Dynamic Interfacial Tension between Crude Oil and Dodecylmethylnaphthalene Sulfonate Surfactant Flooding Systems

Abstract

The surface tension of surfactant aqueous solutions and dynamic interfacial tensions (DIT) between crude oil, offered from Shengli Oil Field in China, and surfactant flooding systems, and the single-component dodecylmethylnaphthalene sulfonate (DMNS) surfactant, developed in our laboratory, were measured. In the present report, both buffered alkali and no alkali flooding systems were investigated. It was found that DMNS surfactant possessed great capability and efficiency of lowering the solution surface tension and the critical micelle concentration (cmc) is 0.002 mass% and the surface tension at this concentration is 29.39 mN.m^?1. It was also found that the DMNS surfactant is also greatly effective in reducing the interfacial tensions and can lower the tension of crude oil-water interface to ultra-low at very low surfactant concentration and an optimum range of sodium chloride. The lower alkali concentration is favorable for lowering DIT. The higher alkali concentration needs a higher surfactant concentration for oil flooding systems lowering DIT. Moreover, the results indicate that there obviously exists both synergism and antagonism among the surfactant, alkali and inorganic salt. The added surfactant play an important role in reducing DIT, and the prepared DMNS surfactant possesses great capability and efficiency in lowering the interfacial tension between oil and water. The salt-modified surfactant flooding systems without alkali, decreasing the cost of oil recovery and avoiding the stratum being destroyed would have a great prospect for enhanced oil recovery.     

Research Interfacial Properties of the Novel Lignosulfonates

Abstract

The interfacial tensions between the crude oil and the novel modified lignosulfonate solutions were measured by a spinning drop interfacial tension apparatus. Some effects that influence on IFT were discussed. With the increase of alkyl chain length or the number of lipophilic groups introduced, the interfacial activity of the modified lignosulfonate increases, and the optimum surfactant concentration required to reach ultra-low IFT decreases. Excellent activity at the interface of crude oil and the solutions was observed. The interfacial tensions of the modified lignosulfonates could be ultra-low over a wide range of surfactant concentration and alkali concentration without the addition of other surfactants. They are capable of being the principal surfactant in enhanced oil recovery (EOR).     

中深层稠油蒸汽驱注采剖面调整工艺技术研究

从1997年开始,辽河油田进行了中深层稠油蒸汽驱先导试验,目前已进入蒸汽驱先导试验的后期调整阶段,先导试验区的稠油采出程度由试验前的24%提高到57%,基本达到方案设计指标,先导试验获得成功。然而,在蒸汽驱先导试验及随后的扩大试验中,存在着纵向动用程度不均、平面动用程度差等问题,影响蒸汽驱先导试验效果。为此,从2004年开始,辽河油田钻采工艺研究院开展了中深层稠油蒸汽驱注采剖面调整工艺技术研究工作,形成了中深层稠油蒸汽驱注采剖面调整系列技术,主要包括耐高温化学调堵技术与机械封堵技术,并应用于现场,有效解决了蒸汽驱层间、层内动用不均的问题,提高了中深层稠油的采收率。下一步仍需加大高温调剖剂的深入研究,研制高效、经济的高温调剖剂;对生产井机械封堵工艺技术的研究重点,是加快对耐高温胶筒的选优,满足现场生产需求。