Experience that Delivers
Integrated Modeling of Complex Gas-Condensate
Networks
Elliott Dudley (Senior Consultant – MSi Kenny)
Subsea UK 2013 – Aberdeen, UK
• Integrated Modelling Methodology
– Scope of integrated modelling
– Benefits to design and operational guidelines
• Application of Software to Gas-Condensate Networks
– Restart Procedure Case Study
– Removal of Pigging Case Study
Agenda
Overview
• Start-up/shutdown
• Commissioning Operation
• Line Pack Testing
• Chemical requirements
OPERATING PROCEDURES
• Pigging
•Multiphase mass
Transfer
OIL / GAS EXPORT
• IPR
•Casing and Insulation
WELL BORES
•Multiphase engine
•MEG Tracking
•Composition
Tracking
•Blend Management
SUBSEA TIEBACKS
• Artificial Lift
• Insulation/annulus
DRY TREES
• Dynamic simulation
• Separation/Dehydration
TOPSIDES
• Slug catchers
•Compression/Pumping
•Heat Exchangers
ONSHORE
Integrated Modelling Links Systems
Wells – Pipelines – Processing - Distribution
• Benefits of fully
integrated modelling:
– Simulate the real
impacts of each
system on the
connecting systems
– Develop Operating
Guidelines
– Test Operational
Strategies
Integrated Modelling Moves Boundaries
Realistic Boundary Conditions
VS.
• Isolating pipeline modelling requires
more assumptions about boundary
conditions
• Combination of pipelines with the
processing units creates more
realistic behaviour
• Simulates effect of downstream
pipe and compressor/pump control
philosophy
• Thermo-Hydraulic Pipeline Modelling
• All-in-one software used
• In-house software
Thermo-Hydraulic Pipeline Integrated with Dynamic Topsides Processing
Software Solutions: Core Technology
• Dynamic Unit Operations and Processing Models
• Customized user friendly displays and controls specific
to client
Network Layout
Case Study: Restart Philosophy
Development
• Multiple Wells per drill center
– Dynamic blending of compositions
• Primary separation
• Hydraulically connected gas pipeline network
• Liquid pipelines
• Dehydration and stabilization units
• Dynamic Compressors and Pumps
• Dry gas trunkline and liquids trunkline
• Separation conditions vary during
restart, the phase compositions are
dynamic
• Pressure and temperature float
• Integrated simulator couples wells
with gas and liquid pipelines
• Used composition tracking to capture
change in fluid properties
0
20
40
60
80
100
120
140
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180
-150 -100 -50 0 50 100 150
Pre
ssu
re (
Bar
a)
Temperature (°C)
Phase Envelopes of Gas Compositions During a Restart
P85_T50_Gas
P115_T70_Gas
P130_T85_Gas
0
20
40
60
80
100
120
140
160
180
-200 -100 0 100 200 300 400 500
Pre
ssu
re (
Bar
a)
Temperature (°C)
Phase Envelopes of Liquid Compositions During a Restart
P85_T50_Liquids
P115_T70_Liquids
P130_T85_Liquids
Case Study: Restart Philosophy
Development
Case Study: Restart Philosophy
Development
Goals and Results from Study
• Optimize well ramp up rates
› Led to new well ramp up strategy and requirements, slug capacity
• Optimize depressurization rates
› Showed optimal valve layout and sizing
• Demonstrate ability to utilize depressurization to restart topsides processing
› Predicted timing and flowrates required to start up topsides processing
• Onshore downtime estimate
Case Study: Restart Philosophy
Development
More Results from Study
• More operational cases to test line pack, partial production trips, and turndown
timing
• First start up and commissioning procedures
› Expanding network to include MEG distribution
Case Study: Pigging Frequency
Goal: Decrease Pigging Frequency
• High liquid content was resulting in high pigging frequencies
• With an integrated model, the study was able to deliver an operational
strategy that removed the need to pig entirely
› Varying well ramp up rates can remove liquid slugs safely without
flooding the slug catcher
› Required including wells, platforms, trunkline, and slug catcher in one
simulator
Summary
Integrated Modelling Allows Realistic Operational Studies
• Can be used to design and develop strategies for:
› Partial or system wide restarts and shutdowns
› First start up and commissioning procedures and requirements
› Ramp up and turndown procedures
• Includes restrictions of entire network
› Increases understanding of network interaction
• Uniform software platform environment keeps the simulation stability
• Can pin-point operational bottle-necks early on in design phase