Distribution and treatment of harmful gas from heavy oil production in the Liaohe Oilfield, Northeast China

The distribution and treatment of harmful gas (H 2 S) in the Liaohe Oilfield, Northeast China, were investigated in this study. It was found that abundant toxic gas (H 2 S) is generated in thermal recovery of heavy oil. The H 2 S gas is mainly formed during thermochemical sulfate reduction (TSR) occurring in oil reservoirs or the thermal decomposition of sulfocompounds (TDS) in crude oil. H 2 S generation is controlled by thermal recovery time, temperature and the injected chemical compounds. The quantity of SO 4 2-in the injected compounds is the most influencing factor for the rate of TSR reaction. Therefore, for prevention of H 2 S formation, periodic and effective monitoring should be undertaken and adequate H 2 S absorbent should also be provided during thermal recovery of heavy oil. The result suggests that great efforts should be made to reduce the SO 4 2-source in heavy oil recovery, so as to restrain H 2 S generation in reservoirs. In situ burning or desulfurizer adsorption are suggested to reduce H 2 S levels. Prediction and prevention of H 2 S are important in heavy oil production. This will minimize environmental and human health risks, as well as equipment corrosion.