Abstract: Disclosed are a method and apparatus for recovering and/or upgrading hydrocarbons utilizing in situ combustion and horizontal wells. Vertical injection wells are utilized to inject an oxidant into a reservoir for in situ combustion, with the combustion gases vented through vertical wells offset from the injection wells, thus causing the combustion front to travel toward the vertical offset wells. Production of hydrocarbons is through horizontal wells positioned beneath the vertical offset wells. Upgrading occurs when the horizontal wells are shut in and hot fluids injected through the offset wells into hydrocarbons that have accumulated at the bottom of the offset wells.