准噶尔盆地中部2区块高分辨层序地层研究

根据沉积相序变化、准层序叠加样式、测井曲线特征,运用关键坡折带知识,通过伴生的低水位域底界面的识别及附近的超失、削截特征分析,仔细追踪和查明了准噶尔盆地腹部地区中部2区块9条关键界面.进行了侏罗系的高分辨层序地层的划分。研究表明C1井区J_1b_2-J_2t沉积时期可划分出8个三级层序,均具有完整的三分结构:LST、TST和HST;共划分出27个体系域,共识别出准层序组56个,准层序118个。单个层序的厚度105.6～176.8 m,平均140.7 m;单个准层序组平均24.9 m;单个准层序平均11.8 m。

High-resolution sequence stratigraphy of Block 2 in the interior of the Junggar basin

Nine key sequence boundaries in Block 2 in the interior of the Junggar basin are traced and ascertained and high-resolution sequence stratigraphic division of the Jurassic was carried out according to the change in sedimentary facies sequence,stacking patterns of parasequences and features of log curves and by using the knowledge of key slope break zones,identifying the basal boundaries of lowstand systems tracts and analyzing onlaps,downlaps and erosional truncations nearby.The study indicates that eight third-order sequences were distinguished in the well C1 area during deposition of the Second Member of the Lower Jurassic Badaowu Formation to Middle Jurassic Toutunhe Formation.Each sequence was characterized by a complete tripartite structure,including lowstand systems tracts(LST),transgressive systems tracts(TST)and highstand systems tracts (HST)from below upward,and 27 systems tracts,56 parasequence sets and 118 parasequences were identified. The thickness of a single sequence is 105.6-176.8 m and averages 140.7 re;the thickness of a single parasequence set is 24.9 m on the average and the thickness of a single parasequence is 11.8 m on the average.