standard size for slug catcher 3

[nlpm]

I used PIPESIM to determine the volume of slug in pipeline but i want to know if there is standard size for slug catcher like standard size for pipeline or we use the volume of the slug as the size for slug catcher

 

[GregLamberson]

nlpm

You got it right, slug catchers will vary in size with the pipeline length and a variety of factors (gas/fluid densities, viscosities, flow rates, etc.). There is no "standard" size.

Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website:

http://www.oil-gas-consulting.com

 

[nlpm]

thanks, but may i couldn't display my question, the question is in pipeline size there is Nominal Pipe Size or National Pipe Size which i choose the pipe dimension from it , is the same thing in slug catcher

 

[GregLamberson]

nlpm

Appologies for the later return. You would size it (diameter, WT, grade) according to the design code. Nothing special or standard, same basis as your process piping.

Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website:

http://www.oil-gas-consulting.com

 

[dcasto]

You can make the slug catcher out of pipe, vessels, from standard fittings, or custom made forged pieces.

 

[nlpm]

dear dcasto

sorry i can't understand what you mean

 

[nlpm]

the slug catcher will be vertical

 

[dcasto]

Once you decide what volume you want to catch or recieve, then you can make the vessel from pieces of pipe, from a fabricated vessel, or from custom made forged material. This means, a ASME VIII
vessel could be used, forged fittings and pipe per B 31.3 could be used.

 

[nlpm]

thanks mr,

if the liquid swept in front of a pig = 290 bbl

what will be the slug cather size and how i can Calculate it?

 

[GregLamberson]

nlpm

If you are saying the 290 bbls is volume of liquid holdup in the line, then what you would do is take that volume and subtract the liquid flow rate and multiply that times the time for your pig to run (in days, i.e. if it takes 12 hours, then that is 0.5 days).

In your case, if the liquid hold up is 290 bbls, the liq flow rate is 75 bbls/day (example) and the pig run is 5 hours (example), then the slug catcher size would be 274 bbls.

Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website:

http://www.oil-gas-consulting.com

 

[GregLamberson]

nlpm

Just a clarification, it's probably clear by using the pig run time in days, but the liquid flow rate unit would be in bbls/day. That will allow the proper units to cancel out leaving bbls.

Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website:

http://www.oil-gas-consulting.com

 

[nlpm]

Thanks GregLamberson for your quick replay but i used pipesim in my calculation and according to pipesim the output will be :
-liquid hold up will be =450 bbl
- liquid swept in front of a pig ("liquid by sphere") = 290 bbl

That in case of the liq flow rate = 3900 bbl/day and big time = 3 hr

And if I apply the above method then the slug catcher size would be = 450-(3900*3/24) = ???

But I think pipesim program consider
liquid swept in front of a pig ("liquid by sphere") = slug catcher size
and I hope if you help me in that if you work with pipesim


Below is case study from pipesim manual , I understand from it that pipesim consider liquid swept in front of a pig ("liquid by sphere") =slug catcher size , is that right ?

===================================================
from pipesim manual
===========================================================

Task 6. Size a Slug Catcher
Having established that normal slug flow is expected, it is now necessary to size a slug catcher. The size will be determined by the largest of three design criteria:
1.The requirement to handle the largest slugs envisaged (chosen to be statistically the 1/1000 population slug size).
2.The requirement to handle liquid swept in front of a pig.
3.Transient effects, i.e. the requirement to handle the liquid slug generated when the production flow is ramped up from 5,000 to 10,000 STB/d.
This can be achieved as follows:
•Review the simulation output to establish the slug catcher volume required for each of the three design criteria and select the largest volume.
Review the output file and it can be seen that the turndown case generates larger slugs.

The 1/1000 slug length is 1,781.2 ft, which gives a slug volume of 971.5 ft3.
Now select the <reports/view summary> menu and check the liquid swept in front of a pig ("liquid by sphere").
Case no 1
Liquid hold up = 692 bbl liquid by sphere =279.113 bbl
Case no 1
Liquid hold up = 623 bbl liquid by sphere =264.113 bbl
It can be seen that the turndown case gives the larger volume of 279.1 bbl or 1,567 ft3.
Now calculate the liquid generated when the flow is ramped up from 5,000 STB/d to 10,000 STB/d. This is the difference in total holdup between the two cases, i.e. 692 - 623 = 69 bbl or 522 ft3.
Therefore the pigging volume of 1,567 ft3 (279.1 bbl) is the determining design case.
===========================================================
END
============================

 

[GregLamberson]

nlpm

Sorry, I do not work with pipesim. I find the liquid hold up/slug size versus the liquid flow rate to be odd, but I will have to defer to more learned colleagues.

Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website:

http://www.oil-gas-consulting.com

 

[nlpm]

very very thanks mr.GregLamberson for your time and effort.

I hope if any one work with pipesim can help me

 

[GregLamberson]

nlpm

I see no one has gotten back to you. Can you advise the following with regards to your system:
- pipe OD
- pipe wall thickness
- pipe length
- gas density
- liquid density
- gas viscosity
- liquid viscosity
- gas flow rate
- liquid flow rate
- gas mol wt

With the above I can calculate the liquid hold up and slug sizes and although I don't use pipesim, at least it will give you a comparison. FYI - I will use forumlas based on Perry's (pg 5-41).

Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website:

http://www.oil-gas-consulting.com

 

[nlpm]

very thanks Mr,GregLamberson

- pipe OD = 8 inches
- pipe wall thickness= .5 inches
- pipe length = 10.7 km
- gas S.G = 0.79
- Water S.G = 1.2
- API = 40
- GOR = 673 SCF/STB
- liquid flow rate = 3700 STB/d
-Water Cut 57.000 (%)
- Gas Flow Rate .......... 1.0707 (mmft3d)
and below the data used in pipesim calculation

===========================================================
Correlations and Options Selected :
---------------------------------

Solution Gas (RS) .............. LASATER
Gas Z-factor ................... Standing fit to Standing-Katz chart
Oil Formation Volume Factor .... Standing
Dead Oil Viscosity ............. Beggs & Robinson
Live Oil Viscosity ............. Chew & Connaly
Undersaturated Oil Viscosity ... Vasquez & Beggs
Liquid Viscosity Option ........ Set to oil viscosity below 60% watercut, set to water

viscosity above


Black Oil Calibration Data : Bubble Point Saturation Gas ... uncalibrated
Live oil FVF & Density ........ uncalibrated
Reservoir Density ............. uncalibrated
Reservoir FVF ................. uncalibrated
Gas Z-factor .................. uncalibrated
Gas Viscosity ................. uncalibrated
Live Oil Viscosity ............ uncalibrated
Dead Oil Viscosity ... 1.2514 cP) @ 200.0 (F) 14.70 (PSIA)
Dead Oil Viscosity ...14.666 (cP) @ 70.0 (F) 14.70 (PSIA)



Contaminants Data : (measured as a mole fraction of the gas phase at stock-tank

conditions)
-----------------

Mole fraction CO2 ............. .00000
Mole fraction H2S ............. .00000
Mole fraction N2 .............. .00000
Mole fraction H2 .............. .00000
Mole fraction CO .............. .00000


Stock-Tank Fluid Property and Rate Data :
---------------------------------------

Volume % Liquid ....... 1.9032 (%)
Mass % liquid ...... 94.946 (%)
Gas / Oil Ratio ...... 673.00 (scf/stb) Liquid / Gas Ratio .. 3455.5 (bbl/mmscf)
Water Cut ................ 57.000 (%) Oil / Gas Ratio ......... 1485.9 (bbl/mmscf)
Gas S.G. (air = ......... .79000 Gas / Liquid Ratio ........ 289.39 (scf/stb)
Water S.G. ............. 1.0200
Gas / Water Ratio ........ 507.70 (scf/stb)
Oil API Gravity ......... 40.000 Water / Gas Ratio ...... 1969.7 (bbl/mmscf)
Dead Oil Density ....... 51.508 (lb/ft3)

Fluid Heat Capacity Data :
------------------------
Oil CP ................ .45000 (Btu/lb/F)
Gas CP ................. .55000 (Btu/lb/F)
Water CP .............. 1.0000 (Btu/lb/F)


Fluid Thermal Conductivity Data :
-------------------------------
Oil Conductivity .......... .80000E-01 (btu/hr/ft/F)
Gas Conductivity ....... .20000E-01 (btu/hr/ft/F)
Water Conductivity ........ .35000 (btu/hr/ft/F)

Run Data :
--------
Gross Liquid Flow Rate .... 3700.0 (stb/d) Gas Flow Rate .............. 1.0707 (mmft3d)
Inlet Pressure ........... 149.65 (psia) Total Mass Flow Rate ........ 14.800 (lb/s)
Inlet Enthalpy ......... 60.243 (Btu/lb) Inlet Temperature ............. 77.000 (F)
 =========================================

 

[GregLamberson]

nlpm

Keep in mind, there are 3 basic causes of slugging - 1 pigging. 2 start up & blow down, and 3 transient conditions.

I have addressed only slugs by pigging. For slugs due to startup and blow-down, transient simulations should be used. And for slugging due to transient effects, a transient multiphase flow program should be used.

Based on what you gave me, for pigging, I calculate a 392 bbl slug. This is based on a liquid hold up of 802 bbls and a pigging time of 2.89 hours (based on an estimated gas/liquid velocity of 3.37 fps and 1.72 fps respectively).

As mentioned, I don't use pipesims and do not have access to any transient multiphase flow programs, just a basic Excel spreadsheet - so this is only an FYI.


Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website:

http://www.oil-gas-consulting.com

 

[nlpm]

Very thanks for quick replay

Are that mean that slug catcher size = 392 bbl = 62 m3

Or we use 392 bbl slug in others equations to calculate slug catcher size

thank you again

 

[GregLamberson]

nlpm

In my response above it would mean a slug catcher sized for 392 bbls - I owuld add a little contingency space to it.

You might do a site search for slug catchers if you have not already, there have been some previous discussions on some of the forums.

Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website:

http://www.oil-gas-consulting.com

 

[nlpm]

I do search on site (

http://eng-tips.com)for

slug catchers desgine and also search all internet web but i can not get acquired answer on how to desgine slug catcher.
if there is book or web site or procedure which i can use as guide in this subject i will be thankful.

also depend on the above slug catcher size = 392 bbls
i think it will be huge slug catcher, is this size acceptable to be installed on offshor platform or there is others more acceptable solution