建南地区飞仙关组三段白云岩分布与成因--基于三维地震、岩石学和地球化学综合分析     

王广伟  李平平  郝芳  邹华耀  余新亚 《沉积学报》2016,34(1):168-180

建南地区飞三段是现今研究区重要的产气层,储层类型主要为致密颗粒灰岩和细晶白云岩,然而,相对优质储层均发育于白云岩中。因此,对飞三段白云岩分布规律的研究是预测优质储层的基础。本研究基于录井、测井、岩芯和三维地震等资料,在构建单井白云石含量曲线的基础上,利用多属性转换分析建立三维地震属性与白云石含量曲线的关系,反演白云石含量在平面和剖面上的分布,结合岩石学、地球化学和沉积相对白云岩化流体的性质与来源进行了分析。建南地区飞三段白云岩以细晶、平面自形-半自形为主,非平面它形晶少量分布。阴极发光下白云石为暗红色,无或少量环带状结构。利用多属性转换方法建立地震属性与白云石含量的关系,当选取5个地震属性组合时对白云石含量的预测最佳,预测误差为9%。五个属性分别为 Amplitude Weighted Frequency、Amplitude Weighted Cosine Phase、Derivative Instantaneous Amplitude、Quadrature Trace 和 Integrate。将预测的白云岩分布与沉积相叠合显示白云岩主要分布于台内洼地的两侧,向台地内部规模和厚度逐渐减小。综合地球化学数据和白云岩的分布特征说明,白云岩化流体主要来源于台内洼地的泥灰岩和泥晶灰岩的压实海源流体。随埋深的加大,洼地沉积物中的富Mg流体优先侧向运移至洼地两侧的孔隙性颗粒滩中并发生白云岩化作用。因此,洼地边缘颗粒滩是优质白云岩储层的有利勘探区。  相似文献   

Autochthonous Dolomitization and Dissolution in the Microbial Carbonate Rocks of the Fengjiawan Formation in the Ordos Basin     

ZHANG Jing  ZHANG Baomin  ZHANG Shuichang  WANG Huajian 《《地质学报》英文版》2022,96(4):1376-1387

Many euhedral dolomite crystals and related pores are found in the microbial siliceous stromatolite dolomite and siliceous oolitic dolomite in the Fengjiawan Formation of the Mesoproterozoic Jixian System in the southern Ordos Basin. With the application of the microscope, scanning electron microscope, cathodoluminescence and in-situ trace element imaging, it can be seen that different from the phase I dolomite that was damaged by silicification, the intact euhedral phase II dolomite occurred through dolomitization after silicification, concentrated mainly in the organic-rich dark laminae of the stromatolite and the dark spheres and cores of the ooids. A considerable number of phase II dolomite crystals were dissolved, giving rise to mold pores and vugs which constituted the matrix pores and also the major pore space of the Fengjiawan Formation. The formation and dissolution of the dolomite were controlled by the microenvironment favorable, respectively, for carbonate precipitation and dissolution under the influence of microbial biological activities and related biochemical reactions. The driving force and material supply of dolomitization and dissolution were confined to the fabrics enriched with microorganisms, which are highly autochthonous. This mechanism may be a key factor for the development of Precambrian dolomite and related reservoirs, in the context of the domination of microbial rocks.  相似文献   

四川盆地东部茅口组白云岩成因: 来自岩石学、矿物学和地球化学的证据^*          下载免费PDF全文

王良军  李红  曾韬  柳益群  潘磊  李让彬  李文厚  张冬冬  焦鑫  杨康  董杨坤 《古地理学报》2022,24(5):989-1016

四川盆地中二叠统茅口组白云岩中蕴藏丰富的天然气资源,但是这套白云岩的成因多年来一直存在争议。盆地东部茅口组白云岩储集层多发育在茅三段中下部,纵向上厚度介于3.0~46.8 m之间,平面上沿北西—南东向基底断裂呈带状展布。野外和钻井岩心观察发现,白云岩内发育交织状张性裂缝,将岩石切割呈角砾状,裂缝多被粗晶方解石、白云石充填或半充填。根据围岩和裂缝中白云石晶体形貌和产出状态,在显微镜下识别出4类不同组构的白云石: 第1类为灰泥基质中“星散状”自形粉晶—细晶白云石; 第2类为半自形面状组构细晶白云石,呈他形—半自形镶嵌状; 第3类为具“雾心亮边”的自形晶面状组构细晶—粗晶白云石,具糖粒状结构,晶间孔隙发育; 第4类为脉体充填的粗晶鞍状双晶白云石。背散射照片显示前3类白云石的“雾心”部分晶面混浊、表面分布方解石残斑及微孔, 而第3类白云石的“亮边”部分与第4类鞍状粗晶白云石脉则晶体明亮、洁净、致密,属新生矿物。上述4类白云石的成分均具有富Ca和贫Fe、Mn、Sr的特点,MgO含量变化较大,其中前两类白云石MgO含量总体低于白云石标准计量,而后两类白云石的MgO含量则接近或略高于标准计量。岩石学、矿物学和地球化学特征表明:茅口组白云岩主要经历了2期白云化作用,初次白云化作用形成第1类、第2类白云石及“雾心”白云石,二次白云化作用形成“亮边”白云石和粗晶白云石脉体; 2期白云化作用均发生得很早,可能始于同沉积期至浅埋藏期。白云石原位微量元素和原位锶同位素分析表明,白云化作用流体具有混源的特点,流体可能由富Ca地下水以及与火山活动有关的热液混合而成。推测中二叠世末期峨眉山地幔柱的喷发引起四川盆地内基底断裂再次活动,造成茅口组内张性构造裂缝发育,这为白云化流体混合及运移提供了通道。  相似文献   

四川盆地下奥陶统桐梓组白云岩多元成因          下载免费PDF全文

刘志波  邢凤存  胡华蕊  陈孝全 《地球科学》2021,46(2):583-599

四川盆地下奥陶统桐梓组白云岩的成因研究较少,模式存在多样性,尚未达成共识.通过系统的岩心观察、薄片鉴定、地球化学分析等方法,在四川盆地桐梓组识别出晶粒白云岩、颗粒白云岩和含石英白云岩及含白云质石英砂岩等与白云石相关的岩石类型.地球化学分析揭示不同类型白云岩具有不同的地球化学特征及白云石化机理,晶粒白云岩的MgO含量与CaO含量呈现出明显的正相关性,具有相对高的δ18O_PDB值、δ13C_PDB值、Sr值及较高的Mg/Ca比值,Fe、Mn含量较低,为准同生期蒸发泵白云石化成因;A类含石英白云岩及含白云质石英砂岩具有与晶粒白云岩相似的地球化学特征,也主要为准同生期白云石化成因;颗粒白云岩的MgO含量与CaO含量表现出弱负相关性,δ13C_PDB值和δ18O_PDB值与同期海水碳、氧同位素值分布范围基本一致,Sr含量相对较高,为回流渗透白云石化成因;B类含石英白云岩及含白云质石英砂岩只在研究区靠近物源的局部地区发育,其MgO含量与CaO含量呈正相关,δ13C_PDB值和δ18O_PDB值表现为明显负偏,与其他两类白云岩相比具有较高的Al₂O₃、Fe、Mn含量和相对较低的Sr含量,且受到陆源碎屑混入的影响,认为是混合水白云石化成因.四川盆地桐梓组具有3种白云石化机理共存的特征,总体继承了上寒武统白云石化机理.   相似文献   

通南巴地区飞仙关组三段储层成因机制探讨   总被引：1，自引：0，他引：1  

段新国  李英  李忠权  王洪辉  李仲东  李德敏  胡永章 《沉积学报》2010,28(6):1165-1174

通南巴地区飞仙关组三段储层近年获得了工业气流,储层压力较高,储层岩性主要为颗粒灰岩与泥微晶灰岩,物性较差,储集空间以铸模孔、粒内溶孔和晶间溶孔为主,且储集层横向变化大,纵向差异显著,总体看,该区储层发育欠佳。通过研究区成岩作用类型及其对孔隙演化的影响分析、成岩演化序列分析以及与邻区普光气田储层成岩作用对比分析,对通南巴地区的储层成因机制进行了深入讨论。通过研究发现,通南巴地区飞三段储层形成的主要控制因素有以下三个方面:（1）由于沉积成岩环境的限制,白云化作用非常微弱,基本不发育白云岩储层,这导致本区储层较差;（2）原生孔隙基本消失殆尽,溶蚀作用成为飞三段储层形成的关键因素,同生期的溶蚀作用在各期溶蚀作用中占主导地位;（3）由于在中—深埋藏阶段没有烃类注入,飞三段储层基本无TSR反应,破坏性成岩作用相对增强,储层无法得到改善。  相似文献   

白云石化作用及白云岩问题研究述评     

汤朝阳  王敏  姚华舟  段其发  赵希林 《华东地质学院学报》2006,29(3):205-210

近年来,关于白云石化作用及白云岩问题,取得了更深层次的发展。从白云石化作用入手,介绍根据古代白云岩的成因所建立的五个主要成因模式:蒸发作用模式、渗流-回流模式、混合白云石化模式、埋藏白云石化模式及海水白云石化模式,并介绍了国内外最新研究进展和成果。认为利用染色薄片鉴定、阴极发光显微镜观察、微量元素分析、碳氧稳定同位素测定及包裹体测温等综合手段进一步研究,最终将解决这些问题。  相似文献   

湖北宜昌地区寒武系岩石学特征及沉积环境   总被引：2，自引：0，他引：2       下载免费PDF全文

张秀莲  于德龙  王贤 《古地理学报》2003,5(2):152-161

鄂西宜昌地区寒武系出露齐全、连续，且岩石类型多样、化石丰富，是我国寒武系的标准剖面之一。其沉积环境以潮下高能浅滩为主，其次为间歇能量的潮间带、滨岸的中小型浅滩，少数为开阔海较深处的静水灰泥沉积。石灰岩集中分布于下寒武统天河板组和水井沱组，其次在下寒武统的石牌组、中寒武统的磕膝包组、官山瑙组有少量夹层出现。其岩石类型有颗粒灰岩（鲕粒灰岩、核形石灰岩、砾屑灰岩及砂屑灰岩）、含颗粒泥粉晶灰岩（含生屑泥粉晶灰岩、含生屑灰岩）及泥晶灰岩。白云岩是本地区数量最多的岩石类型。从下寒武统石龙洞组开始都是白云岩沉积，白云岩可据白云石化作用机理和时间的不同分为准同生白云岩和准同生后白云岩两大类。准同生白云岩广泛出现于中上寒武统，岩石呈土黄色、砖红色，具纹层、鸟眼、干裂构。准同生后白云岩根据残余颗粒的有无可分为残余颗粒白云岩和晶粒白云岩两大类。晶粒白云岩有两种成因。一为回流渗透云化；二为深埋藏云化。根据本区寒武系岩石的岩石学特征、生物组合特征和结构构造特征本文重建了各组段的沉积环境.  相似文献   

Silicification and dolomitization of anhydrite nodules in argillaceous terrestrial deposits: an example of meteoric-dominated diagenesis from the Triassic of central Spain     

A. M. Alonso-Zarza  Y. Sánchez-Moya†  M. A. Bustillo‡  A. Sopeña§  & A. Delgado¶ 《Sedimentology》2002,49(2):303-317

Cauliflower-shaped nodules are widespread in a single red mudstone bed in the Buntsandstein (Triassic) facies of the Iberian Range. They consist mostly of quartz, dolomite and calcite, but other minerals, such as barite, kaolinite and iron oxyhydroxides, are also present. The nodules are spherical, ovoid or elongate in shape and range from 1 to 8 cm across. The surface of the nodules is irregular, and some show a pedogenic coating of microspar. The sedimentological and petrographic data suggest that the initial anhydrite nodules formed through a progressive increase in the porewater concentration of Ca²⁺ and SO₄^2– in a vadose environment, occasionally under the influence of pedogenic processes. Partial replacement of the anhydrite by megaquartz occurred under more dilute conditions in the same type of setting, as indicated by the presence of organic filaments on the quartz crystal surfaces. In type A nodules, the dissolution of the innermost anhydrite was complete, and different types of quartz cement filled the porosity. Fracturing and meteoric cementation by calcite and minor amounts of kaolinite were the latest processes affecting these nodules. In type B nodules, the dissolution of the anhydrite was incomplete, inhibiting quartz cementation and enabling later dolomitization of the anhydrite. Dolomitization appears to have been driven by sulphate reduction, as indicated by the presence of bacterial bodies within the dolomite crystals. Dedolomitization and precipitation of barite, kaolinite and calcite spar cements occurred later under the influence of meteoric solutions. The nodules may mark the former locations of the water table and provide evidence for an episode of highly evaporitic conditions throughout wide areas of the basin. Their occurrence reveals not only a complex diagenetic history but is also indicative of palaeogeographic and palaeoclimatic conditions.  相似文献   

济阳坳陷桩海地区下古生界潜山储层成因机制研究   总被引：10，自引：3，他引：7  

秦永霞  黄思静  武文慧  袁海峰 《物探化探计算技术》2005,27(2):141-146

通过对桩海地区下古生界碳酸盐岩的锰、锶、镁等微量元素及氧、碳、锶等同位素的测试与分析研究认为,白云石化作用和岩溶作用是济阳坳陷桩海地区下古生界碳酸盐岩潜山储层最为重要的成因机制。该区有价值的冶里～亮甲山组储集层与埋藏成岩过程的白云石化作用,尤其与粒屑的优先白云石化造成的体积收缩作用有关,主要分布于成岩白云岩成因类型中。在不整合面附近的海相碳酸盐岩主要受到印支、燕山再曝露期古喀斯特作用强烈的大气淡水的改造而形成良好的岩溶储层,这种改造作用的记录表现在各种洞或脉中的碳酸盐矿物的^87Sr／^86Sr比值显高于基质碳酸盐,而大多数样品的δ^13C和δ^18O值则显低于基质。单井地球化学剖面说明,大气淡水作用深度主要集中在不整合面之下150m的深度范围,并对先前形成的白云岩储层进行岩溶改造。  相似文献   

Dolomitization of the Middle Devonian Winnipegosis carbonates in south-central Saskatchewan, Canada     

QILONG FU  HAIRUO QING  KATHERINE M. BERGMAN 《Sedimentology》2006,53(4):825-848

The Middle Devonian Winnipegosis carbonate unit in south‐central Saskatchewan is partially to completely dolomitized. Two major types of replacive dolomite are distinguished. Microcrystalline to finely crystalline dolomite (type 1) displays nonplanar‐a to planar‐s textures, mimetically replaces the precursor limestone, accounts for about four‐fifths of dolomite phases volumetrically, and mainly occurs in the Winnipegosis mounds and the Lower Winnipegosis Member directly underlying the mounds. Medium crystalline dolomite (type 2) shows planar‐s to planar‐e textures, commonly occurs in the Lower Winnipegosis and Brightholme members, and decreases upward in abundance. The ⁸⁷Sr/⁸⁶Sr ratios of type 1 dolomite (0·70795 to 0·70807) fall within the estimated Sr‐isotopic range for Middle Devonian marine carbonates. Stratigraphic, petrographic and geochemical data constrain the formation of type 1 dolomite to hypersaline sea water in a near‐surface environment, after marine cementation and sub‐aerial diagenesis and prior to precipitation of the Middle Devonian Leofnard salts. Movement of dolomitizing fluids could be driven by density differences and elevation head. The shift to lower δ¹⁸O values of type 1 dolomite [?7·4 to ?5·1‰ Vienna Pee Dee Belemnite (VPDB)] is interpreted as the result of recrystallization at elevated temperatures during burial. Type 2 dolomite has higher ⁸⁷Sr/⁸⁶Sr ratios (0·70809–0·70928), suggesting that the dolomite probably formed from basinal fluids with an increased richness in the radiogenic Sr isotope. In type 2 dolomite, Sr²⁺ concentrations are lower, and Fe²⁺ and Mn²⁺ concentrations are higher, compared with the associated limestone and type 1 dolomite. Type 2 dolomite is interpreted as having been formed from upward‐migrating basinal fluids during latest Devonian and Carboniferous period.  相似文献