Synthesis and application properties of a sulfobetaine Gemini surfactant

In order to change the heterogeneity difference, improve the acidizing and unplugging effect of carbonate reservoir, a series of sulfobetaine Gemini surfactants (2Cn-SGS, where n is the number of carbon atoms in the hydrophobic chain, n=12, 14, 16, 18) were synthesized by a two-step reaction using long chain alkyl dimethyl tertiary amine, 3-chloro-2-hydroxypropane sulfonic acid sodium and 1,4- dibromobutane as raw materials. Taking 2C16-SGS as an example, the structures of mid product (C16-SGS) and 2C16-SGS were characterized by FTIR. Surface activity of 2Cn-SGS was analyzed by surface tension method. The results show that 2Cn-SGS have good surface activity, and the CMC and surface tensions of 2Cn-SGS decrease with the increase of hydrophobic chain, and the micellization ability is enhanced. It can be used in viscoelastic surfactant self-steering acidification technology, with good steering and shunting ability. The optimal formula is 4% 2C16-SGS+20% hydrochloric acid + 20% Ca2+. The high viscosity gel of acidizing system is easy to break when mixing with hydrocarbons such as kerosene. It is easy to backflow and has no damage to the formation. © 2019, Chemical Industry Press. All right reserved.