INFLUENCE OF STEAM-DRIVE PRODUCTION ON THE PROPERTIES OF HIGH-MOLECULAR-WEIGHT COMPONENTS OF HEAVY ASHALCHINSK CRUDE-OIL

A comparative analysis has been made of the composition and properties of heavy Ashal'chinsk crude oil produced both by natural flow and by the steam-drive method. It has been shown that the use of the steam-dr ive method in order to improve the oil yield leads to certain changes in the composition of the oil produced, which is reflected in a change in quality of the target petroleum products. In particular, because o f the additional presence in the crude oil of high-molecular weight n- alkanes, there is an increase in the pour point and viscosity index of paraffinic-naphthenic hydrocarbons, which are the main components of residual base oils. An experimental study of the influence of temperat ures characteristic of the steam-drive method (300-degrees-C) on the a sphaltene-resinous components of Ashal'chinsk crude oil confirmed that during steam-drive production these substances undergo degradation pr ocesses associated with detachment of alkyl substituents at peripheral fragments containing sulphur, oxygen, nitrogen and other heteroatoms and consequently are a potential source of alkane hydrocarbons.