Relationship
Between the Petroleum Potential and Structural Evolution of Coals
VU Thi Anh, Tiem1, Richard
Sykes2, H. J. Schenk3, Brian Horsfield4 (1)
GFZ, Potsdam, Germany (2) Institute of Geological & Nuclear Sciences, Lower
Hutt, New Zealand (3) FZ Jülich, Jülich, Germany (4)
GeoForschungsZentrum-Potsdam, Potsdam, Germany
The
The obtained data shows that New Zealand
coal is classified as mixed gas- and oil-prone, HI values increase from 120 to
280 (mg hydrocarbons/g TOC) with increasing maturity. The subtracted-normalised
yields between non-extracted and extracted coals were compared with direct
yields based on the analysis of bitumen. The important role of bitumen in
defining the petroleum generation potential was elucidated. Specially, second
order reactions between kerogen and bitumen occurred which reduce the primary
gas yield, but increase the potential secondary gas as well as oil yields. The
comparative investigation with previously studied higher rank Carboniferous
German coals (0.7- 6.1 R0%; Schenk and Horsfield, 1998) showed an excellent fit
for both pyrolysis and infrared spectrometry data, suggesting that the New
Zealand coals can be considered as natural precursors of the German coals.
References
Suggate, R. P., 2000. The Rank(Sr) scale:
its basis and its applicability as a maturity index for all coals.
Schenk, H. J. and Horsfield, B., 1998.
Using natural maturation series to evaluate the utility of parallel reaction
kinetics models: and investigation of Toarcian shales and Carboniferous coals,
AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California