Southwest Research Institute® (SwRI®) has developed the CAsed Pipeline COrrosion Model (CAPCOM) software to evaluate corrosion conditions of cased pipeline sections. The software enables SwRI corrosion engineers to evaluate the effectiveness of cathodic protection (CP) systems under the complex geometrical, electrical, and environmental conditions associated with pipeline segments that are cased to prevent external damage or stresses that can occur when pipelines cross or go under a highway, railroad, or river. The software also can be used to evaluate corrosion conditions of the cased pipeline section when there is electrolytic or electrolytic-plus-metallic contact between the casing and the carrier pipe.
CAPCOM can be constructed for a specific set of geometric parameters and field conditions. The constructed model can be visualized using the graphical user interface.
[Image: CAPCOM video thumbnail]
View the CAPCOM video.
These assessments are vitally important for evaluating the thousands of cased crossings estimated by the U.S. Department of Transportation to be located nationwide, many in high-consequence areas. Evaluating corrosion conditions is crucial to improve understanding of:
- Pipe-to-soil potentials along the cased pipeline under various scenarios
- Degree of CP current diversion to the casing pipe
- Level of CP protection received by the carrier pipe
SwRI developed this software specifically to analyze and evaluate corrosion conditions and determine the ability of a CP system to mitigate corrosion of the cased-pipeline segment. CAPCOM is capable of modeling a wide range of pipe, casing, and environmental conditions.
CAPCOM use can be tailored to the availability of data. When sufficient data are available, the model can be fed with the significant number of input parameters required to accurately simulate corrosion conditions of the cased pipeline, and to determine whether CP can protect the casing pipe when there is electrolytic or electrolytic-plus-metallic contact between the casing and the carrier pipe.
Alternatively, when sufficient parameter values, many of which are determined by field measurements, are not available, nominal values can be selected and a range of variability explored. For this mode of application, CAPCOM will provide an expected range of the corrosion conditions, as well as the electrode potential of the pipeline casing.
Geometry and soil conditions at the cased pipeline sections vary from site-to-site and operator-to-operator. CAPCOM can be easily constructed for a specific set of field conditions, and then executed for various scenarios. To provide a basis for effective interpretation, the software offers a variety of interactive tools, including:
- User interface for input parameters including parameter ranges
- Display of structure-to-soil electrical potential color maps along the carrier pipe, including inside the casing
- CP current distribution along the carrier pipe