含油污泥微纳米颗粒驱油体系的研制与性能评价

Development and Performance Evaluation of Oily Sludge Oil Displacement System with Micro-nano Particle

油田生产中含油污泥无害化处理困难、成本高,含油污泥回注是一种低成本的无害化处理技术。常规回注调剖法仅能回注粒径较小的含油污泥颗粒,不能充分回收利用含油污泥。为此,将含油污泥颗粒经球磨处理至微纳米尺度,并添加石油磺酸盐类表面活性剂,通过搅拌、超声、离心形成稳定的驱油体系,研究了含油污泥微纳米颗粒驱油体系的粒径分布、乳化能力和驱油性能。结果表明,驱油体系中含油污泥微纳米颗粒的粒径中值为158 nm。该体系在室温(25℃)下静置4 d后仍能保持较好的悬浮性,油水完全分离的时间≥5 min;在60℃下与煤油的界面张力为7.4×10-3m N/m,乳化能力较强。由于乳化与封堵的双重作用,含油污泥微纳米颗粒驱油体系的注入能力和驱油效果好于表面活性剂驱,适用于中低渗透油藏。在60℃、注入量为0.5 PV、注入速度为1 m L/min的条件下,其驱油效率较水驱提高约20百分点,较表面活性剂驱提高约8百分点。含油污泥微纳米颗粒驱油体系的制备方法可完全处理含油污泥,实现含油污泥的高效再利用。

The harmless treatment of oily sludge in oilfield production is difficult and costly.Reinjection of oily sludge is a low-cost harmless treatment technology.The conventional reinjection profile control method can only reinject the oily sludge particles with smaller particle size,which can not fully recycle the oily sludge.Therefore,the oily sludge particles were ball milled to the micro-nano scale,and then petroleum sulfonate surfactant was added to form a stable oil displacement system by stirring,ultrasonication and centrifugation.The particle size distribution,emulsification ability and oil displacement performance of oily sludge flooding system with micro-nano particle were studied.The results showed that the median particle size of oily sludge micro-nano particle in oil displacement system was 158 nm.The system could maintain good suspension after standing at room temperature(25℃)for 4 days.The time of complete separation of oil and water was equal or greater than 5 min.The interfacial tension between the system with kerosene at 60℃was 7.4×10-3 mN/m,indicating strong emulsification ability.Due to the dual effects of emulsification and plugging,the oily sludge micro-nano particle flooding system had better injection capacity and oil displacement effect than surfactant flooding,which was suitable for medium and low permeability reservoirs.Under the condition of 60℃,injection volume of 0.5 PV and injection rate of 1 mL/min,the oil displacement efficiency was about 20 percentage points higher than that of water flooding and about 8 percentage points higher than that of surfactant flooding.The preparation method of oily sludge micro-nano particle flooding system could completely treat oily sludge,and then realize the efficient reuse of oily sludge.