Phase change plays an essential role in wettability during steam injection, and oil becomes the wetting phase in the steam zone. This study investigates this unfavorable phenomenon using visual data obtained from micromodel experiments and how the wettability can be reversed using chemicals. All measurements were conducted at temperatures up to 200°C on glass-bead micromodels. The models were initially saturated with brine solution and then displaced by two types of mineral oils (450 and 111,600 cp at 25°C). Steam was then constantly injected into the micromodels to evaluate the effect of phase change and wettability status on residual saturation development. Next, chemical additives, screened from the previous contact-angle and thermal-stability measurements, were added to the steam to observe their ability in modifying phase distribution and wettability state. The results showed that phase distribution and residual oil saturation are critically sensitive to the steam phase. At any circumstances, wettability alteration with chemicals was possible. The shape and characteristics of the trapped oil with and without chemicals were identified through micromodel images, and suggestions were made as to the conditions (pressure, temperature, and time to apply during the injection application) at which these chemicals show optimal performance.

在蒸汽注入过程中，相变对润湿性起着至关重要的作用，并且油成为蒸汽区的润湿相。本研究使用从微模型实验获得的视觉数据调查了这种不利现象，以及如何使用化学物质逆转润湿性。所有测量均在高达200°C的温度下在玻璃微珠模型上进行。模型最初用盐溶液饱和，然后用两种类型的矿物油（在25°C下为450和111,600 cp）置换。然后将蒸汽不断注入微模型中，以评估相变和润湿性状态对残余饱和度发展的影响。接下来，从先前的接触角和热稳定性测量中筛选出化学添加剂，将其加入到蒸汽中以观察其改变相分布和润湿状态的能力。结果表明，相分布和残余油饱和度对蒸汽相非常敏感。在任何情况下，都可以用化学药品改变润湿性。通过微模型图像确定了有无化学药品时所捕集油的形状和特性，并就这些化学药品表现出最佳性能的条件（压力，温度和注入时间）提出了建议。