Drilling Fluids Having Reduced Sag Potential and Related Methods

摘要

Invert emulsion drilling fluids that have extended emulsion stability and reduced sag potential can be realized through incorporation of colloidal particles therein. The invert emulsion drilling fluids can be free of organophilic clays. The organophilic clay-free drilling fluids can comprise: an oleaginous fluid continuous phase; an aqueous fluid internal phase; a surfactant; a weighting agent; and a plurality of colloidal particles, the colloidal particles comprising fibrous colloidal particles and at least one other type of colloidal particle; wherein at least a portion of the plurality of colloidal particles interact with the surfactant to form an associative supporting structure that inhibits sag of the weighting agent.