Patent ID: 8408299

Claim:
A method for producing viscous hydrocarbons from a subterranean formation, comprising: a. selecting a hydrocarbon liquid and an aqueous liquid for generating an emulsion, wherein the hydrocarbon liquid has at least one of the following properties: (i) greater than about five weight percent (wt %) asphaltene content, (ii) greater than about two wt % sulfur content, and (iii) less than about 22 dyne/cm interfacial tension between the hydrocarbon liquid and the aqueous liquid; b. generating the emulsion having a continuous phase formed from the hydrocarbon liquid and an internal phase formed from the aqueous liquid, wherein the emulsion is a basic emulsion and the emulsion retains at least 70% of the aqueous liquid when the emulsion is used as a drive fluid, wherein a basic emulsion is substantially free from stabilizing solids and substantially free of any added stabilizing agent or component such as those found in artificially stabilized emulsions; c. injecting the basic emulsion into the subterranean formation for use as a drive fluid; and d. producing said viscous hydrocarbons from the formation using the basic emulsion.