INVESTIGATION OF THE FRACTIONAL COMPOSITION OF HEAVY OIL RESIDUE-BEARING ROCKS FROM THE CHIMYON AREA OF THE FERGANA REGION

Abstract

This study investigates the geological, petrographic, and bituminological characteristics of heavy oil residue-bearing rocks from the Chimyon–Shor-Su area of the Fergana Region. Field observations showed that bituminous material is mainly distributed along fractures, pores, and cavities within the host rocks. The investigated samples included limestone, sandstone, marl, sulfur-bearing rocks, and bituminous “waxy stone.” Petrographic examination demonstrated that the bituminous matter occurs within carbonate-clayey aggregates, pore-filling cement, and rock fractures. Luminescence-bituminological analysis showed that the chloroform-soluble extract content ranged from 0.00016 to 0.160%, whereas the alcohol-benzene-soluble extract varied from trace amounts to 0.080%. The highest concentrations of neutral bitumoids were detected in shell limestone, sandy limestone, and calcareous “waxy stone.” Ozokerite-bearing rocks from the Shor-Su area were characterized by a high proportion of solid hydrocarbons, indicating enrichment in heavy, high-molecular-weight, and high-boiling petroleum components. The obtained results provide a scientific basis for further investigation of the fractional composition of the extracted organic matter and for evaluating its potential for thermal or catalytic processing.