Under-Deposit Corrosion of Carbon Steel Beneath Full Coverage of CaCO3 Deposit Layer under Different Atmospheres

Electrochemical Study on the Macro-Cell Corrosion of Pipeline Steel Partially Covered by Different Kinds of Mineral Deposits

“…The mineral deposits always entrain in the oil and gas production water, − resulting in the partial coverage of the pipe bottom. The accumulation of the mineral deposits might cause localized corrosion at six o’clock of the pipe circle, , which is normally defined as under deposit corrosion (UDC). , Due to the inhibition of the ion diffusion beneath the deposition barrier, the local chemical and electrochemical environment beneath the deposit would be different from that of the steel in the bulk solution. , Accordingly, the inhomogeneous surface status beneath the deposit , and the potential difference , between the bare steel and deposit-covered steel are attributed to the main influencing factors for the initiation and propagation of UDC.…”

“…It evidently shows that the application of WBE to monitor UDC is satisfactory. Consequently, the WBE technique has been used as an effective method for UDC studies. ,,,, …”

“…Consequently, the WBE technique has been used as an effective method for UDC studies. 4,8,16,20,21 This article is licensed under CC-BY-NC-ND 4 To restore the mineral deposits presented in oil and gas pipelines, mixed deposits including several species were used in previous studies. 16,20,22 Zhang et al 20 employed mixed deposits (including sand, clay, corrosion products, and sulfur) to investigate the galvanic corrosion between the deposit-covered electrode and the bare electrode using WBE in CO 2 -containing formation water.…”

Role of Fe oxide in the underdeposit corrosion of pipeline steel in oilfield produced water containing SRB

“…[2] Research shows that UDC is often accompanied by accelerated corrosion rates, localized perforation of steel, and pipeline failures which may result in environmental pollution and loss of lives and properties. [3][4][5][6] Following decades of research, several mechanisms have been proposed to explain UDC, such as occlusion corrosion cells due to the hindrance of oxygen diffusion under the deposits, blocking of corrosion inhibitors from the steel surface, and galvanic interactions between areas of the steel covered by deposits and the bare surface. [5,6] Documented reports show that UDC often occurs with microbiologically influenced corrosion (MIC) in a process known as UD-MIC, characterized by severe localized perforation of steel.…”

“…The deposits in oilfield pipelines mainly consist of sand, CaCO 3 , mineral scales, and corrosion products (e.g., ferrous oxide, siderite, and iron sulfides). [1][2][3][4]12,13] Pang et al [4] reported that the CaCO 3 deposit enhanced the corrosion of #20 carbon steel in an oxygenated environment. In a study by Yan et al, Fe oxide in red soils exacerbated steel corrosion under the deposit in soil water.…”