Tullow Oil PLC reported Wednesday mixed success in the latest appraisal on its large Jubilee oil field offshore Ghana.

The Mahogany Deep-2 well provided further confirmation of the size of the Jubilee field and found two new light oil reservoirs, but the deepest section of reservoir that the well was targeting contained only water.

"Confirming the southerly extent of the main Jubilee reservoirs and encountering two new oil pools takes us another step closer to realizing the full potential of the Greater Jubilee Area," said Tullow's Exploration Director Angus McCoss.

Tullow expects to produce first oil from Jubilee, which is estimated to contain between 600 million and 1.8 billion barrels of oil equivalent, in the fourth quarter of 2010. It's partners in the field are Anadarko Petroleum Corp. (APC) and Kosmos Energy, which has agreed to sell its share to ExxonMobil Corp.