Spudding of First Well on Marine XI

SOCO announces that the Liyeke Marine 1 well has spudded on 22nd August 2009 in the Marine XI Block, located in the Congo Basin, offshore the Republic of Congo. The Liyeke Marine well is the first in a two well drilling programme on Marine XI and is targeting a Sendji sandstone prospect, previously called S1, above the salt layer. The well will be drilled by using the jack-up drilling rig Pride Cabinda and is expected to take 25 to 35 days, with a planned depth of approximately 1,130 metres below mean sea level. The follow-up well will appraise the existing pre-salt Viodo oil field at a location approximately one kilometre from the field’s discovery well. The spudding of the Liyeke Marine well launches the most active drilling programme in the Company’s history, which includes a 12 month drilling campaign in the Cuu Long Basin, offshore Vietnam, one exploration well on the Marine XIV Block, offshore Republic of Congo, a further exploration well on Marine XI, and two exploration wells on the Nganzi Block, located onshore the Democratic Republic of Congo (Kinshasa).

Liyeke Marine 1 Well on Marine XI

The Liyeke Marine 1 well, spudded on 22 August 2009 in the Marine XI Block, located in the Congo Basin, offshore the Republic of Congo, was plugged and abandoned after reaching a total depth of 1,140 metres. The objective horizon in the Sendji formation was encountered in accord with the prognosis though the reservoir was water saturated. A 62 metre heavy oil column was encountered in the overlying sediments, but the log and sample data indicated that the oil would not flow. As the salt section to the south and west of the Liyeke well is thinner and discontinuous, the result of this well has no bearing on the post-salt prospects in this area. More importantly it has no impact on the pre-salt prospects where the source rocks are adjacent to the prospective reservoirs. The jack-up drilling rig Pride Cabinda is now being prepared to be moved to the second well, an appraisal of the existing pre-salt Viodo oil field at a location approximately one kilometre from the field's discovery well.

Successful Test of the Viodo 4 Well on Marine XI

The Viodo Marine 4 vertical appraisal well ("VIM-4") located in the Marine XI Block offshore the Republic of Congo (Brazzaville) has tested at a combined maximum flow rate of approximately 2,600 barrels of oil per day ("BOPD") and 7.0 million standard cubic feet of gas per day ("MMSCFD") following two drill stem tests ("DSTs"). In the first drill stem test from the deeper Carbonate section between 2,240 to 2,273 metres, the well flowed at initial post-acid rates of approximately 2,600 BOPD and 2.5 million MMSCFD on a 3/4 inch choke. Flow rates stabilized at approximately 1,100 BOPD on a 1/2 inch choke after an approximate seven hour flow period. A test of the upper Carbonate section, between 2,205 and 2,230 metres, flowed at post-acid rates of approximately 4.5 MMSCFD. The objectives of the well are to further delineate the field, gather data that would allow the 3D seismic to be used to map the distribution of reservoir quality limestone and to test the effectiveness of a completion strategy that could be applied to high angle development wells. The results of the well and the reprocessed seismic will now be incorporated into a 3D model that will be used as a tool to assess the commerciality of the accumulation. As planned the well will be plugged and abandoned and the jack-up drilling rig Pride Cabinda will be released.