EVALUATION AND INVESTIGATION OF MAIN FAILURES IN SOUR GAS ENVIRONMENT

Large amount of the natural gas produced in Iran is sour. The presence of hydrogen sulfide and carbon dioxide in hydrocarbon reservoirs can create significant materials problems. In this paper tried to evaluate and investigate the failures that produced in the sour gas environment in oil and gas industry and the parameters that affect these failures. Materials degradation can take many forms, including sulfide- stress cracking, Hydrogen-induced cracking, Stress-corrosion cracking and weight- loss corrosion. Each of these must be understood if appropriate measures are to be taken to minimize its effect in field operations. Parameters such as H2S concentration, PH, temperature, strength level, cold work, on the first type corrosion (SSC), the amount of total stress and shape of defects on second type corrosion (HIC) can have basic effects. Concentration of chloride and H2S, and temperature also can cause SCC to decrease or increase. It is clear that safety issues are of primary importance in selecting materials for sour service. Even a small leakage of H2S into the environment can cause extreme danger to the surrounding area. Exposure to H2S can produce adverse effects on human health and behavior, depending on concentration and length of exposure. It could be controlled by appropriate choose of material (material selection) or by use suitable inhibitors. Equipment design is often very important in obtaining resistance to SSC.

Keywords:

sour gas , sulfide-stress cracking , Hydrogen-induced cracking , Stress-corrosion cracking and weight-loss corrosion