Successful baseline ILI project completed by Quest Integrity in Nigeria

By Chinedu Oragwu, Technical Advisor, Quest Integrity

Project Overview

A major Operator in Nigeria contacted Quest Integrity to perform a baseline ultrasonic (UT) in-line inspection (ILI) for an offshore 10-inch flowline. The baseline inspection was part of a larger offshore pre-commissioning scope with multiple offshore contractors on standby to commission the pipeline as soon as the baseline inspection had been completed. Project delays would adversely affect the client’s KPI and product delivery commitments.

Challenge

The flowline had 8”/10” dual-diameter sections and 26mm wall thickness. In addition to the limited platform space, the launcher and receiver barrels were short (1.2m). The client had a narrow window for the cleaning and ILI campaign due to construction and commissioning demands and required Quest Integrity’s urgent mobilization to complete the baseline inspection.

Solution

Quest Integrity mobilized a two-man crew and two dual-diameter 8”/10” InVista™ UT ILI tools on an emergency basis within two weeks after receiving the initial invitation from the client. No modifications were required to the existing short 1.2m launcher and receiver barrels as the InVista tool was used for this project had a compact length of just 1.1m. Since all InVista tools provide 100% coverage for wall thickness and geometry (caliper) data in a single run, this eliminated the need to run an additional caliper (geometry) or gauge tool, ultimately reducing the time required to complete the baseline survey. Additionally, offshore mobilization and tool handling was enhanced by the 8”/10” InVista tool’s small form factor and extremely lightweight (25kg), making it ideal for the space-constrained environment.

On-site confirmation of a successful baseline inspection was provided within two hours after receiving the InVista tool. Following the field inspection data verification and preliminary report, an API 579-1 / ASME FFS-1 Level 2 fitness-for-service assessment was performed on the entire length of the line. The pipeline inspection data was analyzed for wall thinning and anomalies such as corrosion, denting and ovality, and the fitness-for-service of the pipeline was determined. The remaining strength factor (RSF) and reduced maximum allowable operating pressure (MAOPr) were also reported for the line.

A baseline inspection provides the basis against which integrity management evaluation can be performed through the pipeline service life. Quest Integrity’s final inspection report documents any deviations from the design or installation drawings and identifies any manufacturing anomalies for future integrity management, including condition monitoring locations and recommended inspection intervals.

Quest Integrity’s custom UT ILI technology

Benefits of the InVista Technology

The Quest Integrity InVista technology overcomes challenges associated with traditionally difficult-to-inspect and unpiggable pipelines.

• Improved safety and flexibility – InVista tools are extremely lightweight, short and easy to handle. This allows them to be launched in short barrels, require no lifting equipment, less logistics and shorter preparation time which leads to time and cost savings.

• Simplified inspection process – High-resolution UT sensors acquire direct measurements providing geometry and wall thickness data in a single inspection run; no gauging and caliper pigging is required.

• 30% Local collapsibility - Collapsible design allows for full navigation of the pipeline with a reduced local cross-section up to 30%. Combined with bi-directional capabilities, this alleviates the need to remediate ID restrictions in the case of malfunctioning valves or restrictions.

• Reduced operational risk – InVista tools are low friction, neutrally buoyant, un-tethered, and bi-directional.

• Secondary tool mobilized on-site - A backup tool is mobilized on-site as a standard operational practice to increase project efficiency and minimize the chance of delays at no extra cost to the client.