13.—(1) The Licensee shall measure or weigh by a method or methods customarily used in good oilfield practice and from time to time approved by the Minister all Petroleum won and saved from the Licensed Area.
(2) If and to the extent that the Minister so directs, the duty imposed by paragraph (1) of this clause shall be discharged separately in relation to Petroleum won and saved—
(a)from each part of the Licensed Area which is an Oil Field for the purposes of the Oil Taxation Act 1975;
(b)from each part of the Licensed Area which forms part of such an Oil Field extending beyond the Licensed Area; and
(c)from each Well producing Petroleum from a part of the Licensed Area which is not within such an Oil Field.
(3) If and to the extent that the Minister so directs, the preceding provisions of this clause shall apply as if the duty to measure or weigh Petroleum included a duty to ascertain its quality or composition or both; and where a direction under this paragraph is in force, the following provisions of this clause shall have effect as if references to measuring or weighing included references to ascertaining quality or composition.
(4) The Licensee shall not make any alteration in the method or methods of measuring or weighing used by him or in any appliances used for that purpose without the consent in writing of the Minister and the Minister may in any case require that no alteration shall be made save in the presence of a person authorised by the Minister.
(5) The Minister may from time to time direct that any weighing or measuring appliance shall be tested or examined in such manner, upon such occasions or at such intervals and by such persons as may be specified by the Minister’s direction and the Licensee shall pay to any such person or to the Minister such fees and expenses for any such tests or examinations as the Minister may specify.
(6) If any measuring or weighing appliance shall upon any such test or examination as is mentioned in paragraph (5) of this clause be found to be false or unjust the same shall, if the Minister so determines after considering any representations in writing made by the Licensee, be deemed to have existed in that condition during the period since the last occasion upon which the same was tested or examined pursuant to paragraph (5) of this clause.