We developed FlexScan® and Neptune, our inspection tool, to allow integrity engineers to quantify metallic armour layer characteristics. Today, it’s an established subsea tool and has been used in more than 220 inspection programmes around the world.
The answer lay in combining our patented UT scanning technology with Oceaneering’s advanced inspection tool Neptune: an innovation that has taken flexible pipe inspection to a new level.
The integrity data derived from FlexScan® has proved invaluable in allowing Integrity Engineers to be able to quantify metallic armour layer characteristics thus allowing conservatism to be quantified.
Large National Operating Company, Petrobras has suffered a number of serious failures of gas re-injection risers attributed to stress induced corrosion cracking. Analysis revealed that these riser failures occurred in conditions where flexible pipes were being subjected to strong tension and suffered a breach of the external ‘sheath’, allowing seawater to infiltrate the annular sections mixing with CO2. The powerful corrosive effect of this seawater influx compromised the annular sections causing the pipe structure to rupture after only a few years of service, despite a stated design life of 25 years (Upstream).
The client has contracted specialised technical services to carry out external inspections and assess the integrity of its lines in a bid to have a continuous monitoring of flexible riser integrity. This inspection is carried out by Flexlife’s partners Oceaneering using their ROV deployed Neptune Subsea UT scanner supported by Flexlife expertise and proprietary Intellectual Property.
The client conducted extensive hyperbaric testing which advanced knowledge in the field of detecting state change within riser annuli using Ultrasonics. To date we have scanned more than 120 flexible pipe sections clearly identifying risers which have dry or flooded annuli and providing valuable data to verify the safe operating parameters of each flexible pipe section.
We were requested to use our patented ultrasonic scanning technology on flexible gas flowlines, to determine the presence of moisture in the insulation layer, in order to ascertain that they would be suitable for a change of service from gas to oil. The presence of water could potentially cause degradation of tapes in the pipe and affects its structural capacity.
Our ultrasonic technology confirmed the presence of moisture in the insulation layer and our client was able to make an informed, technical and commercial decision regarding the future use of the pipes and field development.
Our client had a, 12” production, free hanging, catenary riser, which was nearing the end of its design life. The riser had a breach within the splash zone and concerns existed over its remnant life.
We were requested to assess the remnant service life of the tensile and pressure armour wires by performing global dynamic analysisand liaising with the pipe manufacture to assess fatigue. Data derived from the UT scanning of the riser provided an invaluable means of quantifying the conservatism regarding the degradation of the armour wires, even given the riser’s breached annulus. The analysis concluded that the riser had a remaining fatigue life of 120 years – more than the production life of the field. Our client continued to operate the riser, retaining Flexlife as its IMR contractor.