THE INFLUENCE OF SURFACTANTS ON THE RHEOLOGICAL PROPERTIES OF CRUDE OIL OF NORTH-KOMSOMOLSKOYE FIELD

Abstract

The present work analyses the effects of stearic acid, 2-bis(2-hydroxyethyl) amino ethyl stearate, 2-bis (2-hydroxyethyl) amino ethyl oleate, N-(2-hydroxyethyl) stearamide, N-(2-hydroxyethyl) oleamide, triglyceride of oleic acid with purity of 98 % and neonols AF 9-6, AF 9-10 on crude oil rheology of North-Komsomolskoye field aimed at develop-ment of oil viscosity regulatory methods, consistency setting of spatial structures of coagulator - crystallization type formation within different temperatures. The study of the effective viscosity dependence on shearing rate showed that in the investigated tempera-ture range -10 - +50 °C crude oil floods according to the law of Newton, i.e. the emul-sion is in the range behaves as a Newtonian liquid. At temperatures above 16 °C in a water-oil emulsion appears the destruction of low-energy paraffin- asphaltenes structures at the border of phase separation (the average energy stability 14.4 kJ/mol), in which paraffin hydrocarbons, resin- asphaltenes compounds and mineralized water probably take part. It has been established that surfactants based on stearic and oleic acids which contain fragments of monoethanolamine and triethanolamine increase the effective vis-cosity of the water-oil emulsion, and the triglyceride of oleic acid and neonols AF 9 - 6 and AF 9-10 reduce it. The results showed that neonol AF 9-10 reduces the viscosity of crude heavy oil in the North-Komsomolskoye deposit by 25 times. The use of the Turbiscan technology which allows us to analyze the stability of dispersed systems helps us to determine that the decreasing of the crude oil effective viscosity in the presence of neonol AF 9 - 10 is the result of the loss of stability of oil-water emulsion, which is evi-denced by the increase in the Turbiscan stability index in ~15 times. The laser scanning method shows that at a 5 % neonol concentration of AF 9 - 10 within 20-30 h, more than 20 stable emulsion forms of different density are evolving as a result of adsorption of neonol AF 9 - 10 at the edge of phase separation and its interaction with asphaltenes and oil resins in the formation of solvate layers of the dispersed phase.