苏6井区下石盒子组高分辨率层序地层学特征

以高分辨率层序地层学理论和技术方法为指导，在苏里格气田苏6井区地表露头、钻井岩心、测井、地震资料综合研究的基础上，通过基准面旋回结构、叠加样式的沉积动力学分析，将该井区下石盒子组划分为2个长期、5个中期和14个短期旋回层序；并较为详细地讨论了各期旋回层序特征；建立了以长期旋回层序界面和最大洪泛面为等时年代地层框架，以中期旋回层序为等时地层单元的高分辨率层序地层格架；通过分析，认为下石盒子组盒₈下段天然气储、盖条件最为有利；有利于储层发育的河道砂体主要出现在长、中期上升半旋回的中、下部，层序界面上相当短期旋回级别的单河道砂体是下石盒子组天然气勘探开发的主要目标。

CHARACTERISTICS OF HIGH-RESOLUTION SEQUENCE STRATIGRAPHY OF LOWER SHIHEZI FORMATION IN SULIGE GAS FIELD, ORDOS BASIN

Guided by the high-resolution sequence stratigraphy theories and methods and based on comprehensive study of surface occurrence, coring, well logging and seismic data, the Lower Shihezi Fm in the Su-6 wellblock in Sulige gas field is divided into 2 long-term, 5 medium-term and 14 short-term cyclic sequences through sedimentary dynamics analysis of the structures of base level cycle and superimposition patterns. The characteristics of each cyclic sequence are discussed in detail. A chronostratigraphic framework is built with the long-term cyclic sequential boundaries and the highest flooding surfaces as isochronous stratigraphic units, and a high-resolution sequence stratigraphic framework is built with the medium-term cyclic sequences as isochronous stratigraphic units. It is believed that the lower 8th member of the Lower Shihezi Fm has the most favorable gas reservoring and sealing conditions, the channel sandbodies favorable for reservoir development mainly occur in the middle-lower parts of the long-term and medium-term ascending half cycles, and the single channel sandbodies corresponding to the short-term cycles on sequential boundaries are the main targets for gas exploration and development in the Lower Shihezi Fm.