The provisions of the Natural Gas Act of June 21, 1938, as amended [15 U.S.C. 717 et seq.], shall not be applicable to the sale, extraction, processing, transportation, or storage of helium either prior to or subsequent to the separation of such helium from the natural gas with which it is commingled, whether or not the provisions of such Act apply to such natural gas, and in determining the rates of a natural gas company under sections 4 and 5 of the Natural Gas Act, as amended [15 U.S.C. 717c, 717d], whenever helium is extracted from helium-bearing natural gas, there shall be excluded (1) all income received from the sale of helium; (2) all direct costs incurred in the extraction, processing, compression, transportation or storage of helium; and (3) that portion of joint costs of exploration, production, gathering, extraction, processing, compression, transportation or storage divided and allocated to helium on a volumetric basis.