The boundary between Ibn Saud's territories of Najd and the Eastern Province and the British protectorate of Kuwait was first regulated by the Al Uqair Convention in 1922. In an effort to avoid territorial disputes, another diamond-shaped Saudi-Kuwaiti neutral zone of 5,790 square kilometers directly south of Kuwait was established. In 1938 oil was discovered in Kuwait's southern Burqan fields, and both countries contracted with foreign oil companies to perform exploration work in the Divided Zone. After years of discussions, Saudi Arabia and Kuwait reached an agreement in 1965 that divided the zone geographically, with each country administering its half of the zone. The agreement guaranteed that the rights of both parties to the natural resources in the whole zone would continue to be respected after each country had annexed its half of the zone in 1966.