水基纳米聚硅乳液体系应用研究

Application of Water-based Nano-Polysilicon Emulsion

制备了具有水分散性的疏水纳米聚硅,以水作为携带剂代替常规的有机分散剂,并将其用于低渗油田注水井的降压增注。通过分析宝浪油田储层孔喉特征,确定纳米聚硅的匹配粒径为10 20 nm。纳米聚硅乳液澄清透明,通过研究其分散性和稳定性,确定水基纳米增注液配方为1.75‰纳米聚硅、2‰助分散剂。水基纳米聚硅乳液可使岩石表面由亲水性变为强疏水性,接触角由23.7°增至131.8°。岩心流动实验结果表明,经水基纳米聚硅处理后,水相渗透率平均提高40%。对注污水或油转注的欠注井实施纳米聚硅増注前,进行酸化预处理可取得较好的增注效果。在宝浪油田5口井进行现场试验,增注有效率达80%,有效期可达一年以上。

Nano-polysilicon dispersible in water was synthesized and resultant nano-polysilicon was used for decompression and augmented injection of the water-injection wells in low-permeability reservoir with water as a replacement cartier of organic dispersant. Based on the analysis of pore-throat characteristics in Baolang reservoir, it was suggested that the size of nano-polysilicon should be 10--20 nm so as to well match with the size of pore-throat. Besides, the nano-polysilicon emulsion was transparent. Through the study of dispersion capacity and stability of the emulsion, the formula of nano-polysilicon water-based decompression and augmented injection fluid was： 1.75 %0 nano-polysilicon and 2%0 assistant dispersant. After being treated with nano-polysilicon water-based emulsion, it was feasible to convert the hydrophilic core surface into a great hydrophobic with contact angle increasing from 23.7~ to 131.8~. Core flow tests showed that the water permeability increased by 40% in average after being treated with this fluid. For sewage injection well and water injection well changed from oil well, it was supposed that an excellent decompression and augmented injection effectiveness could be achieved when pre-acidizing was done before nano-liquid augmented injection. Field test in Baolang oiltleld indicated that the title augmented injection agent was able to increase the augmented injection effectiveness by a rate of 80% and could retain effectiveness in more than one year.