Oman is 27 times larger than Qatar.
Area: 309,500 km2 World Factbook
Population: 3,219,775 (July 2014) World Factbook
Oman, officially called the Sultanate of Oman, is an Arab state in southwest Asia on the southeast coast of the Arabian Peninsula. It has a strategically important position at the mouth of the Persian Gulf. Wikipedia
Area: 11,586 km2 World Factbook
Population: 2,123,160 (July 2014) World Factbook
Qatar, officially the State of Qatar, is a sovereign Arab country, located in Western Asia, occupying the small Qatar Peninsula on the northeasterly coast of the Arabian Peninsula. Its sole land border is with Saudi Arabia to the south, with the rest of its territory surrounded by the Persian Gulf. Wikipedia