Indonesias ownership of the Natural Gas-rich fields offshore of the Natuna Islands was undisputed until China released an official map with unclear maritime boundaries indicating that Chinese-claimed waters in the South China Sea may extend into the waters around the Natuna Islands. Indonesia responded, in 1996, by holding large military exercises in the Natuna Islands region. Since then, Indonesia has done major natural gas production in the Natuna area and China has not voiced any objection. The three blocks in the Natuna area are estimated to contain about 5 Tcf of recoverable gas. Indonesia has been exporting Natuna gas to Singapores Jurong island via a 400-mile undersea Pipeline since 2001.