinity; CO2 sequestration

中文翻译：

---

CO2 强化采气过程中原生水矿化度对固结岩心弥散系数影响的实验研究

原生水盐度是油藏的一个重要特性，它对驱油效率的影响怎么强调都不为过。尽管有大量关于不同参数条件下 CO2 在 CH4 中的扩散行为的分析文献，但迄今为止的研究仅限于该过程的系统效应，而储层的原生水盐度等参数并未得到太多关注，这可能会重新定义储层中的 CO2-CH4 相互作用。本研究旨在通过实验确定储层条件下原生水盐度对固结多孔介质弥散系数的影响。实验室岩心驱替实验描述了使用 Grey Berea 砂岩岩心样品在 50°C 温度和 1300 psig 压力下进行 CO2-CH4 驱替的详细过程，以确定最佳注入速率，从 0.2-0.5 ml /min，用于基于分散系数和水平方向甲烷回收率的实验。这被确定为0.3毫升/分钟。在相同条件下，原生水饱和度为 10%，盐度为 0（蒸馏水）、5 和 10% wt 的影响。研究了 CO2 注入速率为 0.3 ml/min 时对分散系数的影响。岩心驱油过程结果表明，弥散系数随着盐度的增加而减小，因此，固定相（原生水）的密度越高，CO2 向 CH4 的分散越低。这是一个重要的发现，因为包含原生水及其盐度会对岩心样品中的气体混合产生影响，因此在提高气体采收率 (EGR) 的现场规模应用的模拟研究中应该给予重视和包含. 这是对固结多孔介质中原生水盐度与弥散系数之间关系的首次实验研究。关键词：提高天然气采收率；色散系数；原生水盐度；二氧化碳封存 这是一个重要的发现，因为包含原生水及其盐度会对岩心样品中的气体混合产生影响，因此在提高气体采收率 (EGR) 的现场规模应用的模拟研究中应该给予重视和包含. 这是对固结多孔介质中原生水盐度与弥散系数之间关系的首次实验研究。关键词：提高天然气采收率；色散系数；原生水盐度；二氧化碳封存 这是一个重要的发现，因为包含原生水及其盐度会对岩心样品中的气体混合产生影响，因此在提高气体采收率 (EGR) 的现场规模应用的模拟研究中应该给予重视和包含. 这是对固结多孔介质中原生水盐度与弥散系数之间关系的首次实验研究。关键词：提高天然气采收率；色散系数；原生水盐度；二氧化碳封存 原生水盐度；二氧化碳封存 原生水盐度；二氧化碳封存