To address fundamental issues (energy release, temperature increase, produced gases, etc), we experimented gas combustions of various combinations of fuels (methanol, ethanol and propane) and oxidizers (oxygen, ozone and hydrogen peroxide) at different conditions (temperature, pressure, fule/oxidizer ratio, etc.) by molecular dynamics (MD) simulations with the reactive force field (ReaxFF). System energy, temperature, pressure, produced gases and their composition as well as their overall kinetics are analysized in detail for all stuided systems. In practice, major handicaps in the DSG include the excessive rate of metal corrosion by the hot combustion products in the presence of wet steam and the possible incomplete combustion because of the limitted well diameter. A catalystic combustion may be a good approach to eliminating these problems in the DSG. Thus, we also simulated the catalytic reactions in gas comubstion for a few systems to test the possibility how a catalyst can improve the combustion in DSG. Finally, we suggest a combination of fuel and its oxidizer for the design of the DSG for a better oil recovery.