Abstract:

The  tectonic evolution and hydrocarbon accumulation  in  the  foreland  fold-and-thrust belt of  the southern Junggar
Basin  is complex.  In order  to  reveal  this complexity and  in  turn provide basic  information  for  regional petroleum exploration
and  fundamental geological studies,  this paper analyzes petroleum accumulation  features. The study area  is characterized by
structurally different segments along the east-west direction, and by structurally different belts along the north-south direction. The
hydrocarbon accumulation  in  these different areas was discussed  from a variety of aspects,  including sources,  reservoirs,  traps,
conduits, preservation, hydrocarbon accumulation and controlling factors. A strong difference in hydrocarbon formation is shown
by reservoir age and source-reservoir-cap type in different geotectonic units. In the eastern segment (i.e., the Fukang fault belt), the
Permian-sourced (including Jurassic-sourced) hydrocarbons were mainly accumulated in Jurassic reservoirs, and the hydrocarbon
accumulation was predominantly controlled by  traps, preservation and reservoirs; In  the middle segment  (i.e.,  the  foreland  fold-
and-thrust belt),  the Jurassic- and Permian-sourced  (including Cretaceous-sourced) hydrocarbons were mainly accumulated  in
Paleogene and Cretaceous reservoirs, and the hydrocarbon accumulation was predominantly controlled by source rocks, oil-source faults and  reservoirs;  In  the western segment  (i.e.,  the Sikeshu sag area),  the Jurassic-sourced  (including Paleogene-sourced)
hydrocarbons were mainly accumulated in Paleogene-Neogene and Cretaceous reservoirs, and the hydrocarbon accumulation was
predominantly controlled by migration pathway and reservoirs.

Key words: hydrocarbon accumulation, difference, foreland thrust-fold belt, southern Junggar Basin