Optimized Downtime Inspection of a Loading Line at a Terminal
Optimal defect detection for both internal and external corrosion features with a bi-directional solution
An operator was in need of a solution to inspect loading lines at a terminal, these lines are used to transport refined products from vessels into the terminal. The assets in question consisted of two 20” gasoline transport lines.
Asset description:
- Pipeline diameter: 2 x 20 inch
- Product: Gas
- Inspection time: 6 days
- Additional information: single access
The challenge
A variety of obstacles made this inspection particularly challenging, these, amongst others, included:
- One entry point to the pipeline
- Complex access for installing the temporary trap for launching and receiving
- Strict time allocation for pipeline modifications and inspection runs
Considering these challenges ROSEN needed to fulfill the following conditions:
- Data quality – optimal defect detection for both internal and external corrosion features to ensure accurate analysis of these crucial assets.
- Optimized field operation planning and execution in order to comply with the time allocated for the inspections
Our solution
Before any tool could be launched and received it was required to implement a series of modifications to the pipeline at the terminal side to allow for the installation of a temporary launching and receiving trap. The trap had to ensure access to the pipeline while allowing our team to safely operate within the complexity of the installations at the terminal.
The tailored solution for the loading lines included a way to ensure the MFL tool would have a clear passage in the line, which required a bi-directional gauging run to validate minimum passage.
Once completed, a bi-directional MFL system was launched to enable corrosion mapping of these assets and thereby enabling the operator to comply with their integrity program. These assets were last inspected in 2009. After careful planning and preparation both the gauging and MFL runs were successfully executed within a time span of 6 days, while each run was completed within 3 to 4 hours in a continuous 36 hrs. operations according to terminal requirements.
According to the method used for these runs, the ILI systems are launched from the terminal site until they reach the subsea Pipeline End Manifold (PLEM).
The end of inspection (EOI) was verified by monitoring discharge pressures at the terminal pumps. When the system reaches EOI, the instruction to the terminal is given to shut down the pumps. ROSEN engineered a circuit by interconnecting both 20” lines with a top side interconnection implemented at the mono buoy. In order to allow for the ILI system to return to the terminal, pumping is done in the reverse direction until the gauging and MFL units reached the receiving trap.
Because of careful planning we were able to launch and receive all ILI systems and achieve successful inspection runs and hereby deliver our outstanding service.
Your benefit
Optimized Downtime
Through the bi-directional approach the time required to complete the inspections runs is shortened, hereby optimizing the asset’s downtime and therefore the operational cost of the operator.
Data Quality
Full coverage maximizes data potential reducing unnecessary digs and downtime for repairs. MFL technology requires only moderate cleanliness diminishing the need for an expensive cleaning campaign.
Safety
Controlled, bi-directional operation including fail safe mechanisms ensuring performance under most possible operational scenarios.
This success of this service was particularly important because the loading lines transport all of the refined product in a high consequence area. Its operation could not be suspended for any reason beyond the pre allocated time for the runs. Additionally, the operator has now validated that bi-directional inspection method as valuable alternative when inspecting loading lines. These methods may add certain level of complexity during the preparation stage but the reliability of the runs and the data quality of acquired sets compensate the extra attention deemed to successfully complete the job. This has lead the operator to perform an immediate repair of a defect at the beach valve site to insure continuous safe operation of the pipeline.