Operators have to contend with many obstacles in order to obtain high-resolution data for their pipelines. The inspection of gas storage laterals is no exception. Though they vary in complexity, with each lateral containing its own unique characteristics, the following obstacles were consistent in each gas lateral presented in this challenge:
- No launchers and no receivers
- Single access point
- 10” lines connect to 20” trunk line
- Limited flow conditions available
After all alternative solutions were evaluated, it was determined that a bidirectional MFL-based crawler solution best suited the challenges present in these storage laterals.
Within five months, ROSEN designed, manufactured, assembled and tested the new self-propelled inspection solution. The robotic solution tool consists of a crawler unit based on an innovative CAM approach. The cams are able to generate enough traction to ensure greater passage capability, safely negotiate various obstacles, all while towing a high-resolution low-friction MFL unit.
As with all solutions, a well-designed fail-safe system is essential; what goes in the pipeline must come out. For this application, ROSEN’s Solution Experts utilized a collapsing “gripper” failsafe and a tethering retrieval unit.
The solution contained innovative elements such as:
- High-resolution MFL technology capable of delivering 100% data coverage
- Bidirectional/low-friction magnetizers
- Onboard power storage
- Visual monitoring
- Power-consumption monitoring
- Sensor detection of T’s
High-resolution complete data sets allow for a full assessment of the storage laterals’ condition and play a vital role in the integrity management plan. This ensures compliance with safety standards and regulations while extending the asset’s lifetime. Due to the small equipment footprint and quick setup on-site, multiple inspections can be completed within one day, allowing for optimal operational effort.
The bidirectional approach avoids the need for costly pipe modifications at the interface between trunk line and lateral as the same location is utilized for insertion and retrieval of the inspection system. As the crawler propels itself, no further field services are required for the execution of the work.