Alternative packer setting method

Fluid setting pressure is delivered to a hydraulically set well packer through an external conduit strapped to the exterior of a well workstring above the packer assembly. The continuity of the external conduit is continued past the packer assembly by following a flow channel along the mandrel sleeve thickness. Representatively, the external conduit may serve a primary well function other than packer setting (e.g. well chemical delivery). A calibrated rupture element in the external conduit is disposed to initially obstruct external conduit flow past the packer element. Consequently, fluid pressure transferred down the external conduit is first channeled to the packer setting pressure chamber. After setting, the fluid pressure in the external conduit is increased to rupture the calibrated element. When the external conduit flow channel is opened by rupture of the calibrated element, and the additional well service function may be accomplished.