五墩凹陷中-下侏罗统物源体系及沉积演化特征

The Characteristics of Lower Jurassic Source System and Its Sedimentary Evolution in Wudun Sag

敦煌盆地五墩凹陷勘探程度低,根据钻井、地震及野外踏勘等资料,利用古地貌分析确定物源方向,单井相、地震相分析确定相类型,对五墩凹陷侏罗系物源体系及沉积演化展开综合研究。结果表明,研究区中-下侏罗统发育辨状河、辨状河三角洲、扇三角洲和湖泊沉积体系,物源主要受北西向北山、南部三危山和东部物源体系控制。在五敦凹陷北部和东部发育辫状河三角洲沉积体系,在南部发育扇三角洲沉积体系,凹陷中部为湖泊沉积。

Wudun Sag of Dunhuang Basin had a low exploration degree according to the drilling,seismic and field reconnaissance and other data,Palaeogeomorphology analysis was used to determine the source direction and single well facies and seismic facies analysis were used to determine the phase type.A comprehensive research was carried out on the Jurassic source and its sedimentary evolution in Wudun Sag.Results show that in the Mid-lower Jurassic of the study area,there mainly develop a braid river,braid river delta,fan delta and lake depositional systems,the source rocks are mainly controlled by the north west of Beishan Mountain,he south of Sanweishan Mountain and the eastern source control system.The braid river delta sedimentary system develops in the north and east of Wudun Sag.Fan delta sedimentary system develops in the south and lake sediment develops in the central sag.