低频人工地震波复合泡沫驱协同增效机理研究

The combination of low frequency artificial seismic wave and foam flooding is a brand new type of physics-chemical enhanced flooding technology. The composite technology utilize the seismic wave to form physical intervention on the dynamic evolution of the foam in order to improve the stability of the foam in the deep part of the reservoir and reduce the adsorption loss of the agent in the formation. It is expected to break through the key bottleneck faced by the current foam flooding. The composite technology has been successfully applied in Yanchang Oilfield. However, the further application of the composite technology is limited due to the absence of the mechanism study. On account of this reason, exploring the synergetic mechanism is at all imminent. Key to this development is the finding that the stability synergetic mechanical mechanism of low-frequency artificial seismic wave composite foam flooding. The microscopic characterization experiments of foam dynamic performance and the foam drainage dynamics model under the intervention of low frequency wave will be studied for this purposes. To gain more insight, foam flooding experiments under low-frequency vibration waves by the glass etching model and the core separately will be conduct. Accordingly, the dynamic coupling seepage law of the foam formation, migration and distribution in porous media under low frequency seismic waves will be explained and the enhancement and synergistic characteristics of the composite technology will be clearly clarified. These developments would provide an significantly theoretical basis for the optimization decision of the low-frequency vibration wave composite foam flooding technology.

低频人工地震波复合泡沫驱技术是一种新型物理-化学强化调驱技术，借助地震波对泡沫动态演化形成物理干预，提高泡沫在油藏深部的稳定性，降低壁面对药剂的吸附损耗，有望突破当前泡沫驱所面临的关键瓶颈。该技术已在延长油田进行了成功矿场先导试验，但低频地震波与泡沫驱的协同增效机制尚不明确，成为制约该复合技术深化应用的核心。基于此，本课题首先开展低频地震波激励下泡沫性能的微观表征实验，进而采用润滑理论，构建低频地震波干预下泡沫液膜排液动力学模型，揭示波动复合泡沫动态稳定性协同力学作用机制；在此基础上，开展波动复合泡沫玻璃刻蚀微观、岩心流动宏观实验，阐明低频地震波激励下泡沫在储层多孔介质中的生成、运移、分布等动态耦合渗流规律，明确该复合技术的强化增效特征。研究成果将为低频人工地震波复合泡沫调驱工艺优化决策提供重要理论依据。

泡沫调驱是低渗裂缝性油藏水窜调控和提高采收率的有效途径，而提高泡沫在渗流过程中的动态稳定性是促进泡沫调驱在该类储层推广应用的关键。基于此，本项目创新性将低频人工地震波与泡沫调驱技术进行复合，利用地震波对泡沫动态演化形成物理干预，提高泡沫在油藏深部的稳定性。.项目通过实验研究了不同孔隙直径多孔介质内，振动参数对泡沫半衰期的影响，并基于泡沫Plateau边界渗流理论，建立了低频波激励下泡沫Plateau边界流体微流动模型；利用毛细管模型和不同孔隙直径的刻蚀模型，研究了振动参数对泡沫在毛细管中和刻蚀模型内起泡性能的影响并进行定性力学分析；建立了低频波激励下的垂直液膜排液模型，探讨了振动频率、振动加速度等参数对泡沫液膜排液过程影响的敏感性；利用非均质刻蚀模型，对比了泡沫驱和振动复合泡沫驱对不同类型剩余油的驱替特征和驱油机理；利用填砂管模型对比研究了泡沫驱和振动复合泡沫驱在单管和双管岩心内的封堵性能及其驱油效果。.研究结果表明，低频波通过改变流体微元的移动速度，缩短流体微元的移动距离来提高泡沫半衰期；低频波通过降低泡沫液膜垂直方向上的拖拽力、增加水平方向上的剪切力以及降低气泡缩颈分离的临界半径，来提高泡沫在毛细管中和刻蚀模型内的起泡效果；低频波能提高Marangoni效应的作用效果，且与不加振动相比，表面活性剂初始浓度越小，振动效果越好；低频波能提高泡沫对盲端剩余油和连片状剩余油的驱替效果，能提高泡沫对柱状剩余油和孤岛状剩余油的驱替速度，与泡沫驱相比，振动复合泡沫驱最终采收率提高了6.78 %；与泡沫驱相比，振动复合泡沫驱能降低压力下降的速度，提高岩心内泡沫的封堵压力，振动复合泡沫驱在单管岩心中的采收率提高了7.7 %，在并联岩心中低渗填砂管的采收率提高幅度约为高渗填砂管的2倍。