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

160

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