Print this pageFormation and Distribution of Coal Measure-Derived Hydrocarbon Accumulation in NW China
Wenxhi Zhao, Yan Zhang, Dafeng Xu, and Changyi Zhao
This study recognizes that the following conditions are necessary for the
Jurassic coal measure-derived oil and gas fields in NW China: (1) The Jurassic
original basins, which were dominated by lacustrine to low-positional swamp
environments, should exist to accept coal-measure related sediments; (2) the
original depositional settings were characterized by low and gentle depressions
and humid climate where oil-prone organic materials accumulated; (3) the
development of the subsequent basins and successive sedimentation should occur
on the Jurassic original basins, which are necessary to keep the coal measure
source rocks progressively maturing; and (4) a certain degree of tectonic
compression took place soon after the 
maturation
of source rocks, which provided
the driving force for the effective expulsion of oil and gas from coal measures.
Most of the coal measure-derived oil & gas fields in NW China are
horizontally distributed along the inner side of lake strandlines. They occur
vertically above or below the threshold of maturation
. Owing to the sharp
variations of lithology and facies in coal measures, the lithologies and
hydrocarbon compositions of oil and gas reservoirs play a significant role in
the oil and gas accumulations of the coal measures sequences.
AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California