For the purposes of this Act, the quantity of petroleum recovered by a permittee, lessee or licensee from a well during a period shall be taken to be:
(a) the quantity measured during that period by a measuring device approved by the Minister and installed at the well-head or at such other place as the Minister approves, or
(b) where no such measuring device is so installed, or the Minister is not satisfied that the quantity of petroleum recovered by the permittee, lessee or licensee from the well has been properly or accurately measured by such a measuring device--the quantity determined by the Minister as being the quantity recovered by the permittee, lessee or licensee from the well during that period.