Chemical composition of pipe steel corrosion products in gas condensate

The composition of corrosion products and solid deposits in the form of conical protrusions in the vicinity of a through-hole discovered during the repair of a gas condensate well after 256 days of operation in the Dengizkul field (Uzbekistan) was investigated. The area of corrosive destruction was located 5–8 cm from the perimeter of the through hole and extended in the direction of gas condensate flow. The quantitative distribution of nine chemical elements in corrosion products and solid deposits was determined. These deposits contain all the alloying and impurity elements of the pipe steel, as well as chlorine originating from gas condensate, hydrochloric acid used for well treatment, and water. In addition to iron, the highest concentration of sulfur in the corrosion products is observed, ranging from 19.29 to 33.85 wt %, indicating that iron is predominantly present in the form of sulfides. The concentration of the remaining alloying and impurity elements is generally less than 1%, but in samples from certain areas it reaches up to 2.23 wt %. The concentrations of chlorine, calcium, and silicon in solid deposits from gas condensate-containing fluids exceed their levels in corrosion products. These elements are present in concentrations greater than 1%. The research findings may prove useful in understanding the mechanism of pipe steel degradation and in optimizing acid treatment processes during well operations.