敦煌盆地五墩凹陷中新生代构造演化及其油气地质意义

敦煌盆地五墩凹陷是河西走廊新发现的含油气凹陷,对其研究尚处于初始阶段。通过二维地震和钻井的精细解释,综合分析凹陷的结构特征和构造演化历史,研究认为,根据凹陷的结构特征,将其划分为北部斜坡带、中央洼陷带和南部断阶带3部分;构造演化史可分为5个阶段,即早-中侏罗世断陷期、中-晚侏罗世坳陷期、早白垩世断陷期、晚白垩世-新近纪挤压抬升剥蚀期、新近纪-第四纪走滑-逆冲坳陷期。五墩凹陷下侏罗统大山口组和中侏罗统中间沟组沉积期,有利于主力烃源岩的形成,北部斜坡带发育的辫状河三角洲水下分流河道和南部扇三角洲为有利砂体,是下一步的勘探方向。

Meso-cenozoic tectonic evolution and significance in petroleum geology of Wudun sag in Dunhuang basin

Wudun Sag of Dunhuang basin was newly discovered in Hexi corridor petroliferous sag, its research was still in the initial stage. The structural characteristics and the evolution history were analyzed comprehensively based on 2 D seismic and some boreholes interpretation. Study results indicate based on the structure, the Wudun sag can be divided into three parts: the northern slope belt, central depression belt and the southern fault-bench belt. The evolution history can be classified into five stages, which is early-middle Jurassic faulting period, middlelate Jurassic depression period, early Cretaceous faulting period, late Cretaceous to early Neogene compressional uplift period, late Neogene and quaternary strike slip thrust depression. The sedimentary period of Dashankou group in early Jurassic and Zhongjiangou group in middle Jurassic was favorable for major source rocks, the future direction of exploration area is the braided river delta distributary channel in northern slope belt and the fan delta in southern fault-bench belt.