Deepwater block OML 120 lies in the western Niger Delta 70 kilometres offshore. Statoil discovered the Oyo oil field in 1996 but it was considered uncommercial at the time. The field was eventually developed by Eni with two subsea production wells tied back to a leased FPSO (floating production storage and offloading) vessel. First production was achieved in December 2009. Oyo has not performed according to expectations. After coming onstream at 22 000 b/d production fell very rapidly due to gas breakthrough in the Oyo 5 well. Within 12 months oil production had dropped to 6 000 b/d and over 70 mmcfd of gas was being produced. Reserves were slashed from initial estimates of 50 million barrels.