低渗透致密储层用改性纳米驱油压裂液

Development of Nano-modified Displacement Fracturing Fluid for Low Permeability Tight Reservoir

刘城成 李帅帅 任 强 贾 飞 白叶雷 王 进 王世彬 赵金洲

LIU Chengcheng LI Shuaishuai REN Qiang JIA Fei BAI Yelei WANG Jin WANG Shibin ZHAO Jinzhou

低渗致密油藏作为未来我国非常规油气资源勘探开发的主要新领域，是接替常规油气资源、支撑油气革命的重要力量。纳米流体在低渗致密油藏中驱油效果较好，但纳米粒子作为助剂在水溶液中易堵塞地层微纳米孔喉，纳米粒子的团聚问题一直难以解决。通过水溶液引发自由基共聚法，以丙烯酰胺（AM）、2-丙烯酰胺-2-甲基丙磺酸（AMPS）和N-12-（2-丁烯酰氧基）正十二烷基-N，N，N-三甲基溴化铵（MEDDA）为底物单体，引入改性纳米SiO2合成了一种改性纳米SiO2/聚合物驱油压裂液。借助红外光谱仪、核磁共振氢谱仪和透射电镜等方法分析表征改性纳米 SiO2/聚合物驱油压裂液稠化剂；再将渗吸驱油实验和核磁共振技术相结合来研究改性纳米 SiO2/聚合物驱油压裂液的驱油效果。研究结果表明，聚合物体系中的改性纳米SiO2最优加量为1.5%。通过对比不同改性纳米 SiO2加量的改性纳米 SiO2/聚合物驱油压裂液在饱和油岩心片表面的接触角，证明改性纳米 SiO2/聚合物驱油压裂液驱油效率的提升是通过改善岩石表面润湿性来实现的。相较于未添加改性纳米 SiO2的聚合物驱油压裂液体系，添加改性纳米 SiO2（1.5%）/聚合物驱油压裂液的自发渗吸效率接近 40%，渗吸效率提升超过 1倍。通过核磁共振成像结果也可明显看出：随着渗吸时间的延长，添加了改性纳米 SiO2的驱油压裂液中的岩心原油饱和度大幅降低，渗吸速度明显加快，渗吸效果显著。

As a major new field of unconventional oil and gas exploration and development in the future，low-permeability tight oil and gas reservoir is an important force to replace conventional oil and gas resources and support the oil and gas revolution. The nano-fluid displacement in low permeability tight oil reservoir is effective，however，nanomaterials are easy to block micro-nano pore throat，and it is difficult to solve the problems of agglomeration of nanomaterials in aqueous solution. In this study，acrylamide （AM），2-acrylamide-2-methylpropanesulfonic acid（AMPS）and N-12-（2-crotoxyloxy）n-dodecyl-N，N，N-trimethyl ammonium bromide（MEDDA）were used as substrate monomers by the method of free radical copolymerization induced by aqueous solution， the modified nano-SiO2/polymer displacement fracturing fluid was synthesized by introducing modified nano-SiO2. The modified nano-SiO2 displacement fracturing fluid was analyzed and characterized by infrared spectrum，nuclear magnetic hydrogen spectrum and transmission electron microscopy. Then the oil displacement effect of modified nano-SiO2/polymer displacement fracturing fluid was studied by combining imbibition displacement experiment with nuclear magnetic resonance technology. The results showed that the optimal dosage of modified nano-SiO2 in polymer system was 1.5%. By comparing the contact angle of different fluids on the core surface，it was proved that the oil displacement efficiency of modified nano-SiO2/polymer displacement fracturing fluid was achieved by improving the wettability of the rock surface. Compared with the oil displacement fracturing fluid system without modified nano-SiO2，the spontaneous imbibition efficiency of modified nano-SiO2/polymer displacement fracturing fluid system was close to 40%，and the imbibition efficiency was increased by more than 1 times. It could also be clearly seen by NMR image that with the increase of imbibition time，the core crude oil saturation in the displacement fracturing fluid with modified nano-SiO2/polymer was significantly reduced，and the imbibition rate was accelerated，and the imbibition effect was significant.

10.19346/j.cnki.1000-4092.2024.03.005