关键词: 陆相油气, 地球化学特征, 油气来源, 远距离成藏模式, 古近系, 塔河油田

Abstract: The Paleogene oil and gas in the Tahe oil field were concluded to be continental in origin according to the physical
properties and geochemical characteristics, including saturated hydrocarbon chromatography, molecular biomarkers and carbon
isotopes. This is in sharp contrast to the marine oil and gas in the Tahe oil field. Combined with previous results of source rock in the
Tabei area, it is concluded that the Paleogene oil and gas were originated from the Triassic and Jurassic source rocks in the Kuqa
depression. Abundant oil and gas sources in the Kuqa depression provide material foundation for the Paleogene oil and gas
accumulation in the Tahe oil field. The Cretaceous and Paleogene have dipped toward the Kuqa Depression in the northern Tarim
Basin, being affected by the collision of the India block in the Himalaya period. This provides the structural condition for oil and gas
migration southward. Source rocks in the Kuqa depression reached high maturity during the sedimentary period of the late Kangcun to
early Kuqa formations. The oil and gas generated from the Kuqa depression migrated to the Paleogene trap along the southern flank
slope. The unconformity between Paleogene and Cretaceous in the Tabei area is an important channel of the long-distance lateral
migration in the northern area. The migration distance could be over 100 km in straight line. The Paleogene mudstones in the Tabei
area act as good regional cap rocks. A variety of elements cooperate with each other to form a long-distance oil and gas accumulation
pattern of the Tahe oil field. As such, distribution of the Paleogene reservoirs in the Tahe area was explained reasonably by the
hydrocarbon accumulation model in this work. This enhances the understanding of the petroleum migration and accumulation laws in
the region, and will be helpful to extend the exploration of Cenozoic clastic rocks in the Tabei area.

Key words: continental hydrocarbons, hydrocarbon geochemistry；oil and gas sources, ultra-long distance hydrocarbon accumulation model, Paleogene reservoir, Tahe oilfied