Recent technical advances in the understanding of in situ combustion have m
ade it worthwhile to consider this process as a serious means of recovering
heavy oil. However, it must first prove itself to be economically viable,
particularly in comparison with steam based recovery processes. This paper
examines the factors that are necessary to make in situ combustion work in
the field, including the need to ensure operation at high temperatures,opti
mal well layouts and spacing, and why economies of scale must be used to en
sure competitive economics. Based on these requirements, an in situ combust
ion process is then compared to a similarly designed steam process and the
comparative economics are discussed.
The results of this work show that in situ combustion should be laid out in
a line drive pattern, based on a 4 ha (10 acres) well spacing. Sufficient
air injection capacity must be installed to best ensure high temperature co
mbustion, thus achieving reasonable oil production rates. It is recognized
that in situ combustion has higher front end costs than steam processes, bu
t recovery factors for in situ combustion can be as much as 60% higher. The
cost comparison for a 20 well combustion project and a I comparable steam
project set in Western Canada yields a per m(3) cost of $104.10 for steam a
nd $78.00 for in situ combusiton (%16.55 for steam and $12.40 for in situ c
ombustion).