Abstract: Disclosed is a gravity-drainage assisted steam flooding process for the recovery of all from thin viscous heavy oil reservoirs using a single horizontal wellbore. Steam is injected through a fully or partially insulated tubing to exit at or near the toe of a long horizontal well penetrating a viscous oil reservoir. Initially, low (10-30%) quality steam is circulated along the well to condition the wellbore and increase the heated radius to about 1 or 2 meters. Oil and reservoir fluids immediately adjacent to the wellbore are produced through the annular space between the insulated tubing string and a slotted liner that surrounds it. After the period of low quality steam circulation, the production outlet is shut in or constrained and steam injection is continued to initiate an active steam chamber zone along a portion of the wellbore.

Abstract: An in-situ combustion method is provided for the recovery of viscous oil from an oil-bearing reservoir. A linear array of vertical air injection wells is drilled into the reservoir; the wells are completed in the upper portion of the reservoir. One or more gas production wells are provided, remote from the row of injection wells, said gas production wells also being completed in the upper portion of the reservoir. A horizontal oil production well is completed in the bottom portion of the reservoir, aligned with and positioned in spaced relation beneath the vertical injection wells. The reservoir is prepared for ignition and combustion is initiated at each of the injection wells. A hot fluid-transmissive chamber is formed around each of the injection wells as combustion proceeds. Combustion gas communication is established with the gas production wells.