Chemical, Microemulsion and Macroemulsion Flooding

Chemical flooding involves the injection of a surfactant solution that can cause oil-aqueous interfacial tension to drop from about 30 mN m to near-zero values on the order of 10 -10 mN m , allowing spontaneous or nearly spontaneous emulsification of the oU, with an increase in the capillary number by several orders of magnitude and with greatly increased displacement and recovery of the oil [6, 10,19, 67, 75, 79-87]. The micelles present also help to solubilize the released oil droplets hence, this process is sometimes referred to as micellarflooding. Having mobilized the oil, these processes are even more efficient if the oil droplets are 

Displacement of oil in petroleum reservoirs Py water or ohemioal flooding (five-spot pattern) 

Assuming a typical oil reservoir containing medium heavy-crude oil and employing a reservoir flow rate of 0.26 m/day. The solution viscosity could be increased to 30 mPa S by adding about 1000 pgml- (0.1%) partially hydrolysed polyacrylamide polymer (at pH 8.5). The interfacial tension could be reduced to 0.1 mN m by adding 1% sodium carbonate, which reacts with the crude oil to produce natural surfactant. The interfacial tension could be further reduced to 0.03 mN m by adding 0,1% ethoxylated alcohol sulfate co-surfactant. 

Brine Formation water or water from sea, lakes and rivers with variable saline conditions and concentrations (mgl to gl ) 

Chemicals Primary surfactant (e.g. petroleum sulfonate) Co-surfactant/co-solvent (e.g. C3 to Cj alcohol) Polymer (e.g. xanthan) Alkaline agents (e.g. sodium carbonate) Bactericides (e.g. formaldehyde) Sacrificial adsorption agents 

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