With this feature...
Do this...
net pay area 
units
Type the volumetric area in which to estimate reserves.
net pay units
Type the average pay amount per unit.
porosity
Type the average porosity in percent.
oil saturation
Type the average oil saturation in percent.
GOR units
Type the average gas-oil ratio.
Bo or Bg
Type the formation volume factor for oil or gas.
oil recovery
Type the average oil recovery factor.
category
Select from the following:
possible
probable
proved
proved
developed
proved undeveloped
gas recovery
Type the average gas recovery factor.
calculate
Click to display the reserves estimate in the reserves area.
register
Click to save these values in the Reserves
folder of the Explorer Tree View.