 In the early 1960s, in an effort to restore declining production, several enhanced recovery methods were employed.The first waterflooding operation began in 1963 in the Portals-Fairfax area, and in 1964 both waterflooding and cyclic steam were in use in several areas of the field, with the steam recovery being used on the heavy oil reservoirs such as Racetrack Hill, where a steam system is still in place.The major oil companies, and companies that are ancestors of today's major oil companies, gradually left the field in the decades following 1950.