I would think 12-3 UF or even 14-3 UF would be good from the control panel to the well casing. Full load on the pump would only draw about 7 amps so you don't need a 30 amp circuit. Of course from the well casing down to the pump you will use well pump wire so you can make the proper waterproof connections, etc. The breaker (probably 15 amp)needs to be the double pole type for the 220 volts. Don't use two independent 15 amp breakers as the two legs need to be tied together so if one side overloads and trips, it takes the other leg with it.