Artificial Simulation of Hydrocarbon Generation in Coal Using Hydrous Pyrolysis Techniques

Coal, which is usually land plant in origin, occurs in many oil-producing basins. Microscopically, coal consists of various macerals (liptinite, vitrinite, and inertinite). The generative potential of coal reflects the hydrocarbon potential of the composing macerals (Kelly et al., 1985). Although most coals consist of predominantly vitrinite, some contain significant amounts (>20% of total maceral content) of oil-prone liptinite macerals. Work by Brooks and Smith, 1967; Connan, 1974; Durand and Paratte, 1982; Thompson et al., 1985; and MacGregor and McKenzie, 1986 suggests that certain coals can be considered as source rocks for liquid hydrocarbons. Their conclusions are based on the close association of coal with liquid hydrocarbon occurrences and promising source potential supported by various geochemical analyses. However, the liquid hydrocarbon potential of coal cannot easily be evaluated because of its variable maceral composition, its unique occurrence compared to most source rocks, and difficulty in quantifying liquid hydrocarbon expulsion.