1. Treatment of Produced Fluids: Crude Oil and Water:
Emulsion Treatment and
Dehydration of Crude Oil
By Pn Khairunissa Syairah
Credit to Pn Azduwin

4. GENERAL UPSTREAM OIL PROCESSING

5. Outline 1. Emulsion Treatment and Dehydration of Crude Oil
2. Desalting of Crude Oil
3. Crude Oil Stabilization and Sweetening
4. Storage Tanks and Other Field Facilities
5. Produced Water Treatment

6. • Oil emulsions are mixtures of oil and water.
In general, an emulsion can be defined as a mixture of two
immiscible liquids, one of which is dispersed as droplets in the
other (the continuous phase), and is stabilized by an emulsifying
agent.
• Emulsifying agents, which are commonly found in crude oil or water
in the natural state or introduced in the system as contaminants
during drilling and/or maintenance operations, create this film.
• Some of the common emulsifiers are as follows:
1. Asphaltic materials
2. Resinous substances
3. Oil-soluble organic acids
4. Finely dispersed solid materials such as sand, carbon, calcium, silica,
iron, zinc, aluminum sulfate, iron sulfide, and so on.

7. BASIC PRINCIPLES 1. Breaking the emulsion, which could be
achieved by either any, or a combination of the
addition of heat, the addition of chemicals, and
the application of electrostatic field
2. Coalescence of smaller water droplets into
larger droplets
3. Settling, by gravity, and removal of free water

8. WATER PRODUCED WITH CRUDE OIL
WATER WITH
CRUDE OIL
FREE WATER
(F.W.)
SUSPENDED
WATER (SS.W.)
SOLUBLE
WATER (S.W.)
EMULSIFIED
WATER (E.W.)
W/O EMULSION
O/W EMULSION

9. STABLE EMULSION
For two liquids to form a stable emulsion, three conditions
must exist:
1. The two liquids must be immiscible.
2. There must be sufficient energy of agitation to disperse one
phase into the other.
3. There must be the presence of an emulsifying agent.

10. DEHYDRATION/TREATING PROCESSES
(F.W. = fresh water, SS.W. =suspended water, E.W. =
emulsified water.)

11. Removal of Free Water
• Free water is simply defined as that water produced with crude
oil and will settle out of the oil phase if given little time.
• There are several good reasons for separating the free water first:
1. Reduction of the size of flow pipes and treating equipment
2. Reduction of heat input when heating the emulsion (water takes
about twice as much heat as oil)
3. Minimization of corrosion because free water comes into direct
contact with the metal surface, whereas emulsified water does not.
• Free water removal takes place using a knockout vessel, which
could be an individual piece of equipment or incorporated in a
flow treater.

12. Two-phase free-water knockouts.

13. Three-phase free-water knockouts.

14. Resolution of Emulsified Oil
• This is the heart of the dehydration process, which consists
of three consecutive steps:
1. Breaking the emulsion: This requires weakening and
rupturing the stabilizing film surrounding the dispersed
water droplets. This is a destabilization process and is
affected by using what is called an ‘‘aid,’’ such chemicals
and heat.
2. Coalescence: This involves the combination of water
particles that became free after breaking the emulsion,
forming larger drops. Coalescence is a strong function of
time and is enhanced by applying an electrostatic field,
impingement on a solid surface area, and water washing.
3. Gravitational settling and separation of water drops: The
larger water droplets resulting from the coalescence step
will settle out of the oil by gravity and be collected and
removed.

15. HEATING
• Heating is the most common way of treating water–oil emulsions.
• As the water and oil mixture is heated, the density (specific
gravity) of both water and oil is reduced.
• Heaters are generally of two basic types:
1. Direct heaters, in which oil is passed through a coil exposed to the
hot flue gases of the burned fuel or to introduce the emulsion into a
vessel heated using a fire tube heater.
2. Indirect heaters, in which heat is transferred from the hot flue
gases to the emulsion via water as a transfer medium. The emulsion
passes through tubes immersed in a hot water bath.

16. DIRECT VS INDIRECT HEATING

17. CHEMICAL TREATMENT
• Some oil emulsions will readily break upon heating with no
chemicals added; others will respond to chemical treatment
without heat.
• Chemical additives, recognized as the second ‘‘aid,’’ are
special surface-active agents comprising relatively
highmolecular-weight polymers. These chemicals
(deemulsifiers), once adsorbed to the water–oil interface,
can rupture the stabilizing film and/or displace the
stabilizing agent due to the reduction in surface tension on
the inside of the film.
• To select a demulsifier for a given system, one generally starts
with the bottle tests. Representative emulsion samples are
taken and transferred into several centrifuge tubes.
• Final selection of the right chemical will be based on testing a
sample of the oil to find out how complete the water removal
was.

18. Deemulsification of water drops

19. Steps leading
to large drop
formation.

20. ELECTRICAL AID • Heating and chemical treating work in order
to ‘‘break the emulsion’’, whereas electrical
emulsion treating is aimed at speeding up
‘‘coalescence,’’ hence settling.
• In other words, electric dehydration does not
break the emulsion electrically.
• The principle of breaking oil–water emulsions
using electrical current is known as
electrostatic separation.

21. PRINCIPLE OF DEHYDRATION USING ELECTRICAL AIDS
1.The water droplet -polar molecules
2.These polar forces are magnetized and respond to an external electrical force field
3. Form a dipole attraction between the water droplets leading to coalescence, hence settling and separation
1. The water droplets vibrate rapidly,
2. Causing the stabilizing film to weaken and break.
3. The surface of the water droplets expand ,thus attracted to each other.
4. They collide and then coalesce.
5. As the water droplets combine,
6. They grow in size - become heavy
7. Settling to the bottom of the treater.

22. THE END