HYDROCARBON ACCUMULATION PATTERN AND TYPE IN THE SOUTHERN JUNGGAR FORELAND BASIN

There are 4 sets of petroleum systems in the southern Junggar Foreland Basin:Middle Permian,Middle-Lower Jurassic,Lower Cretaceous and Anjihaihe Formation of Lower Tertiary,defined by source rock evolution and reservoir forming period.Regional tectonic evolution characteristics,tectonic types and reservoir features indicate that,main reservoir types in this region include compaction-wrench anticline and anticline-lithologic ones,and fault-screened anticlinal ones take the second position.Based on studies of tectonic characteristics,reservoir forming condition and main controlling factors,accumulation patterns of 3 accumulation zones are set up:accumulations in the west are characterized by thrust rupture belt and unconformities with one-way injection;accumulations in the center are characterized by fault-screened hydrocarbon accumulation with multi-direction injection;and accumulations in the east are characterized by thrust anticline and fault-screened hydrocarbon accumulation with one-way injection.