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PRCI PR-15-9313
- CO2/HS Corrosion Under Wet Low-Flow Gas Pipeline Conditions in Presence of Bicarbonate, Chloride, & Oxygen
- Report / Survey by Pipeline Research Council International, 06/01/2000
- Publisher: PRCI
$298.00$595.00
L51784e
Southwest Research Institute
Need: The ability to transport wet, untreated natural gases through pipelines offshore or at other inaccessible locations is an important factor in the development of new gas fields. When a wet gas contains CO2 and H2 S, the internal corrosion rate of steel pipelines may be expected to increase. Considerable work has been done to define effects of CO2 and H2 S on corrosion rates of pipeline, casing, and tubing steels, particularly at higher pressures and temperatures typical of downhole environments and in gases in which CO2 is the only acid gas present. In particular, studies by de Waard and Milliams resulted in development of an equation for predicting corrosion rates of steels exposed to water saturated with natural gases containing CO2 . However, the de Waard-Milliams equation cannot be used for gases containing H2 S, since it is applicable when CO2 is the only acid gas present.
Benefit: This report was specifically initiated to provide estimates of internal corrosion rates in inaccessible (offshore) pipeline locations from analyses of gas and water samples taken in accessible (onshore) locations. It addresses the ability to transport wet, untreated natural gases through pipelines offshore or at other inaccessible locations, and the internal corrosion rates of steel pipelines.
Result: The results of this study of internal corrosion in wet gas pipelines indicate that there should be a guideline limiting oxygen contamination of pipeline gases to below 10 ppmv, and that chloride contamination should be monitored. As a general rule, corrosion rates increase with increasing CO2 content. By monitoring the pH of drop-out water and the levels of CO2 and H2 S in gases, data generated in this program allow pipeline operators to estimate when and if use of inhibitors is needed to control internal pipeline corrosion.
Southwest Research Institute
Need: The ability to transport wet, untreated natural gases through pipelines offshore or at other inaccessible locations is an important factor in the development of new gas fields. When a wet gas contains CO2 and H2 S, the internal corrosion rate of steel pipelines may be expected to increase. Considerable work has been done to define effects of CO2 and H2 S on corrosion rates of pipeline, casing, and tubing steels, particularly at higher pressures and temperatures typical of downhole environments and in gases in which CO2 is the only acid gas present. In particular, studies by de Waard and Milliams resulted in development of an equation for predicting corrosion rates of steels exposed to water saturated with natural gases containing CO2 . However, the de Waard-Milliams equation cannot be used for gases containing H2 S, since it is applicable when CO2 is the only acid gas present.
Benefit: This report was specifically initiated to provide estimates of internal corrosion rates in inaccessible (offshore) pipeline locations from analyses of gas and water samples taken in accessible (onshore) locations. It addresses the ability to transport wet, untreated natural gases through pipelines offshore or at other inaccessible locations, and the internal corrosion rates of steel pipelines.
Result: The results of this study of internal corrosion in wet gas pipelines indicate that there should be a guideline limiting oxygen contamination of pipeline gases to below 10 ppmv, and that chloride contamination should be monitored. As a general rule, corrosion rates increase with increasing CO2 content. By monitoring the pH of drop-out water and the levels of CO2 and H2 S in gases, data generated in this program allow pipeline operators to estimate when and if use of inhibitors is needed to control internal pipeline corrosion.
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