Undersea Catodic Protection Inspections
Undersea Catodic Protection Inspections
The majority of materials currently used for the construction of subsea pipelines and flowlines will corrode if they are not protected from the corrosive seawater environment. The mitigation of corrosion in these systems almost always relies on a protective coating and an effective cathodic protection (CP) system.
BaltRobotics had designed and implemented “Cathodic Protection Underwater Automatic Inspection Technology” (CP-UAIT). This technology is based on AUVs (Autonomous Underwater Vehicle) as the carriers of CP-potential sensors.
Cathodic Protection approach is still at the moment the mostly used for undersea structures corrosion protection: for platforms, rigs, pipelines, etc., and for vessels also.
The Challenge is:
- Pressure capability and hence the operational capacity of O&G pipelines deteriorates rapidly over their lifecycle;
- Increasing environmental awareness following BP Deep water Horizon spill necessitates a more diligent approach to maintenance.
New regulatory and audit requirements:
- “Safety and Environmental Management Systems” (SEMS) by “Bureau of Ocean Energy Management, Regulation & Enforcement” (“30 CFR Part 250”)had been approved and implemented in the regulation;
- “American Petroleum Institute” (API) designed “Recommended Practice 75” (RP75) and it was bringing into force. Now it is the norm for obligatory fulfillment for all US operators from the beginning of 2014.
This, in particular, means that all Oil&Gas offshore operators should make audits by the “third party” – as independent company every 4 years. The initial one has to be done for 2–years from the beginning of 2014.
Currently the main approach for the inspections of undersea pipelines cathodic protection potential was the using of ROV (Remotely Operated Vehicle) with the proper sensors.
The ROV-approach advantages:
• existing and proven technology;
• the number of installed ROV: survey equipment, and vessels;
• the pool of trained staff.
The ROV-Approach disadvantages:
• high CAPEX & OPEX;
• high risks (ROV loss);
• limited area of operations – it means - “shallow water” limitation.
Some ROV-approach figures (Malaysian experience):
• Cost of work – 75,000 -100,000 UDS/day;
• Productivity – 6-8 km/day (depends on weather conditions);
• Working period – 80-100 days per year.
AUV-approach: 1) the system allows offshore oil&gas operator to inspect greater pipeline lengths and more frequently with same budget, and 2) allows multiple AUVs operate from single carrier-ship (ROV has to followed by the ship alone).
AUV-approach advantages:
• low CAPEX & OPEX;
• low risks of losses (because of the absence of tether and umbilical);
• unlimited area of operations (deep and shallow water permitted);
• proven worldwide tendency of the development.
As the last item – according to the market forecast of M&M (http://www.marketsandmarkets.com):
“The global UUV (Unmanned Underwater Vehicle) market will exhibit a robust growth over the next five years.
The global ROV market is estimated to be $1.2 billion in 2014 and is expected to register a CAGR of 20.11% in 2019.
The global AUV market is estimated to be $457 million in 2014 and is expected to register a CAGR of 31.95% in 2019”.
Note: M&M is a full service market research company and consulting firm that produces 400 high-level, strategically analyzed, full-length reports a year, tracking more than 10 industries. This intelligence database comprising of about 400 reports a year, will form one of the world's largest business intelligence resources worldwide.
Thus AUV-market is estimated as more fast growing as ROV one as “+10%”.
Of there are disadvantages.
There are some disadvantages for AUV development:
• lack of underwater communications;
• lack of battery capacity;
• new technology;
• needs the investments;
• has to be implemented.
BaltRobotics practically had resolved the technical ones.
In particular we have now the only in the world implemented Underwater Wireless Video Communication Channel in operation mode in our AUV X-3A and the vessel MAEKSA.
The battery capacity permits the missions of AUV X-3A till 10-12 hours and cover till 10 km of pipeline CP-potential inspection.
For the CP-inspection we use the most accurate approach – with the direct wire contact with sacrificial anode on the pipeline. The CP-inspection are provided in fully automatic mode.