残余油导向的纳米聚硅驱油剂制备及其提高水驱油藏采收率作用机制

Chemical flooding is the major enhanced oil recovery (EOR) technologie nowadays. In China, the average water cut of produced fluids is up to 90%, while the average recovery rate is only 28.9%. It is the great difficulty to produce the residual oil in reservoir. Therefore, the R&D of high performance materials for EOR and their mechanism of oil displacement are the scientific problem need to be solved urgently. The nanopolysilicon particles with high surface and interfacial activity are able to adapt the reservoir rocks. Our previous studies showed that nanopolysilicon could effectively increase the water injection and significantly increase the oil production.. The physical and chemical properties of reservoir rock surfaces at the residual oil enrichment areas are obviously different from that at the injection water flow areas because of the injection water changing the initial reservoir conditions. This project aims to modify the nanopolysilicon surface structure by binding different chemical functional groups to preferentially adsorb at the residual oil/rock interfaces and to promote the oil film peeling from reservoir rock surfaces, which is able to greatly improve oil recovery of water flooding. We’ll study the screening and matching interrelations between the functionalized adsorption groups and the reservoir rock surface properties at the different regions after water flooding. The influence laws between the functionalized modifiers and their bond forms and residual-oil-oriented adsorption of nanopolysilicon particles will be also discussed. After exploring the regulation mechanism of nanopolysilicon oriented adsorption and selective aggregation on the residual oil/rock interfaces and revealing the mechanism of oil displacement, we are going to build new prototypes of significantly increased oil recovery.

注化学剂驱油是我国油田现用提高采收率技术，目前全国油井采出液平均含水已达90%，而平均采收率仅为28.9%，剩余原油在地下难以采出。研究驱油效率影响机制，研发提高采收率用高性能驱油材料，是亟待解决的科学问题。纳米聚硅表界面活性高且与油藏岩石适配，项目组前期研究表明纳米聚硅能有效增加注水井的注水量，使油井产量明显增加。. 水驱油藏中外来注入水改变了油藏初始环境，使得注入水流动区域和残余油富集区域岩石表面性质差异显著，本项目拟通过纳米聚硅表面结构调控和吸附基团匹配，实现其在残余油/岩石界面优先吸附并促进油膜剥离，从而大幅提高注水驱油效率。. 通过研究水驱油藏不同区域岩石表面物理化学特征，建立吸附基团筛选和匹配关系，研究修饰剂和结合形式对纳米聚硅微粒残余油导向吸附的影响规律，探索其在原油/油藏岩石界面区域导向吸附、选择聚集的调控规律，揭示驱油机制，构建大幅提高采收率的新技术原型。

中国陆上砂岩油藏开发普遍进入高含水采油阶段，油井采出液平均含水已达90%，而平均采收率仅为28.9%，大量原油剩余在地下难以采出，采油技术亟待创新。在基金的支持下，本项目主要进行了以下三方面研究工作：. 1）开展了水驱高含水油藏岩石和储层流体的物理化学特征分析。项目采集了典型高含水油藏岩心样品和流体样品，依托多种测试手段，获得油藏岩石组成、流体化学组成、部分水驱高含水油藏岩石和储层流体的物理化学特征，为纳米聚硅驱油剂的修饰剂选择、结构设计和流变性设计提供了可行方向；. 2）项目组探索了“化学破碎”技术制备纳米驱油材料的表面修饰与结构调控，研究了不同碳链长度和基团疏水修饰剂的纳米聚硅修饰工艺，开展了接枝密度调控研究，形成了三大类纳米聚硅驱油剂、辅助助剂，完成了部分样品的试制和测试，建立了水溶性纳米聚硅驱油技术原型。在提高水驱油藏采收率用纳米聚油材料的表面修饰、结构调控与驱油剂组合研究方面取得了显著进展；. 3）在纳米聚硅驱油剂性能测试与构效关系研究方面，项目组采用砂岩油藏岩心、人造岩心和模拟油藏流体，开展了多种纳米聚硅驱油剂的水驱油藏采收率影响程度和作用机制研究，探索了驱油剂结构与其在油藏岩石界面吸附行为的关系；提出了表界面张力和润湿性是驱油剂驱油的主控机理，而增加驱油剂粘弹性将对驱油效率产生积极作用。项目组制备的纳米聚硅驱油剂，在物模试验中获得了提高水驱油藏采收率58%的良好效果，为我国研发高含水油藏提高采收率用新型驱油材料奠定了基础。. 本项目发表论文15篇，其中SCI收录论文9篇；获得中国发明专利授权24项，形成企业标准1项；荣获中国石油化工集团公司科技进步二等奖1项，第三届中国“互联网+”大学生创新创业大赛银奖等局级以上奖项共9项。同时，本项目培养学生共12人，其中博士研究生2人，硕士研究生6人（已毕业4人、2人在读），本科生4人。