InspectTM Computed Tomography for NDT of Subsea Pipelines

Abstract

Using Computed Tomography (CT) for 3D spatial analysis is a well-established technique primarily used in the fields of medical imaging and precision defect analysis of materials such as aircraft CT technology is gradually evolving for asset integrity within the Oil and Gas sector for two main applications: in-line inspection (ILI) verification and non-intrusive inspection (NII) of coated subsea pipelines. The CT scanning philosophy for both types of inspection challenges varies significantly and in this paper is considered in terms of alignment of inspection deliverables with scan definition. This paper explores the redesign of the traditional CT approach to optimize scanning for high-density target volumes by implementing a ground-up approach to all hardware and mathematics. The advanced algorithms used in the InspeCTTM technology enables a novel technique for image reconstruction; allowing for cleaner images than are possible using traditional CT whilst using less data and hence smaller radioactive sources. In addition, this paper demonstrates a selection of important findings from the InspeCTTM system qualification to API Standard 1163. To maximize the effectiveness of the subsea campaign, use of automated analysis is demonstrated to provide consistency in interpretation and reduce the considerable time demands of high-volume data analysis enabling any remediation decisions or change to inspection strategy to be actioned at the time of inspection rather on a future campaign.