Heavy Oil Dehydration - Tekna

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8 Νοε 2013 (πριν από 3 χρόνια και 9 μήνες)

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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
Conductivity, 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
+
H
2
O
H
2
O
H
2
O
H
2
O
H
2
O
Cl
-
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
Attraction
Electrophoretic 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
®
Oil Flux
Desalting
Technology
Electrostatic
Desalter
Single Stage Flow
Diagram
Mixing
Valve
Effluent
Pump
Dilution
Water
Feedstream
Oil Outlet
Water To
Disposal
Electrostatic
Desalter
to
HEX
Electrostatic
Desalter
Two Stage Flow
Diagram
Mixing
Valve
Effluent
Pump
Feedstream
Water To
Disposal
Electrostatic
Desalter
Mixing
Valve
Effluent
Pump
Dilution
Water
Oil Outlet
Electrostatic
Desalter
to
HEX
Interstage
Recycle
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
Threshold Voltage
Voltage
Oil Conductivity
Instantaneous Voltage
High Oil Conductivity
Frequency Effect on Voltage Decay
Low Frequency
High Frequency
Threshold Voltage
Voltage
Time
Average Field Strength
Instantaneous Voltage
Dual Frequency Waveform
Coupled with Voltage Modulation
-600
-400
-200
0
200
400
600
Time
Primary Voltage, volts
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)
Outlet BS&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 Polarity
Dual
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/ft
2
)
@
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/ft
2
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 Technology
Electrostatic
Technology
BS&W
%
NaCl
ptb
Mixing Efficiency = 40%
Questions?
Heavy Oil Technology for
Offshore Applications
May 2009