In Asia Pacific, a 40” loading line connecting to a subsea PLEM for transporting crude oil from a local tank farm to sea-going vessels was in need of inspection. The client had initiated a modification of the existing PLEM which would require that part of the pipeline be raised and placed on a structure above the water line. This places significant strain on the pipeline which could further damage existing features. To ensure that this modification could be carried out safely, more knowledge concerning the integrity status of the line was essential. This project presented challenges associated with accessibility, negotiability, and propulsion, specifically:
- Single access to the line from the tank farm area
- The tool must be propelled in both directions
- The tool must stop five meters before the wye piece connected to the PLEM
In order to combat the various challenges presented in this case, the ROSEN team utilized the various elements from the Toolbox to customize the optimal solution package for the customer, including:
- Bidirectional low-friction 40” MFL unit
- High-resolution MFL technology
- 1.5D back-to-back bend passage capabilities
- Pumps controlling a propulsion medium of treated salt water
- Electronic Tool Detector III (EPD III) read-out consoles
- EPD subsea antennas placed on the pipeline for permanent and undisrupted communication
Subsea antennas detected the MFL unit as it traveled through the pipeline and approached the PLEM. The salt water pumps, through which the speed of the unit was controlled, successfully stopped the tool within 5m of the wye piece. The flow was then reversed and the inspection tool was pushed back to the launcher/receiver station. MFL technology was chosen because it provides ideal measuring performance and it is less susceptible to debris in the pipeline.
In spite of unforeseen environmental influences, such as multiple typhoons, the project was completed as scheduled. The collected data ensured a detailed integrity assessment of the entire pipeline. In fact, multiple anomalies were observed within the critical 500-meter zone before the PLEM. With this detailed information, the client was able to make informed decisions to avoid any incidents.
Minimized Risk Exposure
This solution, offering 100% coverage in one pass, not only saves operational cost, but also offers the highest probability of anomaly detection, allowing the operator to engage in an asset integrity management program.
Inspecting loading lines must occur in a timely and efficient manner due to their vital positioning within distribution networks. The solution in this case offers a quick turnaround time as well as a robust and proven technology.
The current market situation calls for an even sharper focus on the care of existing and aging assets in the oil and gas industry. In the case of this particular loading line, the main reason for conducting this inspection was to provide required information to ensure the safe rehabilitation of a vital component.