关键词: 库车坳陷, 构造演化, 生烃史, 两期成藏, 成藏过程, 油气分布

Abstract: Oil and gas accumulation periods and reservoir forming process in Kuqa Depression were studied.There were geological conditions for twice-period oil and gas accumulation in Kuqa Depression.The structural traps of Kuqa Depression were formed in piedmont front of mountain under the compression action in the period of Late Cretaceous to the end of Eogene.The traps mainly collected oil and gas migrated from the Triassic hydrocarbon source rocks.The foreland basin had been developed and the structural distortion had been the most intensive since the Miocene.The formed traps mainly collected the natural gas generated in late period of accumulation.The conclusion of oil and gas to source correlation and the study on the reservoir bitumen and inclusion show the direct geo-chemical evidences for twice processes of oil and gas accumulation.One is the filling and destroying process in early period,and the other is the filling and adjusting process in late period.The early (end of the Cretaceous period to the Eogene age)formation of reservoir was predominated by lateral migration,and the late (since Neogene,primarily N₂-Q) formation of oil and gas reservoirs was controlled by both lateral and vertical hydrocarbon migrations.The twice accumulation processes had very obvious influence on oil and gas distribution.

Key words: Kuqa Depression, tectonic evolution, hydrocarbon accumulation history, oil and gas twice-period filling, accumulation process, oil and gas distribution