| 摘要: |
| 以氨基聚硅氧烷与绿色表面活性剂脂肪酸甲酯磺酸钠(MES)为主要原料,应用正交设计实验优化得到致密气井压裂控水用纳米乳液形成的最佳条件。分析纳米乳液中液滴尺寸分布与致密岩心孔喉的匹配性,考察纳米液滴吸附后对致密岩心表面微观结构与界面性质的影响,评价纳米乳液的耐冲刷与控水性能。结果表明:为形成良好的纳米乳液,应调节氨基聚硅氧烷与水质量比为1∶2,乳化剂MES、正丁醇、氯化钾加量分别为氨基聚硅氧烷质量的40.0％、20.0％、5.0％,乙酸调节pH至6.5;纳米乳液中液滴中值粒径平均为28.5 nm,与致密岩心孔喉尺度匹配良好;随着纳米乳液质量分数的增加,岩心孔隙表面从尖锐的沟槽形貌逐渐转变为均匀、平滑的峰谷结构,润湿性也呈现强疏水性质;纳米乳液耐冲刷性能良好,0.5％的纳米乳液能降低水相相对渗透率超过60％,而对气相渗透率影响较小,说明纳米液滴借助氨基、硅氧键与硅氢键等极性基团通过物理化学吸附作用牢固附着在岩石表面,而分子链中疏水基团硅甲基改变了岩石表面润湿性质,对气/水在致密孔隙裂缝中的渗流产生了较大影响。 |
| 关键词: 正交设计 氨基聚硅氧烷 纳米乳液 控水 压裂 致密气层 |
| DOI：10.3969/j.issn.1673-5005.2016.01.022 |
| 分类号::TE 357.46 |
| 基金项目:山东省优秀中青年科学家科研奖励基金项目(BS2012HZ029);山东省自然科学基金项目(ZR2012EEM001) |
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| Preparation and performance evaluation of nanoemulsions for water control fracturing in tight gas formations |
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LUO Mingliang, SUN Tao, L Zilong, WEN Qingzhi, SUN Houtai
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(School of Petroleum Engineering in China University of Petroleum, Qingdao 266580, China)
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| Abstract: |
| With amino polysiloxane and one environmental-friendly surfactant fatty acid methyl ester sulfonate (MES), the optimal formation conditions of nanoemulsions were obtained by the orthogonal design experiments, which can be applied to water control fracturing in tight gas wells. The matching between the size distribution of droplet in nanoemulsions and pore throat in dense cores was analyzed. The effects of nano-droplets adsorbed on core surface on microstructure and interfacial properties were investigated. The water-flooding erosion resistance and water control performances were evaluated by core flooding tests as well. It is found that the optimal formation conditions of nanoemulsion are as follows:weight ratio of modified amino silicone and water 1∶2, the amount of emulsifiers MES, n-butanol, potassium amino are 40.0 ％, 20.0％, 5.0％ in that of modified silicone oil,respectively, and adjusted to pH 6.5 with acetic acid. The average median diameter of droplets in nanoemlsions is about 28.5 nm, which matches well with pore throat sizes in tight formation cores. And with the increase of nanoemulsions concentration, the surface morphology of core pore are gradually transformed from sharp groove shape to a uniform, smooth peak valley structure and the wettability also presents strong hydrophobic properties. Core flooding tests show that nanoemulsions possess good erosion resistance, reduce water phase relative permeability over 60％ and have little effect on gas permeability with 0.5％ nanoemulsions. These demonstrate that nanodroplets are firmly attached on the surface of cores through the physical or chemical adsorption of polar groups such as Si-O bond, Si-H bond and amino groups. And the hydrophobic silicon methyl groups in molecular chains alter the rock wettability properties, which results in greater impact on gas/water flow in porous media. |
| Key words: orthogonal design amino polysiloxane nanoemulsion water control hydraulic fracturing tight gas formation |
