【作者】 徐长贵；

【导师】 邓宏文；

【作者基本信息】 中国地质大学（北京） ， 能源地质工程， 2007， 博士

【摘要】 渤海海域属于发育在华北克拉通上的裂陷盆地，在多幕裂陷、多旋回叠加、多成因机制复合的构造背景下，渤海海域古近系充填沉积中可识别出15个主要的等时界面，其中一级层序界面2个，二级层序界面3个，三级层序界面10个，相应的将渤海海域古近系划分为一个一级层序，四个二级层序，十四个三级层序。渤海海域古近系断陷湖盆可划分为断裂陡坡带、缓坡带、凹中隆起带、洼陷-轴向带四种类型三级构造单元，其中缓坡带可分为断裂缓坡带和简单缓坡带，简单缓坡带包括沉积坡折型缓坡带和斜坡型缓坡带。不同构造带的构造活动方式、构造演化过程各不相同，因而其所形成的地貌形态有较大的差别，可容空间和沉积基准面的变化各具特色，从而导致不同的构造带具有不同的层序格架模式和沉积体系构成。对辽东湾、渤中地区层序地层的平面展布特征研究表明，沙四-孔店层序分布局限，沙三层序沉积在全区广布，地层分布主要受凹陷边界大断层的控制，沙一、二层序全区厚度稳定，但厚度总体较薄，东营组沉积时期早、中、晚期各有不同的沉积特点，形成其不同的地层分布特征。辽东湾古近系的沉积中心在辽中凹陷北部，且由南向东北发生迁移。渤中凹陷有古近系沉积中心位于渤东凸起的西侧，具有良好的继承型。渤海海域古近系发育冲积扇、扇三角洲、辫状河三角洲、河流三角洲、湖底扇、碳酸盐岩台地、湖泊(滨浅湖和半深湖)等7种沉积体系类型。构造-层序地层格架内的沉积体系的展布研究表明，总体上，渤海海域沙三层序沉积时期以短源、内源沉积为主，陡坡发育近岸水下扇，缓坡发育扇三角洲，局部较大规模砂体前端可发育浊积扇。沙一二时期仍是以短源、内源沉积为主，洼陷区主要以半深湖沉积为主，滨浅湖在缓坡边缘发育，陡坡发育近岸水下扇，局部发育扇三角洲，缓坡发育扇三角洲，局部由于受断层影响，发育有水下扇(缓坡浊积扇)。东三段沉积时期，低位体系域主要发育湖底扇沉积，高位体系域除辽东带发育辫状三角洲沉积外，其它地区主要以泥质沉积为主。东二层序沉积时期沉积充填特征明显，湖区范围明显缩小，以远源、外源沉积为主，局部有短源、内源沉积，长轴方向多以发育大型的河流三角洲为主，三角洲分期性明显，常伴有较大规模的滑塌浊积扇；短轴方向或低凸起上发育辫状三角洲，局部为扇三角洲。东一段时期整体地形变缓，水体较浅，大多数地区以滨浅湖或三角洲平原为主。渤海海域大型砂体的分布主要与“山—沟—坡—面”耦合带有关。“山—沟—坡—面”耦合是指影响陆相盆地砂体发育的主要因素是物源体系(山)、碎屑物质供给体系(沟)、坡折体系(坡)、基准面(面)等四大要素时空上的有效配置。渤海海域古近系复杂的构造体系，造就了渤海海域古近系丰富而有层次的坡折类型，根据坡折带的成因、平面组合样式以及控相的差异性，可将渤海海域古近系坡折带划分为伸展型边界断裂坡折带、走滑型边界断裂坡折带、沉积坡折带和基底先存地形坡折带等四种类型。“山—沟—坡—面”耦合带是渤海古近系寻找大中型油气田的主要方向。渤海海域发育地层不整合圈闭、地层超覆圈闭、砂岩上倾尖灭型圈闭、砂岩透镜体圈闭、构造岩性复合圈闭、岩性构造复合圈闭等6种岩性圈闭或者构造—岩性复合圈闭。渤海海域古近系不同的构造单元具有特征的层序构成样式和沉积体系域构成模式，这种特殊的层序地层构成样式也决定了不同构造单元具有特殊的岩性圈闭分布模式。通过层序地层、沉积体系和三级构造带的配置分析，对渤海重点凹陷岩性圈闭有利发育区进行了预测，指出了辽东湾地区辽中凹陷东部陡坡—洼槽带等5个区带、渤中地区石臼坨凸起西南部低凸起及凸起边缘等7个区带是渤海古近系岩性圈闭发育的有利区带，在以后的岩性圈闭勘探中值得关注。通过对渤中西部427构造带西侧渤中2-1地区和辽东湾中部锦州31-6地区进行了高精度层序地层分析和岩性圈闭预测及其成藏条件综合研究，认为，渤中2—1构造除了构造圈闭外，还发育构造岩性圈闭，构造岩性圈闭规模较大，预期勘探效益较好；锦州31—6岩性圈闭除了已经钻探的岩性体外，在周边还有成群的岩性圈闭，资源量较大，具有良好的勘探潜力。这两个地区是目前渤海海域岩性圈闭勘探比较现实的地区。本次研究对渤海古近系低勘探程度区岩性圈闭预测技术方法进行了总结，认为在低勘探程度区由于钻井资料稀少，其岩性圈闭研究思路不同于高勘探程度区，低勘探程度区岩性圈闭的核心思想可概括为：构造研究找背景：“山(物源体系)—沟(输砂体系)—坡(坡折体系)—面(基准面旋回体系)”分析找砂体；砂体与构造配置分析找区带；地震地质一体化技术精雕岩性圈闭。更多还原

【Abstract】 Bohai sea area is a faulted basin developed in Huabei craton. In the tectonic setting of multiple phase faulted depression, multicycle superimpose and multiple genesis mechanism, the fifteen main chronohorizons including two 1^st-order sequence boundaries, three 2^nd-sequence boundaries and ten 3^rd-order sequence boundaries can be recognized in the Palaeogene of Bohai sea area. The Palaeogene in Bohai sea area can be divided into one 1^st-order sequence, four 2^nd-sequences and fourteen 3^rd-order sequences.The paper builds the models of the sequence framework and sedimentary systems constituent of the different structural units in Bohai sea area in Palaeogene. Bohai faulted depression in Palaeogene can be divided into four kands of 3^rd-order structural units which are faulted steep slope zone, gentle slope zone, uplift zone in the sag and sag-axial zone. The physiognomy shapes and characteristics of the accommodation and base level change in the different structural units are very different, which results in the different sequence models in the different structural units.In Liaodongwan area and Bozhong area, the distribution of 4^th member of Sha He Jie Formation-Kong Dian Formation is limited. The distribution of 3^rd member of Sha He Jie Formation which is controlled by the boundary faults is very wide. The thickness of l^st and 2^nd member of Sha He Jie Formation is steady in the whole area, although it is thin as a whole. There are different deposition characteristics in the different period of Dongying Formation, which forms the different strata distribution characteristic. The depocenter of Palaeogene in Liaodongwan area located in the north of Liaozhong Sag and it moved from south to north of Liaozhong Sag. The depocenter of Palaeogene in Bozhong area with good inheritance located in the west of Bodong uplift.The paper analyses the characteristic of sedimentary system in the area. There are seven types of sedimentary systems including alluvial fan, fan delta, braided delta, fluvial delta, sublacustrine fan, carbonatite platform and lacustrine. In 3^rd member of Sha He Jie Formation, the coarse clastic deposit from the proximal and internal source is developed. The proximal sublacustrine fan is developed in the steep slope. Fan delta is developed in the gentle slope. In 1^st-2^nd member of Sha He Jie formation, the deposition is proximal and internal still and the lake district expands farther. The sedimentary system in the sag area is mainly the semi-deep lacustrine facies,and it is mainly proximal sublacustrine fan in the steep slope existing partly the fan delta, and it is mainly fan delta in gentle slope existing partly the sublacustrine fan. In 3^rd member of Dongying Formation, the low stand system developed the sublacustrine fan and the high stand system developed deep or semi-deep lacustrine facies except for the HST of Liaodong zone that developed braided delta. In 2^nd member of Dongying formation, the fluvial delta in the long axis and braided delta in minor axis are developed in the whole area. In 1^st member of Dongying formation, the topography was gentle in the whole area and the lake was shallow and the sedimentary system was mainly the shallow lacustrine or the delta plain in the most of the areas.It is the complicated and ordered fault systems with different time, different scale, different attitude and different attribute in the Bohai sea area in Palaeogene that make the slope break zone in the basin have obvious characteristic. The slope break zone in Paleogene in Bohai sea area can be divided into 4 types, viz. extensional boundary faulted slope break zone, strike-slip boundary faulted slope break zone, depositional slope break zone and basement antecedent topographic slope break zone according to the geneses, the plane combination styles and the differences in sedimentary facies control. The extensional boundary faulted slope break zone can be divided into single-fault steep slope break zone, step fault slope break zone and transitional structure slope break zone. Although the plane combination styles of the single-fault steep slope break zone are complicated, there are mainly two types, viz. straight style and "wall-corner" style. Step fault terrace slope break zone can be divided into synthetic step fault slope break zone and antithetic step fault zone according to the relation between fault trend and center of subsidence. The classification of transitional structure slope break zone is complex. Transitional structure slope break zone in Bohai sea area can be divided into strike-slope transitional structure slope break zone and transverse uplift transitional structure slope break zone according to the differences in the sandstone control characteristics in the view of the oil and gas exploration. The sand-control characteristics of different slope break zone are different. The slope break zones in continental faulted basin are the main location in which the sandstone is rich. But this doesn’t draw a conclusion that the sand body must be found in the slope break. The matching of "hill （provenance system）-canyon （sediment discharge system）-slope （slope break zone）-boundary （base level system）" is the necessary condition of the sandstone enrichment in continental fault basin.There are 6 kinds of lithologic traps including stratigraphic unconformity trap, stratigrapbicoverlapping trap, sandstone updip pinchout trap, sandstone lenticular trap, tectonic-lithologic compounding trap and lithologic-tectonic compounding trap in Bohai sea area, Palaeogene. The paper analyzes the distribution models of lithologic trap in the different tectonic zone in Palaeogene in Bohai sea area resulted from the characteristic constituent styles of the sequence and depositional system tract. According to the couple of the sequence, sedimentary system and tectonic setting, there are 5 blocks in Liaosongwan area such as the eastern steep slop of Liaozhong Sag and 7 blocks in Bozhong area such as the southwestern low uplift of Shijiutuo Uplift, which are favor of lithologic trap development.The high resolution sequence stratigraphy and sedimentary system are analyzed and the lithologic trap are recognized and described in Bozhong 2-1 block in the west of 427 Tectonic Zone and Jinzhou 31-6 block in the center of Liaozhong Sag in the paper. Bozhong 2-1 block developed the tectonic-lithologic trap with a good exploration potentiality besides the structural trap. There are several turbidite sandstone lithologic traps with a good exploration potentiality near Jinzhou 31-6 lithologic trap. The two blocks are the tangible area of the lithologic trap exploration in Bohai sea area.Furthermore, the technique methods of the lithologic trap predication in the low degree of exploration in Bohai sea area in Palaeogene are summarized in the paper. The core contents of the lithologic trap research under the exploration degree are the structure research seeking the development setting of the lithologic trap, the couple research of "provenance system- sediment discharge system-slope break system-base level system" seeking the sand body, the couple research of the sand body and structure seeking the favor zone of the lithologic trap development and the integration analysis of seismic and geologic data for describing subtly the lithologic trap.Sequence stratigraphy, Sedimentary system,Lithologic trap Predication, Under the exploration degree area, Palaeogene, Bohai sea area更多还原