Ethoxylated desorbing agents for enhanced oil recovery
The invention relates to the use of at least one compound corresponding to the formula below: R—O—(—CH 2 —CH(—CH 3 )—O—) m —(—CH 2 —CH 2 —O—) n —H in which: R is a hydrocarbon-based group comprising from 6 to 40 carbon atoms; m is a number ranging from 0 to 20; n is a number greater than 20; for inhibiting the anionic-surfactant retention phenomena in an oil reservoir, especially in a carbonate-based or argillaceous reservoir.
1. A process of enhanced oil recovery from an underground formation comprising:
injecting a fluid comprising a compound of formula (I) into said underground formation, via at least one injection well;
before, during, or after injecting the fluid comprising the compound of formula (I), injecting a fluid comprising at least an aqueous medium, an anionic surfactant and optionally an anionic cosurfactant via the same injection well(s); and then
recovering a fluid conveying the oil leaving the underground formation by at least one production means;
wherein formula (I) is
R—O—(—CH 2 —CH(—CH 3 )—O—) m —(—CH 2 —CH 2 —O—) n —H (I)
in which:
R is a hydrocarbon-based group comprising from 6 to 40 carbon atoms;
m is zero or else a non-zero number ranging from 0 to 20;
n is a number greater than 40 and less than 70.
2. The process as claimed in claim 1 , in which the underground formation is a carbonate-based or argillaceous rock.
3. The process of claim 1 , wherein n is greater than 40 and less than 60.
4. The process of claim 1 , wherein R is a hydrocarbon-based group comprising from 8 to 20 carbon atoms.
5. The process of claim 1 , wherein the anionic surfactants are:
anionic agents of sulfonate and/or sulfate type; or
mixtures of anionic surfactants comprising one or more anionic agents of sulfonate and/or sulfate type.
6. The process of claim 5 , wherein the mixtures of anionic surfactants do not comprise nonionic surfactants other than the compound of formula (I).
7. The process of claim 1 , wherein the anionic surfactants are surfactants of carboxylate, phosphate and/or phosphonate type, or surfactants of zwitterionic nature.
8. The process of claim 1 , wherein the nonionic surfactant of formula (I) is used in combination with at least one viscosity-enhancing polymer.
9. The process of claim 8 , wherein the at least one viscosity-enhancing polymer is a partially hydrolyzed polyacrylamide.
10. The process of claim 1 , wherein the group —R present on the nonionic surfactant of formula (I) is a linear or branched alkyl or alkenyl group.
11. The process of claim 10 , wherein the group —R present on the nonionic surfactant of formula (I) is a linear or branched alkyl or alkenyl group comprising from 6 to 18 carbon atoms.
12. The process of claim 11 , wherein the group —R present on the nonionic surfactant of formula (I) is a linear or branched alkyl or alkenyl group comprising from 10 to 16 carbon atoms.
13. The process of claim 11 , wherein R is an alkyl group.