16-Inch InVista Tool Case Study: Navigating the Bends
By: Lilly Darnell, Senior Marketing Specialist, Quest Integrity Group
As seen in the December 2012 edition of Pipelines International. Download the PDF version.
For the inspection of this line, the 16-inch InVista tool was propelled in diesel and achieved a scan rate of approximately 0.3 meters per second (m/s). The tool traveled a total of 471.9 m. The inspection took approximately two hours to complete, and all of the data was collected in one run. Upon retrieval of the tool, the ultrasonic (UT) measurement data was downloaded and prepared for preliminary analysis.
An API 579-1/ASME FFS-1 2007 fitness-for-service (FFS) assessment was performed on the single-diameter line.
The inspection data was analyzed for wall thinning, and anomalies such as corrosion, denting and ovality were determined using the LifeQuest pipeline software. The remaining strength factor (RSF) and reduced maximum allowable operating pressure (MAOP) for the pipe were also determined.
This assessment is based on the longitudinal extent of thinning found in the pipe and in accordance with a Level 2 assessment as found in Part 5 of the API 579-1 standard. Results from the assessment
• 110 external metal loss anomalies were individually identified. The greatest of these anomalies corresponded to 72 percent wall loss, based on nominal wall thickness. The industry standard is to immediately address wall loss between 60–80 per cent
• Four dents in excess of 0.5 percent nominal outside diameter (OD) were identified. The largest identified dent had a depth of 0.8 per cent nominal OD
• The minimum MAOP calculated according to Part 5 Level 2 assessment methodology in API 579-1 was 4.0 MPa.
|Figure 1: 2D and 3D views of external
|Figure 2: 2D and 3D views of a dent.
||Figure 3: The pipeline integrated
The InVista technology is a light-weight tool that can be hand-carried, lifted and loaded. It performs in low flow/low pressure environments and can navigate 1.0D bends, including back-to-back and mitre bends. It was designed to overcome challenges associated with traditionally difficult-to-inspect and unpiggable pipelines. InVista easily negotiates damaged and restricted pipe with minimum passage and tight, back-to-back bends. The tool can run in low-pressure environments, and its bi-directional capability allows it to be launched and received at the same location, minimizing or eliminating line disruptions.
InVista’s unique design reduces operational risk by minimizing the wear, impact and debris collection that is associated with conventional in-line inspection technologies. The tool provides accurate and repeatable results with its direct high-density UT measurement.
The assessment is comprehensive and includes all line data versus individual flaw locations.
Cost effective and time-efficient
An InVista inspection is cost-effective. Data are collected in a single pass and the combined geometry and metal-loss data provide 100 per cent overlapping coverage. The tool minimizes offline status, as it inspects efficiently and allows real-time operating decisions with its on-site turnaround and rapid data analysis – saving time for the operator. Linear UT sizing minimizes verification digs, improving excavation and repair confidence, and permanent line modifications are not required. In addition, it eliminates demagnetization repairs because UT inspections do not permanently magnetize the pipe.
Benefits of the single-module tool include:
• Lightweight; the tool is handled and transported easily, reducing safety and environmental concerns
• Longer battery life and faster on-board computing for greater axial flaw resolution and increased inspection velocity, providing accurate results and time savings
• Ideal for space-constrained environments such as terminals, refineries and offshore
For more information visit the webpage.