TAQA Bratani Limited Well and Scale Management in a Mature ... · • Fish left in well after...
Transcript of TAQA Bratani Limited Well and Scale Management in a Mature ... · • Fish left in well after...
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POWERING A THRIVING FUTURE
Well and Scale Management in a Mature Subsea Field
September 2020
Charles Adoga
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Contents
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Introduction and Background
Production History
Scale Management History
Rejuvenation of Scale Management
Programme of Activity on MSS1 Rig
P18s1 Intervention Summary
P14s4 Intervention Summary
Conclusion
Next Steps
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Pelican Background
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• Location: East Shetland Basin, NNS
• Discovered: 1975
• Field Online: Jan 1996
– Water Injection Jul - 1997
• Type: Subsea oil development tied back to the Cormorant Alpha
Platform 8 Km away
– 2 x 8” production flowlines, 1 x 8” water injection flowline
– 1 x 6” gas lift flowline
– 5 current gas lifted producers (includes 1 cyclic)
– 22 wells (5 injectors and 17 producers)
– 4 injectors
• Reservoir: Middle Jurassic Brent Group at 10,500 - 12,300 ft
TVDSS, OWC not penetrated
• Cumulative production: 78 MMstb
• STOIIP: 590 MMstb
– STOIIP in low permeability rock
– High permeability channel intervals – premature watercut
• Oil Properties:– API 34.8– Bubble Point 2340 psi– GOR 567 scf/stb
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4
0
2,000
4,000
6,000
8,000
10,000
12,000
14,000
16,000
Oil
rate
(bopd)
Pelican Production History Nov 2008 - Mar 2019P20 Nov 2010 P18s1 Aug 2011 P21 Feb 2012 P22s1 Aug 2013
W23 injector drilled to
support P22 Sep 2015
P14s4 Aug 2018
P10Bs2 Sep 2010
Exte
nd
ed
Sh
utd
ow
n
Production History (TAQA operatorship)
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6
Platform FlowlineDeployment
Rig / LWIV Subsea Acid SkidManifold
2001 - 2002 2005 - 2008 2009 - 2011
Scale Management History
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Deployment option depends on:
• Economics
• Cheapest – Platform flowline
• Most expensive – Rig / LWIV
• Risk of diversion
• Platform flowline – risk of debris impairment
• Other planned well activities
Never
used h
isto
rically
Deployment Technique
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Scale Management History
Pre 2011
• Active infill well drilling & interventions
• Scale prevention via inhibition & treatment (dissolver + squeeze)
• Good water injection uptime
2011-2017
• P10bs2 scale inhibition squeeze in 2011
• Poor water injection uptime
• P22s1 coreflood test – 50% return permeability impairment
2017-date
• Rejuvenation of scale management & change of production storage to direct export
• Laboratory Tests (P22s1 repeat, P12 expanded coreflood tests)
• Scale remediation via scale dissolver treatment
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Timelines
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Rejuvenation of Scale Management
Reservoir Performance
• Downhole pressures
• CITHPs
Well performance
• Well test
• Gas lift design reports
Production Impairment mechanism
• Production chemistry data
• Lab tests
• Barite / Carbonate Envelope
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• Pressure
• Productivity index
• Artificial Lift challenges
• Fines migration
• Scaling
• Fluid / Rock interaction
• Flowline impairment
Approach
UncertaintySystem integration Available Information
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Rejuvenation of Scale Management
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Integration of well performance and scale model output
predicted severe scaling, although by standard
analysis, moderate scaling severity was suggested
Impact of Historical Scale Management Data Interpretation & Integration
P18s1
15
515
1015
1515
2015
2515
3015
3515
4015
4515
50 70 90 110 130 150 170 190 210 230 250
Flo
win
g P
ressure
s(p
sia
)
Flowing Temp (deg F)GLM location
Calcite Envelope with PT transverse.
• Over 90% of initial productivity of well impaired
• Sub-optimal gas lift performance
• Poor well performance contributed 20-30%
reduction in recoverable reserves
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Programme of Work on MSS1 Rig
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#1 P18
Data acquisition (PLT & RST)
Reperforation
Dissolver Treatment (Contingency)
Gas lift valves C/O
GLV Acid pickle (Contingency)
#4a P22
Data acquisition (PLT & RST)
Potential WSO
#2 P13
Dissolver treatment
Gas lift deepening
GLV Acid pickle (Contingency)
#3 P14
Dissolver treatment
Data acquisition (PLT & RST)
Potential WSO
#4b P22
Dissolver treatment
Initial Scopes
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P18 Intervention Summary
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Scale deposition
• Drift hung up at 9,240 ft. Target depth of 12,626ft
• Calliper log revealed the extent scaling
• 3rd and 4th GLM covered completely with scale
• Pervasive scale present across perforation
• CT mobilised and carried out:
• 6 milling runs (~3,300ft scale milled)
• 3 Cal-Acid dissolver treatments (306 bbls) and
• target depth below the perfs reached
Well Access, Caliper Log, Milling & Dissolver Treatments
3.8”
2.8”
Reservoir
Section
Before
After
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P18s1 Intervention Summary
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33% 29% 25%0.20
0.72
1.26
2019 Pre-Intervention 2019 Dissolver Treatment 2019 Reperforation
Watercut Productivity index
• Dissolver Treatment effective in improving well productivity
• Dissolver Treatment enhanced Vertical Lift Performance
• reinstated gas lift orifice valve operability confirmed with FGS
• Selective reperforation from saturation log prevented adding perf in
watered zones
• Planned 3-3/8” gun changed to 2-7/8” to prevent gun getting stuck
post perforation
• GLV change out was cancelled due to perceived challenges to carry out
change out
Re-perforation & Result
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P14s4 Intervention Summary
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Well Initial Scope Executed Scope
P14 • Dissolver treatment
• Data acquisition (PLT &
RST)
• Potential WSO
• Wireline runs & dissolver
treatments to gain access to
perfs
• Slickline fishing
• Dissolver treatment
• Data acquisition
• P14s4 came online in August 2018 with initial watercut reaching 70%.
• Scale encountered ~600ft above top perforation
• Reservoir access established via dissolver treatments c/w wire brush.
• Fish left in well after establishing reservoir access, but access for data acquisition not affected by fish.
• Data acquisition completed
• Saturation logs revealed swept intervals
• Production logs showed oil production being suppressed by jets of water
• Flowing Gradient Surveys across GLMs confirmed optimal performance
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Programme of Work on MSS1 Rig
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#1 P18
Data acquisition (PLT & RST)
Reperforation
Dissolver Treatment (Contingency)
#2 P13
Dissolver treatment
#3 P14
Dissolver treatment
Data acquisition (PLT & RST)
Completed scopes
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0
500
1000
1500
2000
2500
3000
3500
4000
4500
Ju
l-1
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Se
p-1
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Oc
t-1
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Dec
-18
Fe
b-1
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Ma
r-19
Ma
y-1
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Ju
l-1
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Au
g-1
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Oc
t-1
9
BO
PD
Daily Allocated Production
Pelican Pre-
Intervention
Post Intervention
production
Intervention
Incremental
1870 bopd
Programme of Work on MSS1 Rig
Production Incremental
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Conclusions
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Integration & Communication
• Intervention team comprised production engineer, intervention and completion engineers and management
• Daily meetings with management for:
• Intervention progress
• Daily campaign economic return updates
• Scopes balancing
Scale
• Scale modelling was helpful in predicting wells with scaling presence
• Dissolver treatments helped in removal of scale but need mechanical agitation / mill to remove significant quantities
Data Acquisition
• Acquired saturation log was critical in optimising the reperforation to avoid swept zones
• Acquired production log was useful in identifying zone for future water shut-off
Operational contingencies/learnings
• Coil tubing contingency – acidizing and tractor milling alone may not sufficient to remove extensive scale from wells
• Flexibility in perforating guns configuration should be considered
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Scale Management
Next Steps
• Continue Well performance monitoring
• Welltests and
• Production chemistry data acquisition
• Data analyses and integration
• Approval to carry out dissolver treatments in
2021
• Subsea intervention in 2020 to confirm
functionality and operability of the subsea
scale squeeze skids - completed
• Execute approved dissolver treatment scopes
in 3 wells in 2021
• Plan P&A activities with robust contingencies
for scale in tubing
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ROV footage of Pelican Subsea stim skid
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Acknowledgement
Many thanks to TAQA for giving the permission and support to present this material.
Also thanks to Jane Tomkinson and the Cormorant Alpha Subsurface & Wells Teams for their great support during the planning and execution of the 2019 Pelican Intervention on the MSS1 Rig.
Finally, thanks to the Devex organising committee for the opportunity to present today.
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THANK YOU
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P13 Intervention Summary
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• Well had not been entered since its completion in 1996 apart from a
scale dissolver treatment pumped from the Corm Alpha in 2009.
• Initial drift hung up 15ft below tubing hanger. Wax deposit found.
• Tubing eventually cleaned to TRSSSV with combination of wire brush
and Base Oil soaks (200bbls).
• Shock sheared FIT whilst trouble shooting TRSSSV issue. Found fish at
6300ft and recovered.
• Ran 3” deep drift and held up at 6,900ft. Suspected scale.
• Pumped dissolver treatments (683bbls) and GLVs changeout cancelled
Well Initial Scope Executed Scope
P13 • Dissolver treatments
• Gas lift deepening
• GLV Acid pickle
(Contingency)
• Wax removal
• Re instatement of TRSSSV
• Fish recovery
• Dissolvers treatments
2nd HUD – scale suspected
1st HUD – Wax deposit
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P18s1 Intervention Summary
Milling & Dissolver Treatment
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20
3.8”
nominal
Before After
Reservoir Section