Qualification of Enhanced SCR Design Solutions for Improving Fatigue Lifeat Touch Down Zone

摘要

Steel Catenary Riser (SCR) is a proven and economic riser systemrnsolution, as a tie-back production riser and as an export riser fromrnfloating production systems, in development of oil and gas fields inrndeepwater and ultra-deepwater. But application of SCRs is challenged inrnsome cases due to high fatigue damage at Touch Down Zone (TDZ)rnfrom a combination of field specific parameters, such as riser size, fluidrncharacteristics, vessel motions, metocean parameters, soil conditions,rnand water depth. A number of solutions to this problem were evaluatedrnin a JIP during 2004 and four selected solutions were carried forward tornqualification testing and analysis during 2005 and 2006. The JIP isrnbeing supported by 10 companies, including 5 major manufacturersrnwhose products are used in these solutions. The solutions for fatigue lifernenhancement at SCR TDZ include use of: light weight coating over steelrnriser sections; steel riser sections with upset ends; high strength steelrnriser sections with integral connectors; and titanium riser sections. Thernmechanisms through which fatigue life enhancement is achieved varyrnfor these solutions. Two case studies were undertaken in this JIP torndefine the requirements for each of these solutions with potential tornincrease the fatigue life at SCR TDZ by a factor of 10 or more. Therndesign, analysis, manufacturing of samples, laboratory and full scalerntesting efforts undertaken to qualify these solutions for intendedrnapplications and current status of the JIP are identified. With thernqualification effort undertaken in this JIP, the project readiness of thesernsolutions has been increased for their consideration in SCR designs withrnTDZ enhancement at the concept selection and front end engineeringrnstages of deepwater field development projects. The potential alternativernapplications of the solutions developed in this JIP are also identified.