The next generation of risk-based inspection for coal seam gas wells

Abstract

The coal seam gas (CSG) industry presents some unique mechanical integrity and assurance challenges, in particular: (1) the large well count (thousands), many of which are not identical (in design, process, equipment and layout), and hence have varying inspection requirements; (2) the geographic spread of wells within a field; (3) relying heavily on inspection to confirm equipment condition; (4) significant water and sand production; and (5) rapidly changing process conditions over the life of the well. One particular challenge for many operators is the potential for loss of containment in well-site pressure equipment from very high erosion rates. This, combined with the large asset count, makes physical inspection of each component to ensure equipment condition a challenging and costly task. So, what can a business do to develop an adaptive maintenance strategy to address changing process conditions, allowing them to intervene proactively before a failure occurs and maximising the opportunity to lengthen inspection intervals and reducing inspection costs on low-risk assets? One CSG operator, in conjunction with a leading integrity management service provider, has developed and implemented a dynamic digital twin of the physical condition of their assets by combining live production, monitoring and inspection data, allowing the current and future condition of equipment to be modelled and a risk-based inspection (RBI) strategy that is evergreen and reacts to the changing process conditions. The system built on the NEXUS Integrity Centre platform uses several different predictive models to prioritise assets and components for inspection using live process data and a consistent RBI approach across all static pressure equipment, essentially providing a live digital representation of the current asset condition, the essence of a digital twin. The system provides a prioritised list of assets requiring inspection before the planned maintenance strategy while also highlighting opportunities to extend inspection intervals and thus take advantage of the potential reduction in on-going maintenance costs.