https://www.onemillionwells.org   Enter desired slip velocity here in fpm  
  ,   CFM AIR REQD GAL AIR MIN. LITERS AIR MIN.  
  Reverse annular slip velociaty calculator   DISCHARGE PIPE DIAMETER INCHES GPM  
     IN CELLS F11 AND F12 THE TEST VALUES ARE F11=20 AND F12=8 TO YIELD 2.6OO4 IN CELL I15    
  Air Requirement by drill stem size calculation sheet    
      Do Not   
  C is the constant   change  
  IR air requirement calculator      
  Formula    
  Va=0.8Li/(C Log10{(Ls+34)/34}   DEPTH FT  
  Ls= length of submerged section (ft)     Ls=  
  Li = length of the lift section (ft)     L1=  
  PERCENT   
  PSI  
  Va = volume of free air (cu.ft) needed per gallon of water SG=        
  Li (ft.)     C Ls+34/34 1.15    
  10-60   Cu. Ft. volume  air to pump 1 gallon of water      
  61-201    
  201-500    
  501-650    
  651-750    
  C  is a constant based upon the depth of water below the fluid level see source  
  https://www.plantservices.com/articles/2002/12/      
         
           
           
  Air pressuere required    
  B=    
  L= submergence    
  specific gravity    
  P=(b+L)*sg/2.31 psi    
       
  Note, specific gravity will vary between 1 and 1.33