Distribution and composition of organic matter in oil- and bitumen-containing rocks in deposits of different ages

The core samples of oil- and bitumen-containing rocks from Tatarstan's depo sits of different ages were studied by thermal analysis methods (DTA, TG, D TG). Based on the obtained data, a procedure was elaborated for determining the enclosed organic matter content and the index of its fraction composit ion. A significant increase of the organic matter content in the core and its en richment in high-molecular aromatic structures were shown to occur for the oil-containing rock samples when passing from the Devonian to Carboniferous and Permian deposits. The core samples of the Devonian oil-containing rock s may be divided into three groups: the samples taken from the zones where waste water flooding has been started relatively recently (1), or fresh wat er flooding has been carried on for a long time (2) and the samples of rock containing clay minerals as impurities. Thus, thermal analysis can be used in geochemical studies to identify the organic matter enclosed by oil- and bitumen-containing rocks.