Petroleum expulsion efficiency

After primary migration has taken place, a certain proportion of the generated hydrocarbons remains in the pore system of the source rock (Hunt, 1979). The oil fraction that remains in the source rock will be cracked to gas as the source rock is buried to greater depths and temperatures (Section 3.1.5). The effect of primary migration of hydrocarbons can be indicated by the expulsion efficiency. The petroleum expulsion efficiency is the ratio of the expelled petroleum and the sum of the generated and initial petroleum and can vary from zero (no expulsion) to 1.0 (complete expulsion) (Cooles et al., 1986). The expulsion efficiencies are not uniform in time and space (Leythaeuser et al. 1987b). They depend on the tsrpe of source rock, its richness and thermal maturity and the primary migration mechanism. [Pg.115]

For a certain geological heating rate, the petroleum expulsion efficiency, in combination with the type and richness of a source rock, determine whether oil, gas condensate or gas will be expelled over a certain temperature range (Mackenzie and Quigley, 1988 Figure 3.15). [Pg.116]

PGI = Petroleum Generation Index PEE = Petroleum Expulsion Efficiency... [Pg.117]

Hydrogen index Petroleum generated Expulsion efficiency... [Pg.118]

Lewan MD (1998) Sulfm-radical control on petroleum formation rates. Nature 39 164-166 Leythaeuser D, Radke M, Schafer RG (1984) Efficiency of petroleum expulsion from shale source rocks. Nature 311 745-748... [Pg.434]

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