Wintershall said its Maria discovery could hold as much as 120 million barrels of recoverable oil and 175 billion cubic feet of natural gas.
"Our preliminary calculations do not only confirm our original resource estimates, but support the upper end of our discovery volumes," Bernd Schrimpf, managing director of regional subsidiary Wintershall Norge, said in a statement.
Wintershall said it drilled the appraisal well in about 975 feet of water in the Norwegian Sea in an effort to delineate the extent of the Maria discovery. The next step, it said, was to outline a development program with its partners at British energy company Centrica.
"Maria marks another great achievement for Centrica Energy, which is one of the fastest-growing entrants in Norway," Jonathan Roger, managing director of Centrica's upstream division, said in a statement.