Rigs_and_VesselsShell hunts high-spec rig for challenging Nigeria workShell wants rig for high pressure, high temperature duties, while Total and Sahara Group target downhole equipment and flowlines for deep-water and onshore assetsJack-up required: Shell seeks high-specification drilling unit for its shallow-water operations in NigeriaPhoto: REUTERS/SCANPIXIain EsauLondon