On 4 October 2017 Gazpromneft announced a giant oil discovery on the Ayashski block offshore Sakhalin island in Russia's Far East. Initial in place resources are estimated at 1.86 billion barrels of oil equivalent making the Neptune field the biggest discovery in Russia and one of the largest globally in 2017. This opens a new growth area for Gazpromneft with big production potential post 2025. Neptune could produce up to 120 000 b/d at peak. This would allow Gazpromneft to offset decline from its mature asset base in West Siberia and boost company cash flow in the late 2020s.