聚合物强化泡沫复合体系作用机理及驱油动力学模型研究

Polymer Enhanced Foams (PEFs) flooding is a new enhanced oil recovery technology. It improves the performance of foam flooding by adding polymer into foaming agent solution. The process of foam flooding involves a series of complicated physical and chemical effects, such as bubble generation, coalescence, lamella trap, and oil tolerance. Therefore, the impacts of polymer on the performance of foam flooding are in many aspects in the process of PEFs flooding. Whereas the investigations on the mechanisms of polymer enhancing foam are rare. In this study, first, the impact rules and mechanisms of polymer on the foam generation, bubble coalescence, lamella stability, foam block ability, and oil tolerance are studied by static, dynamic, and microscopic visual experiments, gas tracer methods, and molecular dynamics simulation. Henceforth, the influences of polymer concentration on the characteristic parameters of PEFs performances are studied by experiments. On this basis, the enhancing role of polymer to foam can be further quantitatively represented, and the kinetic model of PEFs flooding can be established as well. Finally, the modeling and numerical simulation method of PEFs flooding are implemented on the basis of foam flooding mechanisms. The significances involve that, on one hand, it is favorable to completely and clearly understand the impact mechanisms of polymer enhancing foam and realize quantitative representation, which further promotes the development of numerical simulation of PEFs flooding; on the other hand, it provides theoretical foundation for carrying out PEFs flooding to improve oil recovery in high water-cut reservoirs.

聚合物强化泡沫（PEFs）驱是一种较新型的提高采收率技术，主要通过向发泡剂中加入聚合物来改善泡沫驱油性能。泡沫驱过程涉及泡沫生成、破灭、吸附滞留、耐油性等一系列复杂物化效应，因此，PEFs驱过程中，聚合物对泡沫驱油性能的影响也是多方面的，但目前有关聚合物对泡沫强化作用机理研究较少。本研究首先通过静态、动态、微观可视化、示踪剂实验和分子模拟等手段研究聚合物对泡沫生成特性、气泡破裂、液膜稳定性、泡沫封堵能力及耐油性的影响规律和作用机理；然后，实验研究聚合物浓度对强化泡沫性能特征参数的影响规律，进而定量表征聚合物对泡沫的强化作用，据此建立PEFs驱油动力学模型；最后，结合泡沫驱油机理建立PEFs驱数学模型系统和数值模拟方法。本研究一方面有助于全面、清晰认识聚合物对泡沫强化作用的机理、实现定量表征，促进PEFs驱数值模拟技术发展，另一方面为高含水油藏开展强化泡沫驱提高采收率技术开展提供理论依据。

泡沫体系已广泛应用于石油工程领域，泡沫驱油作为一项三次采油技术已在众多油田广泛应用。大量矿场试验表明，泡沫稳定性、耐油性方面的不足严重影响其封堵能力。泡沫中加入聚合物的强化泡沫体系一定程度上增加泡沫稳定性和改善耐油性能，延长泡沫封堵时间，提高泡沫驱波及体积和驱油效率。泡沫是复杂的气液分散体系，泡沫驱是一个更为复杂的过程，涉及泡沫生成、气泡聚并、液膜稳定性、液膜运移、吸附卡堵及其耐油性等一系列物理化学效应，强化泡沫中聚合物的作用方式、作用机理等缺乏全面、系统的研究和认识，更没有相关的定量表征技术，极大地阻碍了聚合物强化泡沫驱（PEFs）技术推广应用，制约了 PEFs驱数值模拟技术的发展。本研究首先通过静态、动态、微观可视化实验并结合分子动力学模拟技术研究了聚合物对气液生泡特性、气泡破裂特征、液膜稳定性、泡沫封堵能力和耐油特性的作用机理和影响规律；然后，实验研究了常规泡沫封堵特性及其影响因素，据此建立了泡沫综合阻力因子模型，在此基础上结合聚合物浓度等参数对强化泡沫临界生泡能力、临界破灭毛管力、最大阻力因子、临界含油饱和度等参数的影响规律，实现了聚合物对泡沫强化作用定量的表征，并建立了PEFs驱动力学模型；最后，结合泡沫驱油机理建立了PEFs驱数值模拟方法，并对数值模拟方法进行验证和应用，近一步揭示了强化泡沫驱技术作用机理和非均质油藏强化泡沫驱提高采收率效果和影响因素。一方面揭示聚合物对泡沫强化作用的机理，实现聚合物强化作用的定量表征、建立PEFs驱动力学模型，促进PEFs驱数值模拟技术发展，另一方面为高含水油藏开展PEFs驱提高采收率技术开展和方案制定提供理论依据。研究成果应用于胜利油田单10断块、郑41区块，河南油田楼资27先导区、泌浅10块等，中海油天津分公司等高含水及稠油油藏气体-泡沫非均相体系调驱方案优化设计和效果预测，大幅提高了原油采收率，取得了显著的经济效益。