China's largest oil and gas producer PetroChina is increasing investment in oil and gas exploration and development in Indonesia by 30 percent through its local subsidiary this year.

The subsidiary, PetroChina International Indonesia, will increase its investment from $491 million to $639 million in 2010 to boost oil lifting and counteract declining production, said PetroChina Vice President Budi Setiadi.

Budi Setiadi said the company planned to drill 21 exploration wells this year, which could cost the company $23 million. PetroChina has set targets for its Indonesian operation to produce 106,000 barrels of oil per day (BPD) this year, up from 104,000 BPD in 2009.