Assessment of oil displacement performance of new amine-ether gemini surfactant and its application

Abstract

To address the challenges of low injection capacity， low fluid recovery rate， and low recovery in the water flooding development of low-permeability reservoirs in Shengli Oilfield， this paper proposed an oil displacement technology with new amine-ether gemini surfactants. The molecular structure was designed on the new amine-ether gemini surfactant for oil displacement， and the interfacial properties of different molecular structures were evaluated. The sample G-3 with the best interfacial properties was selected， and the emulsification and oil displacement performance were evaluated at different concentrations. The oil displacement mechanism was elucidated by combining micro etched glass models. The experimental results showed that the new amine-ether gemini surfactant with a concentration of 0.2% can reduce the interfacial tension between oil and water to 0.003 9 mN/m， forming the stable emulsion with crude oil， and the particle size of lotion drops is 12 μm. For the postflood core with a permeability of 6.966 mD， the G-3 solution of the new amine-ether gemini surfactant with a concentration of 0.2% is injected at 0.5 PV， and the recovery can increase by 9.6% and the pressure reduces by 17.4% after water flooding again. The micro oil displacement mechanisms are the reduction of the interfacial tension between oil and water and the residual oil emulsification and coalescence. A field test was conducted in the low-permeability block of Shengli Oilfield. After implementation， the injection capacity of the water wells in the block was doubled. The daily oil production of the oil wells was 5.7 t/d， and the water cut decreased by 11.0%. Up to June 2023， the cumulative oil production in the block had been 1 791 t， achieving good development effect.

Keywords

• molecule structure design
• high activity
• strong emulsifying
• low permeability
• new amine-ether gemini surfactant
• performance assessment