塔里木盆地塔中地区奥陶系鹰山组层序地层特征

Characteristics of Sequence Stratigraphy of the Ordovician Yingshan Formation in the Central Part of Tarim Basin

以钻井岩心、测井曲线和地震资料为基础,以Vail的经典层序地层学理论为依据,对塔中地区鹰山组进行了层序地层划分,建立了鹰山组的层序地层格架,共识别出5个层序界面,SB1—SB4为侵蚀不整合,SB5由于长期的暴露风化剥蚀,缺失上覆地层一间房组,为隆升不整合。划分出4个三级层序。层序界面由构造运动及海平面升降控制,层序内部主要发育海侵体系域(TST)和高位体系域(HST)。根据沉积学原理,讨论了泥质含量对测井曲线的影响,从而为利用测井曲线准确划分层序界面和层序间的对比提供了依据。短期暴露形成的储集空间在随后的埋藏过程中极有可能被改造破坏,而SB5形成的古岩溶则可能是储层发育的有利勘探层位。

Based on the observation of tigraphy framework of the Yingshan core, the well log and the seismic data, this study built up the sequence stra Formation using the Vail theory of classical sequence stratigraphy, and identi fled 5 sequence boundaries （SB1 -- SB5）. SB1 -- SB4 are eroded unconformity surfaces, SB5 is the tectonically pressed unconformity surface since it has undergone weathering denudation and misses upper sequence of the Yijian- fang formation. There can be divided into four third-order sequences in the Yingshan Formation. The sequence boundaries were controlled by tectonic events and sea level fluctuation and the inner sequences developed trans- gressive system tract and highstand system tract. According to the sedimentary theory, we discussed the influence of shale content to well-log data, and offered the basis of contrast between well-log and sequence boundary. The ancient karst controlled by SB5 should be developed the reservoir.