Abstract

Considering the low percentage of oil recovery in carbonate reservoirs, EOR methods receive more attention in these reservoirs, and smart water flooding shows some promising experimental results in carbonate rocks. Moreover, low operating cost and capital investment of water flooding compared to other chemical flooding methods, make this emerging technology more attractive for oil companies. In this study, the effect of concentration of influential ions of seawater on the wettability of dolomite rock is investigated. It started by contact angle measurements for determining the efficient concentration, followed by core flood experiments to study the effect of ion concentration on ultimate oil recovery. The novelty of this work is the optimization of injected water for enhanced oil recovery in one of Iran’s oil fields. The results showed that increasing sulfate concentration in the presence of other ions up to a certain level causes more water-wetness of dolomite rock. Furthermore, seawater with no calcium ion showed the best effect on the wettability alteration of dolomite rock and consequently more oil recovery. The same results were also observed for seawater with no magnesium ion.

摘要

考虑到碳酸盐岩油藏的采收率低，EOR方法在这些油藏中受到更多关注，而智能水驱在碳酸盐岩中显示出一些有希望的实验结果。此外，与其他化学驱方法相比，水驱的低运营成本和资本投资使这种新兴技术对石油公司更具吸引力。在这项研究中，研究了海水中影响离子浓度对白云岩岩石润湿性的影响。首先是通过接触角测量来确定有效浓度，然后是岩心驱油实验，以研究离子浓度对最终采油量的影响。这项工作的新颖之处在于优化了注入水，以提高伊朗一个油田的采油率。结果表明，在其他离子存在下将硫酸盐浓度提高到一定水平会导致白云岩岩石更湿润。此外，不含钙离子的海水对白云岩岩石的润湿性变化表现出最好的效果，因此可以提高石油采收率。对于不含镁离子的海水，也观察到了相同的结果。