Drilling Update - Cá Rong Ðo appraisal

PREMIER OIL plc

("Premier" or "the Company")

Drilling Update - Cá Rồng Đo appraisal

11 April 2011

Premier is pleased to announce that the CRD-2X appraisal well in block 07/03 Vietnam has been drilled to a TD of 3785 metres MDRT, appraising the Miocene sands discovered in 2009 with the CRD-1X well.

The well was deepened from the preliminary TD of 3109 metres MDRT to evaluate the Oligocene which was not tested by the CRD-1X well. Two drill stem tests of the hydrocarbon bearing sands in the Oligocene section have been conducted. The first zone tested flowed gas and condensate at rates of 9.7 mmscfd and 870 bopd respectively through a 40/64 inch choke. The second zone tested flowed gas and condensate at rates of 17 mmscfd and 1730 bopd respectively through a 56/64 inch choke.

The well will now be sidetracked to further evaluate the distribution of hydrocarbons in the Miocene sands.

Simon Lockett, Chief Executive Officer, commented:

"We are encouraged by the hydrocarbon flow rates from the Oligocene section in Cá Rồng Đo, which in addition to the previously proven Miocene reservoirs, provide further exploration upside across the area. We look forward to the result of the sidetrack well which will provide additional data to determine the hydrocarbon distribution in this part of the Cá Rồng Đo structure."

Enquiries

Premier Oil plc 020 7730 1111

Simon Lockett

Tony Durrant

Pelham Bell Pottinger PR 020 7861 3232

Gavin Davis

Henry Lerwill