deposition in a formation, wellbore, near wellbore region, and production tubing. Compositions of the invention comprise an asphaltene solvent and a viscosity reducing agent, the asphaltene solvent and viscosity reducing agent present in a ratio so as to substantially reduce viscosity of an asphaltene-containing material while substantially negating deposition of asphaltenes either in a reservoir, in production tubing, or both when mixed or otherwise contacting the asphaltene-containing material Methods of the invention comprise forcing a composition comprising an asphaltene solvent and a viscosity reducing agent to contact an asphaltene-containing hydrocarbon in an underground geologic formation, and producing from the formation a production composition comprising at least some of the treatment composition and at least some of the asphaltene-containing hydrocarbon under conditions sufficient to substantially negate deposition of asphaltenes in the formation.