Use of pressure reduction devices for improving downstream oil-and-water separation

Patent metadata

Field	Value
Publication number	US-9328856-B2
Application number	US-201414166375-A
Country	US
Kind code	B2
Filing date	Jan 28, 2014
Priority date	Jan 29, 2013
Publication date	May 3, 2016
Grant date	May 3, 2016

Abstract

A system and method for improving oil-and-water separation in a blended fluid stream are presented. The system includes a pressure reduction device that causes cyclonic flow in the stream. The pressure reduction device may be a wafer-based hydrocyclone or a modified hydrocyclone having an underflow outlet but no overflow outlet. The system may also include a valve that is located upstream or downstream of the pressure reduction device. Both the valve and the pressure reduction device reduce the pressure of the fluid stream while reducing the shearing of oil and water droplets within the stream. As a result, the droplets are more likely to coalesce and less likely to form emulsions, thus improving oil-and-water separation in downstream treatment processes.

First claim

What is claimed is:

1. An improvement for a system including a source of an oil-in-water or water-in-oil stream and an immediate next downstream process in communication with the source, and a valve located between the source and the immediate next downstream process, the improvement comprising:
a pressure reduction device with a single outlet located between the source and the immediate next downstream process, the pressure reduction device causing a cyclonic flow of the stream, the shearing of oil droplets and water droplets in the stream through the pressure reduction device being less than through the valve alone, wherein pressure of the stream decreases as it flows from the source to the immediate next downstream process.

2. An improvement according to claim 1 , wherein the source is a wellhead and the immediate next downstream process is a separator vessel.

3. An improvement according to claim 1 , wherein the source is a first separator vessel and the immediate next downstream process is a second separator vessel.

4. An improvement according to claim 3 , wherein the first separator vessel is a higher-pressure separator vessel and the second separator vessel is a lower-pressure separator vessel.

5. An improvement according to claim 1 , wherein the immediate next downstream process is a desalter.

6. An improvement according to claim 1 , wherein the pressure reduction device is a wafer-based hydrocyclone.

7. An improvement according to claim 6 , wherein a number of wafers in the wafer-based hydrocyclone varies with a flow rate of the fluid stream.

8. An improvement according to claim 1 , wherein the pressure reduction device is a hydrocyclone having an underflow but no overflow.

9. An improvement according to claim 1 , further comprising a second pressure reduction device located between the source and the immediate next downstream process, the second pressure reduction device causing a cyclonic flow of the stream.

10. An improvement according to claim 1 , wherein the valve is chosen from the group consisting of a flow control valve, a wellhead choke valve, and a mixing valve.

11. An improvement according to claim 1 , wherein the valve is regulated by a level controller.

12. An improvement according to claim 1 , wherein pressure drop for the valve is less than 20 pounds per square inch.

13. An improvement according to claim 12 , wherein pressure drop for the valve is less than 10 pounds per square inch.

14. An improvement according to claim 1 , wherein the pressure reduction device is located upstream or downstream of the valve.

15. A method for improving oil-and-water separation in a fluid stream, the method comprising the steps of:
passing the fluid stream from a source of an oil-in-water or water-in-oil stream to a pressure reduction device with a single outlet; and
causing cyclonic flow of the fluid stream as it passes through the pressure reduction device,
wherein pressure of the fluid stream decreases as it flows from the source through the single outlet to an immediate next downstream process and the shearing of oil droplets and water droplets through the pressure reduction device is less than through a valve alone.

16. A method according to claim 15 , wherein the pressure reduction device is chosen from the group consisting of a Deltaclone™ and a hydrocyclone having an underflow but no overflow.

17. A method according to claim 15 , further comprising the step of causing cyclonic flow of the fluid stream as it passed through a second pressure reduction device.

18. A method according to claim 15 , wherein the source is a wellhead or a separator vessel.

19. A method according to claim 15 , wherein the immediate next downstream process is a separator vessel.

20. A method according to claim 15 , further comprising the step of reducing the pressure of the fluid stream by passing it through a valve that is located upstream or downstream of the pressure reduction device and upstream of an immediate next process.

21. A method according to claim 20 , wherein the valve is chosen from the group consisting of a flow control valve, a wellhead choke valve, and a mixing valve.

22. A method according to claim 20 , further comprising the step of using a level controller to regulate opening and closing of the valve.

Assignees

• Cameron Int Corp

Inventors

• Lee Joseph Min-Hsiun
• Sams Gary W

Classifications

• C10G33/06

  with mechanical means, e.g. by filtration · CPC title

• B01D17/12 Primary

  Auxiliary equipment particularly adapted for use with liquid-separating apparatus, e.g. control circuits · CPC title

• Y10T137/7287

  Liquid level responsive or maintaining systems · CPC title

• C10G31/06

  by heating, cooling, or pressure treatment · CPC title

• Y10T137/0324

  With control of flow by a condition or characteristic of a fluid · CPC title