The document discusses crude oil desalting and the factors that influence crude oil conductivity. Crude oil conductivity increases with temperature, water content, and contaminants. The desalting process uses an electrical field to separate water from crude oil based on differences in conductivity. Transformer capacity must match the conductivity of the crude blend being processed, which varies based on temperature, water content, and crude oil composition.

1. CRUDE OIL
CONDUCTIVITY
NALCO ENERGY
SERVICES
A.C. POTTER
February 8, 2007

2. DESALTING PROCESS
Desalted
Heat Crude
Exchangers
Crude Oil
Mix
Valve
Water
Effluent Water
..
©Copyright 2007 Nalco Company. All rights reserved

3. CRUDE OIL DESALTER
©Copyright 2007 Nalco Company. All rights reserved

4. STOKE’S LAW
KD 2 (ρ w − ρ o )
V=
μ
V = Settling Velocity
K = A Constant
D = Diameter of Water Droplet
ρw = Density of Water
ρo = Density of Oil
μ = Viscosity of Oil
©Copyright 2007 Nalco Company. All rights reserved

5. ELECTRICAL FIELD
+
- - --
- -
-
+ +
++ +
Electrostatic
Induced Charge Attraction
--
- - --
-
++ ++
©Copyright 2007 Nalco Company. All rights reserved

6. ATTRACTIVE FORCE
CV 02 D 6
F =
d4
F = Attractive Force
C = A Constant
V0 = Voltage Gradient
D = Droplet Diameter
d = Distance Between Drops
©Copyright 2007 Nalco Company. All rights reserved

7. ELECTRICAL SUPPLY
Transformer Secondary
Line Voltage KVA Voltag
Rating
e
12-36 KV
Taps
800-3,000 Volts 8-24"
Inch Grids
Spacing
©Copyright 2007 Nalco Company. All rights reserved

8. TRANSFORMER CHARACTERISTICS
AC Transformer Response
Voltage
Amperage
©Copyright 2007 Nalco Company. All rights reserved

9. CRUDE CONDUCTIVITY
Crude Oil Resistance (Ohm-cm)
West Texas 3.0
Arabian Light 1.5
Arabian Heavy 1.1
INCREASING
Alaskan North Slope 1.0
CONDUCTIVITY
Maya 0.95
BCF 17 0.9
Lloydminster B 0.6
Source: Howe Baker Engineers
©Copyright 2007 Nalco Company. All rights reserved

10. DILUTION EFFECTS
7000000
CONDUCTIVITY PICOSIMENS/METER
6000000
Crude oil
+ Toluene
5000000
4000000
3000000
2000000
Crude oil
1000000
0
0 20 40 60 80 100 120
TEMPERATURE oC Toluene
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11. BLEND EFFECTS
ARAB HVY / DOBA CRUDE BLENDS
CONDUCTIVITY PICOSIMENS/METER
1400000
20% DOBA IN
1200000 ARAB HVY
1000000 10% DOBA IN
ARAB HVY
800000
600000
DOBA
400000
ARAB HVY
200000
0
0 10 20 30 40 50 60 70 80 90 100
TEMPERATURE oC
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12. DESALTING OPERATION
INSTALLED TRANSFORMER CAPACITY KVA
Crude
Blend “C”
Crude
Blend “B”
Crude
Blend “A”
0
DESALTER OPERATING
TEMPERATURE oC
©Copyright 2007 Nalco Company. All rights reserved

13. EFFECTS ON VOLTAGE
• CONDUCTIVITY
TEMPERATURE
WATER IN CRUDE
CONTANIMANTS
CRUDE OIL
COMPOSITION
PRODUCTION
ADDITIVES
©Copyright 2007 Nalco Company. All rights reserved

14. CRUDE CONDUCTIVITY
• TEMPERATURE
–INCREASES CONDUCTIVITY
• WATER IN CRUDE OIL
–INCREASES CONDUCTIVITY
–DESALTER DESIGNED FOR % QUANTITIES
• CONTANIMANTS
-CONDUCTIVE SPECIES (eg: Metals)
• CRUDE OIL
–COMPOSITION (?)
–FORMATION RELATED (?)
–ADDITIVES USED (?)
©Copyright 2007 Nalco Company. All rights reserved

15. DESALTING OPERATION
CRUDE QUALITY PARAMETERS
FOR DESALTING OPERATION
• SPECIFIC GRAVITY OF CRUDE SLATE
• WATER CONTENT OF CRUDE SLATE
• VISCOSITY OF CRUDE SLATE
• CHLORIDE CONTENT OF CRUDE SLATE
• SOLIDS CONTENT OF CRUDE SLATE
• CRUDE CONDUCTIVITY CRUDE SLATE
©Copyright 2007 Nalco Company. All rights reserved