| Note 24 | Trade receivables and Prepayments and other receivables |
| Amounts in US$ '000 | | 2017 | | 2016 | | ||
| Trade receivables | | | 19,519 | | | 18,426 | |
| | | | 19,519 | | | 18,426 | |
| To be recovered from co-venturers (Note 33) | | | 2,455 | | | 3,311 | |
| Related parties receivables (Note 33) | | | 56 | | | 42 | |
| Prepayments and other receivables | | | 5,242 | | | 4,290 | |
| | | | 7,753 | | | 7,643 | |
| Total | | | 27,272 | | | 26,069 | |
| | | | | | | | |
| Classified as follows: | | | | | | | |
| Current | | | 27,037 | | | 25,828 | |
| Non current | | | 235 | | | 241 | |
| Total | | | 27,272 | | | 26,069 | |
| Amounts in US$ '000 | | 2017 | | 2016 | | ||
| At 1 January | | | 741 | | | 596 | |
| Foreign exchange (income) loss | | | (147) | | | 145 | |
| | | | 594 | | | 741 | |