There have been several foam field applications in recent years. Foam treatments targeting gas mobility control in injectors as well as gas blocking in production wells have been performed without causing operational problems. The most widely used injection strategy of foam has been injecting alternating slugs of surfactant in brine with gas injection. This procedure seems to be beneficial as injection is easy to perform and control below fracturing pressure. Simultaneous injection of surfactant solution and gas may give difficulties, especially with interpretation of the tests, if fracturing pressure are exceeded during the injection period. This paper reviews critical aspects of foam for reservoir applications and intends to motivate for further field trials. Key parameters for qualification of foam are: foam generation, propagation in porous medium, foam strength and stability of foam. Stability is discussed, especially in the presence of oil at reservoir conditions. Data on each of these topics are included, as well as extracted summary of relevant literature. Experimental studies have shown that foam is generated at low surfactant concentration even below the CMC (critical micelle concentration). Results indicate that in situ foam generation in porous medium may depend on available nucleation sites. In situ generation of foam is complex and has been found to be especially difficult in oil wet carbonate rocks. Foam propagation in porous medium has been summarized, and propagation rate for a given experiment seems to be constant with time and distance. Laboratory studies confirm a propagation rate of 1–3 m/day. Field tests performed have not given reliable information of foam propagation rate, and future field pilots are encouraged to include observation wells in order to gain information of field-scale foam propagation. Foam strength is generally high with all gases. The exception is CO 2 at high pressure where CO 2 becomes supercritical. Stability of foam has been studied in laboratory and field tests, and has confirmed long-term stability of foam.

中文翻译：

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多孔介质中的泡沫生成、传播和稳定性

近年来已经有几种泡沫领域的应用。针对注入器中的气体流动性控制以及生产井中的气体阻塞的泡沫处理已经在没有引起操作问题的情况下进行。最广泛使用的泡沫注入策略是在盐水中注入交替的表面活性剂段塞和气体注入。该程序似乎是有益的，因为在压裂压力以下易于执行和控制注入​​。如果在注入期间超过压裂压力，同时注入表面活性剂溶液和气体可能会带来困难，尤其是在解释测试时。本文回顾了用于储层应用的泡沫的关键方面，并打算推动进一步的现场试验。泡沫鉴定的关键参数是：泡沫生成、在多孔介质中的传播、泡沫强度和泡沫稳定性。讨论了稳定性，特别是在油藏条件下存在石油的情况下。包括这些主题中的每一个的数据，以及相关文献的摘录摘要。实验研究表明，即使在低于 CMC（临界胶束浓度）的低表面活性剂浓度下也会产生泡沫。结果表明，多孔介质中的原位泡沫生成可能取决于可用的成核位点。泡沫的原位生成是复杂的，并且已经发现在油湿碳酸盐岩中尤其困难。已经总结了多孔介质中的泡沫传播，并且给定实验的传播速率似乎随时间和距离保持恒定。实验室研究证实了 1–3 m/天的传播速度。进行的现场测试没有提供泡沫传播速率的可靠信息，鼓励未来的现场试点包括观察井，以获得现场规模的泡沫传播信息。所有气体的泡沫强度通常都很高。高压下的 CO 2 是个例外，其中 CO 2 变为超临界状态。泡沫的稳定性已在实验室和现场试验中进行了研究，并证实了泡沫的长期稳定性。