Oil and gas separation process lecture

1. SITP / O & G Ono SLIDE 1
OIL AND GAS SEPARATION PROCESS
 SEPARATION
 Process Whereby Reservoir
Fluid is separated Into its
Component Phases of Gas
Liquid and Solid
 The Liquid Phase is Further
Separated into Water and Oil
 Objectives of Separation
 Removal of Contaminants
 Maximizing Oil Production
 Meeting Transport/Customer
Specification
 Metering for Royalty/Tax
Payment
Non-Solution Gas Required
Removed Before Metering
 Reservoir Fluid
 Complex, High temperature,
High Pressure, High Velocity,
Quite Turbulent, and Constantly
Expanding Mixture of
Hydrocarbon Liquid
Water Vapour
Free Water
Solids
Other Undesirable
Compounds Considered
Contaminants.

2. SITP / O & G Ono SLIDE 2
Reservoir Fluid
During Flowing Process
It Undergoes Continuous
Temperature and Pressure
Reduction
Gases Evolve
Water Vapour Condenses
Some Hydrocarbon Change their
Characteristics Resulting in
 Foaming
 Bubbles
 Mist
 Hydrates
 Free Gas
 Reservoir Fluid Processing
 Processing of Separated Products to
Sellable, Reusable or Disposable
Quality
Gas
 Removal of Contaminants
Removal of Water Vapour
Removal of Condensate and
Hydrocarbon Vapour
Crude Oil
Removal of Water
Removal of Contaminants
Water
Removal of Oil
Removal of Contaminants

3. SITP / O & G Ono SLIDE 3
SEPARATORS
 Pressure Vessels Used to
Separate Reservoir Fluids Into
Gas, Liquid and Sediments.
 Types of Separators
Free-Liquid Removing Vessel
Removes Free-Water From
Well Fluids
Removes Free-Liquid From
Gas Stream
Removal is Preferably Before
Pressure Reduction
Removal Reduces Process Load
Removal Prevents:
 Corrosion
 Hydrates Formation
 Tight Emulsion
Formation
 Types of Free-Liquid Knock-out
 Trap
 Knock-out Trap
 Knock-out Vessel
 Knock-out Drum
 Free-Water Knock-out
 Liquid Knock-out
 Producing Field Vessels
 Used in Processing Lease or
Platform Reservoir Fluids
 Types Include
 Oil & Gas Separators
 Stage Separators

4. SITP / O & G Ono SLIDE 4
SEPARATORS
 Separator Configurations
Vertical Separator
Horizontal Separator
Spherical Separator
.....................
Spherical Separator
Horizontal Separator
Vertical Separator

5. SITP / O & G Ono SLIDE 5
SEPARATORS
 Components of Separator
.....................

6. SITP / O & G Ono SLIDE 6
Separator Components/Functions
 Types of Inlet Diverter Devices
Mechanical Agitation Inlet
Devices
Mechanism
 Well Stream Strikes Device
Reduction in Velocity
Change in Direction of Flow.
 Types of Mechanical Agitation
Inlet Devices
Deflector Baffles
Hemispherical Disc
Flat Plate
Piece of Angle Iron
Metal Cone.
 Primary Separation Section
 Removes Bulk of Liquid Slugs
and Particles
 Removal Achieved Through
Momentum Reduction
 Reduction Achieved by Stream
Inlet Baffling(Regulating) or/and
Inlet Diverter Devices
 Inlet Diverter Devices
 Cause Rapid Change in Inlet
Stream Velocity
 Results Liquid and Gas
Disengagement.

7. SITP / O & G Ono SLIDE 7
Inlet Diverters
 .
Flow Against Plate Flow Through Baffle
Gas Entry With Deflector Inlet Diffuser
Cyclone Inlet Diverter

8. SITP / O & G Ono SLIDE 8
 Secondary Separation Section .
 Reduces Fluid Velocity From the
Primary Section.
 Minimises the Turbulence.
 Creates Room for Gravity Settling.
 Thus Removes Gas Vapour From Oil.
 It Removes Water (in the 3– Phase
Separator).
 Should Be Large and of Sufficient
Height or Length.
 There Should Be Proper Positioning of
Straightening Vanes for Uniform Flow.
 Orienting Plates/baffles
 Reduces Turbulence
Separator Diverters and Sections
 Cyclone Inlet.
 Mechanism
 Creates a High Fluid Velocity
 Fluid Get Spun Around the Wall
on Entry
 Spinning Subjects Fluid to High
Centrifugal Forces up to 500
Times the Force of Gravity
 Forward Motion of Heavy Liquid
is Stopped and It Falls to Flow
Along That Wall to Bottom.

9. SITP / O & G Ono SLIDE 9
Separator Sections
 Liquid Accumulation Section
 Recovery and Disposal of
Collected Liquid(s)
 Should Have Sufficient Volume
to Handle Surges and Prevent
Liquid Carry Over to Gas Outlet.
 Arrangement Should Prevent
Gas Flow From Disturbing
Liquid.
 Should Have Level Controller
/Dump Valve.
 Meters Oil & Water in Metering
Separators.
 Provides Necessary Retention
Time For Gas Breaking Out of
Oil and Water Settling Out Of Oil
 Vortex Breakers at Liquid Outlet
to Prevent Gas Re-entry

10. SITP / O & G Ono SLIDE 10
Vertical Separator Accumulation Section
 .
i

11. SITP / O & G Ono SLIDE 11
Horizontal Separator Accumulation Section
 .

12. SITP / O & G Ono SLIDE 12
Spherical Separator Accumulation Section
 .

13. SITP / O & G Ono SLIDE 13
Accumulation Section Accessories.
 Wave Breakers(Arresters).
 Perpendicular Vertical Baffles
in the Gas-liquid Interface
Which Prevents Waves
Caused by Liquid Surge.
 Defoaming Plates
 Inclined Parallel Plates or
Tubes in the Gas-Liquid
Interface Which Break Foams.
 Foam is Forced Through
Them and Gets Coalesced to
Form Liquid.

14. SITP / O & G Ono SLIDE 14
Accumulation Section Accessories.
 Vortex Breakers.
 Metal Plate Devices Which
Prevent Vortex Formation
When Control Valve is Open.

 Vortices Develop When the
Control Valve is Open
Resulting in Gas Being Sucked
Out of the Vapour Space and
Getting Re-entrained Into
Liquid

15. SITP / O & G Ono SLIDE 15
Separator Mist Extractors/Eliminators
 Mist Extractor /Eliminator.
 Eliminates Entrained Liquid Droplets
From Gas Stream.
 Droplets Density is Quite Close to
That of Gas.
 Droplets Hit Impingement Surface,
Coalesce and Collect to Form Larger
Droplets.
 Eliminates Droplets of size equal to or
greater than 100 microns but less than
200 microns

16. SITP / O & G Ono SLIDE 16
Types of Mist Extractors/Eliminators
 Vane – Type Mist Extractor.
 Consisting of Labyrinth of Metal Plates
Laid Parallel With Liquid Collection
Pockets Leading to Drain Pipe
 Mechanism of Separation
 Impingement With High Centrifugal
Force.
 Obstruction to Entrained Liquid
Particles.
 Change in Direction of Flow.
 Gas Stream Veers Around
Obstruction While Liquid Drops.
 Droplets Collide With the Walls and
Get Separated From the Gas.
 Wire-Mesh Mist Extractor
 Employs Impingement Mechanism
Primarily to Remove Liquid Droplets.
 Entrained Liquid Particles Strike the Metal
Surface Then Flow Down the Capillary
Space Provided by Wires.
 Surfaces Tension Holds the Liquid at the
Lower Face of the Pad Until Such a Time
That the Droplets Weight Let Go Under
Gravity.
 Liquid Collects in the Spaces and
Continue Downward.
 Stainless Steel Woven-wire Mesh Has
Highest Gas and Liquid Separation
Capacity.
 Liquid Carry-over  0.1 gal/mscf
 Efficiency  90%.

17. SITP / O & G Ono SLIDE 17
Separator Mist Extractors/Eliminators
 Chevron Vane Mist Extractor
 Serpentine Vane Mist Extractor
 Demister Wire-Mesh Mist Extractor
………………………………….

18. SITP / O & G Ono SLIDE 18
Separator External Components
 Control Devices
Level Control.
Done by Level Controller in
Either the Gas/oil or
 Oil /Water Interface.
Generally Float-operated
Pilots
Prevents Damages Caused
by Separator Low or High
Level
Normally Activates
 Dump Valve on Sensing
High Liquid Level.
 Block Valve on Inlet
 Bypass Valve
 An Alarm

19. SITP / O & G Ono SLIDE 19
Separator External Components
Pressure Control
 Done in the Vapour Space With a
Pressure Controller and Back
Pressure Control Valve.
 Control Valve is Located on Gas
Exit Line.
 Controller Senses Abnormality
and Regulates the Control Valve
to Release Gas.
 Controls Can be Mechanical,
Pneumatic or Electric
 Normally Activates
 A Shut-in Valve
 A Bypass Valve
 An Alarm
 Temperature Controls
 Mostly on Special cases
Separators
 Functions to
 Shut-in the Separator
 Open or Close a Bypass to
Heater
 Activates an Alarm

20. SITP / O & G Ono SLIDE 20
Separator Operating Pressures
 Maximum Allowable Working
Pressure (MAWP)
Maximum Pressure on Top of
the Separator at Its Normal
Operating Condition for That
Designated Temperature.
Pressure Beyond Which
Vessel or Pipe Should NOT
be Operated
It Is Normally Stipulated by
the ASME.
Determined by Vessel
Material, Thickness and
Temperature
 Set Pressure
Pressure at Which Safety
Device Gets Activated
Normally Equals or Greater
than MAWP
 Operating Pressure (OP)
Pressure in the Vessel
During Normal Operation
OP  90% MAWP
  Pressure Relief
 Device Pressure.

21. SITP / O & G Ono SLIDE 21
Separator External Components
 Safety Devices
 Prevent Accidents and Damage
such as Vessel Rupture
 Generally Prevent
 Over- or Under-pressure
 Low or High Liquid Levels
 Low or High Temperature
Relief Valve
 Spring-Loaded Valve that
Raises Slowly with Pressure
Increase
 Used Mainly for Liquid
Pressure Control
Safety Valve
 Spring-Loaded Valve that
Pops Open with Pressure
Increase.
 Mostly Applicable with Gas
or Vapour Pressure
Controls.
Safety Relief Valve.
 Spring-Loaded Valve
Designed to Work as Both
Safety and Relief Valves.
 Sized and Designed to Open
Before or at MAWP
 Pressure > Separator
Maximum Operating
Pressure.