The present invention is a method and apparatus for the enhanced recovery
of petroleum fluids from the subsurface by in situ combustion of the
hydrocarbon deposit, from injection of an oxygen rich gas and drawing off
a flue gas to control the rate and propagation of the combustion front to
be predominantly horizontal and propagating vertically downwards guided
by the vertical highly permeable hydraulic fractures. Multiple propped
vertical hydraulic fractures are constructed from the well bore into the
oil sand formation and filled with a highly permeable proppant containing
hydrodesulfurization and thermal cracking catalysts. The oxygen rich gas
is injected via the well bore into the top of the propped fractures, the
in situ hydrocarbons are ignited by a downhole burner, and the generated
flue gas extracted from the bottom of the propped fractures through the
well bore and mobile oil gravity drains through the propped fractures to
the bottom of the well bore and pumped to the surface. The combustion
front is predominantly horizontal, providing good vertical and lateral
sweep, due to the flue gas exhaust control provided by the highly
permeable propped fractures.