塔里木盆地阿瓦提地区阿北1井三叠系高含有机碳泥岩的发现意义

Discovery significance of Triassic dark mudstone rich in organic carbon,well AB1,Avat area,Tarim Basin

塔里木盆地阿瓦提地区阿北1井在三叠系揭示了一套高有机碳含量的湖相暗色泥岩,岩石热解有机质丰度指标达到了中等—好烃源岩标准,但有机质成熟度较低,处于未成熟—低成熟阶段。对台盆区三叠系的沉积、构造背景及热演化历史的研究表明,台盆区三叠系有效烃源岩的发育条件有:1)沉积环境为深湖相—半深湖相,其次为滨湖相;2)暗色泥岩具有一定的厚度和分布范围;3)埋深大于5 500m。阿瓦提地区早三叠世为湖相沉积,现今埋深大,热演化模拟、地震相、沉积相综合研究表明,有效烃源岩区发育面积约5 000km2。

In well AB1 of Avat area of the Tarim Basin,lacustrine dark mudstones rich in organic carbon have been found in Triassic.The abundance of organic matter pyrolyzed from rock ranges from medium to high;however,the organic matter is still in the immature and low-mature stages.Studies of sedimentary,tectonic background and thermal evolution history have indicated that several factors control the generation of effective source rock in Triassic of the platform-basin region.1） The deep and half-deep lacustrine facies are the most favorable,and the shore and shallow lacustrine facies the second.2） Dark mudstones should be thick and widespread enough.3） Buried over 5 500 m deep.During the early Triassic,Avat area was in lacustrine background.Triassic in the study area is buried deep presently.According to thermal evolution simulation as well as studies of seismic and sedimentary facies,the area of effective source rocks in Avat is 2 600 km2.