PIPELINE INSPECTION

Sonomatic has a long history of providing specialist inspections that deliver quality data on pipeline conditions. Our approach is to provide data and analysis that maximises the value of the inspection to the client. We can deliver our pipeline solutions both topside and subsea.

Pipelines are key assets for operator companies and their continued integrity underlies successful business performance. They are essential to production and failures or unplanned downtime can have a major impact on company revenues. Pipeline failures can also have severe safety and/or environmental consequences. Sonomatic assists operators by providing a range of pipeline integrity services including innovative statistical analysis methods that ensure decision making is aligned to the real condition of pipelines. These methods offer a significantly more representative view on pipeline condition and remaining life than traditional methods of data analysis and application of inspection data in pipeline integrity assessments. Application of Sonomatic’s analysis methods leads to major benefits to pipeline operators.

Quantitative Pipeline Assessments

Sonomatic has a long history of providing specialist quantitative subsea inspections on pipeline condition, providing data that will offer the accuracies required that are suitable to use as part of the life extension study. Inspection performance requirements, concerning the accuracy of measurement and Probability of Detection (POD), are key to ensuring a low coverage inspection provides a sufficient basis for statistical analysis of data. Advantages of Quantitative Assessments include:

  • Preferential Weld Root Corrosion/Erosion.
  • Internal Corrosion/Erosion.
  • For Wet H2S Damage in Sour Service.
  • Through Coatings using Advanced Techniques such as DRS and CT.
  • External Verification of ILI Tool Findings.
  • Targeted for Unpiggable Pipelines, Planning and Evaluation.
  • Sampling Scheme Development and Evaluation of Results for lines where the conditions are sufficiently homogeneous.
  • Screening for Pipelines.
  • For Chloride Pitting/SCC in Corrosion Resistant Alloys.
  • Component Geometry Measurements including Ovality/Out of Roundness.
  • Probabilistic Integrity Assessments.

Qualitative Pipeline Assessments

For pipelines, where ILI is considered too costly and a low coverage quantitative inspection does not provide suitable coverage to fulfil the requirements of a corrosion risk assessment, then qualitative inspection methods should be considered. Screening inspection is a less invasive method and typically provides for higher coverage; however, they typically provide a coarse percentage of wall loss at each location. Screening techniques such as medium-range horizontally polarised guided shear waves, introduced by electromagnetic acoustic transducers (EMATs) and/or Multiskip, using shear wave pulse echo probes in a pitch/catch mode of operation, make screening of the pipeline possible and can provide a more global perspective of the pipeline. Advantages of Qualitative Assessments include:

  • Preferential Weld Root Corrosion/Erosion.
  • Internal Corrosion/Erosion.
  • Through Coatings using SH-EMAT’s/Multiskip Techniques.
  • Screening for Pipelines.
  • Probabilistic Integrity Assessments.
  • Bespoke, ROV Deployed Magnetic Crawling Equipment.
  • Does not require Dredging of the Pipeline.
  • Identify areas of interest for follow up Quantitative Inspection.

Pipeline Weld Inspection

The operating conditions and design of pipelines may be such that it is susceptible to cracking in-service. Crack growth can be driven by cyclic loading (fatigue) or by the chemistry of the operating environment (stress corrosion or environmentally assisted cracking). These damage mechanisms are more frequently encountered in welds but can also be present in the parent material. Cracking can be a significant threat to the integrity, with the potential for catastrophic failure in the form of rupture, hence cracking mechanisms are a consideration in the integrity management of pipelines.

Inspection plays a vital role in providing and/or validating whether or not a cracking mechanism is present, the dimensions and locations of cracks present, the growth rate and distribution of growth rate for tracks and the characteristics of cracks, so that the mechanism can be understood. The reliability of this information is fundamental to integrity and operational decisions. Pipeline Weld Inspection techniques and advantages include:

  • Automated Shear Wave Pulse Echo
  • Eddy Current
  • Time of Flight Diffraction (TOFD)
  • Consistent performance with minimised human factor effects.
  • Substaintially improved Probability of Detection (POD).
  • Improved sizing capability.
  • Accurate positional control.
  • Accurate position information for each scan.
  • Full recording of all data for more detailed analysis.
  • Reliable repeat comparisons.

PROJECT EXAMPLES

TARGETED INSPECTION OF CRA WELDS ON WATER INJECTION FLANGED FLOWLINES

A pinhole leak was seen in a flange weld on a 12” Water Injection Flowline at 500m water depth. The pipe and flange were carbon steel API 5L X60 with internal CRA (Inconel 625 Corrosion Resistant Alloy) cladding and the butt weld was also CRA (Inconel) welded...

DEEP WATER ROV INSPECTION ON PIPELINE WITH INTERNAL DEGRADATION

Assessment of a deepwater pipeline identified a reasonably high likelihood of internal degradation. The operator determined that inspection was necessary to establish the depths and characteristics of any degradation present...