20100211 sams desalting

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Cover graphic should fill and not exceed the defined grey box. Challenges of Desalting Canadian Crudes Gary W. Sams Director R&D

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Page 1: 20100211 Sams Desalting

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

Challenges of Desalting Canadian CrudesGary W. Sams

Director R&D

Page 2: 20100211 Sams Desalting

Heavy Oil PFD

Crude Oil Quality Association

FWKO

Separator

Treater

• Oil lighter than water• High inlet water cut• Oil internal• Temperatures < 143 C 25% Oil

75% Water 65% Water

72% Oil28% Water 20% Water

9% Water90% Oil10% Water

99% Oil1% Water

• Smaller water drops• Shifted to oil external

• Smallest water drops• Mostly emulsified• Solids stabilized

Gas

Gas

Page 3: 20100211 Sams Desalting

Degassing / Dehydration

Crude Oil Quality Association

Inlet

Gas Oil

Water Water

HiFlo Spreader

Collector

Electrodes

Dual Frequency

Page 4: 20100211 Sams Desalting

Cyclonic Gas Removal

Crude Oil Quality Association

Page 5: 20100211 Sams Desalting

Crude Oil Quality Association

2)K( Rate Settling gdow

Temperature vs. Viscosity

Chemical Treatment

Program

Stoke’s Law dEc

Emulsifying Factors

Water Solubility

4

62

drKEFcoalescing

Desalter Design Issues

Page 6: 20100211 Sams Desalting

Solids & Oil in Effluent

Small micron particulates,crystalline salt, and heavy solids loads

Crude Oil Quality Association

Substantial asphaltene precipitation

Page 7: 20100211 Sams Desalting

Reverse Emulsion

Crude Oil Quality Association

16 API SAGD DilBit

Page 8: 20100211 Sams Desalting

Dro

plet

Pop

ulat

ion,

%

0 50 100 150 200 250 300 350 400 450 500 550 600Droplet Diameter, microns

0

10

20

30

40

50

Final Droplet Distribution

Initial Droplet Distribution

Water Droplet Growth

Crude Oil Quality Association

Page 9: 20100211 Sams Desalting

Kuwait Oil - 25ºAPI

Chemical

Bottle Test Electrostatic Bench Test

Water in Oil% By Difference

BS&WMeasured %

Brand A 3.6 1.4Brand B 4.0 1.51Brand C 4.8 1.51Brand D 5.5 0.7

Best Performance

Best Performance

Based on lab tests – Initial BS&W – 10%Crude Oil Quality Association

Demulsifier Selection

Page 10: 20100211 Sams Desalting

Electrostatic Field Selection

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®

Crude Oil Quality Association

Page 11: 20100211 Sams Desalting

AC Electrostatic Forces

Crude Oil Quality Association

Positive Forces& Velocities

Negative Forces& Velocities

Electrostatic Voltage Field, V/ m

Vertical oil velocity, vv

Droplet Radius, rDrop Spacing, S

DropletWeight, WD

Elec

trod

e #1

Elec

trod

e #2

DipoleForceDrop

Velocity

DragForce

Page 12: 20100211 Sams Desalting

DC Electrostatic Forces

Crude Oil Quality Association

Positive Forces& Velocities

Negative Forces& Velocities

Electrostatic Voltage Field, V/ m

Vertical oil velocity, vv

Droplet Radius, rDrop Spacing, S

DropletWeight, WD

Elec

trod

e #1

Elec

trod

e #2

ElectrophoresisForce

DropVelocity

DragForce

Page 13: 20100211 Sams Desalting

Gradient Electrostatic Forces

Crude Oil Quality Association

Positive Forces& Velocities

Negative Forces& Velocities

Electrostatic Voltage Field, V/ m

Vertical oil velocity, vv

Droplet Radius, rDrop Spacing, S

DropletWeight, WD

Elec

trod

e #1

Elec

trod

e #2

Di-electrophoresisForce

Di-electrophoresisForce

DropVelocity

DragForce

Page 14: 20100211 Sams Desalting

Net Electrostatic Forces

Crude Oil Quality Association

Positive Forces& Velocities

Negative Forces& Velocities

Electrostatic Voltage Field, V/ m

Vertical oil velocity, vv

Droplet Radius, rDrop Spacing, S

DropletWeight, WD

Elec

trod

e #1

Elec

trod

e #2

DipoleForce

ElectrophoresisForce

Di-electrophoresisForce

Di-electrophoresisForce

DropVelocity

DragForce

Page 15: 20100211 Sams Desalting

Viscous Drag

Weight

Dipolar AttractionElectrophoretic

Force

++ --Vol

ts

Voltage FieldDipole Electrophoretic

Direction Force Direction ForceAlternating Current Oscillates 0.4 weight Reverses Net is zeroDirect Current Constant 0.4 weight Constant 7230 weight

+

Volts

-

Electrostatic CoalescenceNet Drop Forces in Voltage Field

Crude Oil Quality Association

Page 16: 20100211 Sams Desalting

} Bulk Water Removal

AC/DC Electrostatic Field

Crude Oil Quality Association

Oil

Flux

Page 17: 20100211 Sams Desalting

Desalter Hydraulic Efficiency

Crude Oil Quality Association

Page 18: 20100211 Sams Desalting

Excessive Oil Conductivity

Crude Oil Quality Association

0200400600800

10001200140016001800

50 100 150 200 250 300

Temperature, F

Cond

uctiv

ity, n

S/m Typical

High

Page 19: 20100211 Sams Desalting

Heavy Oil Dehydrator PerformanceRef: SPE Paper 97786

Crude Oil Quality Association

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)

Out

let 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

ModulatedDual

Polarity

Oil API – 21TAN - 4

Page 20: 20100211 Sams Desalting

Technology RetrofitA Commercial Installation

Before Retrofit* After Retrofit*Technology: Dual Polarity Dual FrequencyTemperature: 220ºF 200ºFOil Flow: 4000 BOPD 9200 BOPDOutlet BS&W: 1% 0.1%

*Data is per vessel. There are four vessels.

Crude Oil Quality Association

Gravity = 12ºAPI

Page 21: 20100211 Sams Desalting

SAGD -Dilbit Desalting Pilot Results

Process Parameters:Dilbit API: 16 , Temp: 280F, 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

Wash Water: 5 % Recycle: 5 % Valve DP: 10 psi

2 DF 0.4 6 0.35 1

Mixing Efficiency = 25%

Crude Oil Quality Association

Page 22: 20100211 Sams Desalting

Desalter Technology Comparison InletSalt

OutletSalt

BSW

AC 258 41 0.5

AC‐pAC

258 12 0.4

DF 211 6.3 0.4

EDD‐EDD

200 3.2 0.4

DF‐DF 210 2.8 0.3

EDD‐DF

200 2.4 0.3

DF‐EDD

210 2 0.4

Crude Oil Quality Association

Page 23: 20100211 Sams Desalting

ConclusionsHeavy Canadian crudes pose unique challenges:

• High Oil Conductivities• Asphaltene Precipitation• High Solids Loading• Reverse Emulsions• Increased Interface Rag• Poor Effluent Water Quality

Crude Oil Quality Association