松辽盆地新立地区浅水三角洲水下分流河道砂体结构解剖  

Sandbodies Frameworks of Subaqueous Distributary Channel in Shallow-Water Delta,Xinli Area of Songliao Basin

作　　者：王家豪[1] 陈红汉[1] 江涛[2] 唐振兴[2] 赵宝峰[1] 徐东浩[1] 

机构地区：[1]中国地质大学构造与油气资源教育部重点实验室,湖北武汉430074 [2]中石油吉林油田分公司勘探开发研究院,吉林松原138000

出　　处：《地球科学（中国地质大学学报）》2012年第3期556-564,共9页Earth Science-Journal of China University of Geosciences

基　　金：国家"973"课题资助(No.2012CB214804)

摘　　要：上白垩统嫩江组三段时期,松辽盆地进入坳陷晚期演化阶段,浅水三角洲广泛发育.在新立地区,与III、II、I3个砂组对应,嫩三段由3个浅湖-三角洲前缘的沉积旋回组成,指示了湖盆水体逐渐变浅的过程.基于研究区密井网资料,通过对3个砂组沉积相平面展布和水下分流河道砂体结构解剖表明,随着盆地坡度逐渐变缓和水体变浅,三角洲规模迅速增大,水下分流河道稳定性增强,单支水道延伸距离增加,分叉-合并频率降低,决口-漫溢作用增强,水下分支间湾面积比例增加,由此导致水下分流河道砂体连通性依次减弱,分别呈中厚席状、窄薄条带-斑块状、宽厚条带状,并控制了油藏类型由构造型向岩性油藏的转变.最终,归结出网状、枝状、似曲流河3种浅水三角洲沉积模式.The Songliao basin evolved into the late down-warping stage, and shallow-water deltas had extensively developed in the third Member of Nenjiang Formation, Upper Cretaceous. In the third member of the Xinli area, three depositional cycles were identified to be evolved from shallow-lake subfacies to delta front subfacies respectively, indicating gradually shallowing lake. Accordingly, three sand-units of III, II and I were divided from the bottom to top. Based on abundant data of dense wells, sedimentary facies maps and sandbodies structures of subaqueous distributary channel in each sand-units were analyzed in detail, and a series of changes accompanied with basin flattening and shallowing gradually were summed up as follows.- ddtas farther extended; subaqueous distributary channels more stabilized; single channel farther elongated; channels less bifurcated and converged; crevasse splay occurred more frequently; subaqueous interdistributary bays distributed more extensively. Con sequently subaqueous distributary channel sandbodies less connected with each other and can be described as moderately thick sheet-shaped, narrow-thin strap-shaped to speckle-shaped, and wide-thick strap-shaped respectively, which resulted in oil pools styles transforming from tectonic reservoirs to lithologic reservoirs. Finally, corresponding to the three sand-units respectively, three depositional models were summarized to be reticular, ramiform and meandering river-liking.

关 键 词：松辽盆地 浅水三角洲 水下分流河道 岩性油藏 石油地质 

分 类 号：P624[天文地球—地质矿产勘探]