Methods and systems relate to an oxy-boiler used to generate steam injected into a well for assisting recovery of hydrocarbons. Operating conditions of a burner for the oxy-boiler limits oxygen contamination in a resulting flue gas for carbon dioxide recovery and limits size of the oxy-boiler, which may thus be located proximate the well rather at a central processing facility. In contrast to a direct steam generation approach where resulting carbon dioxide is mixed with steam, the oxy-boiler also enables selection of a desired level of carbon dioxide injection, which may be provided with the flue gas that may be exhausted from the oxy-boiler at an injection pressure.