BUDAPEST, Oct 21 (Reuters) - Hungarian oil company MOL said caution was needed when estimating oil reserves in an Iraqi exploration well where Gulf Keystone Petroleum announced a discovery earlier this month.
Gulf Keystone shares were down 8.1 percent at 114 pence at 1110 GMT on Wednesday, while MOL was up 1.5 percent at 16,290 forints.
MOL, which holds a 20 percent stake in the Shaikan-1 exploration well in Iraq's Kurdish region, said a more accurate evaluation of the project would not be completed until late 2010.
"Based on the first test results, this find can be considered a significant discovery. But, based on the tests so far, it is not possible to quantify reserves," MOL said, adding the new discovery had improved the project's outlook.
Earlier this month, Gulf Keystone, the field's operator and majority owner, said it discovered oil in the upper portions of the Triassic section of the Shaikan-1 well.
The new discovery was in addition to 2-4 billion barrels of heavier oil previously announced at various levels throughout the shallower Jurassic intervals, Gulf Keystone said.
The discovery of these high energy, light oil zones within the upper levels of the Triassic significantly improved the chances of finding additional light oil targets in the 700-1,000 meters still to be drilled, it said at the time. (Reporting by Balazs Koranyi; Editing by Dan Lalor)