长岭气田登娄库组储层沉积特征及沉积微相研究

松辽盆地南部长岭气田尚处于开发前期,储层沉积微相及砂体展布规律认识不清。为指导后续开发,结合岩心观察、薄片鉴定、测录井等资料进行了沉积特征和沉积微相研究,明确了沉积微相类型及其空间分布和演化规律。结果表明:下白垩统登娄库组储层为辫状河沉积,可细分为辫状河道、心滩、决口扇、泛滥平原等4种微相;沉积微相具有继承性,总体呈SE→NW向,辫状河道和心滩是沉积主体,决口扇分布局限且与泛滥平原共生。其中,d4-2→d3-2沉积期河道带不稳定、横向摆动和局部调整频繁。d3-1沉积期河流作用弱、泛滥平原发育,河道整体向西南部迁移;d2-3→d1-1沉积期河道稳定、横向摆动幅度小。辫状河道及心滩对油气富集有利,93.4%气层为河道及心滩砂体。

Sedimentary characteristics and sedimentary microfacies research of Denglouku formation in Changling gas field

Changling gas field of Southern area in Songliao basin is still at the early development stage and the understanding of reservoir sedimentary microfacies and sand body distribution rule is not clear.In order to make guidance for subsequent development,in combination with core observation,thin section identification and logging data,the research on the sedimentary characteristics and sedimentary microfacies has been carried out,and the sedimentary microfacies types,spatial distribution and evolution regularities have been determined.The results show that Denglouku formation in lower cretaceous belong to braided river sedimentary reservoirs and can be subdivided into four kinds of microfacies,namely braided channel,diara,crevasse splay and flood plain.Sedimentary microfacies are of inheritance characteristic;generally presenting SE to NW,with braided channel and beach deposition as the main sedimentary bodies,limited crevasse-splays distribution and symbiosis with flood plain.Among them,the channel belt in depositional stage of d4-2→d3-2 is is not stable,with horizontal swing and local frequent adjustment.In depositional stage of d3-1,the fluvial is weak,with developed flood plain and wholly migrated channels to southwest.In depositional stage of d2-3→d1-1,the channels are stable,with small horizontal oscillation amplitude.Braided river channel and heart beach are good for oil and gas enrichment,93.4% gas layers belong to river channel and diara sand bodies.These research results has deepened the reservoir understandings and provided practical significance for follow-up development and optimal areas chosen.