This invention relates to a method and to a tool to consolidate a wellbore by displacing conventional cement slurry or any other settable fluid, without any permanent casing. A bladder is inflated inside the bore to act as a mold and to form an annulus that can be filled by cement slurry or any other settable fluid. When the cement or the resin is set, the form is retrieved by straight pull; leaving a cement or resin sheath to support the formation without requiring any re-dulling. The sheath can be perforated if necessary (in the producing zone). Applications include without limitations temporary cementation of mono-diameter wells, through-tubing repair of an open hole, or cementation of a slotted liner in water, oil or gas wells