Rheology of enhanced oil recovery polymers-a review

Chemical flooding, in particular ASP flooding is of increasing interest because of current high prices and the need to increase oil production. Recent lab research has shown significant benefits to using surfactants at high PH even if the oil has a low acid no. & thus little if any surfactant is generated in-situ. So high ph surfactant-polymer flooding is also of great current interest. Normally, the problem in water flooding is unfavorable Mobility Ratio and because of it viscous fingering may occur and as a result of viscous fingering early break through will be observed, so low oil recovery will be obtained. The viscosity and the size of the emulsion formed in the reservoir is of great importance because if the size is too large and viscosity is high it can plug the pore spaces thus reducing the overall recovery and if the size is too small and viscosity is very low than the desirable sweep efficiency will not be achieved thus again causing reduction in recovery.