ABSTRACT Under-deposit corrosion (UDC) is one of the main factors leading to perforation or leakage of gathering pipeline in the oilfield. In this paper, galvanic corrosion of mild steel under CaCO3 deposit was investigated by using wire beam electrodes (WBE) in the oilfield-produced water. Potential and galvanic mappings indicated that the wire electrodes covered by CaCO3 deposit mainly acted as anode while the rest bare wire electrodes acted as cathode at the beginning of corrosion, causing apparent UDC. However, the deposit-covered electrodes were finally transformed from anode to cathode along with the bare electrodes from cathode to anode, indicative of intensive galvanic polarity reversal. It is supposed that FeCO3 corrosion products could fill into the deposit layer and form a physical diffusion barrier to block the transportation of aggressive ions from the bulk solution to the metal substrate.

中文翻译：

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温度对油田采出水中低碳钢沉积腐蚀反极性的影响

摘要 沉积下腐蚀（UDC）是导致油田集输管道穿孔或泄漏的主要因素之一。在本文中，使用线束电极（WBE）在油田采出水中研究了 CaCO3 沉积下低碳钢的电偶腐蚀。电位和电流映射表明，在腐蚀开始时，被 CaCO3 沉积物覆盖的线电极主要充当阳极，而其余的裸线电极充当阴极，导致明显的 UDC。然而，沉积物覆盖的电极最终从阳极转变为阴极，裸电极从阴极转变为阳极，表明强烈的电流极性反转。