On October 29, 2001, the Sakhalin I Consortium officially declared the project commercial — launching one of the largest international oil and gas developments in Russia's history. Operated by ExxonMobil, the consortium united investors from the United States, Japan, India, and Russia to tap into the vast energy reserves off Sakhalin Island. The project targeted three massive offshore fields — Odoptu, Chayvo, and Arkutun-Dagi — estimated to contain 2.3 billion barrels of oil and 17 trillion cubic feet of natural gas. With an expected $12 billion in capital investment, Sakhalin I became the largest direct foreign investment in Russia at the time.