CORROSION BEHAVIOUR OF CARBON STEEL, LOW ALLOY STEEL AND CRA's IN PARTIALLY DEAERATED SEAWATER AND COMINGLED PRODUCED WATER

摘要

A test programme was conducted to study the corrosion behaviour of a range of steels and CRAs in low oxygen content (20 & 200 ppb) seawater. The test materials ranged from carbon and low alloy steels through austenitic, martensitic and duplex stainless steels to nickel-based Alloy 718. Seawater injection conditions were simulated in tests conducted in the above conditions at 30 deg C. Commingled water (a mixture of produced water and injected seawater) was simulated by adding carbon dioxide to these test environments and testing at 60 deg C. High oxygen levels were injected periodically to simulate the effects of poorly controlled seawater deaeration. Tests were conducted in static and flowing conditions. The results show the sensitivity of these materials to the dissolved oxygen content of injection and commingled waters. Pitting, crevice and under-deposit corrosion occurred to varying degrees enabling guidelines to be developed for material selection in this area.