Pipeline design and installation procedure verification

Jee carried out design and installation verification reviews of three pipelines on behalf of Dolphin Energy, for a field they are developing in the Persian Gulf.

Two 914.4 mm (36in) lines by 75 km and 85 km long deliver wellstream fluids to shore in Qatar.   An export line 1219.2 mm (48in) by 390 km long delivers the treated gas to the United Arab Emirates.  These pipelines are in shallow water and care needed to be taken with the relatively thin walls used.

The high temperature of the production streams and the export gas required that all lines include snake-lay and other buckle mitigation measures.

The seabed in the area has variable properties.  For most of their length, the lines remain exposed and untrenched.  At the landfalls, rock dump protection was required.

The initial design calculations and installation procedures for the pipelines were prepared by Saipem. 

Jee reviewed and verified the design calculations and installation procedures by carrying out independent analyses of selected aspects of the designs.  This included assessment of:

• lateral buckling mitigation
  
• stress analysis during S-lay and operational stage
  
• weight coating for on-bottom stability
  
• rock dump at the landfall and supports at the crossings
  
• spanning with particular reference to vortex-induced vibrations (VIV)
  
• intervention measures
  
• quantitative risk assessment (QRA)