Many assumptions can be made to estimate the length and diameter of surface piping required. GETEM and GEOPHIRES both assume 750 m of surface piping per production and injection well. GETEM uses the pipe diameter which results in a surface pipe pressure drop of 68 kPa (10 psi), though this value appears to be arbitrarily chosen. Similarly, GEOPHIRES specifies a 68 kPa pressure loss in surface equipment, but does not calculate a surface pipe diameter. In genGEO, any surface pipe length and diameter may be used, as required for the well configuration.