VISCOSITY AND PHASE-BEHAVIOR OF PETROLEUM FLUIDS WITH HIGH ASPHALTENECONTENTS

The aim of this paper is to provide original experimental data on the viscosity of five synthetic crude oils and of three stock tank oils. T his work completes a series of measurements on eight synthetic crude o ils that have been published previously [A. Werner, F. Behar, J.C. de Hemptinne, E. Behar, Org. Geochem. 24 (10-11) (1996) 1079-1095]. All f luids are composed of dissolved gases (except the stock tank oils), li ght and intermediate hydrocarbons and a heavy oil fraction containing resins and asphaltenes. A large range of petroleum fluids, from source rock to reservoir fluids are thus modelled. The study of crude oil vi scosities first requires the investigation of the phase behaviour in t he same operating conditions. Seven synthetic crudes precipitated asph altenes due to their elevated gas and low aromatics concentration. We observed at our experimental conditions of 35 MPa and 100 degrees C an increased risk of asphaltenes precipitation for petroleum fluids cont aining more than 28 wt.% of gas and less than 25 wt.% of aromatics. Vi scosity measurements cover a range of more than two orders of magnitud es from 0.29 to 67.5 mPa s. The crude oil viscosity depends strongly o n composition, especially on the gas and asphaltene concentrations. (C ) 1988 Elsevier Science B.V. All rights reserved.