The main factor was that the oil companies generally did not think that there were significant enough reserves in the North Sea to warrant the usage of resources to search for oil. This situation changed however, when fields such as the Groningen gas field in the Netherlands, and to a certain extent, Eakring in Nottinghamshire, proved to contain fairly large reserves, thus prompting the oil companies to begin a search in nearby areas, including the North Sea. "Sea Gem" made the first British discovery of natural gas in September 1965, although the find was too small to be commercially profitable.