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

摘要： 对库车坳陷的成藏期次和成藏过程进行了研究,结果表明,库车坳陷具有两期成藏的地质条件.晚白垩世-早第三纪末在山前已经形成挤压背景下的构造圈闭,该时期的圈闭主要聚集源自三叠系烃源岩的油气;中新世以来是库车前陆盆地发育的时期,此时构造变形作用最强烈,形成的圈闭以聚集晚期生成的天然气为主.油气源对比结果和储层沥青、包裹体的研究为库车坳陷两期成藏提供了直接的地球化学证据,库车坳陷经历了早期油气的聚集、破坏和晚期天然气聚集、调整的过程.早期(白垩纪末期-早第三纪)成藏以侧向运移为主;晚期(晚第三纪以来,主要是上新世-第四纪)成藏则具有侧向、垂向运移并重的特点.库车坳陷两期成藏对库车油气系统中的油气分布具有显著的影响.

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