Estimated production volumes are based on detailed data for each field and take into account development plans agreed by management as part of the
long-term planning process. The average production for the purposes of goodwill impairment testing over the next 15 years is 847mmboe per year (2013 597mmboe per year). It is estimated that if production volume were to be reduced by approximately 5% for the whole period, this would cause
the recoverable amount to be equal to the carrying amount of goodwill and related non-current assets of the segment.
It is estimated that if the post-tax discount rate was approximately 10% for the entire portfolio this would cause the recoverable amount to be equal to
the carrying amount of goodwill and related non-current assets of the segment