Flow Assurance and Multiphase flow - part 1 By Prof ... - Aker Solutions
Flow Assurance and Multiphase flow - part 1 By Prof ... - Aker Solutions
Flow Assurance and Multiphase flow - part 1 By Prof ... - Aker Solutions
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
<strong>Flow</strong> <strong>Assurance</strong> <strong>and</strong> <strong>Multiphase</strong> <strong>flow</strong>• <strong>Multiphase</strong> <strong>flow</strong>• Offshore• Subsea• Deepwater• Long transportation• (Near) ArcticSc<strong>and</strong>power Petroleum Technology<strong>Prof</strong>. Rune W. TimeDe<strong>part</strong>ment of Petroleum EngineeringgUniversity of StavangerSeminar at <strong>Aker</strong> <strong>Solutions</strong>, Stavanger – May 31st, 2011
Outline <strong>and</strong> time schedule8.30 – 9.15 <strong>Flow</strong> regimes <strong>and</strong> impact on phase slippage,fluid concentrations <strong>and</strong> pressure drop inpipelines9.25 – 10.15 Hydrates, wax <strong>and</strong> asphaltenes10.25 -11.00 <strong>Multiphase</strong> <strong>flow</strong> – influence from interfaces,compression effects <strong>and</strong> wavesSeminar at <strong>Aker</strong> <strong>Solutions</strong>, Stavanger - May31st, 20112
<strong>Flow</strong> regimes <strong>and</strong> impact on phase slippage, fluidconcentrations <strong>and</strong> pressure drop in pipelinesTransparent pipeQ GGasQ LLiquid• Stratified liquid <strong>and</strong> gas – is there a <strong>flow</strong>? How to decide?• Some concepts are needed:• <strong>Flow</strong> speeds• Fluid fractions• <strong>Flow</strong> patterns (”regimes”)Seminar at <strong>Aker</strong> <strong>Solutions</strong>, Stavanger - May31st, 20113
QUIZ:A simple(st) case of two-phase <strong>flow</strong>Equal in<strong>flow</strong>Q L = Q GGasLiquidHorizontal pipeline312Stabilizedinterface ?• How to decide?• Any guideline principles?4
Basic quantities <strong>and</strong> definitions:- Superficial velocities <strong>and</strong> fluid fractionsq GU GSu GAu Lq LU LSSuperficial velocities :UULSqLAqAA LA GMixture velocity :U U U mix LS GSGGSApparent liquidfraction (”noslip”):qLULSL q q U UL G LS GSSeminar at <strong>Aker</strong> <strong>Solutions</strong>, Stavanger - May31st, 20115
Basic quantities <strong>and</strong> definitions:- True velocities <strong>and</strong> Slipq Gu GAu LA Lq LA GTrue (phase) velocities :uuLGqAqALLGGSlip velocity :uSuGuLNOSLIP condition:<strong>and</strong>u L = u G = U mixSlip ratio :S S=1u Gu LSeminar at <strong>Aker</strong> <strong>Solutions</strong>, Stavanger - May31st, 20116
Basic quantities <strong>and</strong> definitions:- True liquid fraction versus noslip fractionq GU GSu GAu LA Lq LU LSA GTrue (real) volume fractionApparent(”noslip”): LALALAGULSq LU LSL q q U UULS1 USL G LS GSGSSeminar at <strong>Aker</strong> <strong>Solutions</strong>, Stavanger - May31st, 2011S = Slip ratio7
True fraction versus mixture velocityTrue fraction noslip fraction (S = 1)as mixture velocity increasesULSL11 U ULS<strong>Flow</strong> regimeGSS dependence !Liquid fra actionSegregated g <strong>flow</strong>s( Keeping constantratio U LS /U GS )Mixed <strong>flow</strong>sLUULS ULSGS0U mixSeminar at <strong>Aker</strong> <strong>Solutions</strong>, Stavanger - May31st, 20118
<strong>Flow</strong> regimes in horizontal pipes<strong>Flow</strong> directionspeedIncreas sing <strong>flow</strong>LowvelocityInterm mediate velocit tyStratified smooth<strong>flow</strong> (SS)Stratified wavy<strong>flow</strong> (SW)Elongated bubble<strong>flow</strong> (EB)Slug <strong>flow</strong> (I)igh velocityHiSeminar at <strong>Aker</strong> <strong>Solutions</strong>, Stavanger - May31st, 2011Dispersed bubble<strong>flow</strong> (DB)Annular (wavy)<strong>flow</strong> (A-AW)9
I<strong>Flow</strong> regime map – horizontal pipesU LS (m/s)10Elongated1 bubble bbl <strong>flow</strong>(EB/I)0.1Dispersed bubble (DB)Slug <strong>flow</strong> (I)StratifiedwavyStratified smooth <strong>flow</strong><strong>flow</strong> (SS) (SW)Annular -annular wavy -annular mist <strong>flow</strong>Low veloc cityIntermediate velocityTaitel <strong>and</strong> Dukler2.5 cm i.d. Pipeair-water <strong>flow</strong>at atmosphericconditionsM<strong>and</strong>hane<strong>Flow</strong> directionStratified smooth<strong>flow</strong> (SS)Stratified wavy<strong>flow</strong> (SW)Elongated bubble<strong>flow</strong> (EB)Slug <strong>flow</strong> (I)0.01High velocityDispersed bubble<strong>flow</strong> (DB)Annular (wavy)<strong>flow</strong> (A-AW)0.1 1 10 100U GS (m/s)Seminar at <strong>Aker</strong> <strong>Solutions</strong>, Stavanger - May31st, 201110
<strong>Flow</strong> regimes <strong>and</strong> map – vertical pipes<strong>Flow</strong> regime map<strong>Flow</strong> regimes - typesDispersed bubbles(small)Annular<strong>flow</strong>Slug –<strong>flow</strong>churnSeminar at <strong>Aker</strong> <strong>Solutions</strong>, Stavanger - May31st, 201111
Gas – concentration profilesSnapshot of dispersed bubble <strong>flow</strong>PipeGas fraction GUpLeads to vertical differences:• Gas- liquid wetting (evt. water)• Asymmetric corrosion (”6’oclock”)• Shear stress & Erosion rates• Heat transfer ratesSeminar at <strong>Aker</strong> <strong>Solutions</strong>, Stavanger - May31st, 201112
Particle slurries in multiphase <strong>flow</strong>Large gas bubbleD:\BACKUP 2009 - DET ASTRONOMISKE ÅRET 2009\Åpent Hus 17mars09\Utvalgte high-speed videoer\ Water speed 1Seminar at <strong>Aker</strong> <strong>Solutions</strong>, Stavanger - May31st, 201113
Particle slurry regimes - dunesSuspended <strong>part</strong>icles in liqud<strong>Flow</strong>DunesRabenjafimantsoa <strong>and</strong> Time ( UIS) - project with Statoil 2000-2005Seminar at <strong>Aker</strong> <strong>Solutions</strong>, Stavanger - May31st, 201114
Oil-water-gas <strong>flow</strong> regime mapREF:http://www.iceweb.com.au/<strong>Flow</strong>/multiphase_1.htmSeminar at <strong>Aker</strong> <strong>Solutions</strong>, Stavanger - May31st, 201115
Importance of <strong>flow</strong> regimesMuch more than just ”<strong>flow</strong> appearance”:Field plan <strong>and</strong> development• <strong>Multiphase</strong> simulation, pressure <strong>and</strong> fluid fraction determination• Slip ratio <strong>and</strong> fluid transport rates in long pipelines• <strong>Multiphase</strong> pumping• Decisive for quality of multiphase metering<strong>Flow</strong> assurance, safety• Process stability <strong>and</strong> control• Pipeline <strong>and</strong> equipment vibration <strong>and</strong> fatigue• Erosion• CorrosionSeminar at <strong>Aker</strong> <strong>Solutions</strong>, Stavanger - May31st, 201116
The challenge of calculatingpressure drop in long traversesThe pressure gradient varies along the pipedue to variation in pipe diameter, inclination<strong>and</strong> mixture density (pressure dependent)PoutP indlPressure at exit:P P PoutinSum of pressure drop in all pipe segmentChallenge in multiphase <strong>flow</strong>:• The pressure profile depends on the pressure!• Requires iterative numerical solver17Seminar at <strong>Aker</strong> <strong>Solutions</strong>, Stavanger - May31st, 2011
Robust – ”homogeneous” pressure drop modelfor two-phase <strong>flow</strong>xU GSPressure gradient versus UGS for contant ULS12000U LSFriction :dp dx fFriction factor4 1 f (Re) mUD 22mix*Pressure gra adient (Pa/m)100008000600040002000Constant Uls= 3m/sTotalHydrostatic: dp mg sin dxh00 5 10 15 20 25 30Ugs (m/s)Acceleration:dp dU m UmixdxdxamixSeminar at <strong>Aker</strong> <strong>Solutions</strong>, Stavanger - May31st, 2011EXCELversion18
Two-phase pressure drop model – Excel versionU GSU LSQuantity Symbol Value UnitGas density rog 10 kg/m^3Liquid density rol 1000 kg/m^3Kinematisk gas viscosity nyg 1,50E-06 m^2/sDynamic gas viscosity myg 1,50E-05 Pa*sLiquid viscosity myl 3,00E-03 Pa*sPipe diameter D 1,50E-01 mPipe inclination 20,0 deg 3,49E-01 radAcceleration of gravity g 9,81E+00 m/s^2Slip ratio S 1,2Superficial liquid velocity ULS 35m/s 3,5 Superficial gas velocity UGS 1,3 m/sMixture velocity Umix 4,8 m/sGas fraction epsg 0,236363636Liquid fraction epsl 0,763636364 dp 4 n12Mixture density rom 766 kg/m^3 C Re m mUmixdx D2Mixture viscosity mym 2,29E-03 Pa*s f dp mg sin dxhdp dU m UmixdxdxamixReynolds number Re 2,40E+05Friction factor f 3,86E-03Friction pressure drop dPdx_f 9,08E+02 Pa/mHydrostatic pressure drop dPdx_h 2,57E+03 Pa/mAccelerational pressure drop dPdx_a Pa/mTotal pressure drop dPdx 3,48E+03 Pa/m19
The World is Dynamic! – need for Measurement<strong>and</strong> Control- Even constant in<strong>flow</strong> of multiphase <strong>flow</strong> mixtures into pipelinedoes not mean that the individual <strong>flow</strong>rates (G,L) are constant !- Need for multiphase metering for survey <strong>and</strong> control !Separation approachWeatherfordMixing approachMPM20
Change language