SimulationCore2/Equipments/MudSystem/Utube2_and_Trip_In.f90

SUBROUTINE Utube2_and_TripIn    !  is called in subroutine CirculationCodeSelect        annulus to string
    
        Use UTUBEVARS
        Use GeoElements_FluidModule
        USE CMudPropertiesVariables
        USE MudSystemVARIABLES
        USE Pump_VARIABLES
        use CDrillWatchVariables
        use CTanksVariables, TripTankVolume2 => TripTankVolume, TripTankDensity2 => TripTankDensity
        Use CShoeVariables
 
   implicit none
   
    write(*,*) 'Utube2 code'
    
!===========================================================WELL============================================================
!===========================================================WELL============================================================ 
    
        UtubeMode2Activated= .true.
        write(*,*) 'QUtubeOutput=' , QUtubeOutput
        !QUTubeInput=5000.
        StringFlowRate= QUtubeOutput        ! (gpm)
        AnnulusFlowRate= QUtubeOutput
        StringFlowRateFinal= StringFlowRate
        AnnulusFlowRateFinal= AnnulusFlowRate
!=========================================== 
       
        if (FirstSetUtube2==0) then
        !    call St_MudDischarged_Volume%AddToFirst (REAL(sum(F_Interval(1:F_StringIntervalCounts)%Volume)))  !startup initial
        !    call St_Mud_Backhead_X%AddToFirst (Xstart_PipeSection(1))
        !    call St_Mud_Backhead_section%AddToFirst (1)
        !    call St_Mud_Forehead_X%AddToFirst (Xend_PipeSection(F_StringIntervalCounts))
        !    call St_Mud_Forehead_section%AddToFirst (F_StringIntervalCounts)
        !    call St_Density%AddToFirst (REAL(ActiveDensity))       ! initial(ppg)
        !    call St_RemainedVolume_in_LastSection%AddToFirst (0.0d0)
        !    call St_EmptyVolume_inBackheadLocation%AddToFirst (0.0d0)
        !        
        !    call Ann_MudDischarged_Volume%AddToFirst (REAL(sum(F_Interval((F_StringIntervalCounts+F_BottomHoleIntervalCounts+1):F_IntervalsTotalCounts)%Volume)))  !startup initial
        !    call Ann_Mud_Backhead_X%AddToFirst (Xstart_PipeSection(F_StringIntervalCounts+1))
        !    call Ann_Mud_Backhead_section%AddToFirst (F_StringIntervalCounts+1)
        !    call Ann_Mud_Forehead_X%AddToFirst (Xend_PipeSection(NoPipeSections))
        !    call Ann_Mud_Forehead_section%AddToFirst (NoPipeSections)
        !    call Ann_Density%AddToFirst (REAL(ActiveDensity))       ! initial(ppg)
        !    call Ann_RemainedVolume_in_LastSection%AddToFirst (0.0d0)
        !    call Ann_EmptyVolume_inBackheadLocation%AddToFirst (0.0d0)
             !Hz_Density%Array(:)= 0.0
             !Hz_MudOrKick%Array(:)= 104
             
             Hz_Density_Utube= 0.0
             Hz_MudOrKick_Utube= 104
             
            FirstSetUtube2= 1
        endif

        
        
        
!========================Horizontal PIPE ENTRANCE================= 
        
         !if (SuctionDensity_Old >= (ActiveDensity+0.05) .or. SuctionDensity_Old <= (ActiveDensity-0.05)) then     ! new mud is pumped
         !   !ImudCount= ImudCount+1
         !   !SuctionMud= ImudCount
         !   call Hz_Density%AddToFirst (REAL(ActiveDensity))     !ActiveDensity : badan in moteghayer bayad avaz beshe
         !   call Hz_MudDischarged_Volume%AddToFirst (0.0d0)
         !   call Hz_Mud_Forehead_X%AddToFirst (Xstart_PipeSection(1))
         !   call Hz_Mud_Forehead_section%AddToFirst (1)
         !   call Hz_Mud_Backhead_X%AddToFirst (Xstart_PipeSection(1))
         !   call Hz_Mud_Backhead_section%AddToFirst (1)
         !   call Hz_RemainedVolume_in_LastSection%AddToFirst (0.0d0)
         !   call Hz_EmptyVolume_inBackheadLocation%AddToFirst (0.0d0)
         !   call Hz_MudOrKick%AddToFirst (0)  
        
         !   deltaV= 0.
         !    
         !    SuctionDensity_Old= ActiveDensity
         !endif

!========================Horizontal PIPE STRING================= 
        
        !commented

!                Hz_MudDischarged_Volume%Array(1)= Hz_MudDischarged_Volume%Array(1)+ ((StringFlowRate/60.)*DeltaT_Mudline)    !(gal)
!         
!imud=0                               
!    do while (imud < Hz_Mud_Forehead_X%Length())
!        imud = imud + 1               
!        
!            if (imud> 1) then
!                Hz_Mud_Backhead_X%Array(imud)= Hz_Mud_Forehead_X%Array(imud-1)
!                Hz_Mud_Backhead_section%Array(imud)= Hz_Mud_Forehead_section%Array(imud-1)
!            endif
!            
!                
!            DirectionCoef= (Xend_PipeSection(Hz_Mud_Backhead_section%Array(imud))-Xstart_PipeSection(Hz_Mud_Backhead_section%Array(imud))) &
!                / ABS(Xend_PipeSection(Hz_Mud_Backhead_section%Array(imud))-Xstart_PipeSection(Hz_Mud_Backhead_section%Array(imud)))
!            ! +1 for string  ,   -1 for annulus
!                
!                                                                                                                    
!            Hz_EmptyVolume_inBackheadLocation%Array(imud)= DirectionCoef* (Xend_PipeSection(Hz_Mud_Backhead_section%Array(imud))- Hz_Mud_Backhead_X%Array(imud))* &
!                Area_PipeSectionFt(Hz_Mud_Backhead_section%Array(imud)) !(ft^3)          
!            Hz_EmptyVolume_inBackheadLocation%Array(imud)= Hz_EmptyVolume_inBackheadLocation%Array(imud)* 7.48051948        ! ft^3  to gal
!            
!
!            if ( Hz_MudDischarged_Volume%Array(imud) <= Hz_EmptyVolume_inBackheadLocation%Array(imud)) then
!                Hz_Mud_Forehead_section%Array(imud)= Hz_Mud_Backhead_section%Array(imud)
!                Hz_Mud_Forehead_X%Array(imud)= Hz_Mud_Backhead_X%Array(imud)+ DirectionCoef*(Hz_MudDischarged_Volume%Array(imud)/7.48051948)/Area_PipeSectionFt(Hz_Mud_Backhead_section%Array(imud))
!                                                                            !   7.48051948 is for gal to ft^3
!            else
!                    
!                isection= Hz_Mud_Backhead_section%Array(imud)+1
!                Hz_RemainedVolume_in_LastSection%Array(imud)= Hz_MudDischarged_Volume%Array(imud)- Hz_EmptyVolume_inBackheadLocation%Array(imud)
!                    
!                do 
!                        if (isection > 1) then        ! (horizontal pipe exit)
!                            Hz_MudDischarged_Volume%Array(imud)= Hz_MudDischarged_Volume%Array(imud)- Hz_RemainedVolume_in_LastSection%Array(imud)
!                            Hz_Mud_Forehead_X%Array(imud)= Xend_PipeSection(1)
!                            Hz_Mud_Forehead_section%Array(imud)= 1
!                            if (Hz_MudDischarged_Volume%Array(imud)<= 0.0d0)  then       ! imud is completely exited form the string
!                                call Hz_MudDischarged_Volume%Remove (imud)
!                                call Hz_Mud_Backhead_X%Remove (imud)
!                                call Hz_Mud_Backhead_section%Remove (imud)
!                                call Hz_Mud_Forehead_X%Remove (imud)
!                                call Hz_Mud_Forehead_section%Remove (imud)
!                                call Hz_Density%Remove (imud)
!                                call Hz_RemainedVolume_in_LastSection%Remove (imud)
!                                call Hz_EmptyVolume_inBackheadLocation%Remove (imud)
!                                call Hz_MudOrKick%Remove (imud)
!                            endif
!                            exit
!                        endif
!                                 
!                    xx= Hz_RemainedVolume_in_LastSection%Array(imud)/ PipeSection_VolumeCapacity(isection)   !(gal)
!                        
!                    if (xx<= 1.0) then
!                        Hz_Mud_Forehead_section%Array(imud)= isection
!                        Hz_Mud_Forehead_X%Array(imud)= (xx * (Xend_PipeSection(isection)- Xstart_PipeSection(isection)))+ Xstart_PipeSection(isection)
!                        exit
!                    else
!                        Hz_RemainedVolume_in_LastSection%Array(imud)= Hz_RemainedVolume_in_LastSection%Array(imud)- PipeSection_VolumeCapacity(isection)
!                        isection= isection+ 1
!                        
!                                
!                    endif
!
!                enddo
!            
!            endif   
!        
!    enddo
    
        !commented
    
!========================Horizontal PIPE END=================         

!========================ANNULUS ENTRANCE==================== 
        
         if (ABS(AnnulusSuctionDensity_Old - Hz_Density_Utube) >= DensityMixTol ) then     ! new mud is pumped
            call Ann_Density%Add (Hz_Density_Utube)   
            call Ann_MudDischarged_Volume%Add (0.0d0)
            call Ann_Mud_Forehead_X%Add (Xend_PipeSection(NoPipeSections))
            call Ann_Mud_Forehead_section%Add (NoPipeSections)
            call Ann_Mud_Backhead_X%Add (Xstart_PipeSection(NoPipeSections))
            call Ann_Mud_Backhead_section%Add (NoPipeSections)
            call Ann_RemainedVolume_in_LastSection%Add (0.0d0)
            call Ann_EmptyVolume_inBackheadLocation%Add (0.0d0)
            call Ann_MudOrKick%Add (Hz_MudOrKick_Utube)      ! Hz_MudOrKick%Last() = 104
            call Ann_CuttingMud%Add (0)
             
             AnnulusSuctionDensity_Old= Hz_Density_Utube
         endif    
         
!========================ANNULUS==================== 

                Ann_MudDischarged_Volume%Array(Ann_MudDischarged_Volume%Length())= Ann_MudDischarged_Volume%Last()+ ((AnnulusFlowRate/60.)*DeltaT_Mudline)    !(gal)
         
imud= Ann_Mud_Forehead_X%Length() + 1

    do while (imud > 1)
        imud = imud - 1 
        
            if (imud< Ann_Mud_Forehead_X%Length()) then
                Ann_Mud_Forehead_X%Array(imud)= Ann_Mud_Backhead_X%Array(imud+1)
                Ann_Mud_Forehead_section%Array(imud)= Ann_Mud_Backhead_section%Array(imud+1)
            endif

!       <<< Fracture Shoe Lost            
            IF ( ShoeLost .and. LostInTripOutIsDone== .false.  .and. ShoeDepth < Ann_Mud_Backhead_X%Array(imud) .and. ShoeDepth >= Ann_Mud_Forehead_X%Array(imud) ) then
                !write(*,*) 'ShoeLost   imud,AnnVolume(imud), VolumeLost:' , imud,Ann_MudDischarged_Volume%Array(imud), (( Qlost/60.0d0)*DeltaT_Mudline)
                Ann_MudDischarged_Volume%Array(imud)= Ann_MudDischarged_Volume%Array(imud)-((Qlost/60.0d0)*DeltaT_Mudline)    !(gal)
                if (Ann_MudDischarged_Volume%Array(imud) < 0.0) then
                    !write(*,*) 'mud is removed by shoe lost, imud=' , imud
                    call RemoveAnnulusMudArrays(imud)
                    imud= imud-1
                    cycle
                endif
            ENDIF
!           Fracture Shoe Lost >>>             
 
            
            DirectionCoef= (Xend_PipeSection(Ann_Mud_Forehead_section%Array(imud))-Xstart_PipeSection(Ann_Mud_Forehead_section%Array(imud))) &
                / ABS(Xend_PipeSection(Ann_Mud_Forehead_section%Array(imud))-Xstart_PipeSection(Ann_Mud_Forehead_section%Array(imud)))
            ! +1 for string  ,   -1 for annulus
                
                                                                                                                    
            Ann_EmptyVolume_inBackheadLocation%Array(imud)= DirectionCoef* (Ann_Mud_Forehead_X%Array(imud)- Xstart_PipeSection(Ann_Mud_Forehead_section%Array(imud)))* &
                Area_PipeSectionFt(Ann_Mud_Forehead_section%Array(imud)) !(ft^3)          
            Ann_EmptyVolume_inBackheadLocation%Array(imud)= Ann_EmptyVolume_inBackheadLocation%Array(imud)* 7.48051948d0        ! ft^3  to gal
            

            if ( Ann_MudDischarged_Volume%Array(imud) <= Ann_EmptyVolume_inBackheadLocation%Array(imud)) then
                Ann_Mud_Backhead_section%Array(imud)= Ann_Mud_Forehead_section%Array(imud)
                Ann_Mud_Backhead_X%Array(imud)= Ann_Mud_Forehead_X%Array(imud)- DirectionCoef*(Ann_MudDischarged_Volume%Array(imud)/7.48051948d0)/Area_PipeSectionFt(Ann_Mud_Forehead_section%Array(imud))
                                                                            !   7.48051948 is for gal to ft^3
            else
                    
                isection= Ann_Mud_Forehead_section%Array(imud)-1
                Ann_RemainedVolume_in_LastSection%Array(imud)= Ann_MudDischarged_Volume%Array(imud)- Ann_EmptyVolume_inBackheadLocation%Array(imud)
                    
                do 
                        if (isection < F_StringIntervalCounts+1) then        ! last pipe section(well exit) F_StringIntervalCounts+1 is the first section in Annulus
                            Ann_MudDischarged_Volume%Array(imud)= Ann_MudDischarged_Volume%Array(imud)- Ann_RemainedVolume_in_LastSection%Array(imud)
                            Ann_Mud_Backhead_X%Array(imud)= Xstart_PipeSection(F_StringIntervalCounts+1)
                            Ann_Mud_Backhead_section%Array(imud)= F_StringIntervalCounts+1
                            
                            if (Ann_MudDischarged_Volume%Array(imud)<= 0.0d0)  then       ! imud is completely exited form the well
                                call RemoveAnnulusMudArrays(imud)
                            endif
                            
                            exit
                        endif
                                 
                    xx= Ann_RemainedVolume_in_LastSection%Array(imud)/ PipeSection_VolumeCapacity(isection)   !(gal)
                        
                    if (xx<= 1.0) then
                        Ann_Mud_Backhead_section%Array(imud)= isection
                        Ann_Mud_Backhead_X%Array(imud)= (xx * (Xstart_PipeSection(isection)- Xend_PipeSection(isection)))+ Xend_PipeSection(isection)
                        exit
                    else
                        Ann_RemainedVolume_in_LastSection%Array(imud)= Ann_RemainedVolume_in_LastSection%Array(imud)- PipeSection_VolumeCapacity(isection)
                        isection= isection- 1
                        
                                
                    endif

                enddo
            
            endif   
        
    enddo
!========================ANNULUS END=================    
    
!========================== tripping in for OP remove ===============================   
                
    !if (DeltaVolumeOp>0. .and. DeltaVolumeOp< Op_MudDischarged_Volume%Last()) then
    !    Op_MudDischarged_Volume%Array(Op_MudDischarged_Volume%Length())= Op_MudDischarged_Volume%Array(Op_MudDischarged_Volume%Length()) - DeltaVolumeOp
    !else
    !    Op_MudDischarged_Volume%Array(Op_MudDischarged_Volume%Length()-1)=  Op_MudDischarged_Volume%Array(Op_MudDischarged_Volume%Length()-1) - (DeltaVolumeOp-Op_MudDischarged_Volume%Last())
    !                
    !    call Op_MudDischarged_Volume%Remove (Op_MudDischarged_Volume%Length())
    !    call Op_Mud_Backhead_X%Remove (Op_MudDischarged_Volume%Length())
    !    call Op_Mud_Backhead_section%Remove (Op_MudDischarged_Volume%Length())
    !    call Op_Mud_Forehead_X%Remove (Op_MudDischarged_Volume%Length())
    !    call Op_Mud_Forehead_section%Remove (Op_MudDischarged_Volume%Length())
    !    call Op_Density%Remove (Op_MudDischarged_Volume%Length())
    !    call Op_RemainedVolume_in_LastSection%Remove (Op_MudDischarged_Volume%Length())
    !    call Op_EmptyVolume_inBackheadLocation%Remove (Op_MudDischarged_Volume%Length())
    !    call Op_MudOrKick%Remove (Op_MudDischarged_Volume%Length())
    !endif
    !     

!============================= Bottom Hole ============================== 
        
                !Op_MudDischarged_Volume%Array(1)= Op_MudDischarged_Volume%Array(1)+ ((GasKickPumpFlowRate/60.)*DeltaT_Mudline)    !(gal)    due to KickFlux    
imud=0                     
    do while (imud < Op_Mud_Forehead_X%Length())
        imud = imud + 1
        
            if (imud> 1) then
                Op_Mud_Backhead_X%Array(imud)= Op_Mud_Forehead_X%Array(imud-1)
                Op_Mud_Backhead_section%Array(imud)= Op_Mud_Forehead_section%Array(imud-1)
            endif
            
                
            DirectionCoef= (Xend_OpSection(Op_Mud_Backhead_section%Array(imud))-Xstart_OpSection(Op_Mud_Backhead_section%Array(imud))) &
                / ABS(Xend_OpSection(Op_Mud_Backhead_section%Array(imud))-Xstart_OpSection(Op_Mud_Backhead_section%Array(imud)))
            ! +1 for string  ,   -1 for annulus
                
                           
                                                                                                                    
            Op_EmptyVolume_inBackheadLocation%Array(imud)= DirectionCoef* (Xend_OpSection(Op_Mud_Backhead_section%Array(imud))- Op_Mud_Backhead_X%Array(imud))* &
                Area_OpSectionFt(Op_Mud_Backhead_section%Array(imud)) !(ft^3)          
            Op_EmptyVolume_inBackheadLocation%Array(imud)= Op_EmptyVolume_inBackheadLocation%Array(imud)* 7.48051948d0        ! ft^3  to gal
            
         
            if ( Op_MudDischarged_Volume%Array(imud) <= Op_EmptyVolume_inBackheadLocation%Array(imud)) then
                Op_Mud_Forehead_section%Array(imud)= Op_Mud_Backhead_section%Array(imud)
                Op_Mud_Forehead_X%Array(imud)= Op_Mud_Backhead_X%Array(imud)+ DirectionCoef*(Op_MudDischarged_Volume%Array(imud)/7.48051948d0)/Area_OpSectionFt(Op_Mud_Backhead_section%Array(imud))
                                                                            !   7.48051948 is for gal to ft^3
                
            else
                    
                isection= Op_Mud_Backhead_section%Array(imud)+1
                Op_RemainedVolume_in_LastSection%Array(imud)= Op_MudDischarged_Volume%Array(imud)- Op_EmptyVolume_inBackheadLocation%Array(imud)
                    
                do 
                        if (isection > F_BottomHoleIntervalCounts) then        ! last pipe section(well exit)
                            if( imud==1) KickDeltaVinAnnulus= Op_RemainedVolume_in_LastSection%Array(imud)      ! Kick enters Annulus space
                            Op_MudDischarged_Volume%Array(imud)= Op_MudDischarged_Volume%Array(imud)- Op_RemainedVolume_in_LastSection%Array(imud)
                            Op_Mud_Forehead_X%Array(imud)= Xend_OpSection(F_BottomHoleIntervalCounts)
                            Op_Mud_Forehead_section%Array(imud)= F_BottomHoleIntervalCounts
                                
                            if (Op_MudDischarged_Volume%Array(imud)<= 0.0d0)  then        ! imud is completely exited form the well
                                call RemoveOpMudArrays(imud)
                            endif
                            
                            exit
                        endif
                                 
                    xx= Op_RemainedVolume_in_LastSection%Array(imud)/ OpSection_VolumeCapacity(isection)   !(gal)
                        
                    if (xx<= 1.0) then
                        Op_Mud_Forehead_section%Array(imud)= isection
                        Op_Mud_Forehead_X%Array(imud)= (xx * (Xend_OpSection(isection)- Xstart_OpSection(isection)))+ Xstart_OpSection(isection)
                        exit
                    else
                        Op_RemainedVolume_in_LastSection%Array(imud)= Op_RemainedVolume_in_LastSection%Array(imud)- OpSection_VolumeCapacity(isection)
                        isection= isection+ 1
                        
                    endif

                enddo
            
            endif   
        
        if (Op_Mud_Forehead_X%Array(imud)== Xend_OpSection(F_BottomHoleIntervalCounts)) then
            totalLength = Op_MudDischarged_Volume%Length()
            do while(imud < totalLength)
                
                !imud = imud + 1
                call RemoveOpMudArrays(totalLength)
                totalLength = totalLength - 1

                
            enddo
            
            exit ! 
            
        endif           

       !WRITE(*,*) imud,'Op_MudDischarged_Volume%Array(imud)' , Op_MudDischarged_Volume%Array(imud), Op_Density%Array(imud)

                   
            
            
            
            
    enddo


    !write(*,*) 'Op_Mud_Forehead_X%Length()' , Op_Mud_Forehead_X%Length()
    !
    !   WRITE(*,*) 'Xend_PipeSection(F_StringIntervalCounts)' , Xend_PipeSection(F_StringIntervalCounts)
    !   WRITE(*,*) 'Op_Mud_Backhead_X%Array(1)' , Op_Mud_Backhead_X%Array(1) 
    !   WRITE(*,*) 'Op_Mud_Forehead_X%Array(1)' , Op_Mud_Forehead_X%Array(1)
    !   WRITE(*,*) 'Op_Mud_Backhead_X%Array(2)' , Op_Mud_Backhead_X%Array(2) 
    !   WRITE(*,*) 'Op_Mud_Forehead_X%Array(2)' , Op_Mud_Forehead_X%Array(2) 
!========================Bottom Hole END=================          
    
    
    
    
  ! NO KICK  
    
    
     
!========================STRING ENTRANCE================= 
        
    if ((ABS(St_Density%Last() - Ann_Density%First()) >= DensityMixTol)  .OR. (DeltaVolumeOp == 0.0 .and. St_Density%Last() /= Ann_Density%Array(1) .and. StringFlowRate/=0.0d0)) then     ! new mud is pumped

    !if ((ABS(StringDensity_Old - Ann_Density%First()) >= DensityMixTol)  .OR. (DeltaVolumeOp == 0.0 .and. St_Density%Last() /= Ann_Density%Array(1) .and. StringFlowRate/=0.0d0)) then     ! new mud is pumped
            call St_Density%Add (Ann_Density%First())
            call St_MudDischarged_Volume%Add (0.0d0)
            call St_Mud_Forehead_X%Add (Xend_PipeSection(F_StringIntervalCounts))
            call St_Mud_Forehead_section%Add (F_StringIntervalCounts)
            call St_Mud_Backhead_X%Add (Xstart_PipeSection(F_StringIntervalCounts))
            call St_Mud_Backhead_section%Add (F_StringIntervalCounts)
            call St_RemainedVolume_in_LastSection%Add (0.0d0)
            call St_EmptyVolume_inBackheadLocation%Add (0.0d0)
            call St_MudOrKick%Add (0)
             
             !StringDensity_Old= Ann_Density%First()
             
             MudIsChanged= .true.
         endif

                         St_MudDischarged_Volume%Array(St_MudDischarged_Volume%Length())= St_MudDischarged_Volume%Last()+ ((StringFlowRate/60.0d0)*DeltaT_Mudline)    !(gal)

!========================Tripping In==================== 
         
!write(*,*) 'DeltaVolumeOp=' , DeltaVolumeOp
write(*,*) 'DeltaVolumeOp=' , DeltaVolumeOp 
            if (DeltaVolumeOp > 0.0 .and. MudIsChanged== .false.) then !.and. DrillingMode== .false.) then      ! trip in mode(loole paeen)  
                
            !write(*,*) 'Tripping In'
                            
                NewDensity= (Ann_Density%First()*((StringFlowRate/60.0d0)*DeltaT_Mudline)+Op_Density%Last()*DeltaVolumeOp)/(((StringFlowRate/60.0d0)*DeltaT_Mudline)+DeltaVolumeOp)
                NewVolume= ((StringFlowRate/60.0d0)*DeltaT_Mudline)+DeltaVolumeOp                

        !write(*,*) 'St_MudDischarged_Volume%Last()=', St_MudDischarged_Volume%Last(), 'NewVolume=', NewVolume

            if (abs(St_Density%Last()-NewDensity)< DensityMixTol) then ! .OR. (St_MudDischarged_Volume%Last()< 42.) ) then   !+ NewVolume)< 42.) then      ! 1-Pockets are Merged
                 St_Density%Array(St_Density%Length())= (St_Density%Last()*St_MudDischarged_Volume%Last()+NewDensity*NewVolume)/(St_MudDischarged_Volume%Last()+NewVolume)
                 St_MudDischarged_Volume%Array(St_Density%Length())= St_MudDischarged_Volume%Last()+DeltaVolumeOp
                 St_Mud_Forehead_X%Array(St_Density%Length())= (Xend_PipeSection(F_StringIntervalCounts))
                 St_Mud_Forehead_section%Array(St_Density%Length())= (F_StringIntervalCounts)
                 St_Mud_Backhead_X%Array(St_Density%Length())= (Xstart_PipeSection(F_StringIntervalCounts))
                 St_Mud_Backhead_section%Array(St_Density%Length())= (F_StringIntervalCounts)
                 St_RemainedVolume_in_LastSection%Array(St_Density%Length())= (0.0d0)
                 St_EmptyVolume_inBackheadLocation%Array(St_Density%Length())= (0.0d0)                  
            else        ! 2-Merging conditions are not meeted, so new pocket
                call St_Density%Add (NewDensity)
                call St_MudDischarged_Volume%Add (NewVolume)
                call St_Mud_Forehead_X%Add (Xend_PipeSection(F_StringIntervalCounts))
                call St_Mud_Forehead_section%Add (F_StringIntervalCounts)
                call St_Mud_Backhead_X%Add (Xstart_PipeSection(F_StringIntervalCounts))
                call St_Mud_Backhead_section%Add (F_StringIntervalCounts)
                call St_RemainedVolume_in_LastSection%Add (0.0d0)
                call St_EmptyVolume_inBackheadLocation%Add (0.0d0)
                call St_MudOrKick%Add (0)
            endif
            

            elseif (DeltaVolumeOp > 0.0 .and. MudIsChanged== .true.) then
                 St_Density%Array(St_Density%Length())= NewDensity
                 St_MudDischarged_Volume%Array(St_Density%Length())= NewVolume
                 St_Mud_Forehead_X%Array(St_Density%Length())= (Xend_PipeSection(F_StringIntervalCounts))
                 St_Mud_Forehead_section%Array(St_Density%Length())= (F_StringIntervalCounts)
                 St_Mud_Backhead_X%Array(St_Density%Length())= (Xstart_PipeSection(F_StringIntervalCounts))
                 St_Mud_Backhead_section%Array(St_Density%Length())= (F_StringIntervalCounts)
                 St_RemainedVolume_in_LastSection%Array(St_Density%Length())= (0.0d0)
                 St_EmptyVolume_inBackheadLocation%Array(St_Density%Length())= (0.0d0)
    endif  
    
    
!========================Tripping In - End====================    
    
    
!======================== STRING ==================== 
    
            MudIsChanged= .false. 
            
 imud= St_Mud_Forehead_X%Length() + 1

    do while (imud > 1)
        imud = imud - 1                  
        
            if (imud< St_Mud_Forehead_X%Length()) then
                St_Mud_Forehead_X%Array(imud)= St_Mud_Backhead_X%Array(imud+1)
                St_Mud_Forehead_section%Array(imud)= St_Mud_Backhead_section%Array(imud+1)
            endif
            
                
            DirectionCoef= (Xend_PipeSection(St_Mud_Forehead_section%Array(imud))-Xstart_PipeSection(St_Mud_Forehead_section%Array(imud))) &
                / ABS(Xend_PipeSection(St_Mud_Forehead_section%Array(imud))-Xstart_PipeSection(St_Mud_Forehead_section%Array(imud)))
            ! +1 for string  ,   -1 for annulus
                
                                                                                                                    
            St_EmptyVolume_inBackheadLocation%Array(imud)= DirectionCoef* (St_Mud_Forehead_X%Array(imud)- Xstart_PipeSection(St_Mud_Forehead_section%Array(imud)))* &
                Area_PipeSectionFt(St_Mud_Backhead_section%Array(imud)) !(ft^3)          
            St_EmptyVolume_inBackheadLocation%Array(imud)= St_EmptyVolume_inBackheadLocation%Array(imud)* 7.48051948d0        ! ft^3  to gal
            

            if ( St_MudDischarged_Volume%Array(imud) <= St_EmptyVolume_inBackheadLocation%Array(imud)) then
                St_Mud_Backhead_section%Array(imud)= St_Mud_Forehead_section%Array(imud)
                St_Mud_Backhead_X%Array(imud)= St_Mud_Forehead_X%Array(imud)- DirectionCoef*(St_MudDischarged_Volume%Array(imud)/7.48051948d0)/Area_PipeSectionFt(St_Mud_Forehead_section%Array(imud))
                                                                            !   7.48051948 is for gal to ft^3
            else
                    
                isection= St_Mud_Backhead_section%Array(imud)-1
                St_RemainedVolume_in_LastSection%Array(imud)= St_MudDischarged_Volume%Array(imud)- St_EmptyVolume_inBackheadLocation%Array(imud)
                    
                do 
                        if (isection < 1) then        ! last pipe section(string exit)
                            St_MudDischarged_Volume%Array(imud)= St_MudDischarged_Volume%Array(imud)- St_RemainedVolume_in_LastSection%Array(imud)
                            St_Mud_Backhead_X%Array(imud)= Xstart_PipeSection(2)
                            St_Mud_Backhead_section%Array(imud)= 2
                            
                            if (St_MudDischarged_Volume%Array(imud)<= 0.0d0)  then        ! imud is completely exited form the string
                                call RemoveStringMudArrays(imud)
                            endif
                            
                            exit
                        endif
                                 
                    xx= St_RemainedVolume_in_LastSection%Array(imud)/ PipeSection_VolumeCapacity(isection)   !(gal)
                        
                    if (xx<= 1.0) then
                        St_Mud_Backhead_section%Array(imud)= isection
                        St_Mud_Backhead_X%Array(imud)= (xx * (Xstart_PipeSection(isection)- Xend_PipeSection(isection)))+ Xend_PipeSection(isection)
                        exit
                    else
                        St_RemainedVolume_in_LastSection%Array(imud)= St_RemainedVolume_in_LastSection%Array(imud)- PipeSection_VolumeCapacity(isection)
                        isection= isection- 1
                                
                    endif

                enddo
            
            endif   
        
    enddo
!========================STRING END================= 
    

    
        
end subroutine Utube2_and_TripIn