凹凸棒石提高泡沫驱油体系稳定性的微观机制研究

Foam flooding is an important EOR technique for mature oil fields with high water cut. Foam is known to block thief zones for highly heterogeneous reservoirs and increase the sweep volume of displacement fluid, thereby improving residual oil recovery efficiency. However, its poor stability becomes a bottleneck for field application of foam flooding. Several studies indicated that nano-particles could increase the stability of foam significantly. Moreover, the author found that palygorskite could remarkably enhance the stability of foam as well. In this study, the palygorskite-surfactant mixture foam system will be investigated at reservoir condition based on both crystal structure and surface chemical property of palygorskite. The micro-structure and thermodynamic property of liquid film with surface enrichment of palygorskite will be examined. Furthermore, the relationship between the structure and performance of palygorskite and surfactants will be minutely discussed in this research. Finally by the results, the mechanism of enhancement on the stability of oil-displacement foam by palygorskite would be concluded. The surface medication method will be investigated and the high stability palygorskite enhanced foam system will be proposed. This study will expand industrial application of palygorskite and provide a candidate EOR technique of the mature oil field in China.

泡沫驱是高含水油田开发后期提高采收率的重要接替技术。其原理是利用泡沫封堵储层的优势通道，以扩大波及体积、驱动剩余油。泡沫体系在储层条件下的稳定性不足是当前制约泡沫驱技术应用效果的瓶颈问题。研究表明：在传统气液两相泡沫体系中添加纳米颗粒能够有效提高泡沫的稳定性。申请人也初步发现凹凸棒石提升泡沫体系稳定性的效果尤为突出，但影响机制尚不清楚。本项目将从凹凸棒石特殊的晶体结构和表面化学特征出发，在模拟油藏条件下开展凹凸棒石-表面活性剂泡沫体系研究。考察表面富集凹凸棒石液膜的微观结构和热力学性质，借助原位分析技术和分子模拟手段，分析凹凸棒石和表面活性剂的构效关系，揭示凹凸棒石的界面特性影响泡沫体系稳定性的机制。在此基础上，探索凹凸棒石表面改性方法，研发驱油用高效纳米凹凸棒石粉体强化泡沫体系。为拓展凹凸棒石应用领域和提高我国高含水老油田采收率提供技术支持。

泡沫驱是高含水油田开发后期提高采收率的重要接替技术。其原理是利用泡沫封堵储层的优势通道，以扩大波及体积、驱动剩余油。泡沫体系在储层条件下的稳定性不足是当前制约泡沫驱技术应用效果的瓶颈问题。本项目从凹凸棒石特殊的晶体结构和表面化学特征出发，在模拟油藏条件下开展凹凸棒石-表面活性剂泡沫体系研究。考察表面富集凹凸棒石液膜的微观结构和热力学性质，分析凹凸棒石和表面活性剂的构效关系,揭示凹凸棒石的界面特性影响泡沫体系稳定性的机制。分别研发了凹凸棒石表面疏水改性方法和二氧化碳响应烷基脒发泡剂，在此基础上优化出驱油用高效纳米凹凸棒石强化烷基脒泡沫体系。为拓展我国凹凸棒石应用领域和提高老油田采收率提供技术支持。