UPDATE 2-Indonesia's Pertamina, ExxonMobil plan appraisal drilling in carbon capture effort

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TANGERANG, Indonesia, May 15 (Reuters) - State energy firm Pertamina and U.S. major ExxonMobil plan to conduct appraisal drilling for a carbon capture and storage (CCS) hub in Indonesia, with the companies signing an initial storage deal with South Korea's KNOC on Wednesday.

Indonesia, which estimates its depleted oil and gas reservoirs and saline aquifers could provide storage for hundreds of gigatonnes of CO2, this year allowed CCS operators to set aside 30% of their storage capacity for imported carbon.

During the Indonesia Petroleum Association's annual conference on Wednesday, Pertamina and ExxonMobil signed a deal for preliminary work to design a commercial model for the Asri Basin Project CCS hub.

"Pertamina Hulu Energi and ExxonMobil will carry out appraisal drilling in order to collect data which will later become a reference for the development of the hub," said Awang Lazuardi, chief executive of Pertamina Hulu Energi.

A preliminary joint study by Pertamina and Exxon found that the Asri basin, in Pertamina's Offshore South East Sumatra block, had the capacity to store up to 3 gigatonnes of carbon dioxide and would require investments of $2 billion.

The companies also signed a framework agreement with South Korea's KNOC allowing it to join the partnership and inject emissions into the facility, Nicke Widyawati, chief executive of Pertamina, told reporters on the sidelines of the conference. (Reporting by Bernadette Christina, Fransiska Nangoy; Editing by John Mair and Clarence Fernandez)