低界面张力活性纳米流体的研制与渗吸驱油机理分析

Development of Nano Fluid with Low Interfacial Tension and Analysis of Imbibition Displacement Mechanism

李 佳 陈明贵 耿向飞 呙瑜成 邓 虹 徐 伟 侯宝峰 吴一慧

LI Jia CHEN Minggui GEN Xiangfei GUO Yucheng DENG Hong XU Wei HOU Baofeng WU Yihui

为了提高低渗透油藏的原油采收率，水平井压裂后活性水渗吸吞吐工艺被广泛应用，研制高效渗吸剂配方 是其成功的关键。本文通过“一锅煮”法合成了低界面张力阴非离子表面活性剂三苯乙烯基聚氧乙烯醚羟丙基 磺酸钠（TPHS），考察了该剂的界面活性和耐盐性，将TPHS与α-烯基磺酸钠（AOS）、纳米SiO2颗粒进行复配得到 了低界面张力纳米流体，研究了该低界面张力纳米流体的界面活性和润湿性，并通过自发渗吸实验和强制渗吸 实验评价了该低界面张力纳米流体的驱油效率。研究结果表明：在温度80 ℃、矿化度300 g/L下，在较大的浓度 范围内TPHS溶液与原油间的界面张力保持在10-1 mN/m数量级，具有较好的抗盐耐温性能；TPHS与AOS复配 的配方为0.1% TPHS+0.2% AOS的表面活性剂体系与原油间的界面张力降至10-2 mN/m数量级，有利于置换小 孔隙中的原油。配方为0.1% TPHS+0.2% AOS+0.05% 纳米SiO2低界面张力活性纳米流体中，加入的少量纳米 SiO2颗粒可与TPHS、AOS复配产生润湿协同作用，提高渗吸速率，比表面活性剂体系的采收率提高12.7%，并能 在驱油过程中形成乳液稳定油墙，延长无水采油期。低界面张力活性纳米流体比单纯表面活性剂复配体系用于 低渗透油藏渗吸提高采收率有优越性。

In order to improve the oil recovery of low permeability reservoir，active water imbibition huff and puff technology is widely used in horizontal wells after fracturing，and the key to its success is to develop a high-efficiency imbibition agent formula. In this paper，a low interfacial tension anion-nonionic surfactant，tristyryl polyoxyethylene ether sodium hydroxypropyl sulfonate （TPHS）was developed by "one pot boiling". The interfacial tension and salt resistance performance of HPHS was investigated. A low interfacial tension nano fluid，composed of TPHS，AOS and nano- SiO2 particles，was optimized by contact angle test， spontaneous infiltration test and forced infiltration test，and the displacement evaluation was carried out. The results showed that the interface tension between TPHS solution and the crude oil could still be kept at 10- 1 mN/m at the temperature of 80℃ and at the salinity of 300 g/L，exhibiting good salt and temperature resistance. The interface tension between the complex system of 0.1% TPHS+0.2% AOS and the crude oil decreased to 10-2 mN/m，which was helpful to displace crude oil in small pores. The addition of a small amount of nano- SiO2 particles（0.05%）could produce synergistic effect of wetting with TPHS and AOS，which could improve the imbibition rate and enhance the recovery rate by 12.7%，compared to that of the surfactant flooding. At the same time， the emulsion stabilized oil wall could be formed and the anhydrous oil recovery period could be prolonged. It was confirmed that the addition of nano-SiO2 to surfactant mixtures resulted in enhanced imbibition oil recovery in low permeability reservoirs.

10.19346/j.cnki.1000-4092.2021.02.017