The results of rheological measurements of a composition with two gelling components obtained in rotational mode and oscillation mode at different temperatures are presented. The kinetics of gel formation was characterized, and the strength of the formed structure was assessed. The gelation points and elastic moduli of the gel were determined.

In this work, the rheological properties of low-temperature versions of gel-forming compositions developed at the IPC SB RAS are studied. A composition on an inorganic basis and a composition comprising a polymer and inorganic components are intended to increase oil recovery from low temperature reservoirs. The measurements were carried using a Haake Viscotester iQ rheometer with a CC25 coaxial cylinder measuring system in oscillatory mode with controlled strain at a frequency of 1 Hz. During the oscillation test, the dependences of the elastic modulus G' and the viscosity modulus G" on the strain amplitude were recorded, the ranges of linear viscoelasticity of the samples under study were established, and the strain value for kinetic experiments was chosen. At a given strain value (0.01), the kinetic dependences of G' were obtained and the dynamics of the rheological properties and the strength of the formed structure were evaluated. The time of gelation onset has been found. It was 2300 s at 38 degrees C, 3900 s at A at 30 degrees C, and 21000 s at 20 degrees C for the inorganic composition and 200 s at 70 degrees C, 570 s at 60 degrees C, and 1920 s at 50 degrees C for the polymer-inorganic composition. The time required to form a gel of maximum strength also was found to be increased with increasing temperature. It has been established that for all systems under study the time of gel formation was reduced with increasing temperature, while the strength of the formed structure also increased. A slight increase in the maximum value of the modulus G' (33 490 and 32805 Pa) was observed for the composition on an inorganic basis at 38 and 30 degrees C respectively as compared with the maximum of the dependence obtained at 20 degrees C (24660 Pa). The major increase in the value of the modulus G' has been recorded for the composition on a polymer-inorganic basis with increase in temperature. In this case the value of the modulus G' increased from 8970 Pa at 50 degrees C to 11680 Pa at 60 degrees C and 14590 Pa at 70 degrees C, while the general form of the rheokinetic dependence for different compositions and temperatures remained the same.

The results of rheokinetic measurements of changes in the fluidity of gel-forming compositions of various natures obtained by the methods of rotational and selection viscometry are presented. A technique for processing measurement results obtained by means of vibrational viscometry in measuring vessels of different sizes has been developed. Two directions of the interpretation of nonmonotonic rheokinetic dependences are considered.

Изучены равновесные условия для гидратов, полученных из эмульсий воды в нефтях Юрубчено-Тохомского, Верхнечонского, Герасимовского и Усинского месторождений, а также относительные скорости образования гидратов в соответствующих системах. Сделан вывод, что присутствие нефти не изменяет равновесных условий гидратообразования. Увеличение содержания в нефти смолисто-асфальтовых веществ и парафинов приводит к уменьшению скорости гидратообразования.

Equilibrium conditions for hydrates obtained from water emulsions in crude oils of the Yurubcheno-Tokhomskoe, Verkhnechonskoe, Gerasimovskoe, and Usinskoe fields have been studied, as well as the relative rates of hydrate formation in these systems. It has been concluded that the presence of oil does not alter the equilibrium conditions of hydrate formation. An increase in the concentration of resin-asphaltene substances and paraffins in crude oil leads to a decrease in the hydrate formation rate.

Crystallization onset of paraffins was studied by the low-frequency vibratory method in various kinds of dispersed petroleum systems before and after introduction of additives.

A scanning method for determining the rheological characteristics of two-phase liquids and the corresponding experimental technique are considered. The structure of mechanical resistance of the water-oil contact region and its relation to the interphase tension have been shown.

The recovery of the mechanically broken crystallization structure of a high-paraffinicity oil was studied by a vibrational viscometry technique. A rapid initial step of the process was observed. The mechanical resistance of the broken and the rebuilt structure was measured. A relaxation equation was suggested to describe the kinetics of the process.