In this paper,with a petroleum sulfonate selected as surfactant,the formulation of microemulsion systems in tertiary oil recovery was researched by orthogonal design and equation coefficient method.It was the first time the orthogonal design method was applied in the formulation investigation.Through this method more information could be obtained in as less experiments as possible.In a shorter time the formulation was found out:The con- centration of surfactant was 2%,the low limit of standard values for... In this paper,with a petroleum sulfonate selected as surfactant,the formulation of microemulsion systems in tertiary oil recovery was researched by orthogonal design and equation coefficient method.It was the first time the orthogonal design method was applied in the formulation investigation.Through this method more information could be obtained in as less experiments as possible.In a shorter time the formulation was found out:The con- centration of surfactant was 2%,the low limit of standard values for dilute systems.The interfacial tensions of the system was 3.30×10~(-4)mN/m.The solubilization parameter was about 11-12.In simulating test the oil recovery by microemulsion flooding was 94.6% for residual oil after waterflooding. As concerning to the equation coefficient method,different equations were derived for different bassical and additional alcohols.When the basical alcohol was water-soluble isopropanol,the equation was obtained as:lnS~*=ln〔-0.198A-0.0481(C_s-3.15)+f'(ACN)〕 +0.019(t-28).When it was oil-soluble n-butanol,the equation was:ln〔S~*+0.0481(C_s- 3.15)〕=0.212(ACN)+f'(A)+0.019(t-28)-2.37.With crude oil taken as oil phase,satis- factory formulations were obtained through above equations. |