Generation mechanism and control measures for H2S in oil wells, Liaohe Oilfield

H2S may be generated by the reactions of sulphur-alcohol and sulfoether in the crude oil or by the sulfur-bearing minerals in the formation at high temperatures. Sulphate can also be reduced to H2S by the sulphate-reducing bacteria in formation water at formation conditions. Experiments show that temperature is the key external factor affecting the formation of H2S. When the temperature is over 100 °C, the content of H2S increases by about 0.03% for every 20 °C increase in temperature. The content of H2S increases rapidly with the temperature ranging between 160 °C and 180 °C. When the temperature is higher than 180 °C, the speed of H2S generation decreases obviously. With the addition of surfactants and mixed additives, the release of H2S can be prohibited. With the addition of acid chemicals, the content of H2S will increase. H2S in oil wells can be basically eliminated in some time with self-developed H2S remover added. Key words: oil well, H2S, mechanism, control, Liaohe Oilfiel