How dangerous is an axial crack? It’s not always easy to predict. Now oil & gas pipeline operators have a new tool to help them predict axial crack development and make more effective repair, replacement and monitoring decisions.
Battelle PipeAssess PI™ uses empirically derived and physics-based modeling to provide more complete and accurate life prediction than is possible with traditional software solutions. The software was developed as part of a Department of Transportation (DOT) project. DOT used the models developed by Battelle to better understand how axial cracks impact pipeline integrity and make more effective recommendations for pipeline management and risk reduction. Now, Battelle is making the software available directly to oil & gas pipeline operators.
PipeAssess provides several key advantages for pipeline operators. The software models were built using empirical data from Battelle’s extensive “library” of oil and gas distribution and transmission pipes. Pipes with known defects were tested under various simulated operating conditions until failure. Researchers used this data to provide a more accurate model of axial crack development for various pipe types—including electric resistance welded (ERW) and flash welded (FW) pipes made of brittle, quasi-brittle and ductile steels – under different operating conditions. Because the models are more reliable, the software allows operators to make more effective decisions for repair and replacement and reduce the frequency of costly in-line or hydrostatic testing.
There are 2.6 million miles of liquid petroleum and gas transmission pipelines in the United States – many of which are decades old. Over time, aging pipelines can develop axial cracks through normal wear and tear of operation. Hydrotesting can help detect near-critical axial cracks and other near-critical defects. However, this testing is not predictive and it is not always clear whether a detected crack warrants immediate repair, replacement or simply requires continued monitoring. Many companies monitor crack development through repeated in-line inspections, requiring costly operational shutdowns.
PipeAssess can help companies reduce the frequency of in-line inspection and hydrotesting and optimize re-inspection intervals while still meeting DOT requirements for assessment of liquid and gas pipelines. The software incorporates user-defined hydrotest, operating pressure profiles and attribute inputs such as pipe geometry, material properties and crack geometry (from in-line inspection and/or in-the-ditch non-destructive examination) It can be used to model a variety of axial crack geometries, including cold weld, hook crack, selective seam weld corrosion and stitched cracks, and can be applied to all standard in-line pipe sizes and grades.