By means of vibrational and rotational viscometry, the possibility has been explored to control the rheological properties of heterogeneous systems "viscous paraffin oil-aqueous phase-surfactant" using compositions based on surfactants and alkaline buffer solutions capable of preserving for a long time in a reservoir a set of colloidal-chemical properties optimal for oil displacement. The depressant ability of nonionic surfactants-oxyethylated alkylphenols with various degrees of oxyethylation from 12 to 90 oxyethyl groups in a molecule-with respect to paraffin waxes has been studied, which makes it possible to increase the mobility and lower the pour point of crude oil. The pour-point depressant ability of nonionic and anionic surfactant formulations that are compatible with mineralized reservoir water of oil fields and stable over a wide range of reservoir temperatures has also been studied.