油气藏用微乳剂性能研究

Study on Performance of Micro-emulsion for Oil and Gas Reservoirs

以阳离子表面活性剂和非离子表面活性剂作主剂,并添加其他辅剂研制出了一种微乳剂。性能评价结果表明,该微乳剂可以将亲水性岩心润湿性改变为中性～弱亲水(接触角为65°～90°);加有该剂的压裂液破胶液表面张力小于30 mN/m;与压裂液复配,不会降低压裂液成胶黏度,且有利于降低压裂液的滤失量。进一步的实验结果表明,该微乳剂降低了毛细管力,其排液所需压力仅为常规表面活性剂的35%;在4 mL/s的低顶替速率下,200 mg/L微乳剂溶液的顶替率为54%,而常规表面活性剂溶液的顶替率仅为28%。因此可以得出,该微乳剂有利于减小低渗储层伤害,提高采收率。

The micro-emulsion is developed in this paper,and the main properties and the effiect on wettability of the hydrophilic and hydrophobic core are studied.The results show that,within effective concentration of the microemulsion,the surface tension is less than 30 mN/m,and it can reduce filtration of guar gum fracturing fluid,moreover,it can transform the wettability of the hydrophilic and hydrophobic core to weak hydrophilicity(65°< contact angle < 90°),and decrease the capillary force as resistance force in reservoir pores.By cooperating with the micro-emulsion,the viscosity of fracturing fluid is not be decreased and the surface tension is reduced after breaking,which is good to flow back.