表面活性剂剥离固体表面原油机理

THE MECHANISM OF OIL DISPLACEMENT FROM SOLID SURFACE BY SURFACTANT

在原油中加入含非离子-阴离子型表面活性剂NPM-4-4的NaCl水溶液,观察在表面活性剂作用下原油从固体表面剥离的现象。当在原油中加入表面活性剂溶液后,油-水界面张力迅速降低,在亲油固体表面上,界面张力降低到一定程度后,原油与固体的接触角变小,形成油珠,并且油珠被不断拉长直至拉断。对于亲水固体表面,如果油珠体积较小,在表面活性剂作用下,油珠不断收缩,同时由于表面活性剂对吸附在油-固界面上的胶质和沥青质成分的渗透增溶作用,体积较小的油珠会从固体表面完全脱落;对于体积较大的油珠,在表面活性剂作用下,油珠被拉长,使部分油珠脱落,剩余的部分油珠继续收缩,直到全部脱落。分别从杨氏方程和油珠整体受力的角度分析了油珠从固体表面脱落的机理,证明了实验现象。

The phenomena of oil displacement from solid surface under the action of surfactant were observed, when the NaCl aqueous solution of nonionic-anionic amphoteric surfactant NPM-4-4 was added into crude oil. After addition of surfactant solution, the interracial tension （IFT） between oil and water reduced immediately. For the oil-wet solid surface, the contact angle between oil and solid surface under the action of surfactant would reduce to form oil drips, which was further lengthened and broken. For the water-wet solid surface, if the volume of the oil drip was small enough, the oil drip would contract and finally drop down from solid surface due to the interracial tension, and the permeation and solubilization of surfactant to the asphaltene and resin adsorbed on oil-solid surface. If the volume of the oil drip was large, the oil drip was lengthened, a part of which dropped down from solid surface, left part of which would continue contract until the drip was small enough to drop down from the surface. Finally, above phenomena were explained by the Young Equation and mechanics.