Study of viscosity-temperature properties of oil and gas-condensate mixtures in critical temperature ranges of phase transitions

Transport of oil and gas-condensate mixtures of various compositions is found to be accompanied by a slight increase in viscosity in the coldest period when ground temperatures at depth of a condensate pipeline reach 0 - minus 4 degrees C. Fall in temperature of oil fluids under study to minus 10 -minus 30 degrees. is accompanied by a sharp increase in all structural and rheological parameters of the mixture. Even a slight amount of oil added to a gas-condensate mixture causes a significant decrease in viscosity in the negative temperature range. As a result, cloud and pour point of a mixture falls, its amount decreases, the structure of paraffin deposits changes. (C) 2014 The Authors. Published by Elsevier B. V.