METHOD FOR RECOVERING OIL AND VISCOSIFYING POLYMERS IN POLYMER-FLOOD PRODUCED WATER

Abstract

The present invention concerns a method for recovering pure oil stream and viscosifying polymers in polymer-flood produced water issued from an oil and gas field using a membrane coalescing contactor.

Claims

1. A method for recovering pure oil stream and viscosifying polymers in polymer-flood produced water issued from an oil and gas field, comprising: a first step of directing the polymer-flood produced water to a membrane coalescing contactor (20), a second step of recovering: the pure oil stream from the membrane of said membrane coalescing contactor; and deoiled viscosified water containing residuals of viscosifying polymers remaining outside the membrane.

2. The method according to claim 1, wherein the second step of recovering is carried out by out-in crossflow coalescence.

3. The method according to claim 1, wherein said method comprises a polishing step (50) after the second step.

4. The method according to claim 1, wherein deoiled viscosified water recovered from the second step of this method is reinjected in a hydrocarbon bearing formation (40).

5. The method according to claim 1, wherein deoiled viscosified water recovered from the polishing step is reinjected in a hydrocarbon bearing formation (40) or discharged to a surface water body.

6. The method according to claim 1, wherein the residuals of viscosifying polymer are partially hydrolysed polyacrylamide.

7. A system (10) for carrying out a method for recovering pure oil stream and viscosifying polymers in polymer-flood produced water issued from an oil and gas field according to claim 1, said system comprising a membrane coalescing contactor.

8. The system according to claim 7, said system comprising devices for carrying out a polishing step.

9. The method of claim 1, for treating produced water from chemical enhanced oil recovery using polymer, performed using a system comprising a membrane coalescing contactor.

10. The method of claim 9, further comprising a polishing step using polishing device said system.

11. The method according to claim 2, wherein said method comprises a polishing step (50) after the second step.

12. The method according to claim 2, wherein deoiled viscosified water recovered from the second step of this method is reinjected in a hydrocarbon bearing formation (40).

13. The method according to claim 3, wherein deoiled viscosified water recovered from the second step of this method is reinjected in a hydrocarbon bearing formation (40).

14. The method according to claim 2, wherein deoiled viscosified water recovered from the polishing step is reinjected in a hydrocarbon bearing formation (40) or discharged to a surface water body.

15. The method according to claim 3, wherein deoiled viscosified water recovered from the polishing step is reinjected in a hydrocarbon bearing formation (40) or discharged to a surface water body.

16. The method according to claim 2, wherein the residuals of viscosifying polymer are partially hydrolysed polyacrylamide.

17. The method according to claim 3, wherein the residuals of viscosifying polymer are partially hydrolysed polyacrylamide.

18. The method according to claim 4, wherein the residuals of viscosifying polymer are partially hydrolysed polyacrylamide.

19. The method according to claim 5, wherein the residuals of viscosifying polymer are partially hydrolysed polyacrylamide.

20. The method of claim 7, performed using a system comprising a membrane coalescing contactor.

Description

[0053] Preferred embodiments of the invention are disclosed in following description and the accompanying drawing which are merely illustrative of such invention.

[0054] FIG. 1 is schematic illustration of the process of the present invention.

[0055] FIGS. 2A and 2B are schematic illustration of the process of the present invention including polishing step.

[0056] In FIG. 1, the produced water treatment system of the present invention is indicated generally by the numeral 10. The system comprises a coalescing contactor 20. According to the first step of the method of invention, produced water stream containing residuals of viscosifying polymer is directed into coalescing contactor 20. Said produced water stream is generated in oil and gas production well 30 by polymer-flood enhanced oil recovery. According to the second step of the method of invention, deoiled produced water containing residuals of viscosifying polymers issued from coalescing contactor 20 is reinjected in an oil bearing formation via injection well 40. Pure oil recovered from coalescing contactor 20 in the second step is collected.

[0057] In FIGS. 2A and 2B, the produced water treatment system 10 includes a membrane coalescing contactor 20. According to the first step of the method of invention, produced water stream containing residuals of viscosifying polymer is directed into the membrane coalescing contactor 20. Said produced water stream is generated in oil and gas production well 30 by polymer-flood enhanced oil recovery. According to the second step of the method of invention, deoiled produced water issued from coalescing contactor 20 is directed to polishing step 50 then reinjected in an oil bearing formation via injection well 40 (FIG. 2A) or discharged to surface water body (FIG. 2B). Pure oil recovered from coalescing contactor 20 in the second step is collected.