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CATHODIC POTENTIAL SURVEYS (CP)
 

 

Regulatory authorities require constant evaluation/auditing of CP systems to ensure structural integrity. CP Surveys allow a system’s ability to resist/avoid corrosion to be monitored, and any corrosion issues to be remedied before the onset of major failure.

 

PMAC Inspection offer a complete Offshore Cathodic Protection Survey & Monitoring service to ensure the integrity of pipelines and structures. This service is based on proven technology with further developed hardware and software to meet industry and legislative requirements and experienced engineers.


Ensuring the integrity of oil and gas pipelines and structures requires specialist monitoring with sophisticated hardware and software. This is an area where PMAC have invested heavily, offering the industry proprietary technology with enhanced data acquisition and management software to meet these demands.

The system is controlled by a proprietary Software system allowing the user to measure, store and report in an integrated package. Advanced connectivity options allow configurable real-time gathered data to be freely passed from the PMAC Systems PC to any other onboard system, such as the survey package or video overlay.

The PMAC CPROS acquisition, processing and reporting software, used in conjunction with PMAC’s experience, offers a choice of data reporting and interpretation methods, to meet the specific requirements of the client. The reporting package uses innovative methods to reduce processing times and hence reduce reporting delivery times, making onboard data processing a real alternative to onshore reporting. PMAC also manage an extensive database of historical data which can be used to monitor CP trends to identify areas of interest throughout the design life of CP systems.

 

Based on the use of the Twin Cells (TC) probe technique, the system gives real time data measurement for both subsea pipelines and structures. Continuous Cathodic Potential (CP) can be measured by either 'cell to cell' or 'trailing ('earth') wire' methodologies as well as electrical Field Gradient (FG) readings and contact spot CP readings are all logged simultaneously. Anode current outputs, estimated remaining life of installed anodes as well as pipelien current density profiles can all be calculated.

​The PMAC Subsea Digitiser utilises the latest technology adding increased reliability. With selectable outputs of RS232 and RS485, the bottle allows multiple configurations for various operational requirements. The electronic housing mounting allow the electronics package to be mounted on almost all ROVs from Observation to full Work Class, or even on deck (topside) if necessary for use with Micro/Mini vehicles.

Data is measured by the subsea digitser at a rate of 3Hz allowing for 'fast' surveys upto a theoretical speed of 5.8 knots.

System electronics are calibrated to record at a resolution of;

  • Contact and Proximity CP to 0.1mV,

  • Contact and Proximity FG to 0.1μV/cm

Calibrations on the electronics have an uncertainties confidence level of 95% and are all traceable to UKAS ISO/IEC 17025 certified testing and calibration laboratories.

In addition to 'Cell to Cell' methodology PMAC also offers Trailing Wire surveys for instances where pipelines are buried or lack contact points as well as and Single Cell contact only surveys and equipment. For pipeline land falls PMAC also offer CIPS/DCVG onshore surveys to complete surveys across beach areas up to test posts or where the pipeline connects to an onshore based protection system.

Our CP technicians hold specialist CSWIP and/or NACE qualifications in Cathodic Protection to assure quality of service and may hold other qualifications such as FMD Radiation Protection Supervisors enabling them to fulfill multiple roles on a vessel saving cost and bed space.

Please do not hesitate to contact us for more extensive information or individual CP consulting.

Download the brochure below to learn more about our Cathodic Potential Surveys (CP)

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