Abstract: Standard steel catenary riser form is vulnerable to yielding and fatigue damages at the touch down point （TDP） location in the ultra-deepwater environment. Steel lazy-wave riser （SLWR） introduces a buoyancy section into the standard riser form， which can reduce the stress near the hang-off region， and at the same time isolate the dynamic response of the floating platform from TDP region， so as to improve the fatigue life of riser. SLWR installations are analyzed and compared among S-LAY， J-LAY and R-LAY methods， based on a potential ultra-deepwater project in Gabon. The results show that for the riser without buoyancy section， all three laying methods have sufficient layability， and S-LAY is not feasible for laying the 12" SLWR buoyancy section limited by the capacity of HYSY201; J-LAY and R-LAY are found to be more appropriate for both normal laying and buoyancy section laying of 12" SLWR in 2100m water depth. In general， empty pipe condition is better than the flooded condition in terms of layability regardless of laying methods. The feasibility of SLWR laying by S-LAY method can be improved by reducing water depth， pipe size and optimizing buoyancy module design. For J-LAY and R-LAY installation methods， if pipe catenary with buoyancy module section in empty pipe condition has no interference with lay tower and vessel， SLWR can be laid in empty pipe condition.

Key words: steel lazy-wave rise, S-LAY, J-LAY, R-LAY, buoyancy module section