【摘要】 运用层序地层学的原理和方法,结合钻井、测井以及地震等资料的综合分析,确定了塔北—塔中地区三叠系层序界面的类型可通过地震反射特征和测井标志来识别。三叠纪沉积演化经历了4次周期长、规模大的湖侵和湖退,存在4个较明显的湖泛面,可识别出5个层序界面,据此将三叠系划分为2个二级层序和4个三级层序。在单井层序划分和连井剖面对比的基础上建立了塔北—塔中地区三叠系的层序地层格架,分析认为SQ1,SQ2,SQ3和SQ4层序均可识别出LST,TST和HST。LST以发育扇三角洲及辫状河三角洲相砂砾岩为主;TST多以滨浅湖亚相泥岩和粉砂岩为主;HST则主要为浅湖、半深湖—深湖亚相暗色泥岩。对层序格架中的生、储、盖组合特征进行了分析,三叠系构成了4套明显的生储盖组合关系,并从宏观上控制了塔北—塔中地区三叠系油气的分布。更多还原

【Abstract】 By means of theory and method of sequence stratigraphy, and analysis of mud well-logging, and associated with the analysis of seismic data,the sequence boundary marks are determined in Tabei-Tazhong area. The sequence boundary marks are determined by well logs and seismic data. The sedimentary environment evolution experienced four large scale lake level changes and four MFS can be identified. Base on the five stratigraphic sequences boundary recognized, the Triassic is divided into two tectonic sequence and four third-order sequences. We have constructed the sequence stratigraphic framework of the Triassic on the basis of cross-well profile. Sequences SQ1, SQ2, SQ3, SQ4 can be adopted to recognize low-stand system tract (LST), trangressive system tract (TST) and highstand system tract (HST). The LST are represented by the conglomerates and sandstones of fan delta distributary channel and braided channel. The TST is dominated by coastal-shallow lacustrine mudstones and siltstones, and the HST is mainly composed of coastal-shallow lacustrine and semi-deep to deep lacustrine mudstones. Based on the analysis of the character on the source-reservoir-cap rocks, it is pointed out that four sets of the assemblages are developed, and they control the distribution of oil.更多还原