库车坳陷吐格尔明下侏罗统阿合组储层沉积非均质性

HETEROGENEITY OF RESERVOIRS FROM ARHE FORMATION LOWER JURASSIC IN TUGERMING,KUQA DEPRESSION

吐格尔明下侏罗统阿合组为典型的辫状三角洲沉积 ,可分成三角洲平原和三角洲前缘亚相 ,沉积微相主要有辫状河道、水下分流河道、心滩和河口坝 ,沉积方式主要为侧积、填积、垂积和前积。储层层间非均质性受控于沉积微相 ,不同沉积微相砂体具有明显不同的孔渗值。三角洲平原亚相的辫状河道砂体物性最好 ,水下分流河道砂体、心滩砂体次之 ,三角洲前缘亚相的河口坝砂体最差。储层层内非均质性与沉积方式密切相关 ,侧积和填积而成的辫状河道砂体和水下分流河道砂体 ,,其渗透率成正韵律分布 ,最高渗透率段在底部 ,但辫状河道砂体渗透率最高值明显大于水下分流河道砂体 ;由垂积而成的心滩砂体 ,其渗透率在纵向上形成无规则的分布 ;由前积而成的河口坝砂体 ,其渗透率成反韵律分布 ,最高渗透率段在顶部。

The Lower Jurassic Arhe Formation in Tugerming Region is typical braiedd river deltaic sediment and could be divided into deltaic plain and deltaic front subfacies.The formation consists of braided river channel,subaqueous distributary river channel,diara and river mouth bar subfacies formed by side deposition,filled in deposition,vertical deposition and front deposition.Reservoir interbed heterogeneity is controlled by sedimentary subfacies.Different subfacies possess different porosity and permeability.The physical property of braided channel sand bodies is the best;then that of the subaqueous distributary channel sand bodies,diaras and river mouth bars is secondary;that of river mouth sand bars of deltaic front subfacies is the last.The intrabed heterogeneity of the reservois is related to depositional manners.The permeability of the braided channel sand bodies and subaqueous distributary channel sand bodies formed by side deposition and filled in deposition is distributed in normal rhythm,and the highest permeability section is in the bottom;the permeability of diaras shows irregular distribution in vertical;that of river mouth sand bars shows reverse rhythmic distribution,and the peak permeability section is in the top.