Among the methods provided is a method comprising: providing an oil-based fluid formed by combining components that comprise a glycol ether additive comprising a glycol ether, wherein the glycol ether additive substantially increases the low-shear viscosity of the oil-based fluid at temperatures between approximately 120 degrees Fahrenheit (48.9 degrees Celsius) and 500 degrees Fahrenheit (260 degrees Celsius); and using the oil-based fluid to drill at least a portion of a well bore penetrating at least a portion of a subterranean formation.