【作者】 杨振鸿；

【导师】 鲍征宇；

【作者基本信息】 中国地质大学 ， 地球化学， 2013， 博士

【摘要】 南堡凹陷及其周边地区下古生界碳酸盐岩储层是渤海湾盆地重要的油气勘探热点。通过对研究区各种资料全面认识,选取唐山地区赵各庄下奥陶系冶里～亮甲山组典型剖面为主要研究对象,以潮控碳酸盐岩缓坡的微相分析为主线,对剖面所处下古生界的沉积相、沉积体系和沉积环境时间演化和空间展布的研究。识别出冶里组～亮甲山组主要的微相类型和沉积相特征之后,分别建立了对应的潮控碳酸盐岩缓坡体系在唐山地区的相序演化综合图。在此基础上对相关相带以白云岩化为主的成岩作用进行分析。以典型样品的显微薄片观察、环境扫描电镜形态成分分析和碳氧稳定同位素分析为手段,对不同相带的白云岩化特征进行对比和归纳,建立合适的白云岩化模式以利于探索相关相带中有利储层的配置。通过碳氧稳定同位素分析,对微相分析结论中的碳酸盐岩沉积环境、海平面升降作了对比研究,探索研究稳定同位素分布与碳酸盐地层旋回、白云岩化和古温度古环境的关系。取得一些进展如下：1根据基质、颗粒和组构等关键特征,借鉴Flugle关于碳酸盐岩缓坡微相鉴定标志,识别出7种微相类型。其中新增RMF31磨圆的竹叶状砾屑灰岩,RMF32磨圆的内碎屑-生屑颗粒/泥粒灰岩。其余分别是RMF7含棘皮生物碎屑和内碎屑的泥粒灰岩,RMF8:具生物潜穴的和多种颗粒的粒泥灰岩,MF9-BI具坡源生屑/内碎屑的粒泥/泥粒灰岩,RMF9-F：坡源的磨圆内碎屑为主的漂砾,RMF9-L含磨圆岩屑的粒泥灰岩,RMF9-A磨圆藻屑粒泥/泥粒灰岩,RMF14含多种生屑的泥粒/粒泥灰岩,RMF18含介形虫的粒泥灰岩。2唐山地区冶里～亮甲山组沉积相是上寒武统的延续,为由泄湖、颗粒滩、局限台地亚相构成的潮控碳酸盐岩体系的内坡相。3下奥陶统冶里组经历了一个完整三级层序在台地边缘带演化序列,即：由低位域的内坡局限台地岩相开始,经海侵体系域下部的开阔台地海亚相,至海侵体系域上部变为中缓坡相。以外缓坡相出现为标志的最大海泛层之上,转化为中缓坡为标志的高位体系域。亮家山组充分表现出内坡局限台地岩相占主导的沉积构成特征。4按照晶体形态、赋存方式以及矿物成分将本区的白云石分为4类,分别为①白云岩化强烈,粗晶,自形,具环带,晶体边界轮廓清晰,粒内和粒间发育收缩孔隙；②白云石含量低,细晶,半自形-它形,边界模糊;③白云石含量低,细晶,半自形-它形,边界模糊,伴生石膏和石盐晶型完好；④白云岩化强烈,粗晶,自形,具环带,晶体边界轮廓清晰,粒内和粒间孔隙不发育,偶尔伴生石膏和石盐。5根据微相分析的沉积环境特征,结合不同沉积相上白云岩化特征,归纳出研究区在冶里～甲山期的两种白云岩化模式。分别为成岩期毛细管泵汲—蒸发白云岩化模式和同沉积～同生期过蒸发—海水浓缩白云岩化模式。前者主要发生在潮缘相和局限台地相,后者发生在泄湖相和颗粒滩相。6全岩碳酸盐氧碳同位素分析表明冶里组白云岩的δ13C值为-7.119‰～76‰,均值-2.98‰,δ18O值为-9.09‰～4.65‰,均值为-6.12‰(PDB),亮甲山组δ13C值-115‰-0.3‰,均值-0.57‰，δ18O值为-8.76‰～7.48‰，均值-8.06‰(PDB)。冶里组较小的碳值说明形成于正常海水,而亮甲山组碳值较高,属于咸化介质。氧同位素分析表明亮甲山组高负值可能来自暴露后大气淡水的加入或深埋藏环境中高温的影响。7研究区碳同位素分布特征与沉积相类型存在着较强的对应关系,表现为极大值出现在RMF31磨圆竹叶状砾屑灰岩,沉积相类型为内坡颗粒滩相/局限台地相,极小值出现在RMF18含介形虫生屑砾泥灰岩沉积相类型为内缓坡/开阔台地相。8冶里期经历完整的三级沉积系列变化,δ13C值从较高到较低的变化主要与海平面的降低有关,变化趋势与全球同时期低纬度碳同位素—致。亮甲山组下部随着海侵海平面的升高δ13C值上升,而中上部分属高位体系域占优势,内缓坡颗粒滩相和泄湖相为主,使得δ13C值围绕0‰波动,没有明显的漂移。9在6次海进海退事件对比中,研究区具有与其它剖面更低δ13C值,通过对剖面的岩石特征、沉积体系以及微区分析等手段,认为营养海/饥饿海模式和海底有机质氧化机制是导致较低δ13C值的主要因素,而δ13C的最低负值则与硫酸盐还原作用有关。10同位素计算古温度表明：冶里组下段古温度在15℃～25℃，冶里组上段-亮甲山组上段温度在较高位置波动30℃-45℃，而亮甲山组中-上段温度最低,波动范围10℃-15℃。较高温度出现的沉积相是局限台地相-开阔台地相,较低温度则出现在颗粒滩相-泄湖相。较高温度段中出现马鞍状白云石,有铁氧化圈是否指示经历过埋藏作用有待进一步研究。更多还原

【Abstract】 Lower Paleozoic carbonate rock reservoir of Nanpu sag and adjacent aera is one of the hot spot in oil/gas exploration of Bohai bay. Based on the the materials of study area, selected the Zhaogezhuang profile to analyse the characters of microfacies, sediment enviroment and their spatial distrubution. After indentified the main facies types and sediment features of Yeli-Liangjiashan Formation, estabished the facise-order evolution integrate map of tide-conctrol carbonate slop system of Tanshan aera. Then, anlysised the the correlative facies-zone’s diagenesis which dominant by the dolomitizaton.By the means of the thin section observation of all rock sampes, the analyse of microscopy shape and elemental component in typical rock under environmental scanning electron microscope, and the analyse of Carbon Oxygen stable isotope of the representative sampling, established the appropriate dolomitization models to the correlative facies-zones.Contrasted and concluted the results between the carbon stable isotope analysis, the sediment enviroment and the changes of global sea-level. Discussed the reservior unit compartmentalize and reservior capability of Yeli-Liangjiashan formation by the analysis of sediment microfacies, sediment facies, diagenesis, post-diagenesis and stable isotope analysis.Acquired some coclution as follow:1、According to the key charecters of matrix,gain and rock fabric, and use Flugle’s microfacies identify class about carbonate slop,7microfacies type was recorgnized. In this paper, two newly facies, namely, RMF31and RMF32was recorgnised and added into the type of cabonate ramp facies. Respectively, RMF7:aboundant echinoderms bioclastic packstone and intra-bioclasts mudstone. RMF8:packstone with arillaceous and multi-grians RMF9-BI with ramp-derived ioclastic/intra-packstone/mudstone. RMF9-F:floatstone dominated by ramp-derived rounding intra-clasts. RMF9-A:rounding alga-clasts wackestone/packstone. RMF14:multi-bioclastic packstone/wackestone. RMF18:bioclastic wackestone with ostracods. RMF31:rounding Spatulate float rudite limestone, RMF32:rounding intraclastic-bioclastic grain/wackestone.2、The sediment feature of Tangshan Yeling-Liangjiashan formation continues from the Upper Cambrian, it is belongs to the tide control cabonate rock system of inner slop facies which was made up by lagoon/grain-shoal/restrict plateform sub-facies.3、The evolution serial of Yeli formation is a intergrity third class sequence plateform. Namly, it is begains at at the inner restrict plateform facies of LST, then changed to the open-plateform sub-facies of lower TST, and to the mid-slop facies of the upper HST. Ovber the surfaces of maximum flooding, it changed to HST which marked by middle slop. On the other hand, the Liangjiashang formation shows the character of dominated by the inner slop restrict platform facies.4、Fur types of dolomaite was distinguished in the study area.①intensity dolomitization, coarse crystal, euhedral, ring-zone, clear crystal boundary ouline, with well growth shrink hole between inner and space of grain.②few dolimite, fine crystal, ubhedral to anhedral.③blur edge few dolimite, fine crystal, subhedral to anhedral, adjoint with fine crystal of gypsum and halite.④intensity dolomitization, coarse crystal, euhedral, ring-zone, clear crystal boundary outline, few of growth shrink hole between inner and space of grain, sporadic with fine crystal of gypsum and halite.5-Cncluded two dolomitization models refers tothe resuults of sediment facies and dolomitization character. One is the diagenetic capillary punp draw to evaporation dolomitization model, it mainly occurred in the tide-edge facies and restrict platform facies, and the other is the syngenetic over-evaporation-sea-water condense solomitization model, the former, taken placed in the lagoon facies and grain-shoal facies.6、Whole rock carbonate rock isotope analysis shows that the813C value of Yeli formation dolomite is-7.11‰～0.769‰(PDB), means-2.98‰,δ18O is-9.09‰～-4.65‰, means-6.12‰, and the813C of Liangjiashang formation dolomite is-1.15‰～0.3‰, means-0.57‰,δ18O-8.76‰～7.48‰, means-8.06‰(PDB). The lighter carbon value of Yeli formation indicated that it was forming with normal water, but the higher value of Liangjiashang formation showed the environment of salted medium. Oxygen isotope analysis demonstrated that, the higher negative value of Liangjiashang formation maybe come from the join of meteoric fresh-water after exposure or was affected by the high-temperature during the deep burial enviroment.7、There is a tight relation between the carbon isotope distribution and sediment facies. The maximum carbon value appearenced at RMF31, rounding Spatulate calcirudite, with sediment facies of the inner grain-shoal/restric platform, the minimum value at RMF18, related with the inner slop/open-plateform facies.8、As the result of a integrated3-rd sequence evolution to the Yeli formation went through, the changes of813C value was tightly related with globe sea level eustacy, and the trends of carbon isotope was accordanced to the lower latitude in same period. The813C value of bottom Liangjiashan Formation was rise, but in the middle-uuper parts which dominated by HST, the main facies was inner ramp lagoon and grain-shoal, it rotate around0‰, and without obvious dtift.9、The δ13C value in study area was lighter than other profiles. With the analysis of rock character, sediment system and micro-area when compaired the6events of transgression and regression. It’s convinced that the main reason to the lighter δ13C value should be related with the model of over-nutrition/starvation sea and the organic oxidation mechanism in seafloor. and the lowest neagtive value was explained by the sulphate reduction.10、Paleo-temperature caculated by carbon isotope in the lower Yeli formation was ranged from15℃～25℃. The upper Yeli formation to Liangjiashang formation has the more higher value range of30℃～45℃, and the mid-upper Liangjiashang formation has the lowest range of10℃～15℃. The higher temperature occured at the restrict platform facies to open platform facies, however, the lowest temperature at grain-shoal facies to lagoon facies. Therefor, further study was needed to estimate whether or not the higher temperature of upper Yeli formation to Liangjiashang formation undergo burial diagenesis, which has saddle dolomite and the iron content of dolomite.更多还原