It is shown, that for a number of West Siberia fields application of different types of reversed emulsions as killing fluids can be not expedient due to their partial demulsification in porous reservoirs because of water globule＇s armouring cover weakening under influence of formation temperatures. Determined is an expediency to apply as killing fluids on such fields oils, gelated and weighted oil-based drilling muds, which are more compatible with reservoir rocks; additional advantage of these fluids is easiness of their utilization by discarding them into field oil treatment system and reduction of stock-tank oil transportation costs. Presented are equations for determination of required volumes of killing fluids for different well killing technologies and their reological parameters with the account to reservoir properties and formation thickness, formation fluids viscosity, applied completion technology and other factors.