辽河西部凹陷曙一区杜84块兴Ⅰ组高分辨率层序地层

摘要

In order to demonstrate the characteristics of high resolution sequence stratigraphy of XingⅠFormation in the Du 84 Block,cores and logging data were applied to conduct the research on the sequence boundaries reorganization,se-quence analysis on single well profile and cross-well profiles of cored wells,interpretation of different level cycle types. We establish the chronostratigraphic sequence framework in the study area.One long-term sequence cycle( LSC1) and two mid-term sequence cycles(MSC1-MSC2)are identified according to unconformity,scour surface and flooding surface. Meanwhile,four short-term sequence cycles( SSC1-SSC4) are further identified according to the sedimentary transforma-tion surfaces and rhythm conversion surfaces.These SSC are subdivided into three basic types and 7 sub-types according to the stacking patterns of cycles of various levels,planar and spatial distribution of sedimentary facies.The three basic types are deepening upward nonsymmetric type( typeA) ,shallowing upward nonsymmetric type( type B) and symmetric type( type C) .Type A mainly develops in the MSC and LSC.And the type C develops in the SSC2.The strata in the whole basin belong to retrograding sequences formed during expansion of lake basin, featuring in multi-cycle mostly having only ascending half cycle and zonation in plane distribution during the SSC.The reservoir sands are best deve-loped at the bottom of the ascending half cycle( SSC1-SSC2) .They consist of stacked underwater distributary channel sand bodies of different periods,and have good reservoir property,thus are the main targets of remaining oil potential tapping in the future.%为阐明辽河西部凹陷曙一区杜84块兴Ⅰ组高分辨率层序地层特征，应用岩心和测井资料，通过层序界面的识别、取心井单井和两条连井（垂直物源和平行物源）剖面层序分析、不同级次基准面旋回类型及特征剖析，建立了全区高分辨率层序等时地层格架。按照从大到小的原则，兴Ⅰ组通过不整合面、冲刷面和洪泛面识别出1个长期旋回（LSC1）、2个中期旋回（MSC1—MSC2），通过沉积环境转换面和韵律转换面细分为4个短期旋回（SSC1—SSC4）。按照不同级次旋回的叠加样式、沉积相平面及空间展布特征，短期基准面旋回细分为向上变深非对称型（A型）、向上变浅非对称型（B型）和对称型（C型）3个基本类型及7个亚类型，中期旋回发育以A型为主，C型在SSC2处发育，长期旋回为A型。全区地层发育体现湖盆扩张期退积型沉积序列的特点，具有多期旋回性、大多数仅发育上升半旋回、短期基准面旋回在平面上分布具有分带性的特征。在上升半旋回的下部（ SSC1—SSC2）储集砂体最为发育，由不同期次水下分流河道砂体叠置而成，储层物性较好，为今后剩余油挖潜的主要目的层段。