Abstract: Carbon black particles and/or optional additional particle(s) may be introduced into fluids, such as drilling fluids, completion fluids, production fluids, stimulation fluids, and combinations thereof. The carbon black particles and/or optional additional particle(s) may increase the electrical and/or thermal conductivity, enhance the stability of an emulsion, improve wellbore strength, improve drag reduction properties, decrease corrosion, and the like. In a non-limiting embodiment, the base fluid may include a brine having at least one multivalent cation.