Cover graphic should fill and not exceed the defined grey box.

Jan Tore Klausen

Stavanger 14.04.2011

Heavy oil separation

Electrostatic Coalescers

Todays presentation

• Overview of oil treating using electrostatic forces

• Presentation of the Dual Frequency Electrostatic by Cameron

• Presentation of the Compact Electrostatic Separator (CES)

• Novel separator used for heavy oil separation

• Presentation of lessons learned in the development of the CES

2

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Electrophoretic Force

Di-Electrophoretic

Force

Oil/Water Interface

PROCESS SYSTEMS

Increasing

water

concentration

+

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+

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+

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+

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+

+

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Dipole Force+

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NATCO® Dual Frequency® ElectrostaticsFundamentals of electrostatic treating

NATCO® Dual Frequency® Electrostatics

Low FrequencyNote deep RC discharge

between voltage peaks.Note shallow RC discharge

between voltage peaks.

High Frequency

F = KV2 r6

d4

Threshold

Voltage

Effects of Frequency on Voltage Decay

-600

-400

-200

0

200

400

600

Time

Pri

ma

ry V

olt

ag

e, v

olt

s

Base

Frequency

Pulse

Frequency

Threshold

Voltage

Sinusoidal Wave

(or trapezoidal,

triangular, square,

etc)

Droplet

charge follows

the Modulation

waveform

Critical

Voltage

NATCO® Dual Frequency® Electrostatics

AC, Dual Frequency and Dual Polarity

• Movie showing the difference performance between AC, DF and DP

• Black corresponds to oil

Alternating Current Dual Frequency Dual Polarity

NATCO® Dual Frequency® ElectrostaticsComparisson to other types of treaters

ConventionalA/C

14’ x 65’4.2mx19.5m Dual polarity

Technology12’ x 40’

3.6mx12m

DualFrequency®

10’ x 26’3mx7.8m

CoalescingDroplets

Example:

80,000 BOPD

32 API Crude

4 cps Viscosity

Inlet: 5% BS&W

Outlet: 0.5% BS&W

Divider graphic should fill and not

exceed the defined gray box.

Cameron

Compact

Electrostatic

Separator

(CES)

Basic CES Process System, design objectives

Inlet to 75%

water cut

Gas

< 3% Liquids

Power

Power

Oil

<< 10% water

Water < 200 ppm Oil

To reinjection

GOR to 1000

scf/bbl

180 Sm3/m3

Lessons learned from the EPIC inline coalescer from

NATCO

• In-Line Coalescer

• EPIC – 1989 – 1996

EPIC In line coalescer

EPIC Between Stages, coalescer only

11

Water

Oil / Water

Emulsion> 65% BS&W

Gas

FirstStage

Separator

EPIC Manifold

Transformer Oil

Water

SecondStage

Separator

Lesson Learned

• Rapid and compact coalescence is possible

• Electrostatically formed water droplet are fragile.

• In-line coalescer must be close to separator

• Piping between the coalescer and the separator is critical

• Insulated electrodes will fail.

CES Separation System

Electrostatic

Coalescence

+ Separation

Electrostatic

Coalescence

+ Separation

Water

Recovery

Free

Gas

Free

Water

Separated

Water

Solids

Solids

PSAT Flow Loop used for internal testing

• Oil Rate – 3000 bpd (~480 m3/d) Gas – 10 MMscfd

• Water – 3000 bpd (~480 m3/d) @ 200 psi (14 bar), 200F (93 deg C)

CES tested in laboratory

• Following parameters

checked– Synergy

– Angle

– Liquid flux

– Temperature / Viscosity

– Voltage / Frequency

Effect of Flux Rate

0,0

5,0

10,0

15,0

20,0

25,0

30,0%

Wate

r in

Oil

Ou

tlet

Liquid Flux Rate (bopd/m2)

Standard Dehydrator

Compact Separator

Operating Flux

Compact Separator works well at high flux rates.

Performance drops after critical Weber number is exceeded.

Critical

Weber

Number

Synergy – 1 versus 2 stages

0

10

20

30

40

50

60

70

80

90

Flow Rate

% W

ate

r R

ed

uc

tio

n

Both Stages - Actual

Both Stages

No Voltage

Stage 2 Only

Stage 1 Only

Both Stages - Predicted

Effect of Vessel Angle

0

1

2

3

4

5

6

Wate

r in

Outlet

[%]

Liquid Flow rate [BOPD]

45 degrees

22 degrees

Horizontal

40

50

60

70

80

90

100

15 17 19 21 23 25 27 29

% R

eco

ve

ry H

2O

Viscosity, cp

Effect of Oil Viscosity at liquid design conditions

Effect of Voltage

Higher Voltage Better Performance

Rate and Voltage Sensitivity at AC, 60 Hz, 120 F

0

1

2

3

4

5

6

7

8

1000 1500 2000 2500 3000 3500

Flux Rate, BFPD/m2

% W

ate

r in

Oil

Ou

tlet

Base Voltage

Higher Voltage

Effect of Electrostatic Field

Advanced AC performed better than AC

Rate and Technology Sensitivity at 120 F

0

1

2

3

4

5

6

7

8

1000 1500 2000 2500 3000 3500

Flux Rate, BFPD/m2.

% W

ate

r in

Oil

Ou

tlet

AC, 60 Hz

AC, 1000 Hz

Results with POWER OFF

Inlet Water %

Outlet Water %

Test 1 34 34

Test 2 37 33

Average 35.5 33.5

Test 1 75 26

Test 2 77 22

Average 76 24

Results with POWER ONInlet Water % Outlet Water %

Test 1 30 3.8Test 2 31 3Test 3 32 3.2Test 4 34 3Test 5 31 3.4Test 6 31 4Average 31.5 3.4

Test 1 75 4.5Test 2 73 3.5Average 74 4

POWER OFF POWER ON

Lesson Learned

• Two electrostatic stages promote increased separation.

• Performance agrees with process condition variation.

• Pre-treatment permits wide water cut range.

• Advanced electrostatic field will improve performance.

• Can achieve water quality between 100 and 500 ppm

• Liquid – 3000-3500 bpd/ft2 (~ 45 m3/m2)

• Gas – 25 MMscfd @1000 psi (~70 bar)

• Inlet Water to 75%

• Outlet water < 10%

• Temperature to 200 F (93 Deg C)

• Water Quality < 300 ppm

Any questions?