Sec. 8. A tax at a rate equal to the greater of:
(1) one percent (1%) of the value of the petroleum; or
(2) three cents ($0.03) per one thousand (1,000) cubic feet (MCF) for natural gas and twenty-four cents ($0.24) per barrel for oil;
is hereby imposed as of the time of the severance of such petroleum from the land, upon all producers and owners thereof as an excise for the privilege of severing the same from the land and producing the same from the well, except when the gas from any well is used to pump or treat the same or when such gas is piped to a landowner's private buildings for the landowner's own use.