【摘要】 Nugara坳陷东凹勘探面积大,地质条件复杂,钻井数量过少而地震资料丰富。通过优选主干地震剖面,识别特殊的地震反射波终止型式与波阻特征、井-震标定的合成记录以及三维空间的交叉闭合验证结果,建立起Nuga-ra坳陷东凹Darfur群S1和S2两套三级地震层序格架。以地震剖面上可识别出的外部几何形态、内部反射特征、顶底接触关系和地震物理属性等构形要素,并结合已有的钻井、测井资料在研究区内识别和划分出5类13种地震相。其中,席状平行相和席状波状相、充填平行相、楔状前积相是凹陷中的优势地震相类型,分别代表了滨浅湖、半深湖和三角洲沉积,且垂向上具有显著的继承性。从层序S1到层序S2,在沉积环境上反映为湖域的缓慢收缩和三角洲砂体的不断进积。更多还原

【Abstract】 The eastern sag of Nugara Depression has huge exploration area and complex geological situation, with abundant seismic data while few well informations. Major seismic profiles were optimized, and special terminal types and impedance of seismic reflection wave were identified. Synthetic seismogram and the situation about intersectional and closed seismic lines in 3Dspace were verified. Based on the above,S1 and S2 two sets of third -order seismic sequence frames have been established in Darfur Group, eastern depression of Nugara Depression. After that, combined existing data on drilling and logging, 13 seismic facies belongs to S categories are classified in the study area by external geometric shape,internal reflection configuration,contact relationship of top or bottom and seismic physical property which can be found on the seismic profiles. Sheet and parallel seismic facies together with sheet and wavy seismic facies,fill-ing and parallel seismic facies,wedge and foreset seismic facies are the dominating types in the sag, which represent shore -shallow lake or semideep lake and delta deposition respectively. And,the depositional facies are evidently successive from bottom sequence to top sequence which indicate that slow shrinkage of lacustrine facies transforms consecutive prograda-tion of delta sandstone gradually from S1 to S2 sequence.更多还原