塔里木盆地西端中生界沉积环境与油气地质特征

对塔里木盆地西端喀什凹陷地区地球物理和地面地质资料的综合分析表明,该地区中生界具有多个沉积中心,总体上西厚东薄,向东尖灭。侏罗系具有塔拉斯- 费尔干纳断裂带内的断陷盆地和南天山、西昆仑山前坳陷两个沉积体系,它们之间具有明显的岩相差别。以这两个体系的烃源岩为基础,相应地发育两个体系的含油气系统。喀什凹陷中生界的油气地质特征明显不同于东部库车坳陷与西部阿富汗- 塔吉克盆地,造成这种差异的主要原因是中生代期间的沉积环境不同。

Sedimentary Setting of Mesozoic and Its Petroleum Geologic Features in Western Tarim Basin

The geophysical information and surface geologic data from Kashi sag in Tarim basin are comprehensively analyzed.The study shows that several sedimentary centers appear in Mesozoic of this area,characterized by that the thickness in the west is bigger than that in the east and pinch-out toward the east.There exist two sedimentary systems in Jurassic: one is the fault basin within Talas-Ferghana fracture belt;the other is the piedmont depressions in South Tianshan and West Kunlun mountains,with distinct differences between them in lithology.Accordingly,the source rocks in the two systems produce two petroleum systems,and the petroleum geologic feature of Mesozoic in Kashi sag is obviously different with Kuqa depression in the east and Afghanistan-Tajikistan basin in the west.It is believed that the reason for such differences is that the sedimentary settings in Mesozoic era are different among them.