Transcript Polymer behavior in the reservoir

BrightWater® – A Step Change in Sweep
Improvement
- What is it?
- What isn’t it?
- Where did it come from?
-Where can it go?
Poor Reservoir Sweep Efficiency
Bypass Oil
BrightWater can help to improve
Reservoir Sweep Efficiency, and produce
the bypass Oil
Outline
•
•
•
•
What is BrightWater?
How does BrightWater improve waterflood?
Any field success?
How to use in mature fields?
• Candidate selection
• Tests
• Implementation.
• Conclusions
What is BrightWater®
• BrightWater is a technology that improve the
sweep efficiency of water flood by using a Novel
robust particulate system for in–depth
waterflood conformance control
• Designed to overcome injectivity and cost
limitations of classical polymer treatments.
(i.e., injected as small particles then can
become larger with time in the presence of a
“trigger” - temperature)
BrightWater® History
Contributor Involvement
BrightWater®, as a BP project, started in 1997
It was considered as a speculative, but high-reward project, and
was proposed as a
Joint Venture project to the “MoBPTeCh” consortium which has
now disbanded.
Nalco was identified as best potential development/supply
partner, and joined as equal contributors.
1997
1998
Now:
BP
Mobil, BP, Texaco, Chevron
BP, Chevron, Nalco
+
Nalco
BrightWater® – what it’s not
• BrightWater material is NOT a classic viscous polymer
• During injection it has viscosity very close to water
• It cannot be damaged by shear during injection
• It is not active initially
• Totally different from conventional gel jobs.
• No CAPEX – Simple to deploy
No Capex
½” NPT
fitting to
be used for
EC9368A
injection
BW
Particulate
½” NPT
fitting to
be used for
EC9360A
injection
2” Well
Line
Well Head
Well House
Floor
Dispersant
What is BrightWater®
• BrightWater is particles
• The median of the particle
size distribution is about 0.3
to 0.5 microns
• BrightWater particle is
supplied as a dispersion in
hydrocarbon solvent
• The active content in the
dispersion is about 30%
What is BrightWater®
Bright WaterTM material is a tightly bounded, thermally activated particle injected
as a dilute slug which flows with the water and pops open deep in the reservoir
and blocks the swept zones.
0.1 to 1
1 to 10
micron
microns
Warmth
This allows chase water to be diverted into zones that were previously poorly swept.
Inert BrightWater Material
BrightWater Particles
Pre-activated
–
Activated
This magnification is 10x greater than this one
Before Expansion
After Expansion
Scale bar is 500 nanometers
A polymer particle which is able
to propagate through rock
pores without injectivity loss
Scale bar is 5000 nanometers
Under the influence of heat the
particle expands to a size which
can block rock pore throats.
Diluted, inert
BrightWater
(after injection)
Activated
Time and temperature
EC9368A, 5000 ppm in SSW
40
99C
35
70C
50C
30
Visc (cp)
25
20
15
10
5
0
0
50
100
150
Days
200
250
Temperature response of BW products
35
30
25
Visc (cP)
5000 ppm
3900 ppm
20
4500 ppm
15
10
EC9368A/70C
5
EC9378A/70C
EC9398A/55C
0
0
50
100
150
Days
200
250
What is BrightWater®
• The injected sub-micron particles are inert
- they give virtually no viscosity or adsorption
- they are far smaller than the pores they move through
• The expanded particles are “sticky”
- they have increased solution viscosity, showing they now
interact with each other
- they act to restrict water flow rate in the reservoir
- the restriction can be permanent showing they are
interacting with the porous rock
BrightWater are Small Crosslinked
polymer particles (particle size) to propagate
deep into reservoir (pore size)
80
70
Kernel sample 1
Kernel sample 2
Frequency
60
North Sea core
50
Minas core
40
F-sand
30
20
10
0
0.001
0.01
0.1
1
Diameter (Microns)
10
100
What is BrightWater®
• The time before activation can be selected
• The strength of the block can be selected
• A complete block is not usually the aim or
necessary
So how does BrightWater work in
the reservoir?
Usually there is a temperature front set up by cold water injection
Temperature
Front
Cooled by injection
Still at reservoir temp
Usually there is a temperature front set up by cold water injection
BW
Temperature
Front
Cooled by injection
Still at reservoir temp
Setting BrightWater at a temperature front
water
Temperature
Front
• Setting at a temperature front can be very
convenient and is the ideal and usual mode for hot
reservoirs
• But we may not need a temperature front
• We can select the grade to control the setting time,
and set at any temperature up to 80-90C
EC9368A, 5000 ppm in SSW
40
99C
35
70C
50C
30
Visc (cp)
25
20
15
10
5
0
0
50
100
150
Days
200
250
Setting BrightWater in an isothermal case
Typical treatment objectives:
• Vertical conformance improvement by diverting water
from a thief layer
• Vertical and horizontal sweep improvement by
diverting water from a channel
• Slow down water cycling
- allow use of increased injection pressure
- allow use of increased drawdown at producers
BrightWater
List of Field Trials
• Minas, Indonesia (Chevron, 2001)
• Arbroath, North Sea, UK (BP, 2002)
• Milne Point and Prudhoe Bay, Alaska, USA
(BP)
(several, 2004-5)
•
•
•
•
•
Strathspey field, North Sea, UK (Chevron, 2006)
Argentina (several, 2006)
Pakistan (BP, 2006-7)
Alaska (several, 2007)
Being considered: more treatments in Indonesia
Australia, Alaska and Gulf of Mexico, USA
Bright Water trial and application types
Completed
In planning
Terminated
On hold
In progress
Commercial
In planning
Field
name
No. of
injectors
Nature
Thief Perm
Injection water T inj
Perm contrast
TDS
(°C)
(mD) with other
sand
2001
1
Technical trial
1200
2002
1
300
2004
1
Well Pair in channel sand commercial trial. Oil in Levees
Repeat well pair in channel sand commercial trial
Pattern to test full field recovery
potential
Channel sand, High res temp Planned while asset was within BP
2004- 3
05
Gy
1
HM
1
2006- 2
07
2006 3
Ko
1
2006
2007 1
2007 1
2007 2
800
500-800
T res
(°C)
Injector to
Producer
separation
68
74
1000 ft
15
98
8 PBU Injection
49
79
1.5 to 27 PBU Injection
56
93
Mixed
sea/produced
15
160
Sea Water
35
91
2700 ft
EC9368A
2 to 4 Low salinity
13
Sea Water
Product
planned/used
Tonnes of
product as
supplied
Conc
(%)
Catalysed
EC9368A
100
1.6
3300 ft
EC9368A
100
0.5
4000 ft
EC9368A
60
1
118, 90, 123
1
1500 to 2000 EC9378A
ft
EC9368A
1500
30
Higher perm thief in channel sand, Oil
in Levees (Sea water)
1360
4.4 to 7.4
High salinity injection water
400
?
121,000
52
99
4500 m
EC9378A
75, 48
1
4 to 6
18,000
49
71
980 ft
EC9378A
34, 70.5, 91.2
1
3 to 6
Fresh
66
138
Sea water
15
100
1200 to 2000 High
ft
temperature
product
EC9398A
138
1.68
Fresh
10
50
80
80
2440, 2160 ft EC9378A
EC9378A
65
65
1
1
1500 to 2000 ft EC9378A
75, 65
1.68, 1.5
Higher perm thief in channel sand, Oil 300-500
in Levees (pH7.5 fresh water)
Pattern flood
1200 1500
Trial of Low temperature material
3500
1300
continuation on the 2004 pattern
1600, 800
7
80
1.68
Alaska Bright Water Applications
BP Alaska Field Trial
Trial of pattern treatment, three adjacent injectors, 03-13, 16-11 and 16-16 treated in
2004 - 05
• High water cut at low to medium total Pore Volume injected
• Patterns mature to Miscible Injectant with breakthrough time 3 to 4 months
Design Process
1. Candidate selection : criteria; know
the reservoir
2. BrightWater formulation selection
3. Treatment volume and cost
estimation
4. Implementation plan : QA,
Contingency, monitoring
5. Post treatment plan
Characteristics of good
Candidate Reservoirs
• Sandstone reservoirs
• Vertical or horizontal high permeability contrast, Actual
sweep efficiency less than anticipated. Presence of bypass
oil.
• Thief > 150 md; no direct interwell fractures.
• Fluid transit time between injector and producers > 50 days
• Injection water temperature lower than reservoir
temperature (Temperature gradient between injector and
producer desired but not necessary).
• Down-hole temperature above 50 C.
BrightWater
Potential Tests desired
1. Bottle test (injection water, temperature) – to select
BrightWater formulation, if needed.
2. Sandpack Test – to confirm pop time at temperature, if
needed.
3. Interwell water breakthrough estimate: field data;
tracer, pressure test - to select BrightWater formulation or
identify area of potential bypassed oil, if needed.
4. Block Test (actual core material) – to select BrightWater
concentration. Needed only for very high or very low perm
rock
5. Simple temperature model (distance between wells;
reservoir and injection water temperature, rate and duration
of water injection) - to estimate thief zone temperature
profile.
6. Simple reservoir model – to estimate potential oil
recovery. (Required)
Difference between BW and Polymer
Function
Treatment fluid
Shear
degrading
Injectivity
Mechanism of
EOR
Treatment
volume
Set up zones
Implementation
Matrix rock
Fractures
BW
flow diverting
agent
water like
Classic polymer
flood
A pusher,
mobility control
viscous fluid
Classic WSO
polymer gel
flow diverting
agent
gel
NO
Like water
Yes
Low
Yes
Low
Expand WF
reachable zones Mobility control
small
Far away from
injector
Bullhead
Yes
No
large
small
near
Isolation
Yes
Yes
Conclusions
•
BrightWater is a new robust precrosslinked polymer particle that can expand
in size at design temperature and time.
• There are successful field implementations
(onshore and offshore)
• Increase oil production and recovery.
• Bullhead into injection line easily, even from a great
distance or into subsea completion.
• No facilities upset.
The Early stage Research team
members
BP
Nalco Energy
Services
K.T. Chang
Dennis Williams
Harry Frampton
Jim Morgan
ChevronTexaco
Steve Cheung
Rick Ng
Billy Surles
Les Munson
Thank you !
Questions?