量子点基活性纳米材料制备及其自发渗吸排油机理研究

Nanomaterials have attracted much attention in the field of enhanced oil recovery due to their special properties. As the large scale of traditional nanomaterials, nanomaterials are difficult to enter nano-pore in the matrix of ultra-low permeability reservoir and the application of nanotechnology in ultra-low permeability reservoirs is limited. In response to this problem, a series of nanomaterials with interfacial activity is developed based on silica quantum dots (QDs) and carbon QDs through chemical synthesis. The influence rule of the size and surface chemical structure of QDs-based active nanomaterials on their functional properties can be clarified through advanced analytical equipments and experimental simulation methods. Based on this, the best preparation method of QDs-based active nanomaterials is developed. The influencing mechanism of QDs-based active nanomaterials on oil-water interfacial tension, reservoir wettability, fluid spreadability, oil recovery efficiency, distribution characteristics of oil and water, and seepage flow behavior in microchannels is studied. On basis of the above research, the oil recovery mechanism of QDs-based active nanomaterials is revealed. The lowest permeability of reservoirs which can be effectively developed by QDs-based active nanomaterials, is identified. This work will provide new scientific foundation and technical support for enhanced oil recovery in ultra-low permeability reservoirs.

纳米材料由于其特殊的性能在提高原油采收率领域备受关注。本项目针对传统纳米材料尺寸大，难以进入超低渗储层基质纳米级孔结构中，限制了纳米技术在超低渗油藏中的应用，这一科学难题。以硅量子点和碳量子点为载体，借助化学合成法制备系列量子点基活性纳米材料。采用先进分析设备和实验模拟方法，阐明量子点基活性纳米材料的尺寸和表面化学结构对其功能特性的影响作用规律，获得理想的量子点基活性纳米材料的最佳制备方法。探讨量子点基活性纳米材料对油水界面张力、储层润湿性、流体铺展性、渗吸排油效率、油水分布特征和微通道内渗流特征的影响作用机制，揭示量子点基活性纳米材料渗吸排驱机理，明确量子点基活性纳米材料有效提高渗吸排油效率储层渗透率下限，为提高超低渗油藏采收率提供新的科学理论与技术支持。

针对传统纳米材料尺寸大，难以进入超低渗储层基质纳米级孔结构中，限制了纳米技术在超低渗油藏中的应用，这一科学难题。本项目以降低原料成本、简化生产设备、降低生产条件要求三方面为出发点，选取工业化程度高、廉价易得的硅烷偶联剂（3-氨基丙基三甲氧基硅烷、3-巯基丙基三甲氧基硅烷等）作为硅源和有机化合物（对苯醌、PEG-200、PEG400等）作为碳源，在常温常压环境中，低耗时（0.5-24 h）情况下，成功制备了符合项目需求的硅量子点和碳量子点。选择由不同疏水基团（烷烃链、环烷烃、芳香烃等）和亲水基团（磺酸盐基、磷酸盐基、聚氧乙烯基等）组成的界面活性基团为表面修饰基团，以耐温性、耐盐性、降低油水界面张力能力、渗吸排油性能为评价指标，在常温常压环境中，低耗时（0.5-24 h）情况下，成功制备了系列粒径小且分布窄、油水界面活性好、耐温、耐盐的量子点基活性纳米材料。阐明了量子点基活性纳米材料对油水界面张力、储层润湿性、流体铺展性、渗吸排油效率、油水分布特征和微通道内渗流特征的影响作用机制。实现了纳米流体荧光示踪分析，建立了微流控与传感分析结合的定量分析方法，为实现基质微纳孔喉结构中单/多纳米颗粒定量分析提供了理论与技术支持。揭示了量子点基活性纳米材料渗吸排驱机理，明确了量子点基活性纳米材料有效提高渗吸排油效率储层渗透率下限为0.05 mD，为提高超低渗油藏采收率提供新的科学理论与技术支持。