The adoption of x-ray inspection by the oil and gas industry brought with it the widespread use of non-destructive testing (NDT) techniques. X-ray inspection technology has made many contributions in determining the integrity and viability of welds and informational or profile shots. The innovation for field use of x-ray continues to be incubated by the oil and gas sector as the need for clear, accurate images of difficult to access or highly-sensitive areas in equipment continues to foster innovation applications to x-ray, particularly when it comes to accessing (imaging) and measuring damaged mechanisms.
The application development and utilization of Digital Detector Arrays (DDAs) in field radiography environments in upstream, midstream and downstream applications, previously limited to film and computed radiography (CR) techniques, has taken off in recent years. The use of DDAs for these applications show benefits of significantly reduced exposure times versus traditional film and CR techniques. These results are enabled by technology investments with a focus on image quality with respect to dose. Unlike cabinet-based radiography, where dose is less important as humans are shielded from the x-ray exposure, field and medical applications must take this into greater consideration. This was a major factor in DDA design and choices for photodiodes, scintillator and display electronics.
Application development efforts have included, and have been successfully implemented in, a wide range of field applications for the oil and gas and industry. The reduction in exposure time not only enables productivity through shorter shot times and the instant availability of images for review and analysis, but also improves overall safety for radiation workers and other employees. This is achieved by decreasing radiation source deployment, and in some cases allows for a decrease in energy or source strength (for review and analysis).
New Possibilities for Inspection
Digital radiography provides new opportunities to inspect and test equipment for damaged mechanisms, particularly due to corrosion and erosion. Items that were not inspected due to time constraints or the removal of insulation may now be inspected quickly and accurately, including:
- Small or large bore piping circuits for TML/CML and wall thickness surveys
- Overhead crude lines
- Choke and Block Lines
- Pipe Supports, including external touch point inspections
The ability to detect corrosion under insulation (CUI) is a huge advantage when utilizing digital and computed radiography. Often digital radiography is used in conjunction with other NDT methods to detect CUI without needing to strip insulation.
New digital methods can help control cost. In production plant inspection the cost of stopping work, building scaffold, providing power and logistics can be reduced. In many cases the actual cost of the total process can be substantially reduced and performed in less time.
Operators and asset owners can now conduct inspections of structures that are thicker and more complex in less time and often with lower radiation sources. New technologies and improvements may be used for both in-process inspection as well as new construction. Enhanced image quality is associated with improved measurement capabilities and increased probability of damage detection.
Corrosion/erosion is a serious problem in the oil and gas industry, and early detection can be the difference between repairing equipment and needing to do a complete replacement. By means of digital radiography, and especially with DDAs, the inspection process can be much more efficient and safer than with traditional film radiography and helps operators and asset owners to optimize preventive maintenance activities and preserve the value of their infrastructure.
To read more about how digital x-ray solutions have advanced NDT techniques, read the full article in Inspectioneering here.
By Richard Mills, GE Radiography SME and ASNT Level III