【作者】 邹德江；

【导师】 于兴河；

【作者基本信息】 中国地质大学（北京） ， 矿产普查与勘探， 2009， 博士

【摘要】 冀中坳陷深县凹陷古近纪以来盆小水深,地层产状较陡,双同沉积断裂控制湖盆发育,断裂系统复杂,目的层段储集体具有规模小、相带窄、砂层侧向变化复杂等特点,勘探程度较低。研究该类型湖盆层序地层特征、沉积特征及其控砂机制,对深县凹陷及类似地区的构造—岩性地层油气藏勘探具有重要的理论与实践意义。论文在岩心观察的基础上,根据录井、测井及地震等资料,采用高分辨率层序地层学及储层沉积学原理与方法,利用井震结合地层对比、地震属性分析、井震多元回归拟合含砂率计算、波形分类地震相分析、古地貌恢复、层拉平、平衡剖面、构造沉积耦合关系研究等多项技术,遵循由点(井)→线(剖面)→面(平面)→域(时间演化与空间展布)→点(目标)的研究思路,在高分辨率层序地层格架内分析研究区目的层段各时期沉积体系平面展布及垂向演化特征,进而研究断陷湖盆层序充填模式及控砂机制,结合油气成藏特征进行构造—岩性地层圈闭预测及确定有利勘探目标。通过以上研究,本文主要取得以下认识:1、根据地层的旋回特征和叠加方式进行地层划分与对比,将深县凹陷古近系地层共划分3个II级层序,11III级层序,22个IV级层序,首次完成整个凹陷高分辨率层序划分与格架建立,并与冀中坳陷层序划分结合,实现了局部与整体的统一。2、归纳出本区岩性上南粗北细、相带上南扇北辫并分析其成因、总结出深县凹陷总体控砂规律:构造控物源、地貌控沉积;缓坡调节带、陡坡下切谷;3、共识别出五种沉积相,总体为湖相背景,具有断陷湖盆沉积充填的典型特征。Ek-SQ～Es4-SQ为湖盆初始裂陷期沉积,地势起伏,水体独立,冲积扇、扇三角洲及大型辫状三角洲较发育,沉积大套粗粒的砂砾岩及砂岩,油气显示较弱;Es3-SQ1～Ed-SQ3沉积经历了断陷湖盆深陷扩张、构造抬升、构造回返、湖盆消亡的完整过程,早期湖盆发育各类近源扇三角洲、辫状河三角洲沉积体系,同时Es3-SQ2与Es1-SQ1上升半旋回与下降半旋回的转换位置发育的暗色泥岩为油气生成提供了良好的烃源岩;后期河流相中的河道、心滩和边滩砂体,为本区主要的油气储集砂体;4、在层序地层格架内,分区带评价了油气成藏特征及油气控制因素,分析了两个有利目标区带(深西洼漕斜坡和衡水断裂下降盘)。分析认为本区油气勘探以构造油气藏和岩性油气藏并举为主要策略。更多还原

【Abstract】 Since Paleogene,the basins were small and the water was deep in Shenxian sag Jizhong depression, thus,attitude of stratum was steep. Furthermore, double contemporaneous faults controlled the development of the lacustrine basins, rift system was complicated, the reservoir of intended interval was small, of which facies belt was narrow and lateral variation of sands was complicated, whose exploration degree was also lower. It has great theoretic and practical significance for structural stratigraphic hydrocarbon reservoir exploration of Shenxian sag and similar areas to study the sequence stratigraphic characteristics and sedimentary characteristics of the lacustrine basins and its mechanism about how to control the sands.On the basis of core observation, according to the data of geo-logging, well logging and seismic, applying the principle and methodology of high resolution sequence stratigraphy and sedimentology, adopting many techniques such as strata correlation by combinating well with seismic, seismic attribute analysis, sand ratio calculation by multiple regression with well and seismic data, waveform classification and seismic facies analysis, palaeogeomorphology reversion, flattening seismic strata, balanced section, study of coupling relations of structure and sedimentation, etc, following the research path of point(well)-line(profile)-map(plane map)-tract(temporal evolution and spacial distribution)-point(trap), the depositional system’s planar distribution and vertical evolution of intended intervals of each period in the region of interest were studied in the HR isochronous stratigraphic framework and then the sequence packing model and mechanism about how to control the sands of the downfaulted lacustrine basins were also researched. Finally, structural stratigraphic hydrocarbon reservoirs were predicted and beneficial explortion targets were ascertained. Through the above studies, the following achievements were acquired.1. According to the stratigraphic cyclicity and superimposed patterns, stratigraphic division and correlation were made using the base level as sequence boundary.The intended intervals were divided into three second-order sequences, eleven third-order sequences and twenty-two four-order sequences. It was the first time to complete the high resolution sequence divisions and establish framework in the whole sag;2. The conclusion that grain size of southern area was large and that of northern area was small, fan delta was developed in southern area and braided delta was in northern area was generalized and analyse its origins.The regularity about how to control sands in Shenxian sag was summarized, which was that structure controls provenance, physiognomy controlled sedimentation, regulator belt was in gentle slope and down cutting valley was in abrupt slope;3. Five kinds of depositional facies were distinguished,which were alluvial fan,fan delta, braided delta, lacustrine facies and fluvial facies. On the whole, they were lacustrine sedimentations,which present the typical characteristics of sediment fill in downfaulted basins. Ek-SQ～Es4-SQ were the depositions of initial chasmic stage of lake basin.At that time, relief was high; water was separate;alluvial fan, fan delta and large braided delta were relatively developed well; a big set of coarse glutinites and sands were deposited and hydrocarbon show was less. Es3-SQ1～Ed-SQ3 were the depositions that suffered the complete process of downfaulted lake basin expansion, tectonic uplift, tectonic reversion and lake basin consumption.At early stage, kinds of proximal fan delta and braided delta were developed in the lake basins. Meanwhile, dark mudstones at the dislocation of rising half cycle and falling half cycle in Es3-SQ2 sequence and Es1-SQ1 sequence offered good mother rocks for hydrocarbon generation.The late sands of fluvial channel, channel bar and point bar in fluvial facies were the dominate reservoir rocks;4.The characteristics and control factors of play in each divided area were evaluated in the sequence stratigraphic frame.Two beneficial targets were analysed(slope of Shenxi sag and downthrow block of Hengshui fault). Through the above analysises, the combination of structural hydrocarbon reservoir and lithologic hydrocarbon reservoir should be taken as the chief strategy.更多还原