One of the urgent problems in the extraction of hard-to-recover reserves (TRIZ) of oil is the formation of asphalt-resin-paraffin deposits (AFS) at oil fields, which entails a number of complications when extracting reserves from the subsoil. In solving the problems associated with the study of the mechanism of deposition of asphalt-resin-paraffin complexes on the downhole equipment or inside the reservoir, the leading role is played by laboratory studies with modeling of objects and conditions inherent in a particular field. In particular, it is necessary to prepare model solutions of hydrocarbons simulating downhole oil containing asphalt-resin-paraffin deposits.
The purpose of this work was to establish by an experimental method the dependence of the rheological properties of model oil solutions on the amount of asphalt-resin-paraffin deposits dissolved in it, and to study the efficiency of displacing the prepared model oil solution from the bulk model of core with sodium laurine sulfate.
The novelty of the work lies in comparing the effect of the mass content of asphalt-resin-paraffin deposits on the viscosity and density for light and heavy oils and in studying the effectiveness of sodium laurine sulfate when displacing paraffin oil.
Several oil solutions were prepared with various mass proportions of ARPD in them, after which the temperature dependence of the viscosity and density of each solution was determined.
It has been established that the presence of asphalt-resin-paraffin complexes more strongly affects the density when they are dissolved in light oil. As the mass concentration of paraffin deposits increases, their effect on density decreases for both the light oil sample and the heavy oil sample.
The viscosity of the presence of paraffin is much more pronounced if they are dissolved in heavy oil than in light oil. There is a phase transformation point for asphalt-resin-paraffin complexes, which will need to be taken into account when setting up laboratory studies to study the mechanism of deposits of asphaltenes, resins, paraffins in the reservoir or downhole equipment.
An experimental method was also used to study the displacement ability of sodium laurinsulfate on a bulk core model saturated with prepared model oil solutions, which are paraffinic oil. It was established that this surfactant has a greater oil displacement efficiency compared to water, in addition, based on the result, it follows that the oil displacement coefficient non-linearly depends on temperature. So, when oil is being displaced with paraffin deposits dissolved in it, there is an optimum temperature at which the maximum oil displacement coefficient is ensured.
Modeling of Heavy-Oil Flow with Regard to Their Rheological Properties
