Every person who in this city engages in a business consisting mainly of manufacturing, packing, processing, canning, or fabricating any goods, wares, merchandise, or produce, or in processing or refining oil, natural gas or products derived therefrom, shall pay an annual license tax which shall be in the same amount and computed in the same manner as the annual license tax specified in Section 5.04.550. The cleaning and dehydration of crude oil at the well where it is produced does not constitute the processing thereof within the meaning of this section.