摘要
四川盆地下侏罗统大安寨段发育有４１～４７个短期、５个中期、２个长期基准面旋回。短期旋回有非对称和对称型两种旋回样式。由短期旋回叠加而成的中期旋回具有不同的堆积模式，分别代表低水位进积、湖侵加积－退积、湖泛加积、高水位早期加积－弱进积和晚期强烈进积小层序组。由中期旋回叠加组成的两个长期基准面半旋回分别代表大安寨期湖水位的长期上升和下降周期，并构成完整的湖进－湖退沉积旋回。通过各级基准面旋回转换点的等时地层对比建立的大安寨段层序地层格架，显示了储层、生油岩、盖层的分布规律与各级次基准面旋回的演化关系，此特征可作为储层预测和评价的重要依据之一。
According to the data of rock cores and well logging interpretations,three order base level cycles were recognized from Daanzhai Formation,Lower Jurassic in Sichuan Basin,which consist of 41-47 short term base level cycles,5 mid term base level cycles and 2 long term base level cycles from bottom to top of the formation.The short term base level cycles could be divided into two cycle types of nonsymmetry and symmetry,of which the former developed fining upward and the latter developed fining upward coarsening.The 5 mid term base level cycles were composed of several short term base level cycles in different stacking pattens and represented respectively the lowstand progradation sequence set,lake transgressive aggradational retrogradational sequence set,lake flood aggradational parasequence set,early highstand aggradational to weak progradational sequence set and later highstand strong pragradational sequence set.The 2 long term base level cycles consisted of 5 mid term base level cycles,and demonstrated separately the changes of the lake level rise and fall in long term during the Daanzhai Epoch,Early Jurassic,and constituted the complete depositional sequence of lacustrine transgressive regressive cycles.According to the high resolution isochronostratigrapnic correlation of the turnround points of the multi order based level cycles,the Daanzhai Formation high resolution sequence stratigraphic framework can be built and it showed the relationship among the evolution of the multi order base level cycles and the distribution of the reservoirs,source rocks and caprocks of the formation.
出处
《沉积学报》
CAS
CSCD
北大核心
1998年第2期42-49,共8页
Acta Sedimentologica Sinica
关键词
高分辨率
层序地层学
四川盆地
下侏罗统
high resolution sequence stratigraphy\ base level cycle\ parasequence set\ isochronostratigraphic correlation\ stratigraphic framework\ Daanzhai Formation\ Sichuan Basin
