Oil production will not remain at the peak level of 500,000 barrels (80,000 m3) per day for long as the national oil fields are projected to be largely depleted by 2023. Large natural gas reserves have, however, been located off Qatar's northeast coast. Qatar's proved reserves of gas are the third-largest in the world, exceeding 250 trillion cubic feet (7,000 km3). The economy was boosted in 1991 by completion of the $1.5-billion Phase I of North Field gas development. In 1996, the Qatargas project began exporting liquefied natural gas (LNG) to Japan. Further phases of North Field gas development costing billions of dollars are in various stages of planning and development.