Building Input File
Recurrent Data

• Includes
  • output time step control
  • control code for output of grid arrays
  • simulation time step control
  • well definition
  • well location & layer
  • well productivity

Example of Recurrent Data

• Output Time Step Control
  • IOMETH
    • code to specify output method
    • based on time step # or elapsed time
  • ICHANG
    • applicable only when IOMETH based on time step #
    • # of time steps output control & time step control apply
  • IWLCNG - code to read well information
  • FTIO
    • array containing total elapsed times, 50 values max
    • when elapsed time = an FTIO value, summary report is printed
• Control Code fo Output of Grid Arrays
  • Ipmap - pressure
  • ISOmap - oil saturation
  • ISWmap - water saturation
  • ISGmap - gas saturation
  • IPBmap - bubble point
    • IAQmap - aquifer influx
  • KROmap - relative permeability of oil
  • KRWmap - relative permeability of water
  • KRGmap - relative permeability of gas
  • RSOmap - oil formation volume factor
  • PCOWmap - capillary pressure oil-water
  • PCGOmap - capillary pressure gas-oil
  • KPHImap - porosity
• Simulation Time Step Control
  • DT - initial time step size in days
    • automatic time step control modifies DT - if saturation or pressure changes exceed limits
  • Dtmin - minimum time step size in days
  • Dtmax - maximum time step size in days
• Well Definition
  • NWELLN - # of new wells
  • NWELLO - # of old wells
• Well Location & Layer
  • WELLID - five letters or numbers describing wellname
  • IDWELL - sequential integer, starting at 1, by production start date
  • (IJ) - node (grid block) index, col-row in grid space
  • PERF1 - layer # of uppermost completion layer
  • NLAYER - total # consecutive completion layers, beginning with and including PERF1
• Well Productivity
  • PID - layer flow index
    • to shut-in a layer set PID=0
    • to shut-in well set all layer PIDs=0
    • once a layer has been completed in a well
      • must be specified in all succeeding production sequences
        • even if layer or well is shut-in
    • formation damage & simulation - change PID
    • if PID is specified
      • Pwf (flowing bottomhole pressure) is not required
      • specified PID and rates used to calculate Pwf
  • PWF - flowing bottomhole pressure for each layer (psia): at each well - use arithmetic average per layer
  • WELLID & IDWELL - defined earlier
  • KIP - code for specifying well type
    • well performance determined by flowing rates or PWF - implicit pressure calculations recommended
  • Qo - oil rate in stb/d
  • Qw - water rate in stb/d
  • Qg - gas rate in mcf/d
  • Qt - total reservoir voidage rate @ reservoir conditions - Qo + Qw + Qg = Qt (remember unit conversion)
  • only 1 Q value may be non-zero
  • negative Q values indicate fluid injection