This User's Guide presents the important mechanisms which occur during gas injection
processes and the equations that describe those mechanisms. The techniques used in GEM to
solve these equations are also described. This User's Guide is aimed at reservoir engineers
who want to use GEM to design gas injection processes for enhanced oil recovery. It requires
some basic knowledge of reservoir engineering and some rudimentary exposure to reservoir
simulation. This User's Guide provides a step-by-step procedure for preparation of input data
for this program. A tutorial section is provided as well as a set of appendices.