The objective of this work is the comparative evaluation of pipe resistance (P110 strength grade) under API 5CT from alloys containing chrome, nickel and molybdenum, to pitting corrosion in environments with a high partial pressure of H2S and temperatures of up to 120 °С, as well as the assessment of a possible impact of the increase of a molybdenum and nickel concentration level in alloys, upon the resistance to pitting corrosion.
Experimental research showed that pipes made from high-strength alloys have different resistance to pitting corrosion, and their selection for further operation requires additional integrated corrosion tests in the conditions that are similar to the actual operating conditions. The use of pipes (P110 strength grade) under API 5CT from alloys containing 25 % chrome, 35 % nickel and 5 % molybdenum, provides significant operating advantages at natural gas fields which are high in H2S, CO2, chlorides and temperatures of up to 120 °С, including the Astrakhan Gas Condensate Field. For such pipes, non-metallic impurities and pores are not places where corrosion pits and pittings primarily appear. The more the operating life of equipment in corrosion environments, which contain H2S, CO2, chlorides at their high concentration and temperatures of up to 150 °С, is, the faster the pitting growth speed is.
Keywords: GAS CONDENSATE FIELDS HIGH IN H2S AND CO2, PITTING CORROSION, OIL-WELL TUBING.