Lessons Learned From the Qualification Program and J-Laying Campaign of 12-Inch Steel Catenary Risers for the P55 Deepwater Project

摘要

This paper reports the Lessons Learned from an innovative linepipe solution that was successfullyrnimplemented on P55 Deepwater Project. The P55 field is located offshore Brazil, in the northern area ofrnCampos Basin, in a water depth ranging from 1500m to 1900m. The scope of work consisted inrnengineering, procuring, fabricating and installing 16 rigid Steel Catenary Risers (SCRs), which are thernfirst of their kind in this area. The corresponding 12-inch SCR qualification results are presented in thernperspective to show the significant benefits of the technology used and its potential developments to HighrnPressure & High Temperature applications.rnIn order to meet tight Hi-Lo requirements together with high fatigue performances, innovative Pipe EndrnDesign and associated automatic welding procedures were developed and qualified. The paper describesrnthe complete sequence of pipe manufacturing process, from hot-rolling to final machining, which resultedrnin a concentric and reproducible pipe end geometry, ideal for limiting Stress Concentration Factors.rnAn extensive qualification program of Full Scale Fatigue test was conducted on girth-welded stringsrnand the associated results showed performance levels at least four times above the target curve. Moreover,rnLessons Learned from the offshore campaign established that developed Pipe End Design led tornsignificant improvements in welding times and subsequent J-laying rates. Details on how the technologyrneffectively reduces critical times and lowers rejection rates are provided on the basis of the actual P55rnoffshore campaign.rnIn addition to the advantages detailed in the paper, the presented linepipe solution proves to be alsornapplicable to High Temperature fields, since the enhanced fatigue behavior was found to compensate arntemperature derating up to 270°C. In fact, the presented manufacturing and welding technologies havernopened the perspective of ongoing Developments, which are believed to bring a reliable solution forrncombined High Pressure and High Temperature applications.