志丹地区延安组沉积微相与油藏控制因素分析

陕西延长石油(集团)有限责任公司研究院,陕西 西安 710075

沉积微相; 油藏类型; 成藏控制因素; 古地貌; 延安组; 志丹地区

Microfacies and controlling factors of hydrocarbon reservoir formation of Yan'an formation,Zhidan area
XU Jing,DONG Li-hong,DU Yan-jun,MA Lang,SHI Xiao-zhang

(search Academy of Shaanxi Yanchang Petroleum(Group)Co.,Ltd.,Xi'an 710075,China)

sedimentary microfacies; reservoir types; reservoir controlling factor; paleo-morphology; Yan'an formation; Zhidan area

DOI: 10.13800/j.cnki.xakjdxxb.2016.0508

备注

利用志丹地区600余口钻井的测井、录井、物性、试油等资料,采用单井相、连井相和平面相多角度综合分析方法进行多期河道叠置的砂体展布和沉积相研究,在此基础上通过对已发现油藏的解剖,分析了油藏类型及油气成藏的主控因素。结果 表明:延10+11期发育辫状河亚相,可划分为河道、边滩、心滩与河漫滩微相,古地貌对沉积微相发育控制显著; 延9期发育三角洲前缘亚相,分为水下分流河道、分流间湾、天然堤与河口坝微相,延8期砂体较延9期发育; 延安组下部油气富集同时受沉积微相、鼻状构造与古地貌的控制,油藏类型以构造-岩性油藏为主; 辫状河的边滩、心滩及三角洲前缘水下分流河道、天然堤微相为有利储集相带,遇到良好圈闭即可成藏。综合分析可判断出古地貌中的斜坡带和河间丘既是有利储层的分布区,又是鼻隆的发育区,最有利于油气成藏。

Integrated of logging,mud logging,reservoir physical property and oil testing data of 600 wells was first utilized to reveal spatial and temporal distribution pattern of sedimentary facies and multi-phase channelized sandbody through well log facies analysis.Moreover,detailed anatomy of discovered hydrocarbon reservoirs shed new lights on controlling factors of their formation.The results show that the paleo-environment of study area during Yan 10+11 period is dominated by braided river,and could be further divided into channel,point and channel bars and flood plain.The distribution of sedimentary facies is controlled by pre-Jurassic paleo-geomorphology.Sedimantary facies during Yan 8 and 9 periods evolved into delta front,including subaqueous distributary channel,interdistributary bay,levees and mouth bar mircofacies.Sandbody during Yan 8 period is greater than Yan 9.Reservoirs within lower Yan'an formation are dominatedly controlled by lithology and tectonics,indicating petroleum accumulation is controlled by sedimentary facies distribution and paleo-geomorphology.Interdistributary bay and mouth bars in braided river,and subaqueous distributary channel and levees in delta front are preferred architectural elements for hydrocarbon reservoirs.Furthermore,the slope and mound occupied by favorable architectural elements should be regarded as sweet pots.