When the Flow Stops, Integrity Continues
Innovative sensor design ensures reliable ILI data collection in fluctuating flow conditions
The Challenge
A major liquid pipeline system in North America transports crude oil in batches, with sections up to 500 km inspected in single in-line inspection runs. Due to batching constraints, flow interruptions during inspections are unavoidable.
When batches switch, the abrupt stop in flow creates pressure waves that cause short-lived oscillations in the liquid column. This can cause the in-line inspection (ILI) tool to move back up several meters (Figure 1), which poses challenges for sensitive sensor components and affects data consistency. It may even lead to a failed ILI run. In the past, such events required additional maintenance efforts and repeat ILI runs. Planning inspections under continuous flow conditions was difficult due to operational constraints and unplanned shutdowns.
Asset Description
| Location | North America |
| Product | Crude Oil |
| Pipeline Diameter | 8’’ – 42’’ |
| Survey Length | up to 500 km |
| Operating Conditions | Abrupt flow interruptions, batch operation, pressure waves |
| ROSEN Service | RoGeo XT with reverse-capable sensor |
Our Solution
To address this recurring issue, ROSEN developed a new a reverse-capable sensor design for its RoGeo XT geometry inspection service. The innovation consists of a wedge-shaped sensor head that prevents damage to the sensor suspension while it slides backwards over the pipe surface for longer distances.
The solution was rigorously tested in ROSEN pull-tests, simulating backward movement across girth welds without any sensor or sensor arm damage. Field runs confirmed its effectiveness: Even when minor backward movements occurred during inspections, the RoGeo XT service tools remained fully operational. This design maintains full functionality while eliminating the need for costly workaround solutions, such as using an MFL tool as a “brake.”
Your Benefit
By improving operational stability during flow interruptions, this solution delivers operational and financial improvements.
The key benefits are:
- Increase in ILI run success rate
- Improved scheduling flexibility, with less reliance on the longest shipment batches, resulting in simpler planning and fewer delays
- Cost savings by avoiding per-incident expenses and additional operational costs
- The sensor design keeps the tool fully operational throughout the run, ensuring an uninterrupted inspection workflow
- Enhanced reliability through consistent data quality for integrity management, including in challenging conditions such as permafrost regions
Interested in discussing inspection challenges related to geometry inspection and tool movement? Contact a ROSEN expert.