The effect of supercritical water on conversion of resins, asphaltenes and kerogens in rocks of different lithofacies of Domanic deposits of Tatarstan

Experimental Study on Hydrocarbon Generation Characteristics of Type II Kerogen from Low-Maturity Shale in Supercritical Water

“…The oxidation index ( X oxid ), , the aliphatic index ( X ali ), and the index of branching degree of aliphatic chains ( X brn ) , were respectively calculated by Equations – X o x i d = A 1710 A 1465 X a l i = A 720 + A 1380 A 1630 X b r n = A 2960 A 2930 where italic A represents the peak area, and the results are shown in Table . The increasing X oxid with temperature indicated that SCW not only acted as a heat carrier but also provided oxygen to the kerogen, since the •OH from water readily reacted with the CC bonds of olefins and aromatic rings in addition reactions and then underwent hydrogen rearrangement and dehydrogenation. , The increase of X ali indicated increasing light hydrocarbon fractions that were generated from destruction of large kerogen molecules . The value of X brn of oil generated at 380 °C and 400 °C was similar to the results of Nasyrova’s study on type II kerogen treated by SCW (374 °C), but the value of X brn of the generated oil increased to 1.16 at 500 °C, which indicated the oil generated at higher temperature had more branched aliphatic side chains.…”

“…The increasing X oxid with temperature indicated that SCW not only acted as a heat carrier but also provided oxygen to the kerogen, since the •OH from water readily reacted with the CC bonds of olefins and aromatic rings in addition reactions and then underwent hydrogen rearrangement and dehydrogenation. , The increase of X ali indicated increasing light hydrocarbon fractions that were generated from destruction of large kerogen molecules . The value of X brn of oil generated at 380 °C and 400 °C was similar to the results of Nasyrova’s study on type II kerogen treated by SCW (374 °C), but the value of X brn of the generated oil increased to 1.16 at 500 °C, which indicated the oil generated at higher temperature had more branched aliphatic side chains. The increases of X ali and X brn with temperature, from 0.46 to 1.98 and from 0.60 to 1.16, indicated that raising the temperature promoted cracking of macromolecular organic structures into large quantities of smaller hydrocarbons with long and branched side chains, which was consistent with the lightening of the generated oil from fractional distillation analysis.…”

Structural Alterations of Oils and Domanic Shales During Supercritical Water Injection

“…In refs – , the impact of SBW and supercritical water (SCW) on the transformation of OM in carbonate-siliceous rocks from three deposits in Tatarstan: Romashkino, Tavely, and Bavly, was investigated. The experiments were conducted at various temperatures and pressures in a neutral nitrogen atmosphere.…”