47303 1。 According to the official website information of the postal code library, the area code of Wancheng Oilfield in Nanyang City is 0377 and the postal code is 47303 1. The first two digits 47 represent provinces, municipalities and autonomous regions, the third digit 3 represents postal areas, the fourth digit 0 represents counties and cities, and the last two digits 3 1 represent specific delivery areas.