Day5 1 Network

8/13/2019 Day5 1 Network

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PIPESIM Training CourseSection 2 - Network Model Presentation

Network Module


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Networkmodule - overview

Rigorous and comprehensive steady-state multiphasenetwork simulator

Combines the detailed well modeling capability of thesingle branch model with the ability to solve large

complex networks Networks of any size and topology (loops, multiple

sources & sinks, parallel flowlines)

Black oil/compositional

Rigorous thermodynamic calculations All single branch components can be included in a

network


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PIPESIMNetwork Modeling

Surface multiphase network simulator

Fluid interaction from various sources

Account for backpressure effects and well interaction

Surface facilities (Compressor, Booster etc)


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Types of networks

Gathering flowline systems

Distribution (including water injection and gas liftdistribution)

Looped networks (calculations in flow direction aroundthe system)

Large Complex Fields


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Model example ProductionGathering


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Model example Looped Networks


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Model example Water Reinjection


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Model example Large Network


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Some Results

X stb/d

< 2X stb/d800

850

900

950

1000

1050

1100

1150

1200

0 10000 20000 30000 40000

Total Distance (ft)

Pressure

(psia)

One well

Two well


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Some Results

Carbon Dioxide 0.91

Nitrogen 0.16

Methane 37.121

Ethane 15.28

Propane 6.95

Isobutane 1.44

Butane 3.93

Isopentane 1.44

Pentane 1.41

Hexane 4.33

C7+ 27.029


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Toolbox

Pointer

Re-injector

Folder

Branch

Manifold (Node)

Source

Sink

Production Well

Injection Well

Annotation


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Steps in building a model

Set units & job title

Define components in the model:

production wells

injection wells sources

sinks

branches (flowline or trunklines)

Enter physical data for each component (dbl click oneach)

Define global/local fluid models and flow correlations


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Steps in building a model (cont.)

Set boundary conditions (pressure (P) and flowrate

(Q)):

number P + Q MUST equal sum of (sources + wells +

sinks)* at least one boundary pressure must be specified

Set boundary conditions (temperature (T)):

all source fluid T MUST be specified* all sink temperatures are calculated by the network solver


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Steps in building a model (cont.)

Set the network tolerance

This is the degree of error allowed at each internal node

A network has converged when the pressure and flowratetolerances at every node are within the network tolerance

The pressure balance at each node is satisfied when allpressures are within the network tolerance

The flowrate balance at each node is satisfied when theflowrate into the node minus the flowrate out of the nodeis within the network tolerance

Enter userestimatesto reduce simulation time


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Import command

Well and flowline models built in the single branch

model can be easily imported into a network model to

form part of the field network

Data consistency

Time saving

Import by right clicking on a well or branch in the

network


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Operations

Check model

Checks boundary conditions

Run model

Runs network model using boundary specification

with estimates for unknowns

Restart model

Runs model using results from previous simulationas initial guessesfor next simulation.

Reduces simulation time significantly if only minorchanges are made to a model.


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Simulation results

Output report (.OUT)

Full output

List of iteration routine

Summary report (.SUM)

Summary report for each source and branch

Graphical output

PSPLOT

Concatenation

On screen output table

Main source/branch data


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Tips for large network models

1.Try to split the model into smaller networks, which can besolved independently, before linking them all together. (Thishelps trouble-shooting of the model)

2.When first building the model, leave out equipment such as

compressors and separators, then build them in one at atime. (Again this helps trouble-shooting)

3.Build all well models and branches containing equipmentitems in PIPESIM first. Run some sensitivity analyses tocheck they are behaving as expected.

4.Try to avoid unnecessary nodes in a network, this increasesthe computing time required to solve the network.


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If the sinks are flowrate specified, and are appearing consistently at

atmospheric pressure (see messages in engine window), try changing

the boundary condition to an outlet pressure to see what flowrate can

be achieved.

8. If minor changes have been made to a network such as flowrates, pipedimensions etc. the restart function should be used. However if

structural changes (i.e. new pipe, well deleted etc) have occurred then

the model should be run from scratch.

9. Before using the restart function, make a backup of the restart file

(*p00.rst) in the model folder. If the model fails to solve, the previousrestart file can be used to make another attempt.


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When first attempting to solve a large network, increase the

convergence tolerance to 5%, and check the validity of the results. If

necessary the tolerance can later be reduced and the model restarted.

If a branch appears to be behaving strangely or is ill conditioned, split it

into smaller segments. This will aid trouble-shooting and improve

continuity along the branch.

If the program crashes part way through an iteration with file open

errors or macopen errors, this is due to the processor running out of

memory. The model can simply be restarted and the program will start

from where it left off.

Documents

Day5 1 Network