Selection of optimal surfactant blends for waterflood enhancement

Patent metadata

Field	Value
Publication number	US-10858576-B2
Application number	US-201916354510-A
Country	US
Kind code	B2
Filing date	Mar 15, 2019
Priority date	Mar 19, 2018
Publication date	Dec 8, 2020
Grant date	Dec 8, 2020

Abstract

A method of providing an optimal surfactant blend to improve waterflood efficiency comprises selecting candidate surfactant blends based on one or more of the following: a reservoir condition; information of a crude oil; information of an injection fluid; or information of a formation fluid, each candidate surfactant blends comprising at least two surfactants, one surfactant having a higher relative affinity for the crude oil than for the injection fluid and at least one surfactant having a higher affinity for the injection fluid than for the crude oil; evaluating phase behavior of the candidate surfactant blends to select surfactant blends that form a Winsor III system with the crude oil and the injection fluid at a reservoir temperature; and evaluating the selected surfactant blends in a porous media to select an optimal surfactant blend which achieves at least an additional 10% crude oil recovery after waterflood.

First claim

What is claimed is:

1. A method of providing an optimal surfactant blend to improve waterflood efficiency, the method comprising:
selecting candidate surfactant blends, each candidate surfactant blends comprising at least a first surfactant which has a higher relative affinity for a crude oil than for an injection fluid and at least a second surfactant which has a higher relative affinity for the injection fluid than for the crude oil, wherein the candidate surfactant blends are selected based on one or more of the following: a reservoir condition; information of the crude oil; information of the injection fluid; or information of a formation fluid;
evaluating phase behavior of the candidate surfactant blends to select surfactant blends that form a Winsor III system with the crude oil and the injection fluid at a reservoir temperature; and
evaluating the selected surfactant blends in a porous media to select an optimal surfactant blend which achieves at least an additional 10% crude oil recovery after waterflood.

2. The method of claim 1 , further comprising simulating reservoir waterflood with the optimal surfactant blend.

3. The method of claim 1 , further comprising identifying the first surfactant and the second surfactant by blending a surfactant with the crude oil and the injection fluid to form a system having an aqueous phase, an oil phase, and an interface layer between the aqueous phase and the oil phase, wherein the interface layer comprises the surfactant.

4. The method of claim 3 , wherein a concentration of the first surfactant in the interface layer decreases from a first portion approximate the aqueous phase towards a second portion away from the aqueous phase.

5. The method of claim 3 , wherein a concentration of the second surfactant in the interface layer increases from a first portion approximate the aqueous phase towards a second portion away from the aqueous phase.

6. The method of claim 1 , wherein the reservoir condition comprises one or more of the following: a reservoir temperature; a reservoir pressure; or a rock property.

7. The method of claim 1 , wherein injection fluid information and the formation fluid information independently comprise one or more of the following: hardness; pH; a composition of anions; or a composition of cations.

8. The method of claim 1 , wherein the crude oil information comprises one or more of the following: an acid number; a viscosity; a density; an alkane carbon number, or a composition of the crude oil.

9. The method of claim 1 , wherein selecting candidate surfactant blends is based on one or more of the following: a reservoir temperature; an alkane carbon number of the crude oil; or a salinity of the injection fluid.

10. The method of claim 1 , wherein the candidate surfactant blends further comprise one or more of the following: a mutual solvent; a co-solvent; a linker; an alkali chemical; or a polymer.

11. The method of claim 1 , wherein the porous media comprises a sand-pack cell, a coreflood unit, or a microfluidic channel.

12. The method of claim 1 further comprising evaluating adsorption of the selected surfactant blends.

13. A method of enhancing waterflood efficiency in oil recovery in a reservoir, the method comprising:
selecting candidate surfactant blends, each candidate surfactant blends comprising at least a first surfactant which has a higher relative affinity for a crude oil than for an injection fluid and at least a second surfactant which has a higher relative affinity for the injection fluid than for the crude oil, wherein the candidate surfactant blends are selected based on one or more of the following: a reservoir condition; information of the crude oil; information of the injection fluid; or information of a formation fluid;
evaluating phase behavior of the candidate surfactant blends to select surfactant blends that form a Winsor III system with the crude oil and the injection fluid at a reservoir temperature;
evaluating the selected surfactant blends in a porous media to select an optimal surfactant blend which achieves at least an additional 10% crude oil recovery after waterflood;
combining the optimal surfactant blend with the injection fluid to form a surfactant-containing injection fluid; and
injecting the surfactant-containing injection fluid into the reservoir to enhance waterflood efficiency in oil recovery.

14. The method of claim 13 , wherein the optimal surfactant blend further comprises one or more of the following: a mutual solvent; a co-solvent; a linker; an alkali chemical; or a polymer.

15. The method of claim 13 , wherein the optimal surfactant blend is present in an amount of about 0.1 wt. % to 3 wt. % based on the total weight of the surfactant-containing injection fluid.

16. The method of claim 13 , wherein the surfactant-containing injection fluid is injected during a secondary recovery stage, a tertiary recovery stage, or a combination thereof.

17. The method of claim 13 , further comprising injecting water or a brine in the reservoir before injecting the surfactant-containing injection fluid.

18. The method of claim 13 , wherein the crude oil has a viscosity of less than 100 cP at the reservoir temperature.

19. The method of claim 18 , wherein the crude oil has a viscosity of less than 20 cP at the reservoir temperature.

Assignees

• Quintero Lirio
• Nguyen Henry
• Kuznetsov Oleksandr V
• Baker Hughes A Ge Co Llc

Inventors

• Quintero Lirio
• Nguyen Henry
• Kuznetsov Oleksandr V

Classifications

• E21B49/0875

  determining specific fluid parameters · CPC title

• E21B49/088

  combined with sampling · CPC title

• C09K8/584 Primary

  characterised by the use of specific surfactants · CPC title

• C09K8/845

  containing inorganic compounds · CPC title