Indonesia remains Southeast Asia's largest oil and gas producer, as steady gas output of over 6 bcf/d for the last two decades has offset falling oil output. However, liquids production continues to decline and with a limited number of significant new development projects on the horizon, Indonesia's long-term supply outlook is increasingly reliant on investment in mature fields and high-impact exploration. Indonesia's production outlook relies on a handful of strategic projects; the Cepu, Rokan, Offshore Mahakam, Tangguh and Corridor PSCs account for more than half of total supply in 2019. Lower exploration activity in recent years, particularly in frontier areas, has meant fewer material development projects on the horizon. BP's FID of the Tangguh Expansion in 2016 was the last major project sanction. Key upcoming projects include INPEX's Masela (Abadi LNG), Repsol's Sakakemang and Chevron's Indonesia Deepwater Development (IDD).