In December 1981 the Udang Field reached a top production of 3,.000 barrels a day. This field was discovered in 1974 and started production in 1979.

Following the discovery by PERTAMINA-Agip Spa in 1973, in 1983 PERTAMINA -Esso succeeded to prove that the gas reserve in block D Alpha of the Natuna Sea was very huge (210 TCF). The high CO2 content became a challenge in developing the Natuna gas field.

In 1984,the fifth train of the Arun plant was in operation, making its capacity to reach 1,7 billion standard cubic feet of gas per day. The construction of this train was a link for the utilization of LNG as a source to obtain foreign exchange.

In 1981 measures were taken to increase the production of fossil fuel to fulfill the domestic need.