SUBROUTINE FlowStartup
    
    USE Fluid_Flow_Startup_Vars
    USE CStringConfigurationVariables
    USE CMudPropertiesVariables
    USE FricPressDropVars
    USE KickVariables
    USE MudSystemVARIABLES
    USE PressureDisplayVARIABLES
    USE CShoeVariables
    USE TD_DrillStemComponents
    USE TD_WellGeometry, pi3 => pi
    USE CPathGenerationVariables
    USE CWellSurveyDataVariables
    Use CHOKEVARIABLES, pi4 => pi
    

    IMPLICIT NONE
    
    INTEGER :: i
    
    PressureGauges(:) = 0.0
    
    KickSinglePocket = Reservoir%MakeKickSinglePacket
    IF (KickSinglePocket) THEN
        MaxGasPocket = 1
    ELSE
        MaxGasPocket = 4
    END IF
    MaxChokeDensityChange = 25.0     ! [ppg/min]
    ChokeMinDensity = 2.0

    ChokeDensity = MudProperties%ActiveDensity
    
    MinKickVol = 0.5            ! USGal
    
    SecondaryKickVol = 0.0
    SecondaryKickWeight = 0.0
    
    NoGasPocket = 0                 ! No Kick
    WellHeadOpen = .TRUE.
    WellHeadWasOpen = .TRUE.
    BackPressure = 0.0
    GasKickPumpFlowRate = 0.0
    DownHole%KickVolume = 0.0
    DownHole%InfluxRate = 0.0
    ExitMass = 0.0
    MinAllowableKickVol = 1.0 * (42.0 / Convft3toUSgal)      ! 1 bbl * 42 gal/bbl / 7.48 gal/ft^3 = ... ft^3
    StCompressedMudVol = 0.0
    AnnCompressedMudVol = 0.0
    KickFlux = .FALSE.
    KickOffBottom = .FALSE.
    KickWasExitingThroughChoke = .FALSE.
    FloatValveOpen = .TRUE.
    
    Choke%ChokeAreaFullyOpen = 123.0 / 64.0     ! fully open area is 123/64 in^2 = 0.01334635 ft^2
    ChokeBypassArea = PI / 4.0 * BopStackSpecification%ChokeLineId**2
    BHPSafetyMargin = 150.0
    AChBHPTol = 15.0
    
    
    ManChoke1Plug = 0
    ManChoke2Plug = 0
    ManChoke1Washout = 0
    ManChoke2Washout = 0
    BitJetsPlugged = 0
    BitJetsWashedOut = 0
    CasingPressure_DataDisplayMalF = 0
    
    SoundSpeed = 1530.0 / Convfttom
    PressureTimeStepDelay(1) = INT(2.0 * SUM(StringConfiguration%StringConfigurations(2:)%ComponentLength) / SoundSpeed / dt)
    PressureTimeStepDelay(2) = INT(PathGeneration%Items(SIZE(PathGeneration%Items))%MeasuredDepth / SoundSpeed / dt)
    PressureTimeStepDelay(3) = INT(Shoe%ShoeDepth / SoundSpeed / dt)
    
    !WRITE (*,*) SUM(StringConfigurations(2:)%ComponentLength), PathGenerations(SIZE(PathGenerations))%TotalVerticalDepth!, WellSurveyData(SIZE(WellSurveyData))%TotalVerticalDepth
    !WRITE (*,*) PathGenerations(SIZE(PathGenerations))%MeasuredDepth!, WellSurveyData(SIZE(WellSurveyData))%MeasuredDepth
    WRITE (*,*) 'time step delay', PressureTimeStepDelay
    
    DO i = 1 , PressureTimeStepDelay(1)
        CALL PumpPressureDelay%AddToFirst(0.0)
    END DO
    
    DO i = 1 , PressureTimeStepDelay(2)
        CALL BottomHolePressureDelay%AddToFirst(REAL(0.052 * MudProperties%ActiveDensity * PathGeneration%Items(SIZE(PathGeneration%Items))%TotalVerticalDepth))
    END DO
    
    DO i = 1 , PressureTimeStepDelay(3)
        CALL ShoePressureDelay%AddToFirst(REAL(0.052 * MudProperties%ActiveDensity * Shoe%ShoeDepth))
    END DO
        
    
    !!!!!!! Methane Information
    GasType(1)%CritPress = 673.0
    GasType(1)%CritTemp = 344.0
    GasType(1)%MolarWt = 16.04
    GasType(1)%StDensity = 0.04238
    GasType(1)%GasConstant = RUniversal / GasType(1)%MolarWt
    
    !!!!!!!! H2S Information
    GasType(2)%CritPress = 1306.0
    GasType(2)%CritTemp = 673.0
    GasType(2)%MolarWt = 34.08
    GasType(2)%StDensity = 0.09087
    GasType(2)%GasConstant = RUniversal / GasType(2)%MolarWt

    !!!!!!!! CO2 Information
    GasType(3)%CritPress = 1072.0
    GasType(3)%CritTemp = 548.0
    GasType(3)%MolarWt = 44.01
    !GasType(3)%StDensity = 00
    GasType(3)%GasConstant = RUniversal / GasType(2)%MolarWt

    !!!!!!!! Mud density and viscosity
    Theta600Refrence = MudProperties%ActiveThetaSixHundred
    Theta300Refrence = MudProperties%ActiveThetaThreeHundred
    DensityRefrence = MudProperties%ActiveDensity
    
    END SUBROUTINE