The present invention relates to spacer fluids used in subterranean
operations and, more particularly, to spacer fluids that comprise
water-soluble relative permeability modifiers and methods of using the
spacer fluids in subterranean operations. In one embodiment, the present
invention provides a method of displacing a first fluid from a well bore
that comprises introducing the first fluid into the well bore; and
displacing the first fluid with a spacer fluid, the spacer fluid
comprising water, and a water-soluble relative permeability modifier
comprising a hydrophobically modified polymer or a hydrophilically
modified polymer. In another embodiment, the present invention provides a
spacer fluid that comprises water, and a water-soluble relative
permeability modifier comprising a hydrophobically modified polymer or a
hydrophilically modified polymer.