5 replies to this topic

[hariz-process]

Simulation Basis:

HYSYS version = V10

EOS = (Peng-Robinson)

 

PIPESIM version = 2012.4

Pipeline Correlation = OLGAS 2014

Pipeline Friction Factor = 1.0

Pipeline Roughness = 0.04572 mm

 

Pipeline Basis:

Lets say:

Pipeline elevation = 75 m

Pipeline length = 10 km

ID = 247.6 mm

 

Process Input Basis:

Departing pressure = 30 Barg

Assume other values (e.g. materials) are defaulted & coating is negligible for simplicity.

The pipeline service is fully liquid (10-15% oil and 75-80% water).

 

Three mass flowrates (input) were used:

A - Minimum flow during Year 2050

B - Maximum during Year 2030

C - Arbitrary value.

 

C will be >> than B.

 

Using the dP Friction calculation (Darcy-Weisbach formula), dP ~ v^2.

 

The results:

Input A produces dP = 6 Bar

Input B produces dP = 1 Bar

Input C produces dP = >1 Bar (lets say 4 Bar)

 

If you plot out the results and compare it with Darcy's formula, you'll see that there is a region whereby the pressure drop is not governed by friction, instead the pressure drop decreases as the flow increases (opposite of Darcy's eqn).

 

My question:

What other possible parameter is affecting decrease of pressure drop when mass flow rate is increased (which corresponds to an increase in velocity).

 

My theory:

Is it head loss due to the vertical risers? Due to the low flow, there is a high static head in the pipeline especially due to the vertical risers.

 

Let me know if someone needs a TLDR version or any additional info.

 

Hope someone could help me out.

 

Cheers,

 

 

[horatorres]

Please  in order to get a better view

 

Provided Unit of the flow rate

 

Three mass flowrates (input) were used:

A - Minimum flow during Year 2050  ???

B - Maximum during Year 2030   ?????

C - Arbitrary value.

 

 

You said   Pipeline Friction Factor = 1.0         Where it comes from ???

 

however this paper explains the friction factor decrease, like in 2 phase oil gas flow.

 

https://www.witpress...CMEM060214f.pdf

 

 

Is a water-oil flow is an actual problem. On fiel you split the oil and water before sending the oil 10 km away.

 

Horacio

 

Horacio

Edited by horatorres, 03 June 2021 - 10:13 PM.

[hariz-process]

Please  in order to get a better view

 

Provided Unit of the flow rate

 

Three mass flowrates (input) were used:

A - Minimum flow during Year 2050  ???

B - Maximum during Year 2030   ?????

C - Arbitrary value.

 

 

You said   Pipeline Friction Factor = 1.0         Where it comes from ???

 

however this paper explains the friction factor decrease, like in 2 phase oil gas flow.

 

https://www.witpress...CMEM060214f.pdf

 

 

Is a water-oil flow is an actual problem. On fiel you split the oil and water before sending the oil 10 km away.

 

Horacio

 

Horacio

 

Thanks for the feedback Horacio

 

For clarity purposes:

Three mass flowrates (input) were used:

A - Minimum flow during Year 2050  5000 kg/h

B - Maximum during Year 2030   20000 kg/h

C - Arbitrary value. 40000 kg/h

 

The friction factor & roughness was agreed upon after field matching activities.

 

Thank you for the paper and I will give it a go and will report back my findings.

[hariz-process]

[Update]

 

After separating Oil and water, it is clear the oil is the main component for the inconsistent pressure drops.

 

The plug flow ( or in my case is OLGA Bubble Flow) exists at the vertical riser at the receiving end. Also at the receiving end there is significant lower velocity. The PIPESIM result i received is in agreement with the paper shared by @horatorres (Horacio).

 

However, the pipeline inclination is <0.1° (+0.41m inclination of pipeline bathymetry over a span of 10 km).

 

Need to further study this paper but let me know if there is any other theories that I can go through.

 

Rgds,

Hariz

[breizh]

Hi,

For you and others

Consider this link underneath  where you can download books related to multi-phase flow assurance .

http://www.drbratlan...flow-assurance/

 

 

Good luck

Breizh

[hariz-process]

Hi,

For you and others

Consider this link underneath  where you can download books related to multi-phase flow assurance .

http://www.drbratlan...flow-assurance/

 

 

Good luck

Breizh

 

Thanks Breizh. Will look into it.

 

Unfortunately, there is no definitive solution to this problem yet. I hope the thread could continue to open until then, as I would like as much theories as possible.

 

[Update] 14JUNE2021

 

The following parameters have been checked at the Pipeline Inlet:

1. Stream Viscosity

2. Stream Actual Volume

3. Pipeline Diameter

4. Pipeline Ambient Temperature

5. Stream Density

 

The main problem comes from the pseudo components. When replacing the pseudos with HYSYS Property Components, the pipeline works as intended (significantly lower pressure drop across pipeline).

 

The final activity is to check with ASPEN PIPESYS (ASPEN HYDRAULICS) and using a common flow correlation of TULSA 2/3Phase.

Edited by hariz-process, 14 June 2021 - 04:58 AM.