新疆博格达推覆构造及其与油气的关系

Bogda nappe structure and its relations to hydrocarbon in Xinjiang

孙自明 沈杰

Sun Ziming Shen Jie

中国石化 石油勘探开发研究院, 北京 100083 2. 中国石化 西北油田分公司 工程监督中心, 新疆 轮台 841600

SINOPEC Petroleum Exploration and Production Research Institute, Beijing 100083, China 2. Engineering Supervision Center, SINOPEC Northwest Oilfield Company, Luntai, Xinjiang 841600, China

博格达山位于新疆北部，南、北两侧分别为吐哈盆地和准噶尔盆地夹持。博格达推覆构造是指博格达山的西段，由于与油气等矿产关系密切，一直引起人们的关注，但关于其组成与结构、成因机制和演化历史等尚不十分清楚。通过地表地质、勘探地震和大地电磁测深等资料的综合研究，指出博格达推覆构造由近东西向展布的柴窝堡盆地和博格达冲断隆起组成，前锋为阜康断裂，东、西两侧由近北东向延伸的乌鲁木齐—米泉断裂和达坂城—老奇台断裂2条调节断裂围限，底部主滑脱面位于中地壳，推覆体根部位于中天山北缘断裂。推覆构造从南向北由多条分支逆冲断裂分隔为变形特点各异的次级构造单元，构造样式自南向北由基底卷入型过渡到盖层滑脱型。博格达推覆构造的形成受控于准噶尔盆地向南的深俯冲作用，在侏罗纪末期至白垩纪早期已具雏形，白垩纪至古近纪又发生了向北的大规模逆冲推覆，新近纪以来再次向北强烈推覆并导致博格达山急剧隆升，最终形成现今构造面貌。阜康凹陷位于推覆构造前缘，构造稳定，油气保存条件优于推覆构造内的柴窝堡盆地，是寻找大中型油气藏的有利地区。

Located between the Turpan-Hami Basin in the south and the Junggar Basin in the north in the northern Xinjiang, China, the Bogda Mountain extends in the east-west direction, and can be divided into the east and the west segments from Qitai according to geomorphology. The Bogda nappe structure refers to the western segment of the Bogda Mountain, and more attention has been attracted due to its close relationship with oil and gas and other minerals, yet its composition and texture, formation mechanism and evolutionary history are not very clear. The comprehensive analyses of field outcrops, seismic sections and magnetotelluric data show that the Bogda nappe structure mainly consists of the EW-trending Chaiwopu Basin and the Bogda anticlinorium, with the Fukang fault as the frontal boundary while the western and eastern boundaries are defined by the Urumqi-Miquan and Dabancheng-Laoqitai adjustment faults, respectively. The main detachment lies in the middle crust and the root fault is the northern boundary fault of the Middle Tianshan orogenic belt. The Bogda nappe structure is divided by faults into several sub-units with remarkably different features from south to north. Structural pattern changes from basement-involved structure in the south to cover detachment structure in the north. The formation of the Bogda nappe structure is controlled by the deep subduction of the Junggar Basin into the Bogda Mountain. Three evolution stages are identified, as known: rudiment from the Late Jurassic to the Early Cretaceous, large-scale nappe to the north from Cretaceous to Paleogene, and again large-scale nappe to the north which resulted in the strong uplifting of the Bogda Mountain ever since Neogene. Located in the front of the nappe structure and with better settings than the Chaiwopu Basin, the Fukang Sag is a favorable area for middle to large size oil pool exploration.

中国石化科技部项目《西部山前构造带构造建模与有利区带评价》（P07015）资助。

https://doi.org/10.11781/sysydz201404429