吐鲁番坳陷隐伏巨型弧形构造体系与油气勘探

以吐鲁番-哈密盆地燕山期、喜马拉雅期区域构造应力场和构造展布特点分析为基础，以轴面成图为基础的构造趋势分析技术为手段，通过三维空间构造模拟认为吐鲁番坳陷沉积盖层发育EW向展布的3排弧形构造带构成的隐伏巨型弧形构造体系。模拟研究认为，以盆地中部应力突破带为东西方向对称中心，依附于3大主力生烃洼陷(胜北洼陷、丘东洼陷、小草湖洼陷)发育的巨型弧形构造体系东西两侧的油气地质特征具有一定的可比性和对称性。盆地现今构造东西分段、南北分带的特征明显，区域与局部应力场变化是吐鲁番坳陷弧形构造体系形成且具有东西分段、南北分带构造特征的主要原因。由于燕山中晚期到喜马拉雅期博格达山由北向南的冲断推覆，在盆地内发育大规模由北向南的层间差异滑脱推覆构造，弧形构造带西段以NW向展布为主，东段以NE向展布为主，应力的左旋、右旋特征形成了平面构造格局的“弧形”展布并在盆地内部形成3排弧形构造带。近EW向发育的具有挤压性质的断层构成构造圈闭的良好封堵要素，SN向发育的具有走滑性质的平移断层因沟通中下侏罗统水西沟群烃源岩而构成圈闭的良好输导条件。隐伏巨型弧形构造体系的提出在很大程度上改变了对吐鲁番-哈密盆地整体构造格局的认识，依据弧形构造体系东西两侧的可比性和对称性及弧形构造体系本身的构造特点,对进一步扩展吐鲁番坳陷油气勘探领域具有重要的指导意义。

Buried Giant Arc-shape Structure System and Petroleum Exploration in Turpan-Kumul Basin

Based on the analysis of regional stress fields and structure distribution in Yanshan and Himalayan periods,with the technique of structural trend analysis by axial surface mapping,it is concluded that a huge arc-shape structure system mainly consisting of three local arc-shape structure belts is buried in east-west direction in the sedimentary cover of Turpan Depression.With the symmetric centre of stress break belt in the middle of depression,the petroleum geological features are comparable and symmetrical in west and east phases of the arc-shape structure system,which attached the three main hydrocarbon-rich sags (Shengbei,Qiudong and Xiaocaohu Sags).The structure of basin is obviously characterized by different sections in west-east and various belts in north-south.The change of regional and local stress fields is the main reason for the formation of this type of structure scheme.Because of the different slip within strata from north to south during Middle to Late Yanshan and Himalaya movements,the structure belt of the west piedmont section is mainly distributed in northwest-southeast and the east,northeast-southwest.The left and right cycles of stress fields in west and east sections result in the formation of arc structure system in plane.There are three different arc-shape structure belts formed within Turpan depression from north to south,which formed a huge arc-shape structure system.The extrusion faults in EW development are good sealing elements of structure traps.The strike-slip faults in NS development are good hydrocarbon transporting elements of structure traps because they cut through the Lower Jurassic hydrocarbon source rocks of Shuixigou Formation.The conclusion of this buried giant arc-shape structure system largely changes the overall understanding of tectonic framework of Turpan Depression.The opinions of the comparability and symmetry in EW of this huge arc-shape structure belt system are favorable for understanding the future exploration domains of Turpan-Kumul Basin.