纳米流体在储层岩芯表面的铺展及其驱油机理研究

发布时间：2018-02-22 00:28

本文关键词： 纳米SiO2颗粒表面改性岩芯铺展驱油　出处：《西安石油大学》2015年硕士论文　论文类型：学位论文

【摘要】：目前,国内外油田的开采过程中普遍存在着低渗透油田所占比例大、采收率较低的问题。随着纳米技术的不断发展,人们提出了利用纳米颗粒进行驱油以提高原油采收率的新思路。本文采用廉价、易得、无污染的纳米Si O2颗粒作为油田用驱替剂的添加剂,以TEOS为原料,选用溶胶-凝胶法合成纳米级Si O2颗粒,并采用二氯二甲基硅烷对其表面进行疏水化改性,考察不同方法改性后颗粒的粒径、表面润湿性及其分散效果。将亲/疏水化程度不同的纳米Si O2分散在水溶液中制成颗粒水基分散液,从微观角度出发,利用电子显微镜观察纳米流体铺展后,Si O2颗粒对岩芯壁面的微观作用;从宏观角度出发,测试纳米流体与原油之间的界面张力值,进行岩芯驱替实验,评价不同种类纳米流体的驱油效果,旨在提高原油的采收率,探索其驱油的作用机理。研究结果表明,溶胶-凝胶法合成的纳米Si O2颗粒可通过调整母液的酸碱度、搅拌速度等措施有效的控制颗粒粒径、反应时间及最终产量。尤其是当反应母液的p H等于8时,反应时间仅需12小时,且收率可达80%;合成的纳米Si O2颗粒呈均匀分散的球形,平均粒径为38 nm。对其表面进行疏水化改性时,不同改性方法处理后的颗粒粒径出现明显的差异,且疏水化程度的可控范围不同;效果最好的是使用二氯二甲基硅烷进行一步法改性,改性后颗粒粒径分布均匀,仅为10 nm。将亲/疏水化程度不同的纳米Si O2制成质量分数为0.05%的颗粒水基分散液后进行测试可知,纳米流体能够显著的降低油水界面张力,提高原油的采收率,尤其是亲水性的S-05。综合上述实验结果可归纳得出利用纳米流体进行驱油的作用机理。由于纳米Si O2颗粒的加入,油水界面张力大大降低,提高了驱替剂的洗油效率。随着纳米流体不断进入储层,Si O2颗粒可以突破岩芯表面附着的水化层及油层,在部分区域进行选择性吸附,形成微-纳米疏水结构,不仅发挥了剥离原油的作用,且能够在后期的注水过程中起到一定的降压增注效果。
[Abstract]:At present, the problems of low permeability oil fields and low oil recovery exist in the production process of oil fields at home and abroad. With the development of nanotechnology, In this paper, the cheap, easily available and pollution-free nano-SiO _ 2 particles are used as additives of displacement agent for oil field, and TEOS is used as raw material. Nanometer Sio _ 2 particles were synthesized by sol-gel method and hydrophobically modified by dichlorodimethylsilane. Surface wettability and dispersion effect. Nanometer Sio _ 2 with different degree of hydrophobicity and hydrophobicity was dispersed in aqueous solution to form granular water-based dispersion. The microcosmic effect of Sio _ 2 particles on core wall was observed by electron microscope, and the interfacial tension between nano-fluid and crude oil was measured from a macro point of view, and the core displacement experiment was carried out. The purpose of evaluating the oil displacement effect of different kinds of nano-fluids is to improve the oil recovery and explore the mechanism of oil displacement. The results show that the sol-gel synthesis of nano-SiO _ 2 particles can adjust the pH of the mother liquor. The stirring rate can effectively control particle size, reaction time and final yield, especially when pH of the mother liquor is 8:00, reaction time is only 12 hours, and the yield can be up to 80. The synthesized nano-SiO _ 2 particles are uniformly dispersed spherical. The average particle size is 38 nm. When the surface is modified by hydrophobicity, the particle size of different modification methods is obviously different, and the controllable range of hydrophobic degree is different. The best effect is to use dichlorodimethylsilane for one-step modification, and the particle size distribution is uniform after modification. It is only 10 nm. The nano-SiO _ 2 with different hydrophobicity and hydrophilic degree is prepared into 0.05% particle water-based dispersion. The results show that the nano-fluid can significantly reduce the oil-water interfacial tension and improve the oil recovery. Especially the hydrophilic S-05.Combined with the above experimental results, the mechanism of oil displacement using nano-fluids can be concluded. Because of the addition of nano-SiO _ 2 particles, the interfacial tension of oil and water can be greatly reduced. The oil washing efficiency of the displacement agent is improved. With the constant entry of nano-fluids into the reservoir, Sio _ 2 particles can break through the hydration layer and the oil layer attached to the core surface, and selectively adsorb in some areas to form a micro-nano hydrophobic structure. It not only plays the role of stripping crude oil, but also plays a certain effect of reducing pressure and increasing injection in the later water injection process.
【学位授予单位】：西安石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE357.4;TB383.1

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