Changes

==Differential entrapment==

==Differential entrapment==

The differential entrapment of gas in downdip traps<ref name=ch07r1>Gussow, W., C., 1954, Differential entrapment of gas and oil: a fundamental principle: AAPG Bulletin, vol. 38, p. 816–853.</ref> is achieved by successively filling a sequence of traps in the same formation with oil and gas. As each trap fills to its spill point, the phase that is spilled first is the liquid leg. Thus, the gas is retained in the structurally lower traps and the oil is trapped farther up the migration path. This situation is the expected sequence of entrapment (shallow oil, deep gas) from the maturation sequence. [[:file:migration-of-petroleum_fig7-9.png|Figure 2]] illustrates what happens when traps preferentially spill oil and retain gas.

The differential entrapment of gas in downdip traps<ref name=ch07r1>Gussow, W., C., 1954, [http://archives.datapages.com/data/bulletns/1953-56/data/pg/0038/0005/0800/0816.htm Differential entrapment of gas and oil: a fundamental principle]: AAPG Bulletin, vol. 38, p. 816–853.</ref> is achieved by successively filling a sequence of traps in the same formation with oil and gas. As each trap fills to its spill point, the phase that is spilled first is the liquid leg. Thus, the gas is retained in the structurally lower traps and the oil is trapped farther up the migration path. This situation is the expected sequence of entrapment (shallow oil, deep gas) from the maturation sequence. [[:file:migration-of-petroleum_fig7-9.png|Figure 2]] illustrates what happens when traps preferentially spill oil and retain gas.

==See also==

==See also==