SimulationCore2/FluidFlow/Annulus_and_Openhole_Pressure_Distribution.f90

SUBROUTINE PressureAnnAndOHDistribution
    
    !!      Record of revisions
    !!          Date            Programmer          Discription of change
    !!         ------          ------------        -----------------------
    !!        1396/07/30        Sheikh              Original code
    !! 
    
    USE FricPressDropVars
    USE MudSystemVARIABLES
    USE PressureDisplayVARIABLES
    USE GeoElements_FluidModule
    USE Fluid_Flow_Startup_Vars
    USE KickVariables
    USE CMudPropertiesVariables
    USE TD_WellGeometry
    USE CReservoirVariables
    use MudSystemModule
    USE CHOKEVARIABLES
    USE CChokeManifoldVariables
    USE VARIABLES
    USE CError
    USE , INTRINSIC :: IEEE_ARITHMETIC

    
    IMPLICIT NONE
    
    INTEGER :: i , j , k , l
    INTEGER :: ifric
    REAL :: Fraction
    
    
    KBOP = 0.0
        

            
IF (WellHeadOpen .OR. NoGasPocket == 0) THEN    !! (mud circulation is normal wellhead may be open or closed) OR (kick is in the well and well head is open)
        
    
    !!!!!   Determining flow rate in each section
    i = AnnulusFirstEl
    j = OpenholeFirstEl - 1
        
    !!!!!!!!!!!!!!!!!!!!!!!!! flowrates due to external sources like pump and tripping
    !WRITE (*,*) 'MudSystem%StringFlowRate', MudSystem%StringFlowRate
    FlowEl(AnnulusFirstEl : OpenholeFirstEl - 1)%FlowRate = (ClingingFactor * FlowEl(AnnulusFirstEl : OpenholeFirstEl - 1)%Area + FlowEl(StringFirstEl)%Area) * DrillStringSpeed * ConvMintoSec * Convft3toUSgal     ! flowrate in annulus due to tripping
        
    FlowEl(AnnulusFirstEl : OpenholeFirstEl - 1)%FlowRate = FlowEl(AnnulusFirstEl : OpenholeFirstEl - 1)%FlowRate + REAL(MudSystem%MudVolume_InjectedToBH) * ConvMintoSec / dt       ! flowrate in annulus due to pump
    !WRITE (*,*) 'Drillstring speed (ft/s)' , FlowEl(j)%FlowRate
        
    !IF (NoWellToChokeEl > 0) THEN       ! flowrate in choke line
    !    FlowEl(NoHorizontalEl + NoStringEl + NoAnnulusEl + 1 : NoHorizontalEl + NoStringEl + NoAnnulusEl + NoWellToChokeEl)%FlowRate = MudSystem%AnnulusFlowRate + (DeltaVolumePipe * ConvMinToSec / dt)
    !END IF
                
    IF (MudSystem%ShoeFractured) THEN     ! reduction of flowrate due to formation fracture and lost circulation
            
        !WRITE (*,*) ' SHoe fractured', PressureGauges(5), FlowEl(ShoeFlowElNo)%FlowRate
        IF (ShoeFlowElNo > AnnulusLastEl) THEN      ! shoe is in openhole
            FlowEl(ShoeFlowElNo : NumbEl)%FlowRate = - MudSystem%Qlost
            FlowEl(AnnulusFirstEl : OpenholeFirstEl - 1)%FlowRate = FlowEl(AnnulusFirstEl : OpenholeFirstEl - 1)%FlowRate - MudSystem%Qlost
        ELSE        ! shoe is in annulus
            FlowEl(ShoeFlowElNo : OpenholeFirstEl - 1)%FlowRate = FlowEl(ShoeFlowElNo : OpenholeFirstEl - 1)%FlowRate - MudSystem%Qlost
        END IF
    END IF
        
        
    !!!!!!!!!!!!!!!!!!!!!!!!!
    !!!!!!!!!!!!!!!!!!!!!!!!! initial guess flowrates for opening BOP or choke line
    IF (WellHeadWasOpen == .FALSE. .AND. NoGasPocket > 0 .AND. KickIteration == 1) THEN
        IF (ChokeKroneckerDelta == 1) THEN      ! flow on choke line
            IF (TotalOpenChokeArea < 0.01 * Choke%ChokeAreaFullyOpen) THEN
                WRITE (*,*) 'density , TotalOpenChokeArea' , DownHole%Density, TotalOpenChokeArea
                TotalOpenChokeArea = 0.01 * Choke%ChokeAreaFullyOpen
            END IF
            Kchoke = (ChokeDensity / ((2.0 * 89158.0) * (0.26 * 0.61 * TotalOpenChokeArea)**2)) * 4.0    ! *4.d0: seyyed gofte
            GasPocketFlowInduced%Array(:) = MIN((0.6 / NoGasPocket * SQRT(PressureGauges(2) / Kchoke)) , (0.05 * GasPocketNewVol%Array(:) * ConvFt3toUSgal / 60 / dt))
            WRITE (*,*) ' PressureGauges(2) , Kchoke' , PressureGauges(2) , Kchoke
            WRITE (*,*) 'Initial guess after opening choke =', GasPocketFlowInduced%Array(1)
            
            WRITE (*,*) ' valve 49 ', Manifold%Valve(49)%Status
            WRITE (*,*) ' valve 47 ', Manifold%Valve(47)%Status
            WRITE (*,*) ' valve 26 ', Manifold%Valve(26)%Status
            WRITE (*,*) ' valve 30 ', Manifold%Valve(30)%Status
            WRITE (*,*) ' valve 34 ', Manifold%Valve(34)%Status
            WRITE (*,*) ' valve 63 ', Manifold%Valve(63)%Status
            WRITE (*,*) ' valve 28 ', Manifold%Valve(28)%Status
            WRITE (*,*) ' valve 33 ', Manifold%Valve(33)%Status
            WRITE (*,*) ' valve 62 ', Manifold%Valve(62)%Status
            WRITE (*,*) ' valve 36 ', Manifold%Valve(36)%Status
            WRITE (*,*) ' valve 38 ', Manifold%Valve(38)%Status
            
        ELSE        ! flow through bell nipple
            k = NoHorizontalEl + NoStringEl + NoAnnulusEl
            KBOP = FlowEl(AnnulusLastEl)%Density / ((2.0 * 89158.0) * (0.26 * 0.61 * ShearRam%MinimumOpenArea_InBOP)**2)
            GasPocketFlowInduced%Array(:) = MIN((0.1 / NoGasPocket * SQRT(PressureGauges(6) / KBOP)) , (0.05 * GasPocketNewVol%Array(:) * ConvFt3toUSgal / 60 / dt))
            WRITE (*,*) 'PressureGauges(6), KBOP', PressureGauges(6), KBOP
            WRITE (*,*) 'Initial guess after opening BOP =', GasPocketFlowInduced%Array(1)
        END IF
    END IF
        !!!!!!!!!!!!!!!!!!!!!!!!!
        
        !!!!!!!!!!!!!!!!!!!!!!!!! flowrates due to expansion of gas pockets or kick influx
        !i = AnnulusFirstEl
        !j = OpenholeFirstEl - 1
        IF (NoGasPocket > 0) THEN
            DO l = 1 , NoGasPocket          !GasPocketFlowEl
                k = GasPocketFlowEl(l , 1)
                !WRITE (*,*) 'GasPocketFlowEl(l , 1)', l, k, j
                IF (k == 0)     CALL ERRORSTOP('GasPocketFlowEl(l , 1) == 0', l)
               
                IF (k >= OpenholeFirstEl) THEN       ! gas pocket is in open hole only
                    FlowEl(k : NumbEl)%FlowRate = FlowEl(k : NumbEl)%FlowRate + GasPocketFlowInduced%Array(l)     ! openhole elements above pocket
                    FlowEl(AnnulusFirstEl : OpenholeFirstEl - 1)%FlowRate = FlowEl(AnnulusFirstEl : OpenholeFirstEl - 1)%FlowRate + GasPocketFlowInduced%Array(l)     ! annulus and choke line elements
                ELSE IF (k < OpenholeFirstEl) THEN       ! gas pocket is in annulus ond/or choke line only
                    FlowEl(k : OpenholeFirstEl - 1)%FlowRate =  FlowEl(k : OpenholeFirstEl - 1)%FlowRate + GasPocketFlowInduced%Array(l)     ! annulus or choke line elements above pocket
                END IF
            END DO
        END IF
        !IF (ChokeKroneckerDelta == 1 .AND. ABS(FlowEl(i + NoAnnulusEl)%FlowRate / 600.0 - Ann_Saved_MudDischarged_Volume_Final) > 0.05) THEN
        !    WRITE (*,*) 'Difference between flowrates', FlowEl(i + NoAnnulusEl + 1)%FlowRate / 600.0, Ann_Saved_MudDischarged_Volume_Final
        !END IF
        
        !!!!!!!!!!!!!!!!!!!!!!!!!
        !!!!!   END - Determining flow rate in each section
        
        !!!!!!!!!!!!!!!!!!!!!!!!! effect of surge and swab on frictional pressure drop direction
        DO l = AnnulusFirstEl , OpenholeFirstEl - 1
            IF (FlowEl(l)%FlowRate < 0.0) THEN
                FlowEl(l)%FrictionDirection = -1
                IF (FlowEl(l)%FlowRate > -1.0 * PressFlowrateTolerance .AND. ALLOCATED(GasPocketWeight%Array))      FlowEl(l)%FlowRate = - PressFlowrateTolerance
            ELSE
                FlowEl(l)%FrictionDirection = 1
                IF (FlowEl(l)%FlowRate < PressFlowrateTolerance .AND. ALLOCATED(GasPocketWeight%Array))             FlowEl(l)%FlowRate = PressFlowrateTolerance
            END IF
        END DO
        !!!!!!!!!!!!!!!!!!!!!!!!!

        !!!!!!!!!!!!!!!!!!!!!!!!! Calculating Back Pressure, in well to pit path back pressure = 0
                                ! in well to choke manifold path back pressure is equal to pressure before choke not casing pressure
        IF (ChokeKroneckerDelta == 1) THEN

            IF (FlowEl(OpenholeFirstEl - 1)%FlowRate < 0.0) THEN
                WRITE (*,*) ' Negative choke flowrate'
                FlowEl(OpenholeFirstEl - 1)%FlowRate = MAX((REAL(MudSystem%MudVolume_InjectedToBH) * ConvMintoSec / dt) , 10.0)
            END IF
            !Kchoke = ChokeDensity / ((2. * 89158.0) * (0.26 * 0.61 * TotalOpenChokeArea)**2)
            MudSystem%deltaPchoke = (Kchoke * FlowEl(OpenholeFirstEl - 1)%FlowRate * ABS(FlowEl(OpenholeFirstEl - 1)%FlowRate)) * 1.d0
            !WRITE (*,*) '**deltaPchoke , Kchoke, choke flowrate' , deltaPchoke , Kchoke, FlowEl(i)%FlowRate
            !WRITE (*,*) '**TotalOpenChokeArea , Total Open Choke Area Percent' , TotalOpenChokeArea , TotalOpenChokeArea / 4.0 * ChokeAreaFullyOpen
            IF (MudSystem%deltaPchoke < 0.d0)      MudSystem%deltaPchoke = 0.d0
            BackPressure = REAL(MudSystem%deltaPchoke)
            !WRITE (*,*) ' Choke inlet FlowRate, Density, pressure' , FlowEl(j)%FlowRate, FlowEl(j)%Density, FlowEl(j)%StartPress
            !WRITE (*,*) ' Choke outlet Density' , FlowEl(i)%Density
            !WRITE (*,*) ' deltaPchoke , choke flowrate' , deltaPchoke , FlowEl(i)%FlowRate
            !WRITE (*,*) 'Total Open Choke Area Percent' , TotalOpenChokeArea / 4.0 * ChokeAreaFullyOpen
        ELSE
            BackPressure = 0.0
        END IF
        IF (IEEE_IS_NaN(BackPressure))      CALL ErrorStop('NaN in calculating back pressure' , FlowEl(j)%FlowRate)
        !write(*,*) 'BackPressure=' , BackPressure
        
        !!!!!!!!!!!!!!!!!!!!!!!!! when flow passes through choke manifold, solution process may be unstable
        IF (ChokeKroneckerDelta == 1) THEN       ! thus we should stabilize solution
            IF (TotalOpenChokeArea > 0.5 * Choke%ChokeAreaFullyOpen) THEN
                KickCorrectionUnderRelaxation = 0.6     
            ELSE IF (TotalOpenChokeArea > 0.1 * Choke%ChokeAreaFullyOpen) THEN
                KickCorrectionUnderRelaxation = 0.5
            ELSE    ! TotalOpenChokeArea < 0.1 * ChokeAreaFullyOpen
                KickCorrectionUnderRelaxation = 0.4
            END IF
        ELSE
            KickCorrectionUnderRelaxation = 0.6
        END IF
        !!!!!!!!!!!!!!!!!!!!!!!!!
    
        !!!!!!!!!!!!!!!!!!!!!!!!!   calculating frictional pressure drop in annulus, chooke line and open hole elements
        DO ifric = AnnulusFirstEl , NumbEl
            CALL FricPressDrop(ifric)
            !WRITE (*,*) ' element No, FlowRate , Density, FricPressLoss', ifric, FlowEl(ifric)%FlowRate, FlowEl(ifric)%Density, FlowEl(ifric)%FricPressLoss
            IF (IEEE_IS_NaN(FlowEl(ifric)%FricPressLoss)) THEN
                WRITE (*,*) 'H, S, A, Ch, O', NoHorizontalEl , NoStringEl , NoAnnulusEl , NoWellToChokeEl , NoOpenHoleEl
                WRITE (*,*) 'Ann/Op start, end, density, Q, mu, Type' , FlowEl(ifric)%StartX, FlowEl(ifric)%EndX, FlowEl(ifric)%Density, FlowEl(ifric)%FlowRate, FlowEl(ifric)%mueff, FlowEl(ifric)%MaterialType
                CALL ErrorStop('NaN in calculating pressure drop' , ifric)
            END IF
        
        END DO
        !IF (ChokeKroneckerDelta == 1) THEN
            !WRITE (*,*) ' velocity and flowrate', FlowEl(i)%vel, FlowEl(i)%flowrate
            !WRITE (*,*) ' Theta600, Theta300', FlowEl(i)%Theta600 , FlowEl(i)%Theta300
            !WRITE (*,*) ' kIndex , nIndex', FlowEl(i)%kIndex, FlowEl(i)%nIndex
            !WRITE (*,*) ' last el. mueff, gen. Rey.', i, FlowEl(i)%mueff, FlowEl(i)%GenRe
        !END IF
        
        !!!!!!!!!!!!!!!!!!!!!!!!! Pressure distribution in annulus
        j = OpenholeFirstEl - 1
        FlowEl(OpenholeFirstEl - 1)%EndPress = BackPressure
        FlowEl(OpenholeFirstEl - 1)%StartPress = FlowEl(OpenholeFirstEl - 1)%EndPress + FlowEl(OpenholeFirstEl - 1)%FricPressLoss + FlowEl(OpenholeFirstEl - 1)%StaticPressDiff
        
        !write(*,*)   'FlowEl(j)%StartPress=' ,j, FlowEl(j)%StartPress
        !write(*,*)   'FlowEl(j)%Length=' ,j, FlowEl(j)%Length, FlowEl(j)%EndX
        !write(*,*)   'FlowEl(i)%dPdLFric=' ,i, FlowEl(i)%dPdLFric
                        
        DO l = OpenholeFirstEl - 2 , AnnulusFirstEl , -1
            !WRITE (*,*) '123'
            FlowEl(l)%EndPress = FlowEl(l + 1)%StartPress
            FlowEl(l)%StartPress = FlowEl(l)%EndPress + FlowEl(l)%FricPressLoss + FlowEl(l)%StaticPressDiff
            !WRITE(*,*) "ANNULUS: bottom , top Pressure", l , FlowEl(l)%StartPress , FlowEl(l)%EndPress , FlowEl(l)%fricPressLoss
            !WRITE(*,*) "ANNULUS: Start , End X", FlowEl(l)%StartX , FlowEl(l)%EndX

                    
        !write(*,*)   'FlowEl(i)%StartPress=' ,i, FlowEl(i)%StartPress
        !WRITE (*,*) ' FlowEl(i)%GenRe, FlowEl(i)%ReCritLam ' , FlowEl(i)%GenRe , FlowEl(i)%ReCritLam           
        END DO


        !!!!!!!!!!!!!!!!! Pressure distribution in Open Hole
        FlowEl(NumbEl)%EndPress = FlowEl(AnnulusFirstEl)%StartPress
        FlowEl(NumbEl)%StartPress = FlowEl(NumbEl)%EndPress + FlowEl(NumbEl)%FricPressLoss + FlowEl(NumbEl)%StaticPressDiff
        !WRITE (*,*) 'op top and op down' , FlowEl(NumbEl)%EndPress, FlowEl(j + 1)%StartPress
        !write(*,*) 'FlowEl(NumbEl)%dPdLFric=' , FlowEl(NumbEl)%dPdLFric
        !write(*,*) 'FlowEl(NumbEl)%dPdLGrav=' , FlowEl(NumbEl)%dPdLGrav
        
        DO l = NumbEl - 1 , OpenholeFirstEl , -1
                !WRITE(*,*) ' ope'
                FlowEl(l)%EndPress = FlowEl(l + 1)%StartPress
                !IF (FlowEl(i)%FlowRate < 0.0d0) THEN
                !    FlowEl(i)%StartPress = FlowEl(i)%EndPress - FlowEl(i)%FricPressLoss + FlowEl(i)%StaticPressDiff
                !ELSE
                FlowEl(l)%StartPress = FlowEl(l)%EndPress + FlowEl(l)%FricPressLoss + FlowEl(l)%StaticPressDiff
                !WRITE (*,*) ' Length, static, frictional open' , FlowEl(i)%Length, FlowEl(i)%StaticPressDiff, FlowEl(i)%FricPressLoss
                
                !END IF
        END DO

ELSE    ! wellhead is closed and kick is in the well
        !WRITE (*,*) ' well head is closed'
        k = GasPocketFlowEl(NoGasPocket , 1)
        !WRITE (*,*) 'k, Pocket Press', k, GasPocketOldPress%Array(NoGasPocket) - StandardPress
        i = AnnulusFirstEl
        j = OpenholeFirstEl - 1
        FlowEl(k)%StartPress = GasPocketOldPress%Array(NoGasPocket) - StandardPress
        FlowEl(k)%EndPress = GasPocketOldPress%Array(NoGasPocket) - StandardPress
        IF (k > OpenholeFirstEl - 1) THEN     ! Top pocket StartX is in Open hole
            !WRITE (*,*) 'here 1'
            DO l = k - 1 , OpenholeFirstEl , -1           ! below elements in openhole
                !WRITE (*,*) 'here 1-1'
                FlowEl(l)%EndPress = FlowEl(l + 1)%StartPress
                FlowEl(l)%StartPress = FlowEl(l)%EndPress + FlowEl(l)%StaticPressDiff
            END DO
            
            DO l = k + 1 , NumbEl                   ! Above elements in openhole
                !WRITE (*,*) 'here 1-2'
                FlowEl(l)%StartPress = FlowEl(l - 1)%EndPress
                FlowEl(l)%EndPress = FlowEl(l)%StartPress - FlowEl(l)%StaticPressDiff
            END DO
            
                FlowEl(AnnulusFirstEl)%StartPress = FlowEl(NumbEl)%EndPress
                FlowEl(AnnulusFirstEl)%EndPress = FlowEl(AnnulusFirstEl)%StartPress - FlowEl(AnnulusFirstEl)%StaticPressDiff
            
            DO l = AnnulusFirstEl + 1 , OpenholeFirstEl - 1
                FlowEl(l)%StartPress = FlowEl(l - 1)%EndPress
                FlowEl(l)%EndPress = FlowEl(l)%StartPress - FlowEl(l)%StaticPressDiff
            END DO
            
        ELSE        ! Top pocket StartX is in annulus or choke line
            
            DO l = k - 1 , AnnulusFirstEl , -1           ! below elements in annnulus
                FlowEl(l)%EndPress = FlowEl(l + 1)%StartPress
                FlowEl(l)%StartPress = FlowEl(l)%EndPress + FlowEl(l)%StaticPressDiff
            END DO
            
            DO l = k + 1 , OpenholeFirstEl - 1                   ! Above elements in annulus
                FlowEl(l)%StartPress = FlowEl(l - 1)%EndPress
                FlowEl(l)%EndPress = FlowEl(l)%StartPress - FlowEl(l)%StaticPressDiff
            END DO
            
                FlowEl(NumbEl)%EndPress = FlowEl(AnnulusFirstEl)%StartPress
                FlowEl(NumbEl)%StartPress = FlowEl(NumbEl)%EndPress + FlowEl(NumbEl)%StaticPressDiff
            
            DO l = NumbEl - 1 , OpenholeFirstEl , -1
                FlowEl(l)%EndPress = FlowEl(l + 1)%StartPress
                FlowEl(l)%StartPress = FlowEl(l)%EndPress + FlowEl(l)%StaticPressDiff
            END DO
            
        END IF
        
        !
        !    !WRITE (*,*) ' first annulus bottom pressure ' , FlowEl(NoHorizontalEl + NoStringEl + 1)%StartPress
        !    !WRITE (*,*) ' last OpenHole bottom pressure' , FlowEl(NumbEl)%StartPress
        !    !WRITE (*,*) ' Gas Pocket pressure' , GasPocket%NewPress
END IF

    !!!!!!!!!!!!!!!!!!!!!! checking pressure for preventing NaN in pressures
    DO l = OpenholeFirstEl - 1 , AnnulusFirstEl , -1        ! annulus or choke elements
        !WRITE (*,*) 'start, end' , FlowEl(i)%StartX, FlowEl(i)%EndX
        IF (IEEE_IS_NaN(FlowEl(l)%EndPress)) THEN
            WRITE (*,*) 'H, S, A, Ch, O', NoHorizontalEl , NoStringEl , NoAnnulusEl , NoWellToChokeEl , NoOpenHoleEl
            WRITE (*,*) 'Ann/Ch start, end, density, Q, mu' , FlowEl(l)%StartX, FlowEl(l)%EndX, FlowEl(l)%Density, FlowEl(l)%FlowRate, FlowEl(l)%mueff, FlowEl(l)%MaterialType
            CALL ERRORSTOP('NaN in EndPress', l)
        END IF
    END DO

    DO l = NumbEl , OpenholeFirstEl - 1 , -1         ! op elements
        !WRITE (*,*) 'start, end' , FlowEl(i)%StartX, FlowEl(i)%EndX
        IF (IEEE_IS_NaN(FlowEl(l)%EndPress)) THEN
            WRITE (*,*) 'H, S, A, Ch, O', NoHorizontalEl , NoStringEl , NoAnnulusEl , NoWellToChokeEl , NoOpenHoleEl
            WRITE (*,*) 'Op start, end, density, Q, mu' , FlowEl(l)%StartX, FlowEl(l)%EndX, FlowEl(l)%Density, FlowEl(l)%FlowRate, FlowEl(l)%mueff, FlowEl(l)%MaterialType
            CALL ERRORSTOP('NaN in EndPress', l)
        END IF
    END DO
    !!!!!!!!!!!!!!!!!!!!!!
    
    !!!!!!!!!!!!!!!!!!!!!!
    BottomHolePress = FlowEl(OpenholeFirstEl)%StartPress
    !DO i = 1 , NoGasPocket
    !    WRITE (*,*) ' Pocket, Pressure, Vol, Flow Induced, FlowElPress', i, REAL(GasPocketNewPress%Array(i)), REAL(GasPocketNewVol%Array(i)), GasPocketFlowInduced%Array(i), FlowEl(GasPocketFlowEl(i , 1))%StartPress
    !END DO
        !WRITE (*,*) ' BottomHolePress =' , BottomHolePress
    !!!!!!!!!!!!!!!!!!!!!!
    !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
    !IF (ChokeKroneckerDelta == 1) THEN
    !    WRITE (*,*) ' ChokeLine flowrate' , FlowEl(NoHorizontalEl + NoStringEl + NoAnnulusEl + NoWellToChokeEl)%FlowRate , MudSystem%StringFlowRate
    !    !i = NoHorizontalEl + NoStringEl + NoAnnulusEl
    !    !j = NoHorizontalEl + NoStringEl + NoAnnulusEl + NoWellToChokeEl
    !    !WRITE (*,*) ' Well Outlet and Chokeline Outlet Pressure' , FlowEl(i)%EndPress, FlowEl(j)%EndPress
    !END IF
    
    !IF (GasPocket%ElementNo == 0) THEN
    !    KickUnknownVector(2) = BottomHolePress
    !!ELSE
    !!    KickUnknownVector(2) = FlowEl(GasPocket%ElementNo)%StartPress
    !END IF
    !IF (WellHeadOpen)
    !    GasPocket%NewPress = KickUnknownVector(2)
    !END IF
    !WRITE (*,*) 'Ann End'
END SUBROUTINE