vega flow assurance system
TRANSCRIPT
Vega Flow Assurance System
Sampath Munaweera, Statoil
Marit Larsen, FMC Technologies
UTC 2010
2
Vega Flow Assurance System (FAS)
• Background and Motivation
• The Vega Field and Flow Assurance Challenges
• Vega FAS Functionality
• Summary
” FAS is a SW system that helps to operate and control the production safe and effectively”
Subsea to beach
1985
Statpipe
1986
Gullfaks
1993
Sleipner
1994
Statfjord
satellites
1997
Norne
2001
Glitne
1996
Troll
1999
Åsgard
Platform based Subsea & floatingOrmen Lange
& Snøhvit
2007
A 25 year history of technology implementation in Statoil (&Hydro)
• The trend for new fields are developments with subsea tie-ins to existing platforms or subsea installations with long flowlines to shore
=> Flow Assurance and Metering Challenges
• Measurements are available subsea and topside, but normally no or limited information along the flowlines
4
FAS Motivation and History
• Need a model that can give information about the multiphase flow throughout the process
– As a support for the daily operation of the field
• Vital that operators and engineers have a common tool to look into the dynamics of the production system
• To meet these needs the Flow Assurance System (FAS) based on FlowManager™ and OLGA, will be installed for the Vega Field
FlowManager™ Online
• 1995-1999Installed on Troll B, Njord, Visund and Troll C
• 2000-2008>20 installations, in North sea, Canada and Africa
• 2008World’s largest integrated flow assurance system (FAS) for the Ormen Lange field
• 2010Vega FAS installed
5
Vega field
Vega South (R)
51 km production line (12’’ & 14’’)
3’’ MEG injection line
Lazy S riser
Pig launcher
Vega Central (Q)
Vega North (P)
Flow Metering
Continuous MEG Injection
Cont corrosion, scale and
wax inhibitor Injection
Wax formation?
Hydrate formation?
Liquid accumulation/surges?
Leakage/Blockage?
Slow dynamic and long time delay in flowline
Low temperature
during startup/shutdown
Topside MEG regeneration and liquid handling
High reservoir pressure
Water production
High reservoir temperature
Gas/condensate
Three templates, tie-in to Gjøa
51 km (32 miles) flowline
380 m (1247 ft) water depth
Total max gas production: ca 7 MSm3/d (247 MMSCF/d)
Production startup estimated Q4 2010
Two licenses
Vega FAS
” FAS is a SW system that helps to
operate and control the production safe and effectively”
7
FAS Execution modes
1) Real Time (RT) for online monitoring
2) Look-Ahead (LAH) simulation
– Runs automatically
– What happens the next 3-4 hours if no changes are done in the process
Pre
ssu
re
Current time
RT + LAH of current time
Simulationtime
Pre
ssu
re
Simulationtime2
WI Scenario 1 & 2
1 Current time
3) What-If (WI) simulation
– Same applications as for RT
– Can start from any historical timepoint or state in the process
– Planning. Try out operational scenarios. Test limits. Challenge system
– Training. Operation and dynamic process understanding
– Analyzing
Vega FAS Modeling Scope
Reservoir P & T
Tailor made applications
for Vega
Hydrate formation
Production choke
control
Pig operations
Leackage & blockage
Model tuning
Wax formation
Metering &
Sensor surveillance
Liquid volume
management
Real Time Flow Metering and Sensor Monitoring
• Robust metering system in parallel with flow meters
– Rates on each well and manifold
– MEG injection rates on each manifold
• Sensor Monitoring
– Flow meters
– Pressure and temperature
• ”Virtual sensors”
– Bottom hole P and T
– Choke erosion
– Flowline
FlowManager : A Distributed Flow Meter
2
1
,,)(
n
J
jcjmj XXWxF
whereWj : weight on sensor jXm,j: measured value sensor jXc,j: calculated value sensor j
Object function:
• Simultaneous rate allocation of
gas, oil and water
FlowManager Model includes:
- Setup of the actual system
- Mathematical models of all flow elements
• Flow rates are found by matching
sensor measurements using
advanced optimization
P,T
Downhole P,T
Choke
P,T P,T
Upstream
choke
Downstream
choke
Topside
X,Y
Other
sensors
• All sensors can be included in the
rate allocation
- PT, TT
- Choke
- Venturi
- Multiphase meter, etc.
• The rate allocation continues even
if single sensors fails
Monitoring - Possible Wax Formation
• Information about production related to Wax ApperanceTemperature (WAT)
• Early warning if production below WAT
Monitoring – Liquid Content and Distribuition
• Ramp-up and pigging operations
– FAS monitors liquid content (water/MEG and condensate) and relates this to separator liquid levels
– Early warning if separator will be overfilled
Current time
Look Ahead
Summing up FAS is an important tool for Statoil when operating and controlling the Vega Field
• FAS Real Time and Look Ahead
– Understand the current state and take best possible decisions
– Backup system for subsea flow metering
• FAS What-If simulations
– Avoid unplanned shutdowns by running scenarios
– Better planning of shut downs and start ups
– Improved field understanding
• Improved communication
– A common platform between engineers, operators and specialists
Thanks!
Overview and status, also in location with no measurements
Better understanding of flow assurance issues
Support for correct decisions, reduce shutdown time and produce optimized and safe
Marit Larsen
Sampath Munaweera