Abstract: A process incorporating integrated units and combined cycle energy production is provided for the recovery and upgrading of oil containing deposits which are not readily amenable to recovery and upgrading, to produce therefrom a light oil and elemental sulphur. Residual hydrocarbons generated in the process are gasified to produce hot gases which are used as a source of energy for process use, including electric power. The electric power is utilized to electrolyze water and produce hydrogen for use in upgrading and oxygen for use in gasification. The integration of gasification of residual hydrocarbons to produce, inter alia, electric power with the electrolysis of water to produce hydrogen for upgrading, and efficient use, distribution and recovery of energy in combined energy cycles provides an economical and essentially energy sufficient process with the flexibility to be adapted for the recovery and upgrading of various low yield oil deposits.