Abstract: Modified surfactants may be added to an oil-based drilling fluid where the modified surfactant is selected from the group consisting of an extended surfactant, a dendritic surfactant, a dendritic extended surfactant, and combinations thereof. These oil-based drilling fluids may be used for drilling a well through a subterranean reservoir, while circulating the oil-based drilling fluid through the wellbore. The oil-based drilling fluid may include at least modified surfactant, at least one non-polar continuous phase, and at least one polar non-continuous phase. The modified surfactant may have propoxylated/ethoxylated spacer arms extensions. The modified surfactant may have intramolecular mixtures containing hydrophilic and lipophilic portions. They attain high solubilization in the oil-based drilling fluid and may be, in some instances, insensitive to temperature making them useful for a wide variety of oil types.