Three-dimensional forward stratigraphic modelling of the gravel-to mud-rich fan-delta in the slope system of Zhanhua Sag,Bohai Bay Basin,China     

《Marine and Petroleum Geology》2017

An important hydrocarbon reservoir is hosted by the third member of the Shahejie Formation (Es₃) in the Zhanhua Sag, Bohai Bay Basin. Seismic stratal slices reveal different characteristics of channels and fan-delta lobes between the south (slope break belt) and southwest (gentle slope) areas combined with lithology, wire-line logs and three-dimensional (3-D) seismic data in the southern slope of Zhanhua Sag. And an excellent analogue has been provided for understanding various key depositional evolution of fan-deltas in the slope system (from base to top: Es₃^L, Es₃^M and Es₃^U). The Sedsim, a three-dimensional stratigraphic forward modelling programme, is applied to simulate the evolution of fan-deltas in the southern slope break systems and southwestern gentle slope systems of the Zhanhua Sag by considering a number of key processes and parameters affecting the fan-deltaic deposition from 43 Ma to 38.2 Ma. Modelling results indicate that depositional types and scales evolved from the thickest medium-scale gravel- or sand-rich fan deltas (43 Ma ∼41.4 Ma, Es₃^L) to the thinnest small-scale mud-rich fan deltas and lacustrine mud (41.4 Ma ∼39.8 Ma, Es₃^M), and lastly to less thicker larger-scale mixed sand-mud fan deltas (39.8 Ma ∼38.2 Ma, Es₃^U). The types of slope system, sediment supply and lake-level change are three controlling factors for determining the source-to-sink architecture of the gravel-to mud-rich fan-deltas and sediment-dispersal characteristics. This study has demonstrated that the process-based modelling approach can be effectively used to simulate complex geological environments and quantify controlling factors.  相似文献   

Effect of pore structure on shale oil accumulation in the lower third member of the Shahejie formation,Zhanhua Sag,eastern China: Evidence from gas adsorption and nuclear magnetic resonance     

《Marine and Petroleum Geology》2017

As shale oil occurs primarily in micro–nano pores and fractures, research about the effect of pore structure on shale oil accumulation has great significance for shale oil exploration and development. The effect of pore structure on shale oil accumulation in the lower third member of the Shahejie formation (Es₃^l), Zhanhua Sag, eastern China was investigated using gas adsorption, soxhlet extraction, nuclear magnetic resonance (NMR) analysis, and field emission scanning electron microscope (FE-SEM) observation. The results indicated that the samples contained a larger amount of ink-bottle-shaped and slit-shaped pores after extraction than before extraction. The pore volume and specific surface area of the samples were approximately 2.5 times larger after extraction than before extraction. Residual hydrocarbon occurred primarily in the free-state form in pores with diameters of 10–1000 nm, which can provide sufficient pore volume for free hydrocarbon accumulation. Therefore, pores with diameters of 10–1000 nm were regarded as “oil-enriched pores”, which are effective pores for shale oil exploration, whereas pores with diameters smaller than 10 nm were regarded as “oil-ineffective pores”. Samples with only well-developed small pores with diameters smaller than 1000 nm showed high oil saturation, whereas samples with both small pores and also relatively large pores and micro-fractures presented low oil saturation. As the minimum pore size allowing fluid expulsion is 1000 nm, pores with diameters greater than 1000 nm were considered as “oil-percolated pores”. Large pores and micro-fractures are generally interconnected and may even form a complex fracture mesh, which greatly improves the permeability of shale reservoirs and is beneficial to fluid discharge.  相似文献   

北部湾盆地乌石凹陷东区断裂类型及其形成演化     

吴孔友  刘煜磊  胡德胜  刘寅  张帅  崔立杰 《地质力学学报》2021,27(1):52-62

受多重构造作用影响,北部湾盆地乌石凹陷形成了复杂的内部构造,准确识别不同期次构造发育特征对于油气勘探具有重要意义.文中运用高精度三维地震、钻井等资料系统分析了乌石凹陷东区断裂类型、组合样式、形成演化规律及其动力学成因机制.分析结果表明:在太平洋板块、印度板块和欧亚板块间相互作用产生的伸展-走滑-弱挤压联合叠加区域应力影...  相似文献   

Geochemistry and zircon U-Pb ages of the Oligocene sediments in the Baiyun Sag,Zhujiang River Mouth Basin     

Rui Sun  Ming Ma  Kai Zhong  Xiayang Wang  Zhao Zhao  Shuai Guo  Xingzong Yao  Gongcheng Zhang 《海洋学报(英文版)》2021,40(2):123-135

In this study, element geochemistry and zircon chronology are used to analyze the Oligocene sediments in the Baiyun Sag, Zhujiang River Mouth Basin. The experimental results are discussed with respect to weathering conditions, parent rock lithologies, and provenances. The chemical index of alteration and the chemical index of weathering values of mudstone samples from the lower Oligocene Enping Formation indicate that clastic particles in the study area underwent moderate weathering. Mudstone samples exhibit relatively enriched light rare earth elements and depleted heavy rare earth elements, "V"-shaped negative Eu anomalies, and negligible Ce anomalies. The rare earth element distribution curves are obviously right-inclined, with shapes and contents similar to those of post-Archean Australian shale and upper continental crust, indicating that the samples originated from acid rocks in the upper crust. The Hf-La/Th and La/Sc-Co/Th diagrams show this same origin for the sediments in the study area. For the samples from the upper Enping deltas, the overall age spectrum shows four major age peaks ca. 59–68 Ma, 98–136 Ma, 153–168 Ma and 239–260 Ma. For the Zhuhai Formation samples,the overall age spectrum shows three major age peaks ca. 149 Ma, 252 Ma and 380 Ma. The detrital zircon shapes and U-Pb ages reveal that during Oligocene sedimentation, the sediments on the northwestern margin of the Baiyun Sag were supplied jointly from two provenances: Precambrian-Paleozoic metamorphic rocks in the extrabasinal South China fold zone and Mesozoic volcanic rocks in the intrabasinal Panyu Low Uplift, and the former supply became stronger through time. Thus, the provenance of the Oligocene deltas experienced a transition from an early proximal intrabasinal source to a late distal extrabasinal source.  相似文献   

南海北部珠江口盆地烃源岩成因:阳江凹陷的资源潜力     

姜衍  张向涛  龙祖烈  姜素华  索艳慧  刘泽  汪刚  陆蕾蕾  王光增  李三忠 《大地构造与成矿学》2021,45(1):90-107

本文基于最新的三维地震资料和钻井等资料,对阳江凹陷古近系烃源岩的形成条件与资源潜力进行分析和评价.作者从盆地分析入手,明确了走滑拉分的成盆模式有利于烃源岩形成,并首次利用Badlands盆地模拟揭示了阳江凹陷古地貌及沉积发育特征,指出该区属于典型有利于烃源岩的形成和发育的内源沉积;并利用三维地震资料,精细解析其断裂体系...  相似文献   

断层圈闭形成机制及时空配置有效性评价——以歧口凹陷歧南斜坡为例     

汪顺宇  孙晓军  王海学  李静  姜文亚  曹晓峰  毕晨阳  种健 《地质科学》2020,(1):93-108

断层的分段生长和连接控制着断层圈闭的形成,为了研究断层形成过程对圈闭形成的控制作用,应用位移/离距法和位移梯度比法判别断层相互作用阶段,落实断层圈闭的空间匹配有效性。针对空间匹配的断层圈闭,应用最大断距相减法开展断层圈闭形成时期的研究,在成藏关键时期前形成的断层圈闭是油气有利聚集的部位。本文以歧口凹陷歧南斜坡的南大港同向断层与扣村反向断层为例,开展断层圈闭时空配置有效性评价,研究结果表明油气多分布在同时具备空间和时间匹配有效的断层圈闭内,仅具备空间或时间匹配有效性的断层圈闭中未见油气聚集。因此,通过对未钻探断层圈闭开展时空匹配有效性评价,能够有效地降低勘探开发的风险。  相似文献   

Organic Geochemical and Petrographic Characteristics of the Coal Measure Source Rocks of Pinghu Formation in the Xihu Sag of the East China Sea Shelf Basin: Implications for Coal Measure Gas Potential     

WANG Yang  QIN Yong  YANG Liu  LIU Shimin  Derek ELSWORTH  ZHANG Rui 《《地质学报》英文版》2020,94(2):364-375

Coal measure source rocks, located in the Xihu Sag of the East China Sea Shelf Basin, were analyzed to define the hydrocarbon generation potential, organic geochemistry/petrology characteristics, and coal preservation conditions. The Pinghu source rocks in the Xihu Sag are mainly gas-prone accompany with condensate oil generation. The coals and shales of the Pinghu Formation are classified from "fair" to "excellent" source rocks with total organic carbon(TOC) contents ranging from 25.2% to 77.2% and 1.29% to 20.9%, respectively. The coals are richer in TOC and S1+S2 than the shales, indicating that the coals have more generation potential per unit mass. Moreover, the kerogen type of the organic matter consists of types Ⅱ-Ⅲ and Ⅲ, which the maturity Ro ranges from 0.59% to 0.83%. Petrographically, the coals and shales are dominated by vitrinite macerals(69.1%–96.8%) with minor proportions of liptinite(2.5%–17.55%) and inertinite(0.2%–6.2%). The correlation between maceral composition and S1+S2 indicates that the main contributor to the generation potential is vitrinite. Therefore, the coals and shales of the Pinghu Formation has good hydrocarbon generation potential, which provided a good foundation for coal measure gas accumulation. Furthermore, coal facies models indicates that the Pinghu coal was deposited in limno-telmatic environment under high water levels, with low tree density(mainly herbaceous) and with low-moderate nutrient supply. Fluctuating water levels and intermittent flooding during the deposition of peat resulted in the inter-layering of coal, shale and sandstone, which potentially providing favorable preservation conditions for coal measure gas.  相似文献   

准噶尔盆地玛湖凹陷下二叠统古老碱湖成因探究：来自全球碱湖沉积的启示   总被引：1，自引：0，他引：1  

李威  张元元  倪敏婕  唐文斌 《地质学报》2020,94(6):1839-1852

碱湖沉积在全球范围内均有分布,在特定的构造背景、火山活动、热液作用及气候条件下形成。我国准噶尔盆地玛湖凹陷风城组发育的碱湖沉积形成年代老且埋藏较深,在完整的沉积-成岩演化研究中具有独特优势。此外,风城组碱湖沉积的分布与页岩油藏的分布具有密切关系,其形成演化对碱湖页岩油藏研究提供重要支持。通过全球尺度下碱湖及碱湖沉积主要特征分析,总结碱湖沉积特征和成因,为准噶尔盆地玛湖凹陷风城组碱湖沉积成因分析提供借鉴。综合分析表明,同期火山活动和特定气候条件均可主控碱湖沉积的形成。此外,碱湖沉积形成需湖盆水文封闭、充足的溶质供给、低硫酸盐占比及强蒸发环境条件。汇总分析全球碱湖沉积矿物种类与埋深关系,发现成岩作用下矿物转变规律:单斜钠钙石随成岩作用增强依次转变为钙水碱、碳钠钙石,苏打石和天然碱转变为碳酸氢钠石。通过与全球碱湖沉积实例对比分析可知,玛湖凹陷风城组碱湖沉积中碳酸氢钠石和碳钠钙石经成岩作用形成,钠硅酸盐矿物和特征矿物与火山活动及热液作用有关。碳酸氢钠石生长形态及磁黄铁矿指示玛湖凹陷风城组碱湖沉积中心为高盐度分层且底部缺氧的常年生湖泊。下二叠统风城组碱湖沉积形成与周缘火山岩及同沉积火山活动密切相关,受气候、构造背景、火山活动和后期成岩作用的共同控制。  相似文献   

北部湾盆地涠西南凹陷碳酸盐岩潜山储层特征与主控因素分析   总被引：1，自引：1，他引：0  

赵顺兰  赵亚卓  杨希冰  焦立波  陈传福 《海洋学报》2018,40(9):43-53

北部湾盆地涠西南凹陷已发现多个碳酸盐岩潜山油田和含油构造,运用岩心、薄片、钻井、测井、地震等资料,对石炭系碳酸盐岩储层特征及主控因素进行了综合分析。研究认为涠西南凹陷碳酸盐潜山主要分布在一号断裂带至二号断裂带附近,其中一号断裂带碳酸盐岩潜山主要为上石炭统黄龙组,岩性为浅灰色灰岩、白云质灰岩、白云岩互层,沉积微相以碳酸盐台地-台缘生屑灰岩滩为主,发育裂缝、溶孔、溶洞等储集空间;二号断裂带碳酸盐岩潜山主要为下石炭统下部石磴子段、孟公拗段,岩性为灰色、深灰色灰岩,沉积微相以台内灰岩滩沉积和台缘生屑灰岩滩为主,发育良好的裂缝型储集层。碳酸盐岩潜山储层发育程度主要受碳酸盐岩沉积环境、地下水活动、古构造应力以及潜山上覆地层岩性等内因和外因诸多因素影响,在这些因素共同作用下,涠西南凹陷碳酸盐岩潜山发育孔隙、裂缝、溶洞等多种储集空间,具备良好的储集条件。  相似文献   

东海陆架盆地西湖凹陷南部花港组砂岩储层成岩流体演化特征：来自岩石、矿物及同位素地球化学的约束     

郝乐伟  王琪  郭睿良  妥成荣  马东旭  牟炜卫  田兵 《海洋学报(英文版)》2018,37(2):25-34

渐新世花港组是东海陆架盆地西湖凹陷发育的最主要储层,基于普通薄片、铸体薄片、扫描电镜和荧光显微观察,结合同位素地球化学对东海陆架盆地西湖凹陷花港组砂岩储层的成岩作用、成岩序列及成岩流体演化进行了研究。结果表明,花港组砂岩储层目前处于中成岩阶段B期,主要经历了机械压实、绿泥石粘土摸、酸性及碱性溶蚀作用,石英次生加大,碳酸盐胶结和自生高岭石胶结等成岩作用。研究区发育有三期碳酸盐胶结物,早期菱铁矿胶结物,中期铁方解石和晚期铁白云石。根据碳酸盐胶结物的碳氧同位素特征分析认为早期碳酸盐胶结物是由过饱和的碱性湖水沉淀造成的,而晚期碳酸盐胶结物的形成与有机酸密切相关。研究区存在两类溶蚀作用,酸性溶蚀作用和碱性溶蚀作用,早期的酸性溶蚀作用主要是有机酸对长石、岩屑及早期碳酸盐胶结物的溶蚀,晚期的碱性溶蚀作用主要是发生于碱性环境下流体对石英及硅质胶结物的溶蚀。研究区发育有两期油气充注,早期发生于晚中新世,早期发生于晚中新世,早于中期碳酸盐胶结,晚于长石溶蚀和石英胶结充注,充注量较大,第四纪以来研究区发生了第二次充注,第二次充注发生于铁白云石胶结之后,此时储层已非常致密。  相似文献