特低/超低渗油藏纳米驱油剂的制备与性能

Preparation and Properties of Nano Oil Displacement Agent for Low/Ultra-low Permeability Reservoir

贺丽鹏 罗健辉 丁彬 王平美 彭宝亮 耿向飞 李莹莹

HE Lipeng LUO Jianhui DING Bin WANG Pingmei PENG Baoliang GENG Xiangfei LI Yingying

特低/超低渗油藏具有渗透率低、毛细阻力大等特点，因常规注水困难，水驱难以有效波及，仍有大量剩余油存在。本文以自制的纳米SiO2硅溶胶为载体，创新建立了SiO2的亲水/亲油改性方法，研发出分别具有长链烷基、羟基、短链烷基结构的亲油、亲水、憎水改性纳米SiO2系列样品。采用光散射、红外表征了改性SiO2的尺寸与基本结构。通过自主研发的毛细作用分析系统考察了不同类型SiO2样品的注入性能并分析了纳米颗粒改善水注入性能、扩大注水波及体积机理。结果表明：纳米SiO2可以有效改善水的注入性能，纳米SiO2的粒径对水注入能力影响不大。亲水改性的纳米SiO2能够进一步提高水的注入能力，具有提高水驱波及体积、进一步提高采收率的潜力。通常情况下水是以分子团簇结构存在，水分子间依靠氢键形成团簇结构，相互水团簇之间存在动态结合可能是造成特低/超低渗油藏常规注水困难的主要原因。改性纳米SiO2硅溶胶具有胶体溶液的典型特征，硅溶胶中的纳米粒子不断地做不规则布朗运动，改变水分子的运动状态，影响氢键网络的重排机理，从而实现水分子团簇结构的改变，增加了水的注入能力，使纳米驱替液能够进入常规水难以注入的特低/超低渗油藏，扩大了波及体积。图5表2 参11

Due to the low permeability and high capillary resistance，the development of oilfield by water injection is very difficult and the spread of water flooding is limited for low/ultra-low permeability reservoir. The potential of a further substantial increase in oil recovery is displacing the remaining oil in the low permeability area by water flooding. Based on the self-made nano SiO2 colloidal silica，lipophilic，hydrophilic and hydrophobic modified nano SiO2 chemical samples containing long chain alkyl，hydroxy，short chain alkyl group，respectively，was prepared and the basic structure was characterized by dynamic light scattering and IR. The injection ability of these samples was evaluated by capillary analysis system and the mechanism was further studied on the basis of experimental analysis. The results showed that the modified nano-meter SiO2 had the ability of greatly improving the injection capacity of low permeability area compared to that of the surfactant OP-10，which was little affected by the size of the nano-meter SiO2. Moreover，the hydrophilic modified nano SiO2 had the best effect of improving the injection capacity compared to that of the lipophilic and hydrophobic modified nano SiO2. The water clusters structure was formed by the hydrogen bonding between water molecules. The dynamic combination between each water cluster maybe the important reason of the difficult water injection for low/ultra-low permeability reservoir. The nano particles in colloidal silica did the Brownian movement constantly. The motion of water molecules and the hydrogen bond network rearrangement was changed，so as to realize the change of the structure of water molecule clusters，and thus increased the water injection ability to further expand the water sweep volume.

10.19346/j.cnki.1000-4092.2018.01.015