Microemulsion flooding

Reed RL, Healy RN (1977) Some physicochemical aspects of microemulsion flooding a review. In Shah DO, Schechter RS (eds) Improved Oil Recovery by Surfactant and Polymer Flooding. Academic Press, New York, pp 383-347... 

Poettmann, F.H. Microemulsion Flooding in Improved Oil Recovery Interstate Compact Commission Oklahoma City, OK, 1983 pp. 173-250. 

Reed, R.L. Healy, R.N. Some Physico-Chemical Aspects of Microemulsion Flooding A Review in Improved Oil Recovery by Surfactant and Polymer Flooding, Shah, D.O. Schechter, R.S. (Eds.), Academic Press New York, 1977, pp. 383-438. 

In this section, several important aspects of microemulsions in relation to enhanced oil recovery will be discussed. It is well recognized that the success of the microemulsion flooding process for improving oil recovery depends on the proper selection of chemicals in formulating the surfactant slug. 

In summary, several phenomena occurring at the optimal salinity in relation to enhanced oil recovery by macro- and microemulsion flooding are schematically shown in Figure 18. It is evident that the maximum in oil recovery efficiency correlates well with various transient and equilibrium properties of macro- and microemulsion systems. We have observed that the surfactant loss in porous media is minimum at the optimal salinity presumably due to the reduction in the entrapment process for the surfactant phase. Therefore, the maximum in oil recovery may be due to a combined effect of all these processes occurring at the optimal salinity. 

This method is also known as micellar flooding, microemulsion flooding, or low tension water fiooding. The primary effect of the use of surfactants is the lowering of the interfacial tension between the driving fluid and the oil. More formally the capillary number, Ac, is... 

When surfactant solution is injected in a reservoir, it contacts with oil to form three types of microemulsion, depending on the local salinity. Here, we discuss only the fractional curve analysis of Winsor 1 microemulsion. For a discussion of fractional flow of Winsor 11 without retention, see Lake (1989). Fractional flow treatment for three-phase microemulsion flood (Winsor III) has not been extensively investigated (Giordano and Salter, 1984). 

FIGURE 2.23 Fractional flow diagram of a Winsor I microemulsion flood. 

FIGURE 2.24 Saturation profile for a Winsor I microemulsion flood started at interstitial water saturation when S i < S f. 

FIGURE 2.26 Fractional flow diagram of Winsor I microemulsion flood at waterflood residual oil saturation,... 

Healy, R.N., Reed, R.L., 1977a. Immiscible microemulsion flooding. SPEJ (April), 129-139. 

After a waterflood, the residual oil remaining in the porous reservoir is trapped by capillary forces. The corresponding interfacial tension between the aqueous and the oil phase is of a few mN rrT1 [109, 112-115]. Under these conditions, oil production is marginal and the water cut, on the other hand, becomes high [110, 113, 114]. Addition of surface-active substances (i.e. surfactants), however, can lower the interfacial tension by 3-4 orders of magnitude [109, 112-114, 117, 122, 124], which induces the production of more oil and lowers the water cut [113, 139]. Microemulsion flooding tests both at the laboratory and pilot scales have shown that the oil recovery could be more than 60% of the OOIP [ 110-114], which is about twice the current one. Nevertheless, most of the tests carried out in the field yielded an additional oil recovery of only 10-20% of the OOIP [114, 140], which indicates that the process still has to be improved. 

Dodillood Brands. [HoechstAG] Ether sulftmates, ether carboxylates anionic surfactants for enhanced oil recovery and microemulsion flooding. 

Macroemulsion and Microemulsion Flooding If a suitable surfactant is injected into the reservoir, it can form macroemulsions and/or microemulsions with the reservoir oil depending on the composition and reservoir conditions. Several articles have been published on the recovery of oil by microemulsion and macroemulsion flooding processes.Among various factors, the most important factor of surfactant flooding in the form of an emulsion is the lowering of the interfacial tension (IFT) at the oil/water interface. Microemulsions are more effective in oil displacement as compared to macroemulsions because microemulsions can provide low IFT systems. 

---