Vietnam 121-CV-1X well results

PREMIER OIL PLC

("Premier" or the "Company")

Exploration drilling update - Vietnam 121-CV-1X well results

23 July 2013

The 121-CV-1X exploration well in Block 121 in the Phu Khanh Basin offshore East Vietnam has reached a total depth of 3,750 metres measured depth (MD). The well is being plugged and abandoned with gas shows.

The well, which was targeting the Whale (Ca Voi) prospect, encountered sands in the deep clastic section which is prognosed to be Oligocene (primary target) in age. However, these were water wet. Potential source rocks, including coals, were also encountered within this section.

Within the shallower Miocene section, the well penetrated a wet gas bearing interval associated with indications of overpressure. The gas is thermogenic in origin and demonstrates that a working petroleum system is present in Block 121.

The results of the well will now be integrated with the existing seismic data to determine the future exploration plans for Block 121.

Simon Lockett, Chief Executive, commented:

"121-CV-1X was a frontier exploration well and was the first to test the prospectivity of the Oligocene section in the Phu Khanh Basin. The presence of deep clastic reservoir rocks and an active petroleum charge in this first wild cat exploration well is encouraging."