--> Pressure Seals--Hydrocarbon Plugging Hypothesis: Is Enough Gas Available in Natural Systems?, by J. Whelan, J. Seewald, and L. Eglinton; #90986 (1994).
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Abstract: Previous HitPressureNext Hit Seals--Previous HitHydrocarbonNext Hit Plugging Hypothesis: Is Enough Gas Available in Natural Systems?

Jean Whelan, Jeffrey Seewald, Lorraine Eglinton

Previous observations on characteristics of organic matter across Previous HitpressureNext Hit transition zones from this laboratory led to a "Previous HithydrocarbonNext Hit plugging hypothesis" for Previous HitpressureNext Hit seal formation and maintenance: oil and heavy bitumen can dissolve in methane and move upward as a single phase at the high pressures typical of zones beneath Previous HitpressureNext Hit transition zones. Previous HitPressureNext Hit build-up beneath the seal, possibly via oil cracking and gas generation, and seal rupture were proposed to allow episodic streaming of this solution through the Previous HitpressureNext Hit drop of the Previous HitpressureNext Hit transition zone. The resulting Previous HitpressureTop drop was calculated to cause formation of a separate gas phase accompanied by precipitation of heavy oil and asphalts, both of which would contribute to replugging of the seal. Here, we describe field data from the Gulf Coast, Nova Scotia Venture Field, and the Mahakam Delta which suggest that this mechanism of seal formation and rupture may be wide spread. Comparisons are made to laboratory data delineating amounts of gas available from different total organic carbon amounts, kerogen types, and sediment types. We also discuss which systems could generate sufficient gas to drive this process.

AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994