The oil is in the Birba area of south Oman and gas in the Saih Nihayda field.
Petroleum Development Oman said it found "significant new volumes" of oil at the Budour Northeast oil field, which was discovered last year, the Khaleej Times reported.
In addition, the company may also have found a significant volume of oil in a rock formation at the Rabab-Southeast field, also near Birba.
The new discovery at the Budour Northeast field was revealed by Budour NE-2, a well drilled in 2007 to follow up the field's original discovery well, Budour NE-1.
"Both Budour NE wells -- as well as a third drilled in the same area -- have been hooked up to PDO's pipeline infrastructure, thereby contributing to the country's production," said PDO Managing Director John Malcolm. "An aggressive appraisal drilling program will now be executed for Budour Northeast, and we will be drilling a half-dozen new exploration wells in that area."
The newly discovered field -- Simr -- is north of the existing Saih Nihayda gas field, where PDO operates one of its four gas processing plants on behalf of the government of Oman.
"Because of the field's close proximity to existing gas processing infrastructure, it will be rapidly appraised and hooked up to deliver gas to Oman," Malcolm said. "Gas is very important for the growing economy of Oman and I am pleased that PDO can contribute to this growth by delivering new gas volumes."