Injection fluids comprising alkoxylated alcohols and the use of such fluids in oil recovery processes

1. A method for flooding of oil wells by carbon dioxide injection, the method comprising:

i) providing an injection fluid comprising one or more alkoxylated alcohols having the following structure:

R—O-(AO) m+n —H  (I)

wherein

R is a linear alkyl group having from C4 to C8 carbon atoms, and/or a branched alkyl group having from C4 to C18 carbon atoms;

AO is EO and/or PO, independent of each m or n;

m is 0 to 12;

n is 0 to 12; and

m+n is at least 1;

and at least liquid or supercritical carbon dioxide;

ii) injecting the injection fluid into a reservoir comprising a hydrocarbonaceous fluid, the reservoir being operated at a pressure below the minimum miscibility pressure, where the minimum miscibility pressure is the minimum pressure that has to be applied to the carbon dioxide injected for achieving a multiple contact miscible flood;

wherein

(A) the miscibility pressure between the injection fluid and the hydrocarbonaceous fluid is lowered by 4.9% to 30.3% compared to the miscibility pressure between the hydrocarbonaceous fluid and carbon dioxide only, or

(B) the swelling factor of the hydrocarbonaceous fluid is increased by the injection fluid compared to the swelling factor of the hydrocarbonaceous fluid including the carbon dioxide only, or

(C) both (A) and (B);

iii) recovering the hydrocarbonaceous fluid from the reservoir.

2. The method of claim 1 wherein

a) the injection fluid comprises less than 1 wt. % water; or

b) wherein the injection fluid consists of the one or more alkoxylated alcohols and the liquid or supercritical carbon dioxide; or

c) wherein the injection fluid consists of the one or more alkoxylated alcohols, the liquid or supercritical carbon dioxide and a linear C4 to C9 alcohol or a branched alcohol having 4 to 18 carbon atoms or both.

3. The method of claim 1 , wherein the alkoxylated alcohols have the following structure

R—O-(A′O) m -(A″O) n —H  (II)

wherein

R is a linear alkyl group having from C4 to C8 carbon atoms, and/or a branched alkyl group having from C4 to C18 carbon atoms;

m is 1 to 12;

n is 1 to 12;

A′O is an ethoxy group (EO) and A″O is a propoxy group (PO); or

A′O is a propoxy group (PO) and A″O is an ethoxy group (EO).

4. The method of claim 1 , wherein

m is 1 to 8; and

n is 1 to 8.

5. The method of claim 1 , wherein the swelling factor of the hydrocarbonaceous fluid is increased by the injection fluid by 4% to 7% compared to the swelling factor of the hydrocarbonaceous fluid including carbon dioxide only.

6. The method of claim 1 , wherein R is a linear C4 to C8 alkyl group.

7. The method of claim 1 , wherein R is a branched alkyl group having 4 to 18 carbon atoms.

8. The method of claim 1 , wherein R is a branched alkyl group having 8 to 14 carbon atoms.

9. The method of claim 1 , wherein AO is EO.

10. The method of claim 1 , wherein AO is PO.

11. The method of claim 1 , wherein m+n is from 1 to 8.

12. The method of claim 1 , wherein m+n is from 1 to 6.

13. The method of claim 1 , wherein the hydrocarbonaceous fluid is a crude oil and the reservoir is a well.

14. The method of claim 1 , wherein the miscibility pressure between the injection fluid and the hydrocarbonaceous fluid is lowered compared to the miscibility pressure between the hydrocarbonaceous fluid and carbon dioxide only by 8.2% to 30.3%.

15. The method of claim 1 , wherein the miscibility pressure between the injection fluid and the hydrocarbonaceous fluid is lowered compared to the miscibility pressure between the hydrocarbonaceous fluid and carbon dioxide only by 16.3% to 30.3%.

16. The method of claim 1 , wherein the injection fluid does not comprise water.

17. A method comprising:

i) adding one or more alkoxylated alcohols having the following structure:

R—O-(AO) m+n —H  (I)

wherein

R is a linear alkyl group having from C4 to C8 carbon atoms, and/or a branched alkyl group having from C4 to C18 carbon atoms;

AO is EO and/or PO, independent of each m or n;

m is 0 to 12;

n is 0 to 12; and

m+n is at least 1

into an injection fluid comprising at least liquid or supercritical carbon dioxide,

ii) injecting the injection fluid into a reservoir, the reservoir being operated at a pressure below the minimum miscibility pressure, where the minimum miscibility pressure is the minimum pressure that has to be applied to the carbon dioxide injected for achieving a multiple contact miscible flood; and

wherein

(A) the miscibility pressure between the injection fluid and the hydrocarbonaceous fluid is lowered by 4.9% to 30.3% compared to the miscibility pressure between the hydrocarbonaceous fluid and carbon dioxide only, or

(B) the swelling factor of the hydrocarbonaceous fluid is increased by the injection fluid compared to the swelling factor of the hydrocarbonaceous fluid including the carbon dioxide only, or

(C) both (A) and (B); and

iii) recovering hydrocarbonaceous fluid from the reservoir.

18. A method comprising:

i) adding one or more alkoxylated alcohols having the following structure:

R—O-(AO) m+n —H  (I)

wherein

R is a linear alkyl group having from C4 to C8 carbon atoms, and/or a branched alkyl group having from C4 to C18 carbon atoms;

AO is EO and/or PO, independent of each m or n;

m is 0 to 12;

n is 0 to 12; and

m+n is at least 1

into an injection fluid comprising at least liquid or supercritical carbon dioxide,

ii) injecting the injection fluid into a reservoir, the reservoir being operated at a pressure below the minimum miscibility pressure, where the minimum miscibility pressure is the minimum pressure that has to be applied to the carbon dioxide injected for achieving a multiple contact miscible flood; and

wherein the miscibility pressure between the injection fluid and the hydrocarbonaceous fluid is lowered by 4.9% to 30.3% compared to the miscibility pressure between the hydrocarbonaceous fluid and carbon dioxide; and

iii) recovering hydrocarbonaceous fluid from the reservoir.