Role of polyacrylamide concentration on corrosion behavior of N80 steel in the HPAM/H₂S/CO₂ environment

Abstract

The effect of polyacrylamide on corrosion behavior of N80 steel in the HPAM/H2S/CO2 environment was studied by using weight‐loss and electrochemical tests to simulate the environment of production wells in polymer flooding. The morphology and composition of corrosion scales were studied by scanning electron microscopy, energy dispersive X‐ray spectrometer, and X‐ray photoelectron spectroscopy. The results show that as the polyacrylamide concentration increases, the uniform corrosion rate of N80 steel decreases gradually. The safe service life of N80 steel grows along with the increase of the concentration of polyacrylamide. The corrosion scales of N80 steel in the HPAM/H2S/CO2 environment is split into two layers, an inner layer of O‐rich composed of FeCO3 and an outer layer of S‐rich consisting of FeS. Polyacrylamide adsorbs on the surface of N80 steel to form a protective network, which blocks contact between the metal and the solution and then inhibits the anodic dissolution of the metal. Moreover, the growth of polyacrylamide concentration increases the pH value of the solution and promotes the ionization of H2S, HS−, and H2CO3 in the solution.

Study on the failure analysis of four metals for anaerobic fermentation reactor based on numerical simulation and electrochemical method

“…The corrosion products of Q345A steel (4.838-13.725 μm) and 45# steel (6.407-13.988 μm) presented smaller particle size and were stacked, but the compactness was less than that of Q235A steel (20.064-25.723 μm). However, focused on 3Cr13 steel, there was no obvious boundary between corrosion product particles, showing layered accumulation, while there was an obvious boundary between gathered corrosion products, which was independent of each other [11].…”

Insight into polymer concentration, temperature, CO2 content, and Cl− content on corrosion of N80 steel tubing in polymer flooding

“…Due to the viscosity characteristics of the polymer and its anionic character after hydrolysis, the polymer is connected by molecular chains to form a network structure and then adsorbed on the surface of the steel. [ 3 ] As the polymer concentration increases, the space between polymer molecules becomes smaller (Figure 16a,b) and its network structure gradually tends to form a sheet structure, reducing the exposed surface area (Figure 16c,d) and further resulting in the corrosion rate of N80 steel decreases as the polymer concentration increases.…”

“…However, the corrosion of produced well tubing during polymer flooding is still unclear, and further exploration is needed. [3,4] The service environment of tubing in the production wells of polymer flooding is complex, and corrosion failure of tubing tends to occur in the production process. [5][6][7][8][9] Taking Xinjiang Oilfield as an example, N80 steel tubing in polymer flooding production wells often meets with corrosion failure.…”

“…However, the corrosion of produced well tubing during polymer flooding is still unclear, and further exploration is needed. [ 3,4 ]…”

Investigation of service life and corrosion mechanism of tubing in production well on polymer flooding

“…In addition to the associated gas in formation, another important factor that affects steel corrosion is the chlorideion concentration in formation water [14][15][16]. The chloride ions are highly susceptible to induce general and pitting corrosion of tubing [17][18][19]. Liu et al pointed out that the corrosion rate is increased with the growth of Cl − content at a certain temperature and partial pressure [20].…”