The alternative to surface generated steam is downhole steam generation that reduces heat loss and generates high-quality steam in the reservoir that allows for more heavy oil and oil sands production at a faster rate. Downhole steam generators were first proposed by the major oil companies in the early 1960s. Over the last 50 years multiple downhole steam technologies have been developed such as the DOE and SANDIA downhole combustion system known as Project Deep Steam that was field tested in Long Beach, CA in 1982, but was a failure. The only downhole steam generator that has proved successful is branded as eSteam.