Foam for enhanced oil recovery in carbonate reservoirs is generally challenging because the oil-wet formation is not favorable for generating and stabilizing the lamellae. With an alkyl-polyglucoside surfactant, a series of foam core flooding experiments both in the absence and in the presence of crude oil were performed on Estaillades limestone, a dual porosity and heterogeneous carbonate presenting reasonable similarities with the reservoir formation. The effects of wettability, surfactant concentration, and foam quality on foam strength were systematically investigated. It is found that the foam strength in the presence of oil is generally smaller than that in the absence of oil, and the foam strength in the oil-wet condition is typically lower than that in the water-wet condition. However, for the water-wet condition, the foam strength can be greatly improved by increasing the surfactant concentration, which is getting closer to that in the absence of crude oil at a sufficiently high surfactant concentration. The combined effect of a high remaining oil saturation and the disadvantageous wettability can further destabilize foam, thereby greatly reducing the foam strength at oil-wet conditions. As a result, the foam flooding under the water-wet condition outperforms that at the oil-wet condition. Furthermore, it is found that the foam behavior at a high gas fraction is more sensitive to the wettability of rock and the foam hysteresis effect.

中文翻译：

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探讨润湿性对碳酸盐岩油藏提高采收率泡沫输运行为的影响

用于提高碳酸盐岩油藏采收率的泡沫通常具有挑战性，因为亲油地层不利于产生和稳定层状结构。使用烷基多糖苷表面活性剂，在不存在和存在原油的情况下对 Estaillades 石灰岩进行了一系列泡沫岩心驱油实验，这是一种与储层具有合理相似性的双孔隙度和非均质碳酸盐岩。系统研究了润湿性、表面活性剂浓度和泡沫质量对泡沫强度的影响。发现油存在时的泡沫强度一般小于无油时的泡沫强度，并且油湿条件下的泡沫强度通常低于水湿条件下的泡沫强度。然而，对于水湿条件，通过增加表面活性剂浓度可以大大提高泡沫强度，在足够高的表面活性剂浓度下，这与没有原油的情况越来越接近。高剩余油饱和度和不利的润湿性的共同作用会进一步破坏泡沫的稳定性，从而大大降低油湿条件下的泡沫强度。因此，水湿条件下的泡沫驱优于油湿条件下的泡沫驱油。此外，发现高气体分数下的泡沫行为对岩石的润湿性和泡沫滞后效应更敏感。高剩余油饱和度和不利的润湿性的共同作用会进一步破坏泡沫的稳定性，从而大大降低油湿条件下的泡沫强度。因此，水湿条件下的泡沫驱优于油湿条件下的泡沫驱油。此外，发现高气体分数下的泡沫行为对岩石的润湿性和泡沫滞后效应更敏感。高剩余油饱和度和不利的润湿性的共同作用会进一步破坏泡沫的稳定性，从而大大降低油湿条件下的泡沫强度。因此，水湿条件下的泡沫驱优于油湿条件下的泡沫驱油。此外，发现高气体分数下的泡沫行为对岩石的润湿性和泡沫滞后效应更敏感。