As part of an on-going programme of Installations Condition Assessment, Phillips Petroleum Company Norway (PPCoN) have a requirement to obtain high quality, reliable, repeatable and quantitative inspection information. In response to this need, PPCoN have built up a team of highly skilled and experienced inspectors to perform automated ultrasonic testing (UT) on the offshore Ekofisk complex using Force Institute's 'P-scan' equipment.
Having this capability 'in-house' means that PPCoN benefits from:
- Low day-rate inspection costs
- Flexible, rapid response service
- High degree of quality control and quality assurance
- High level of confidence in the results
Recent courses given by TWI have helped PPCoN's 'P-scan' team greatly enhance their capability. The first course covered the automated UT of welds in duplex stainless steel and the most recent course covered the ultrasonic time-of-flight diffraction (TOFD) and creeping wave techniques. This 'know-how', taken in conjunction with previous operational experience, enables the PPCoN team to tackle most of the automated UT applications that they are likely to come across offshore. For example:
- Detect and quantify corrosion in parent metal
- Detect and size weld root erosion/corrosion
- Discriminate between flaws and spurious/geometric indications
- Characterise flaws
- Detect, characterise and size flaws in welds in 'difficult' materials; e.g. duplex stainless steel
- Perform critical flaw sizing for input to fitness-for-purpose analyses
The emphasis on these courses was on gaining 'hands-on' experience of both the acquisition of data and its interpretation. Consequently, practical use was made of TWI's and PPCoN's 'P-scan' equipment and a number of TWI's inventory of welded test samples. Despite the need to freight a significant amount of TWI equipment, PPCoN decided to hold these courses at their shore base in Tananger, Norway.
Lastly, the courses were designed with interaction in mind. Lectures were kept as informal as possible and attendees were encouraged to contribute as much to the course as possible. In this way it was possible for the TWI staff to get a good idea of the inspection topics of primary interest to the PPCoN team and to focus on these issues as far as possible.