Method and apparatus for stimulating heavy oil production

A process for injecting a condensing solvent into an underground hydrocarbon bearing formation having an extraction chamber with an extraction surface, the process comprising the steps of,

• injecting solvent in a vapour form into said extraction chamber;
• managing vapour concentrations of compounds other than said condensing solvent present in the extraction chamber to achieve bubble point conditions at the extraction surface to permit effective heat transfer conditions to be established and to permit said solvent vapour to continue to condense on said extraction surface, and
• recovering a liquid of blend of solvent and hydrocarbon.

A process for injecting a condensing solvent into an underground hydrocarbon bearing formation having an extraction chamber with an extraction surface as claimed in 19 wherein said step of managing a pressure and a temperature in said extraction chamber includes the step of maintaining an extraction temperature at a predetermined temperature.

A process for injecting a condensing solvent into an underground hydrocarbon bearing formation having an extraction chamber with an extraction surface, the process including the steps of displacing a heated solvent vapour mixture into said extraction chamber at a temperature sufficient for said solvent to flow through the extraction chamber as a vapor and to condense on said extraction surface at an extraction pressure, and maintaining process conditions in said extraction chamber to keep a temperature difference between a bubblepoint temperature and a dewpoint temperature of said mixture at said interface of less than 30C.

A process for recovering hydrocarbons from an underground formation using a condensing solvent for heat transfer to a bitumen extraction surface, the method comprising:

• heating said solvent sufficiently for said solvent to flow through an extraction chamber as a vapor and to condense on said bitumen extraction surface at an extraction pressure;
• and
• pressurizing said formation to said extraction pressure, wherein said extraction pressure is sufficient to permit less condensable gases present at said bitumen extraction surface to drain away with a produced liquid at a rate to permit continued condensation to occur at said bitumen extraction surface.