Drilling fluids having reduced sag potential and related methods

An organophilic clay-free drilling fluid comprising:

• an oleaginous fluid continuous phase;
• an aqueous fluid internal phase;
• a surfactant;
• barite particles;
• and
• a plurality of colloidal particles, the colloidal particles comprising fibrous colloidal particles and at least one other type of colloidal particle;
• wherein the fibrous colloidal particles comprise a clay mineral selected from the group consisting of ground sepiolite particles, attapulgite particles, and any combination thereof;
• and
• wherein the drilling fluid has a density that changes by less than about 5% over at least about 62 hours of static aging.

An organophilic clay-free drilling fluid comprising:

• an oleaginous fluid continuous phase;
• an aqueous fluid internal phase;
• a surfactant;
• barite particles having a size of at most about 45 microns;
• and
• a plurality of colloidal particles, the colloidal particles comprising fibrous colloidal particles and at least one other type of colloidal particle;
• wherein the fibrous colloidal particles comprise a clay mineral selected from the group consisting of ground sepiolite particles, attapulgite particles, and any combination thereof;
• and
• 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 barite particles.