Formulations for enhanced oil recovery comprising sulfonates
Compositions suitable for enhanced oil recovery comprising a) a mixture of a-sulfocarbonyl compounds of formula (1) and (2) in a mixture ratio (1) to (2) of from 1:99 to 99:1 wherein R 1 , R 3 and R 5 , which may be the same or different at each occurrence, are hydrogen or a linear or branched alkyl chain having 1 to 20 carbon atoms, R 2 and R 4 , which may be the same or different at each occurrence, may be a linear or branched alkyl group having 4 to 24 carbon atoms and in which the alkyl chain may comprise one or more cycloaliphatic groups, and X is H or a metal forming a salt with the sulfonate group, and b) a salt containing aqueous solution.
1. A process for enhanced oil recovery, the process comprising a first step of determining the salinity of an injection water and thereafter preparing a blend of internal ketone monosulfonates and disulfonates having a mixing ratio of mono- and disulfonates providing the lowest interfacial tension with the crude oil for the given salinity, wherein the blend is a mixture of 12-tricosanone monosulfonate and 12-tricosanone disulfonate in a mixture ratio of monosulfonate:disulfonate of from 1:99 to 99:1; mixing the internal ketone sulfonate mixture with the injection water and optionally further ingredients and pumping the final composition into the reservoir to recover oil from the reservoir.
2. The process according to claim 1 , wherein the mixture ratio of monosulfonate:disulfonate is in the range of from 3:97 to 97:3.
3. The process according to claim 2 , wherein the mixture ratio of monosulfonate:disulfonate is in the range of from 5:95 to 95:5.