An open-hole completion has no production casing or liner set opposite the producing formation. Instead, reservoir fluids flow unrestricted into the open borehole. This type of completion, which is rare and is generally restricted to limestone reservoirs, is useful in wells with only one productive zone and low-pressure formations. In an open-hole completion, intermediate casing is set just above the pay zone, and drilling proceeds into the productive zone as far as necessary to complete the well.