Systems and methods for subsea fluid phase separation

Patent metadata

Field	Value
Publication number	US-2016341024-A1
Application number	US-201415106691-A
Country	US
Kind code	A1
Filing date	Dec 22, 2014
Priority date	Dec 20, 2013
Publication date	Nov 24, 2016
Grant date	—

Abstract

Systems and methods for subsea fluid phase separation. A two phase embodiment of the subsea fluid separation system separates a multiphase flow into gas and liquid phases. A three phase embodiment of the subsea fluid separation system separates multiphase flow into gas, oil, and water phases. The subsea fluid separation systems include a wellhead desander system to remove solids from the multiphase flow, a vertical gas-liquid separation module having associated valves disposed in series with a horizontal gas-liquid separation module having associated valves, one or more pumps to provide fluid flow to the vertical and horizontal separators, and a control system to control operation of the valves and pumps. The three phase embodiment further includes oil-water separators and multi-stage hydrocyclones for produced water treatment in a subsea environment.

First claim

1 . A system for subsea fluid phase separation, comprising:
a vertical gas-liquid separation module having at least one associated valve; a horizontal gas-liquid separation module having at least one associated valve and disposed in series with the vertical gas-liquid separation module; one or more pumps to provide fluid flow out of the vertical and horizontal gas-liquid separation modules; and a control system to control operation of the one or more pumps and the associated valves.

2 . The system of claim 1 , wherein the horizontal gas-liquid separation module comprises a first inlet in fluid communication with the vertical gas-liquid separation module, a second inlet, and a plurality of outlets disposed in a bottom portion of the horizontal gas-liquid separation module.

3 . The system of claim 2 , wherein the horizontal gas-liquid separation module further comprises a header device configured to disperse fluid entering the second inlet across the bottom portion of the horizontal gas-liquid separation module for settled solids removal.

4 . The system of claim 3 , wherein the fluid entering the second inlet is a portion of a fluid discharged from the one or more pumps.

5 . A method for fluid phase separation, comprising:
configuring a horizontal vessel in series with a vertical gas-liquid separation vessel; receiving an indication of a level or a pressure of the horizontal vessel and the vertical gas-liquid separation vessel; and performing, based on the indication, a processing operation that:
generates a control signal to control operation of a pump that provides fluid flow into and/or out of the vessels; or
generates a control signal to control operation of at least one valve associated with the vessels.

6 . The method of claim 5 , further comprising using a level control valve to generate motive fluid for a solids accumulator flushing operation

7 . The system of claim 1 wherein the control system further comprises:
a split-range controller configured to:
adjust at least one of the associated and adjust a discharge speed of at least one of the one or more pumps to optimize operation.

8 . The control system of claim 7 , wherein a minimum flow control loop of the at least one pump is configured to be utilized for a sanding operation of a separator device.

9 . The system of claim 1 , further comprising:
an oil-water separation module comprising at least one vessel having an associated valve; and one or more pumps to enable produced water re-injection; wherein the control system is further configured to control operation of the at least one valve associated with the at least one vessel of the oil-water separation module.

10 . The system of claim 9 , further comprising:
at least one liquid-liquid hydrocyclone in series with a solid-liquid hydrocyclone in series with an additional liquid-liquid hydrocyclone for produced water treatment to enable water re-injection.

11 . The system of claim 10 , further comprising:
an ejector configured to boost pressure of a reject flow exiting one or more of the liquid-liquid hydrocyclones and/or the solid-liquid hydrocyclone.

12 . A method to control and discharge hydrocyclone rejects to an oil pipeline using an ejector subsea, the method comprising:
controlling a motive fluid rate to the ejector by setting a constant differential pressure across a control valve for a last hydrocyclone in a series of hydrocyclones, thereby providing a driving force for rejects from the series of hydrocyclones and optimizing the motive fluid rate.

13 . A system comprising:
a configuration of multi-stage hydrocyclones, including a liquid-liquid hydrocyclone in series with a solid-liquid hydrocyclone in series with another liquid-liquid hydrocyclone, for produced water treatment in a subsea environment to enable water re-injection; wherein the configuration of multi-stage hydrocyclones causes breaking of solids-stabilized emulsion particles in the water and solids removal from the water.

14 . The system of claim 1 wherein the control system further comprises a dynamic multiphase flow simulation model coupled with a dynamic process simulation model.

15 . The system of claim 14 wherein the control system is configured to combine processing conditions of the dynamic process simulation model with a slugging profile of the dynamic multiphase flow simulation model.

16 . The method of claim 5 further comprising combining a dynamic multiphase flow simulation model with a dynamic process simulation model.

17 . The method of claim 16 further comprising:
including processing conditions in the dynamic multiphase flow simulation model using the dynamic process simulation model; then
predicting a slugging profile using the dynamic multiphase flow simulation model.

18 . The method of claim 12 wherein the series of hydrocyclones further comprises at least one liquid-liquid hydrocyclone in series with a solid-liquid hydrocyclone in series with an additional liquid-liquid hydrocyclone.

19 . The system of claim 13 , further comprising:
an ejector configured to boost pressure of a reject flow exiting one or more of the liquid-liquid hydrocyclones and/or the solid-liquid hydrocyclone.

Assignees

• Onesubsea Ip Uk Ltd

Inventors

• Unnam Jagadeesh
• Byeseda John

Classifications

• B04C5/28

  for parallel flow · CPC title

• B01D19/0036

  Flash degasification (the other groups take precedence) · CPC title

• B01D19/0057

  the centrifugal movement being caused by a vortex, e.g. using a cyclone, or by a tangential inlet · CPC title

• B01D17/06

  Separation of liquids from each other by electricity · CPC title

• B01D21/302

  Active control mechanisms with external energy, e.g. with solenoid valve · CPC title