Pore scale release and transport of oil by low salinity water

低盐度注水已被证明在许多但不是所有砂岩中在岩心和油田规模上都能提高石油采收率。宏观尺度的观察表明，改变水的盐度改变了岩石的润湿状态，通常使其更加湿润。然而，到目前为止，还没有系统的孔隙尺度观察这种润湿性改变如何改变油和水的孔隙尺度分布，从而提高石油采收率在这项工作中，X射线显微CT扫描用于成像低矿化度水驱油实验。沿着样品的润湿状态监测孔内流体分布的变化，使用几种测量方法-原位接触角、流体-流体界面曲率和流体-固体部分润湿来表征。然后，这些被用来解释所观察到的水和油分布的变化低矿化度注水，提供了有价值的洞察石油采收率机制。更一般地说，这项工作提供了对润湿状态的孔隙尺度观测的深入了解，其改善对于提高我们对一系列重要领域的理解至关重要，包括碳封存，受污染含水层的修复和地下氢储存

Low salinity waterflooding has been shown to increase oil recovery both on the core and field scale in many but not all sandstones. Macro-scale observations suggest that changing the water salinity alters the wetting state of the rock, usually making it more water-wet. However, as yet there are no systematic pore scale observations of how this wettability alteration alters the pore scale distribution of oil and water and thus improves oil recoveryIn this work, X-ray micro-CT scanning is used to image low salinity water flooding experiments. The change in fluid distribution within the pores is monitored along with the wetting state of the sample, characterised using several measures - in situ contact angle, fluid-fluid interfacial curvature, and fluid-solid fractional wetting. These are then used to interpret the observed changes in water and oil distribution low salinity waterflooding, providing valuable insight into the oil recovery mechanisms. More generally, this work provides insight into pore scale observations of wetting state, the betterment of which is crucial in improving our understanding of a range of important areas including carbon sequestration, remediation of contaminated aquifers, and subsurface hydrogen storage