驱油流体吸附抑制剂的合成与评价

Synthesis and evaluation of adsorption inhibitors for oil displacement fluids

关键词:  吸附抑制  驱油  静态洗油效率  表面张力  界面张力 

Key words:  adsorption inhibition  oil displacement  static oil washing efficiency  surface tension  interfacial tension

摘要:

目的 在化学驱的实施过程中,地层对驱油剂的吸附滞留是表面活性剂进入地层后含量损失的一种主要原因,为了减少驱油流体在地层的损耗成本而展开对驱油液体吸附抑制剂的研究。方法 以二氰二胺(DCD)、1-十八胺盐酸盐(OHC)为原料,基于亲核加成的原理采用熔融法在150 ℃下合成了一种针对驱油流体的吸附抑制剂OHCB,该表面活性剂同时具备强疏水基、强极性原子和阳离子基团,因此具有较强的占据黏土矿物表面吸附位点的能力。对其进行了红外吸收、紫外吸收、元素分析、质谱等结构表征,采用静态吸附法研究了其作为添加剂的最佳配比,并验证在最佳配比下对驱油剂AEO7的吸附抑制效果,以及该体系相较AEO7单一体系的静态洗油效率、乳化性及润湿性的变化。结果 OHCB抑制驱油剂AEO7在黏土矿物表面的吸附效果较好,在驱油剂与吸附抑制剂质量比为5∶1的情况下,抑制效果可达27%以上。结论 OHCB不仅具有较好的吸附抑制效果,且其加入使AEO7的静态洗油效率提升至27.3%、γ_cmc降至27.1 mV/m,CMC降至38 mg/L、油-水界面张力降至0.5 mV/m以下,对体系性能起到了协同增效的作用,并且相较于需要预吸附的牺牲剂,其使用更为便捷。 

Abstract:

Objective During the implementation of chemical flooding, the adsorption and retention of the reservoir on the displacing agent was a major reason for the concentration loss of surfactants entering the reservoir. In order to reduce the loss cost of oil displacement fluid in the formation, the research on the adsorption inhibitor of oil displacement fluid is carried out. Methods A adsorption inhibitor OHCB for oil displacement fluids was synthesized by the nucleophilic addition principle based on the raw materials of dicyanodiamide (DCD) and 1-octadecylamine hydrochloride (OHC) using fusion method at 150 ℃. This surfactant had strong hydrophobic groups, strong polar atoms and cationic groups, and had the ability to occupy the adsorption sites on the clay mineral surface. The structure characterization was carried out by infrared absorption, ultraviolet absorption, elemental analysis, mass spectrometry, etc. The optimum ratio was studied by static adsorption method for using it as an additive, and the adsorption inhibition effects of the optimal ratio on the oil displacement agent AEO7 were verified, as well as the static oil washing efficiency, emulsification and wetting properties of the system were compared with the single AEO7 system. Results The results showed that OHCB had better inhibition effect on the adsorption of oil displacement agent AEO7 on clay mineral surface. The inhibition effect reached more than 27% when the mass ratio of oil displacement agent to adsorption inhibitor was 5∶1. Conclusion sThe addition of OHCB not only has a good adsorption inhibition effect, but also improves the static oil washing efficiency of AEO7 to 27.3%, reduces γ_cmc to 27.1 mV/m, reduces cmc to 38 mg/L, and reduces the oil-water interfacial tension to below 0.5 mV/m. It has a synergistic effect on the system performance. Comparing with sacrificial agents requiring pre-adsorption, the method is more convenient.