Tullow Oil reported that the Enyenra-3A appraisal well, in the Deepwater Tano licence offshore Ghana, has successfully encountered oil in high quality sandstone reservoirs. Pressure data indicates that the Enyenra-3A well has confirmed an up-dip extension of the Enyenra oil field.

Located 6.5km north of the Owo-1 discovery well and 14km north of Enyenra-2A, the well was drilled to test the up-dip extent of the Enyenra oil field. Results of drilling, wireline logs, samples of reservoir fluids and pressure data show that Enyenra-3A has intersected 17 metres of 35o API net oil. Pressure data confirms a continuous oil column of at least 365 metres and that the oil at Enyenra-3A is in static pressure communication with both the Owo-1 discovery well and the Enyenra-2A appraisal well.

The Deepwater Millennium drillship drilled Enyenra-3A to a total depth of 4,031 metres in water depths of 1,102 metres. On completion of drilling operations, prior to flow testing the Enyenra field in late 2011, pressure gauges will be deployed in Enyenra-2A and Enyenra-3A to determine reservoir connectivity. The drillship will depart the Deepwater Tano block in late October having recently been replaced by the Sedco Energy drillship.

The Sedco Energy will later drill the Enyenra-4A well to further appraise the downdip extent of the field. The well will be located 6.8km south of Enyenra-2A and over 20km downdip from the Enyenra-3A well and a result is expected at the end of the year. The Enyenra-5A well also is then likely to be drilled north of Enyenra-3A to test the ultimate updip extent of the field.

Tullow (49.95%) operates the Deepwater Tano licence and is partnered by Kosmos Energy (18%), Anadarko Petroleum (18%), Sabre Oil & Gas (4.05%) and the Ghana National Petroleum Corporation (GNPC) (10% carried interest).

Elsewhere in West Africa, Tullow now expects to announce the result of the Montserrado-1 well offshore Liberia during October.

Commenting today, Angus McCoss, exploration director, said: "This excellent result demonstrates that we are close to declaring the Enyenra and Tweneboa development commercial. Although the ultimate extent of the fields are yet to be fully determined, confirmation of this up-dip extension and long oil column in Enyenra is very encouraging."

Tags: Tullow Oil plc