二连盆地宝勒根陶海凹陷北洼槽下白垩统构造-沉积响应特征

Lower Cretaceous Cedimentary-Structure Response Characteristics of Baolegentaohai Sag North Subsags in Erlian Basin

通过钻井、地震等资料研究表明,宝勒根陶海凹陷北洼槽发育下白垩统赛汉塔拉组、腾格尔组、阿尔善组及侏罗系为非对称单断箕状凹陷。根据不同区带的沉积构造特点,可将该凹陷划分为东部陡带、中央洼槽带、西部斜坡内带和斜坡外带4个次级构造单元。宝勒根陶海凹陷的断裂系统主要由东部边界大断层控制及其派生出来的二级或三级断层组成,以北东走向断层为主,断层控制了地层沉积和构造形成。宝勒根陶海凹陷东断西超的地质结构控制了沉积相带的展布,多期构造运动形成多期沉积间断和多期湖侵(生油中心),沉积地层具有多物源、近物源和粗碎屑的沉积特点,以扇三角洲、辫状河三角洲和近岸水下扇为特色的砂体类型,形成了低成分、低结构成熟度的岩石类型和中低孔、低-特低渗储集类型。北部主洼槽区沉积生烃中心的缓坡带和中央洼槽带,是发现整装工业性油藏的有利区带。

The drilling and earthquake research material shows that Baolegentaohai sag north subsags de- velopt Saihantala Formation, Tengger Formation, Aershan Formation and the Jurassic stratum, Lower Cretaceous, for asymmetric single broken unsymmetrical fault-depression sag. According to different areas of sedimentary structure characteristics, the sag can be divided into eastern steep belt, central subsags belt the. west slope inside belt and Outside belt count up four subprime c, nits. Baolegentaohai sag fault sys- tems mainly composed of the eastern boundary large faults controlled and its derived level 2 or 3 fault, based on the principle of east to north fault, the faults controlled the formation of sediment-ary and struc- ture. The westfaulting east overlapping of Baolegen- taohai sag geologic structure controlled the exhibition of sedimentary facies belt , many structural movements formated serial sedimentary break and transgres- sion （source center）, sedimentary formations that is nearer provenance, multiple origins and coarse sedi- ment, the sand types were fandelta, braid river deltas and nearshore subaqueous fan, reservoir type was low compositional and textural maturities of turbidites and middle-low porosity and low- low penetranee. The hydrocarbon generation center of ramp zone and central subsags belt in north lord subsags area are fa- vorable zones for the stand industrial reservoir.