No abstract

We have used nuclear magnetic resonance relaxometry to study emulsions of viscous crude oils for water concentrations in the range 4.9-50.1 wt.%. We obtained the dependences of the proton relaxation parameters for the components of the emulsions (water in droplets, hydrocarbon medium, and boundary phase) on their treatment parameters and the water concentration. The experimental results are interpreted within a proposed model for the proton dynamics. We establish experimental relations between the NMR relaxation parameters and the integral diameters of the water droplets, characterizing their size distribution, for emulsions of crude oils, residual oils, and bitumens.In recent years, the volume of production has increased for high water-cut viscous sulfur crude oils and bitumens in the form of emulsions, the stability of which is determined by high content of asphaltenes, tars, sulfur, turbulent hydrodynamic conditions for movement of the borehole fluid, dispersal of the crude oil by the pumps, and use of reagents for improving oil recovery. For timely prevention of asphalt/tar/paraffin precipitation and selection of conditions for pumping and treatment of such crude oil systems, we need on-the-fly (on-line) monitoring of the concentration of asphaltenes and tars.On the other hand, fuel emulsions have become increasingly important for world energy production as an alternative to black oil for use as a fuel for thermal power plants. Thus for example, water/residual oil and water/ bitumen emulsions are less viscous, their use ensures more complete burning of carbon for low oxygen concentrations, reduction in nitrogen oxide emissions by 65%-80% and reduction of polycyclic aromatic hydrocarbon emissions. Their ash contains up to 260 mg/kg vanadium and 55 mg/kg nickel, and is used as an ore. Use of fuel emulsions makes it possible to save heavy oil fuel and requires minimal burner retrofitting. It seems that water-cut residual oils, industrial organic effluents, and "cleanup" waste from washing barges, tanks, and oil tankers might be used as fuel emulsions. The conditions for stable operation of burners based on fuel emulsions