A system and method for cracking, hydrogenating and extracting oil from underground deposits is presented. A system includes injecting carbon dioxide and syngas into a deposit of oil under the ground to crack and hydrogenate the heavy oil to produce upgraded oil with a reduced density and reduced viscosity. The carbon dioxide acts as a pressurization agent to further reduce the viscosity of the heavy oil. The method transports the reduced density and reduced viscosity oil aboveground. The carbon dioxide is left underground after the reduced viscosity oil is transported aboveground.