9 replies to this topic

[DANA-IF]

Hi friends I was wondering if anyone could guide me through my problem .
I'm currently trying to do a simulation of a trunkline with pipesys . In reality , the provided document shows that the trunkline was simulated by olga software ans I have to confirm the results obtained from olga . unfortunately , The available software for me are hysys ( using pipesys ) and pipesim . I have added all the information needed in the elevation profile tab of pipesys ( distance and elevation of segments , dimensions , heat transfer , coating information ),
then I obtained an outlet pressure of 12 bar but it should be 7.9 bar as obtained from olga softaware .
N.B :- I used beggs and brill correlation on pipesys (outlet pressure = 12 bar )
- I used olgas (1992) correlation ( outlet pressure = 16 bar )
- when using beggs and brill original on pipesim, the outlet pressure = 16 bar 

Thanks

[Faisalmurad]

Usually Stoner Pipline Simulator ( SPS) of Global Noten & OLGA of SPT group could be used to simulate Cross Country pipelines.

SPS is used for Steady State & Transient Analysis. And Olga is used for multiphase flow, Condensate prediction and Slug Catcher sizing. 

 

What do you want to confirm from your simulation or in other words what is your purpose of simulation?

Edited by Faisalmurad, 28 May 2014 - 06:53 AM.

[DANA-IF]

Usually Stoner Pipline Simulator ( SPS) of Global Noten & OLGA of Flow Assurance could be used to simulate Cross Country pipelines.

SPS is used for Steady State & Transient Analysis. And Olga is used for two phase flow, Condensate prediction and Slug Catcher sizing. 

 

What do you want to confirm from your simulation or in other words what is your purpose of simulation?

the purpose of my simulation is to have an outlet pressure of 7.9bar as obtained by olga 

 

does olga correlation is different from beggs and brill correlation ?

Edited by NADIA BH, 28 May 2014 - 03:22 AM.

[DANA-IF]

the purpose of my simulation is to have an outlet pressure of 7.9bar as obtained by olga 

 

does olga correlation is different from beggs and brill correlation ?

[DANA-IF]

 

 

Edited by NADIA BH, 28 May 2014 - 03:26 AM.

[PaoloPemi]

you can't ask us to compare models withour providing detailed data

(i.e. elevations->predicted flow patterns and amounts of vapor and liquid phases),

those models have specific ranges of application and you need to know that,

for additional discussion on two phase flow see Coulson, Richardson or other textbooks,

according my experience (with a different software, PRODE), 

it may be useful to compare different methods (including Beggs & Brill where applicable)

on a specific application but differences are usually more limited (say about 20%)

[Erwin APRIANDI]

Hi NADIA BH,

 

You have said "In reality , the provided document shows that the trunkline was simulated by olga software ans I have to confirm the results obtained from olga"

OLGA is a dynamic multiphase flow simulation while the software that you are using to compare is a steady state hydraulics software which calculate the back pressure based on corelation.

 

Transient simulation with the OLGA simulator provides an added dimension to steady-state analyses by predicting system dynamics such as time-varying changes in flow rates, fluid compositions, temperature, solids deposition and operational changes.

 

So you can not compare it, since there will be a dynamics behaviour which is not considered in the steady state, and YES steady state will normally gives higher results with the same input.

[DANA-IF]

Hi NADIA BH,

 

You have said "In reality , the provided document shows that the trunkline was simulated by olga software ans I have to confirm the results obtained from olga"

OLGA is a dynamic multiphase flow simulation while the software that you are using to compare is a steady state hydraulics software which calculate the back pressure based on corelation.

 

Transient simulation with the OLGA simulator provides an added dimension to steady-state analyses by predicting system dynamics such as time-varying changes in flow rates, fluid compositions, temperature, solids deposition and operational changes.

 

So you can not compare it, since there will be a dynamics behaviour which is not considered in the steady state, and YES steady state will normally gives higher results with the same input.

Hi , in the flow assurance report , they said : steady state and dynamic multiphase flow simulations were performed with olga 7.2.2

[Bobby Strain]

I believe that OLGA has no equal. So, your best approach is to confirm that the simulation was performed correctly using the proper parameters. You will be wasting time to simply use another simulator when you already have results from the best available.

 

Bobby

[PaoloPemi]

NADIA-BH wrote

"in the flow assurance report , they said : steady state and dynamic multiphase flow simulations were performed with olga 7.2.2"

 

that's correct, on a specific state there should be no differences apart from those generated by different models (i.e. Beggs&Brill vs. Olga),

the differences reported in post #1 should be converted to % of dP and then evaluated,

for example with input pressure is 30 Bar

Case 1 (30Bar-16Bar) = 14 Bar

Case 2 (30Bar-7.9Bar) = 22.1 Bar

difference (22.1-14)/22.1 = 36%

which would be, in my opinion, high for those models when properly applied,

see also my previous post.