Advanced

Electrostatic

Technology for

Heavy Oils

May 2009

AGENDA

• Opportunity Crude Issues

• Electrostatic Technology

• Desalting Technology

• Dual Frequency® Dehydration

• Experience with Heavy Crudes

Heavy Crude Issues

Difficult-to-Treat Oils

The Bad Actors…

• Electrical Conductivity

• Interfacial Tension

• Reverse Emulsions

• Limited Differential Density

• High Solids• Asphaltenes

• Sands, Scale

• Crystalline Salts

Excessive Oil Conductivity

0

200

400

600

800

1000

1200

1400

1600

1800

50 100 150 200 250 300

Temperature, F

Co

nd

ucti

vit

y,

nS

/m Typical

High

Interfacial Tension

Platinum Ring Tensiometer

• At Ambient Temperature– 15 -25 dynes/cm

• At Treating Temperature– 10 – 15 dynes/cm

• With Demulsifier– 7 – 10 dynes/cm

• In Electrostatic Field– 3 – 5 dynes/cm

Water-in-Oil Emulsion

Typical

Reverse Emulsion

16 API SAGD DilBit

Crystalline Salt

A Vexing Problem…

Dissolved Salt

Dry Salt Crystals

+

+

+

-

-

-

Na+H2O

H2O

H2O

H2O

H2OCl-

NaCl

Na+ Cl-NaCl

NaCl

NaCl

Salt Crystals Associated With Brine

Electrical Forces

Water-in-Oil Emulsion

with Salt Crystal

Crystalline Salt

Electrostatic

Technology

Our Choices Include…

• AC – Conventional & Deep-Field

• DC (Only with refined products)

• Dual Polarity® - Combination AC/DC

• Modulated Dual Polarity®

• Electro-Dynamic Desalting®

• Dual Frequency®

Electrostatic Fields

Electrostatic Dehydrators

Net Drop Forces in Voltage Field

Viscous Drag

Weight

Dipolar

AttractionElectrophoretic Force

++ --

Volts

Voltage Field

Dipole Electrophoretic

Direction Force Direction Force

Alternating Current Oscillates 0.4 weight Reverses Net is zero

Direct Current Constant 0.4 weight Constant 53 weight

Electrode

} Bulk Water

Removal

Dual Polarity®

AC/DC Electrostatic Field

Dual Polarity®O

il F

lux

Desalting

Technology

Electrostatic Desalter

Single Stage Flow Diagram

Mixing

Valve

Effluent

PumpDilution

Water

Feedstream

Oil Outlet

Water ToDisposal

Electrostatic

Desalter

to HEX

Electrostatic Desalter

Two Stage Flow Diagram

Mixing

Valve

Effluent

Pump

Feedstream

Water ToDisposal

Electrostatic

Desalter

Mixing

Valve

Effluent

PumpDilution

Water

Oil Outlet

Electrostatic

Desalter

to HEX

InterstageRecycle

Electrostatic Desalter

Essential Components:

1. Mixing

3 – 6% water up to 15 psi DP

2. Internal Recycle

From 5 to 10% of crude rate

3. Electrostatic Field

Target oil viscosity is 5 to 10 cP

4. Enhanced Distribution / Collection

Maximum vessel utilization

Dual Frequency

Dehydration

Oil Conductivity

Effects on Voltage Decay

Low Medium High

Thre

sh

old

Vo

ltag

eV

olta

ge

Oil Conductivity

Insta

nta

neous V

oltage

High Oil Conductivity

Frequency Effect on Voltage Decay

Low Frequency High Frequency Thre

shold

Volta

ge

Voltag

e

Time

Avera

ge F

ield

Str

ength

Instantaneous Voltage

Dual Frequency Waveform

Coupled with Voltage Modulation

-600

-400

-200

0

200

400

600

Time

Pri

ma

ry V

olt

ag

e, v

olt

s

Base

Frequency

Modulation

Frequency

Threshold

Voltage

12 - 25 kV

Sinusoidal Wave

(or trapezoidal,

triangular, square,

etc)

Droplet

charge follows

the Modulation

waveform

Critical

Voltage

20 - 40 kV

System Performance:

1. High Conductance Crudes

High (base) frequency

2. Water Drop Interfacial Tension

Low (pulse) frequency

3. Combined to achieve

Lowest Salt and BS&W

Dual Frequency Dehydrator

Heavy Oil

Performance

Technology Comparison

Pilot Results

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300

Oil Flux (bopd/sf)

Ou

tle

t B

S&

W (

%)

Field AC Dehydrator @ 239 F

AC Dehydrator @ 219F

AC/DC @ 218F

Modulated AC/DC @ 220F

Bimodal AC/DC @ 220F

Solid Curves Predicted by Electrostatic

Dehydrator Computer Model

AC Dual PolarityDual

Frequency

Modulated

Dual

Polarity

Oil API – 21

TAN - 4

Ref: SPE Paper 97786

Technology Comparison

Heavy Oils

Pilot / Field Tests

Increased Oil Flux

Flux (BOPD/ft2)@ BS&W Oil Gravity

ºAPI Dual Polarity Dual Frequency

Comments

16 100 @ 0.63% 125 @ 0.56% Diluted SAGD, Canada

20.2 90 @ 0.38% 220 @ 0.4% West Sak, Alaska

20.7 90 @ 0.35% 175 @ 0.4% Bohai, China

24 125 @ 0.4% 208 @ 0.4% Venezuela

Advanced Dehydration Results

Dual Polarity vs. Dual Frequency

Pilot data on several oils from 13.8 to 25 API.

Dual

Polarity

1.78

0.3

1.45

1.35

0.5

0.9

Dual

Frequency

0.6

0.1

0.85

0.8

0.27

0.55

Outlet BS&W (%)

Venezuela

Venezuela

Wyoming

Oklahoma

Brazil

North Sea

Crude

Identification

25

17

24

22.8

13.8

20.8

Crude API

9

28

11

11

5

Feed

BS&W

(%)

200

94

100

75

80

150

Grid Load

(bopd/sf)

150

280

130

135

240

Temperature

(F)

200

Heavy Oil Desalting

Pilot Results

• Dilbit API - 16

• Temperature - 280 F

• Flux - 70 bopd/ft2

Stage Tech.

Feed Outlet

BS&W, % Salt, ppm Cl- BS&W, % Salt, ppm Cl-

1 AC 5.8 220 0.4 6

2 DF 0.4 6 0.35 1

• Wash Water – 5 %

• Recycle – 5 %

• Valve DP – 10 psi

Mixing Efficiency = 25%

Crystalline Salt Removal

Aggressive Mixing

• WCS Crude - 20 API

• Average Inlet Salt Is 10 ptb

• Flux Rate of 115 bpd/sf @ 280 F

• 5% fresh water

3 Static + Valve Deep-field AC 0.6 2.2

3 Static + Valve Dual Polarity 0.4 1.3

3 Static + Valve Dual Frequency 0.15 0.5

Dynamic Dual Frequency 0.3 1

Mix TechnologyElectrostatic

Technology

BS&W

%

NaCl

ptb

Mixing Efficiency = 40%

Questions?

Heavy Oil Technology for

Offshore Applications

May 2009