The mechanism of H₂S generation in the recovery of heavy oil by steam drive

<p>Laboratory experimental simulation reactions between heavy oil and water at different temperatures are conducted. The large amount of H₂S gas in the steam drive recovery in the Shengli oilfield is mainly formed during the aquathermolysis of sulfocompounds in heavy oil. Temperature is a controlling factor influencing the aquathermolysis of heavy oil. The higher the temperature is, the more H₂S gas is generated. Furthermore, the release of H₂S dissolved in formation water at high temperature and the catalytic effect of mineral ions on the aquathermolysis reduces the temperature of the reaction between heavy oil and formation water in the generation of H₂S gas.