泡沫驱气窜规律及防气窜实验研究

发布时间：2018-09-12 07:41

【摘要】：泡沫驱既具有高强度的调剖能力,又兼具洗油功能,在保护储层的同时可以大幅度提高油藏的波及体积和驱油效率,从而提高采收率。但泡沫驱过程中存在气体窜流现象从而会影响其效果。因此,进一步认识泡沫驱的作用机理及其过程中气窜规律,为该技术先导试验和后期大规模应用提供理论依据和技术支持。本文首先对低张力泡沫体系的起泡性能进行了综合评价,结果表明起泡剂的最优使用浓度为0.5%。该浓度下泡沫具有较强的稳定性和析液半衰期,并能节约经济成本,从而提高经济效益。其次,采用一维填砂管进行单管和双管实验对泡沫驱过程中起泡剂浓度、气液比、注入速度、注入方式、渗透率、含油饱和度等影响气窜现象的因素进行了研究,结果表明:地层的渗透率过高时,在地层中存在着较大的渗流通道,而泡沫的尺寸不能与之对应,泡沫驱的阻力因子较小,泡沫不能对渗流通道形成有效的封堵;高浓度的表面活性剂可以增强液膜的强度,液膜排液作用的进行降低了气窜现象的发生;使用泡沫发生器,产生的泡沫质量优于段塞注入以及气液共注等方式,不易发生气窜;注入速度越小,越容易发生气窜现象,但是注入速度超过一定值以后,泡沫的封堵能力趋于稳定;由于气相流度增大对泡沫稳定性的影响,随着气液比(气相流速)的增大,泡沫在多孔介质中的流动阻力逐渐增大,降低了气窜现象的发生;为了界定气窜时机和程度,在实验基础上提出了含气上升率Ig,以Ig=0.5作为临界点界定气窜。最后进行冻胶泡沫防气窜实验研究,结果表明冻胶泡沫具有比常规泡沫更好的封堵性能,在油田生产中,可以选择使用合理浓度的冻胶泡沫来抑制气窜的发生,在泡沫驱替过程中可以通过注入冻胶泡沫段塞来加强封堵效果,为油田的增产提供保障
[Abstract]:Foam flooding not only has the ability of profile control with high intensity, but also has the function of oil washing. While protecting the reservoir, it can greatly improve the sweep volume and oil displacement efficiency of the reservoir, thus increasing the oil recovery. However, gas channeling in foam flooding process will affect its effect. Therefore, to further understand the mechanism of foam flooding and its gas channeling in the process, to provide theoretical basis and technical support for the pilot test and large-scale application of the technology. In this paper, the foaming performance of low tension foam system is evaluated. The results show that the optimum concentration of foaming agent is 0.5. At this concentration, the foam has strong stability and half life of liquid evolution, and can save the economic cost and improve the economic benefit. Secondly, single and double pipe experiments with one-dimensional sand filling pipe were used to study the factors affecting gas channeling phenomena, such as foaming agent concentration, gas-liquid ratio, injection rate, injection mode, permeability, oil saturation and so on. The results show that when the permeability of the formation is too high, there is a large seepage channel in the formation, but the size of foam can not correspond to it, the resistance factor of foam flooding is small, and foam can not effectively block the seepage channel. The high concentration of surfactant can enhance the strength of liquid film, and the discharge of liquid film reduces the occurrence of gas channeling, the foam quality produced by foam generator is better than that of slug injection and gas-liquid injection, and it is not easy to occur gas channeling. The smaller the injection rate, the easier the gas channeling occurs, but when the injection rate exceeds a certain value, the plugging ability of the foam tends to be stable, because of the effect of the gas phase mobility on the foam stability, with the increase of the gas-liquid ratio (gas velocity), The flow resistance of foam in porous media increases gradually, which reduces the occurrence of gas channeling. In order to define the time and degree of gas channeling, it is proposed that Ig=0.5 be used as critical point to define gas channeling in Ig, on the basis of experiments. Finally, the gas channeling resistance of gel foam is studied. The results show that gel foam has better plugging performance than conventional foam. In oil field production, a reasonable concentration of gel foam can be used to suppress gas channeling. In the process of foam displacement, the plugging effect can be strengthened by injecting gel foam slug, which can provide guarantee for increasing production of oil field.
【学位授予单位】：中国石油大学(华东)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE357.46

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