纳米驱油技术理论与实践

Nanofluid Flooding Technology：Theory and Practice

罗健辉 杨海恩 肖沛文 王平美 郑力军 王光义 邬国栋

LUO Jianhui YANG Hai’en XIAO Peiwen WANG Pingmei ZHENG Lijun WANG Guangyi WU Guodong

根据“尺寸足够小、强憎水强亲油、分散油聚并”3 大特性的纳米智能驱油剂战略设计，针对低渗透油藏“注 不进，采不出”的技术瓶颈，提出“纳米水和纳米油”创新设想，以SiO2纳米颗粒为载体，通过在同一纳米颗粒上实 现多功能集成，研制出具有破坏/减弱水分子强氢键缔合作用的第一代纳米驱油剂iNanoW1.0。通过分子动力学 模拟和毛细作用分析实验，分析了水中加入的介质对减弱/破坏水分子间氢键作用力的影响；通过低场核磁分析 实验和岩心驱替实验，比较了iNanoW1.0 驱和普通水驱的注入性能与驱替效果，并在长庆姬源油田进行了现场 应用。结果表明，iNanoW1.0 通过破坏水分子动态网络结构，使普通水变成“纳米水”。与普通水驱相比， iNanoW1.0 驱的注入性与驱替效果均较好，注入启动压力梯度降低、特/超低渗透油藏普通水驱不可及波及体积 增加。长庆超低渗现场先导试验总体呈现增液、增油、降递减的特点。长庆油田超低渗油藏首次通过注水提高 了采收率，发展了低渗透油藏水驱开发理论。图6表3 参13

Based on the strategic design of intelligent nano-sized oil-displacement agent with three properties of ultra-small size， super lipophilicity and hydrophobicity，and coalescence of dispersed oil droplet，innovative idea of nano-sized water and nano-sized oil was put forward to overcome the technical bottleneck of“no injection，no production”of low-permeability reservoir. By means of modifying nano-sized particle with functional groups，the first generation of nano-sized oil-displacement agent， iNanoW1.0，was developed. Normal water could be transformed into“nano-sized water”in presence of iNanoW1.0 by weakening or destroying the association of hydrogen bonds between water molecules. Through the molecular dynamic simulation and capillary analysis，the effect of adding medium to water on the hydrogen bond by weakening or breaking between water molecules was analyzed. By conducting low field nuclear magnetic resonance displacement experiment and core displacement experiment，the injection performance and displacement effect of iNanoW1.0 and normal water were compared. The pilot test with iNanoW1.0 as oil-displacement agent was carried out in Changqing oilfield of ultra-low permeability reservoir. The results showed that iNanoW1.0 could transform normal water into nano-sized water by destroying the dynamic network structure of water molecule. Compared with normal water，iNanoW1.0 possessed better injection performance and displacement effect. With lower starting pressure gradient， iNanoW1.0 could expand the swept volume in extra-low or ultra-low permeability reservoir which could not be swept by normal water. The field pilot test in Changqing oilfield of ultra-low permeability reservoir had the characteristics of increasing fluid， increasing oil and lowering the rate of decline. The effect of enhanced oil recovery by waterflooding was observed for the first time in Changqing oilfield of ultra-low permeability reservoir. The theory of waterflooding in low-permeability reservoir was developed.