A pipeline operator required the inspection of six 12" pipeline segments transporting light crude oil. They wanted to identify circumferentially oriented crack-like indications within an 814 km (506 miles) pipeline with inspection segments ranging in length from 61 km to 251 km (38 to 156 miles) each.
Previous integrity digs identified circumferential crack-like indications requiring the entire system to be inspected to accurately determine the severity of these threats. The majority of the line segments consisted of grade X46 low frequency ERW pipe with 4.78 mm (0.19 in) wall thickness.
Circumferential cracks form at/or near circumferential welds and/or local stress/strain accumulations. They are caused by soil and pipe movement which are typically the result of local earthquakes and landslides.