flow assurance presentation - rune time i

7/27/2019 Flow Assurance Presentation - Rune Time I

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Multiphase flow Offshore Subsea Deepwater Long transportation (Near) Arctic

Scandpower Petroleum Technology

ro . une . me

De artment of Petroleum En ineerinUniversity of Stavanger

Seminar at Aker Solutions, Stavanger May 31st, 2011


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ut ine an time sc e u e

8.30 9.15 Flow regimes and impact on phase slippage,fluid concentrations and pressure drop in

9.25 10.15 Hydrates, wax and asphaltenes

10.25 -11.00 Multiphase flow influence from interfaces,

Seminar at Aker Solutions, Stavanger - May31st, 2011

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Flow re imes and im act on hase sli a e, fluid

concentrations and pressure drop in pipelines

GasQG

LiquidQL

Stratified liquid and gas is there a flow? How to decide? Some concepts are needed:

Fluid fractions Flow patterns ( regimes )


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QUIZ:

A simple(st) case of two-phase flow

Horizontal pipeline

Equal inflow

QL = QG

GasStabilizedinterface ?

3

1

qu

Any guideline principles?

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Basic uantities and definitions:- Superficial velocities and fluid fractions

uGqG

AGS

AG

uL

qL

ULS

qU LLS Mixture velocity :

qU GGS

GSLSmix UUU

LSL Uq Apparent liquid

L G LS GSq q U U Seminar at Aker Solutions, Stavanger - May31st, 2011

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Basic uantities and definitions:- True velocities and Slip

uGqG

A

AG

uL

qL

L

LL

Aqu

True (phase) velocities :

G

G

GA

u

LGS uuu

Gu

p ve oc y :

and

NOSLIP condition:

uL = uG = Umix

Lu


=

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Basic uantities and definitions:- True liquid fraction versus noslip fraction

uGqG

AGS

AG

uL

qL

ULS

True real volume fraction

LSL

L

UA

S = Slip ratioL GLS GSU U

S

LSL UqA arentL

L G LS GSq q U U

(noslip):Seminar at Aker Solutions, Stavanger - May31st, 2011

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True fraction noslip fraction (S = 1)as mixture velocity increases

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LSL

U

U U

Flow regime

S

ction

( Keeping constant

L SL

L S G S

U

U U

Segregated flows Mixed flowsLiquid

fr

Umix

0


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Flow regimes in horizontal pipesFlow d rect on

Stratified smoothflow (SS)

velo

city

Stratified wavyflow (SW)

Lo

yspeed

Elongated bubble

flow (EB)

ediatevel

oci

sing

flo

w

Slug flow (I)

Inter

Increa

Dispersed bubbleflow (DB)

ighvelocity

nnu ar wavyflow (A-AW)

H


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ow regime map orizonta pipes

10Dispersed bubble (DB)

Elongated Slug flow (I)

a e an u er 2.5 cm i.d. Pipeair-water flowat atmosphericconditions

LS

ms

u e ow

(EB/I)

Annular -annular wavy -

Mandhane

Stratified smoothflow (SS)

Flow direction

city

0.1annular mist flow

Stratified smooth

Stratifiedwavy

flow

Elongated bubbleflow (EB)

Slug flow (I)

Stratified wavyflow (SW)

Lowvelo

Intermediatevelocity

0.1 1 10 100

0.01

Dispersed bubbleflow (DB)

Annular (wavy)flow (A-AW)

I

Highvelocity

UGS

(m/s)


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Flow regimes and map vertical pipes

Flow regimes - typesFlow regime map

(small)

flow

Slug churnow


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Gas concentration profiles

GGas fraction

Pipe Up

Leads to vertical differences: Gas- liquid wetting (evt. water) Asymmetric corrosion (6oclock) Shear stress & Erosion rates Heat transfer rates


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Particle slurries in multiphase flow

D:\BACKUP 2009 - DET ASTRONOMISKE RET 2009\pent Hus 17mars09\Utvalg te high-


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Particle slurry regimes - dunes

Suspended particles in liqud


Rabenjafimantsoa and Time ( UIS) - project with Statoil 2000-2005

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Oil-water-gas flow regime map

http://www.iceweb.com.au

/Flow/multiphase_1.htm 15Seminar at AkerSolutions, Stavanger - May31st, 2011


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Importance of flow regimes

Much more than just flow appearance:

Field plan and development Multiphase simulation, pressure and fluid fraction determination Slip ratio and fluid transport rates in long pipelines

Decisive for quality of multiphase metering

Flow assurance, safety Process stability and control Pipeline and equipment vibration and fatigue Erosion

16Seminar at Aker Solutions, Stavanger - May31st, 2011


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The challenge of calculating

pressure drop in long traverses

T e pressure gra ient varies a ong t e pipedue to variation in pipe diameter, inclination

and mixture density (pressure dependent) outP

dl

P P P Pressure at exit:

in

ou n

Sum of pressure drop in all pipe segment

Challenge in multiphase flow: Thepressureprofile depends on thepressure!


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Robust homogeneous pressure drop model

for two-phase flow

12000Pressure gradient versus UGS for contant ULSUGS

x

6000

8000

10000

dient(Pa/m) Constant Uls= 3m/sConstant Uls= 3m/s

Total

ULS

Friction factor

2000

4000

Pressuregr

*2

m mix4 1(Re) U

2 f

dp fdx D

Friction :

0 5 10 15 20 25 30

Ugs (m/s)

m

h

dpg sin

dx

Hydrostatic:

mixmix

dUU

dxm

a

dp

dx

Acceleration:EXCEL


version18


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Two-phase pressure drop model Excel version

UGS Quantity Symbol Value Unit

LS as ens y rog g m

Liquid density rol 1000 kg/m 3

Kinematisk gas viscosity nyg 1,50E-06 m 2/s

Dynamic gas viscosity myg 1,50E-05 Pa*s

Liquid viscosity myl 3,00E-03 Pa*s

Pipe diameter D 1,50E-01 m

Pipe inclination 20,0 deg 3,49E-01 rad

Acceleration of gravity g 9,81E+00 m/s^2

Slipratio S 1,2 ,

Superficial gas velocity UGS 1,3 m/s

Mixture velocity Umix 4,8 m/s

Gas fraction epsg 0,236363636

Liquid fraction epsl 0,763636364

Mixture density rom 766 kg/m 3

Mixture viscosity mym 2,29E-03 Pa*s

Reynolds number Re 2,40E+05

Friction factor f 3,86E-03

2m mixRe U2

n

m

f

pC

dx D

m

dpg sin

Frictionpressuredrop dPdx_f 9,08E+02 Pa/mHydrostatic

pressure

drop dPdx_h 2,57E+03 Pa/m

Accelerationalpressuredrop dPdx_a Pa/mTotalpressuredrop dPdx 3,48E+03 Pa/m

mixmix

dUUdx

m

a

dpdx

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The World is Dynamic! need for Measurement

an ontro

-does not mean that the individual flowrates (G,L) are constant !

- Need for multiphase metering for survey and control !

Separation approachWeatherford

Mixing approachMPM

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flow assurance presentation - rune time i

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