Facies and sequence stratigraphic architecture of the Mural Limestone (Albian), Arizona: Carbonate response to global and local factors and implications for reservoir characterization     

Rachel Aisner-Williams  Charles Kerans 《Sedimentology》2020,67(7):3735-3768

This study documents the detailed facies and sequence stratigraphic architecture of a multi-cyclic patch-reef and its associated ramp interior facies that formed during Oceanic Anoxic Event 1b in the Mural Limestone, Arizona, USA. Ramp interior facies are comprised of bedded wackestone/packstone, rudist build-up and coral–algal patch-reef facies located north of Bisbee, Arizona, at the Grassy Hill locality. The larger multi-cyclic patch-reef that developed coevally ca 5 km to the south of Grassy Hill consists of a high-angle windward margin with a narrow ca 70 m long reef frame containing vertically zonated Microsolena, Actinastrea, diverse branching coral and rudist assemblages, and an 870 m long low-angle leeward margin comprised of reef debris rudstone and grainstone shoal facies. Similar reef geomorphology and orientation is documented across the Gulf of Mexico and reflects the shelf-wide north to north-east-trending prevailing wind and current energies. Controls affecting reef formation and growth patterns include changes in accommodation space associated with low-amplitude global sea-level rise and regional thermotectonic subsidence, local accommodation space and nutrient fluctuations associated with the inner shelf depositional setting within a humid and siliciclastic-rich environment. Four aggradational to retrogradational high-frequency sequences are documented in Arizona: High-frequency sequences 1 and 2 represent the first pulse of patch-reef development in an overall second-order marine transgression over the Sonora/Bisbee Shelf. These sequences correlate to δ¹³C signatures associated with Oceanic Anoxic Event 1b across the Gulf of Mexico and suggest that carbonate reefs persisted on the ramp interior during this time. High-frequency sequences 3 and 4 record a second brief transgression and backstepping of reef facies followed by the final regression of shallow shelf carbonates that correlates to more robust patch-reef development in Sonora, Mexico. The patch-reef at Paul Spur is an excellent outcrop analogue for productive patch-reefs in the Maverick Basin (Comanche Shelf) of Texas. Detailed facies mapping of this outcrop analogue shows that the greatest reservoir potential is contained within the backreef grainstone shoals where primary porosity of up to 15% is observed.  相似文献   

Sedimentary and geochemical characterization of Middle–Late Miocene formations in the Neogene Tsugaru Basin,Japan by means of DTH27‐1 well sediment analysis     

Paolo Martizzi  Shun Chiyonobu  Hiroyuki Arato 《Island Arc》2020,29(1)

Middle–Late Miocene age siliceous formations outcropping along the northwestern side of Honshu Island are considered prospective source rocks for hydrocarbons. An analysis of geophysical, sedimentological, and geochemical properties is essential to evaluate the formations' source potential, and to understand the factors that determined the accumulation and preservation of organic matter. This study investigates the Middle–Late Miocene geological record of the Tsugaru back‐arc basin, located in the western part of Aomori prefecture, through an analysis of a 200 m long portion of a core from the DTH27‐1 well; this core is composed of the diatomaceous siltstones of the Akaishi Formation and the siliceous mudstones of the Odoji Formation. Sedimentological and geophysical characterization showed that the Akaishi Formation's diatomaceous siltstones are mostly massive and bioturbated, have low magnetic susceptibility, and demonstrate moderate natural radioactivity. Although the Odoji Formation's siliceous mudstones are massive, they have exceedingly low magnetic susceptibility and high natural radioactivity. Geochemical data from a Rock‐Eval Pyrolysis such as total organic carbon and generative potential (S1 + S2) revealed that, in the Tsugaru area, only the Odoji Formation is a likely prospective source rock for hydrocarbons. On the other hand, T_max values indicate that both the formations are thermally immature for generating hydrocarbons. The difference between the Akaishi and Odoji Formation in the sedimentological facies, in terms of the degree of bioturbation and the organic carbon content, indicates variations in lithological properties, such as porosity and grain size; moreover, this difference indicates a variation in the paleo‐oxygenation of bottom waters, with the transition from oxygen‐deficient conditions in the Middle Miocene to the more oxygenated conditions in the Late Miocene. Both the lithological and paleo‐environmental factors possibly influenced the organic richness in the two formations.  相似文献   

太湖梅梁湾藻华暴发消退-周期表层水体溶解性有机质分子特征     

庞佳丽  许燕红  何毓新  史权  何丁  孙永革 《湖泊科学》2020,32(6):1599-1609

人类活动引起的富营养化对太湖的碳循环模式可能产生严重影响，精细描述太湖藻华暴发-消退周期的溶解性有机质分子是了解太湖碳库动态变化的关键.本研究利用傅立叶变换离子回旋共振质谱技术，以太湖北部梅梁湾2017年5月至2018年5月的表层水体为研究对象，解析藻华暴发-消退周期溶解性有机质的来源和分子组成特征，进而理解浮游藻类异常增殖对水体溶解性有机质的影响及其在区域碳循环中的角色.研究结果表明，藻华暴发期浮游藻类生产力显著增加，使得表层水体的溶解性有机质从含量到分子组成均发生剧烈改变.含量上表现为溶解性有机碳浓度升高，分子组成上表现为CHO类化合物和以脂肪族类化合物为代表的活性组分占比增加，特征化合物以相对高饱和度和高含氧的小质量数分子为主.而在藻华消退期，随着藻类有机质贡献的减少和有机质降解过程的持续进行，含量上表现为溶解性有机碳浓度下降，分子组成上表现为CHOS、CHONS类化合物和富羧酸脂环类化合物等惰性分子占比增加，特征化合物以大质量数分子和相对低饱和度和低含氧的小质量数分子为主.研究结果表明，太湖水体的溶解性有机质分子组成在藻华暴发期受藻类有机质输入控制，在消退期受藻类有机质降解的影响.  相似文献   

联合多点地质统计学与序贯高斯模拟的随机反演方法   总被引：1，自引：0，他引：1       下载免费PDF全文

刘兴业  李景叶  陈小宏  李超  郭康康  周林 《地球物理学报》2018,61(7):2998-3007

岩相和储层物性参数是油藏表征的重要参数，地震反演是储层表征和油气藏勘探开发的重要手段.随机地震反演通常基于地质统计学理论，能够对不同类型的信息源进行综合，建立具有较高分辨率的储层模型，因而得到广泛关注.其中，概率扰动方法是一种高效的迭代随机反演策略，它能综合考虑多种约束信息，且只需要较少的迭代次数即可获得反演结果.在概率扰动的优化反演策略中，本文有效的联合多点地质统计学与序贯高斯模拟，并结合统计岩石物理理论实现随机反演.首先，通过多点地质统计学随机模拟，获得一系列等可能的岩相模型，扰动更新初始岩相模型后利用相控序贯高斯模拟建立多个储层物性参数模型；然后通过统计岩石物理理论，计算相应的弹性参数；最后，正演得到合成地震记录并与实际地震数据对比，通过概率扰动方法进行迭代，直到获得满足给定误差要求的反演结果.利用多点地质统计学，能够更好地表征储层空间特征.相控序贯高斯模拟的应用，能够有效反映不同岩相中储层物性参数的分布.提出的方法可在较少的迭代次数内同时获得具有较高分辨率的岩相和物性参数反演结果，模型测试和实际数据应用验证了方法的可行性和有效性.  相似文献   

湖北地区地震震源参数研究     

申学林  魏贵春  丁文秀  戴苗 《中国地震》2018,34(4):781-787

为了研究湖北地区地震震源参数特征,本文基于湖北数字地震台网记录到的S波观测振幅谱,通过遗传算法获得湖北地区的介质品质因子和台站场地响应,并在此基础上计算了湖北地区地震震源参数。结果显示,湖北地区介质品质因子Q值随频率f变化的关系式为Q(f)=501.8·f~(0.309);对于大部分台站获得了与其岩石基底相符的场地响应,没有出现明显放大效应;地震震级与地震矩对数间呈线性关系,即lg M_0=10.06+1.093M_L;震源半径与应力降间呈双对数线性关系,即lgΔσ=10.52-2.01lgr;地震矩与拐角频率间整体上呈反相关;地震矩与应力降间关系不显著。  相似文献   

Some Thoughts on the Earthquake Science Experimental Site——The Underground Cloud Map   总被引：1，自引：0，他引：1  

CHEN Yong  XU Yihe  CAI Huiteng  LI Wen 《中国地震研究》2019,33(1):1-8

The Western Yunnan Earthquake Predication Test Site set up jointly by the China Earthquake Administration, the National Science Foundation Commission of America, and United States Geological Survey has played an important role in development of early earthquake research work in China. Due to various objective reasons, most of the predicted targets in the earthquake prediction test site have not been achieved, and the development has been hindered. In recent years, the experiment site has been reconsidered, and renamed the “Earthquake Science Experimental Site”. Combined with the current development of seismology and the practical needs of disaster prevention and mitigation, we propose adding the “Underground Cloud Map” as the new direction of the experimental site. Using highly repeatable, environmentally friendly and safe airgun sources, we could send constant seismic signals, which realizes continuous monitoring of subsurface velocity changes. Utilizing the high-resolution 3-D crustal structure from ambient noise tomography, we could obtain 4-D (3-D space + 1-D time) images of subsurface structures, which we termed the “Underground Cloud Map”. The “Underground Cloud Map” can reflect underground velocity and stress changes, providing new means for the earthquake monitoring forecast nationwide, which promotes the conversion of experience-based earthquake prediction to physics-based prediction.  相似文献   

2017年九寨沟MS7.0地震场地特征分析     

吴效勇  王晓青  袁小祥  窦爱霞  丁香 《地震》2019,39(4):147-157

场地条件对地震动具有较大影响, 研究不同场地条件下的地震动特征对地震动的校正具有重要意义。 本文以九寨沟地震为例, 收集了66个台站的198条三分量强震观测记录和SRTM(Shuttle Radar Topography Mission)公里格网的DEM(Digital Elevation Model)数据, 从多个角度对场地特征进行分析。 首先根据坡度法使用DEM数据对九寨沟特征进行了场地分类, 然后讨论了不同场地类型下的加速度时程、 加速度反应谱、 地震动衰减等地震动特征。 研究表明, 缺少实测资料的情况下, 地形坡度可以作为Vs30(地表以下30 m范围的平均剪切波速度)的一种替代指标, 利用坡度法可以较快速地对场地进行分类; 利用强震观测记录能够从多角度对台站的场地特征进行分析, 不同场地类型对地震动影响不同, 其中, 土层对地震动具有明显的放大效应。 该结论可以为地震动结果的校正提供依据。  相似文献   

离散Fréchet距离在强震台站场地分类中的应用     

梁基冠  程印  赵岑 《震灾防御技术》2019,14(4):731-741

当强震台站场地资料不完整时，所收集到的强震数据因缺乏准确的场地类别信息而难以有效利用。为解决这一问题，本文提出一种基于离散Fréchet距离的强震台站场地分类方法。将获取到的664个KiK-net台站场地按照《建筑抗震设计规范（GB 50011—2010）》进行分类，并构建2个数据集。利用数据集1得到Ⅰ、Ⅱ、Ⅲ类场地标准谱比曲线，并结合离散Fréchet距离对数据集2中的台站进行场地分类，统计分类成功率与误判率。统计结果表明，本文方法能较准确地对场地进行分类，且误判率在可接受范围内。将本文方法分类统计结果与斯皮尔曼秩相关系数法分类的成功率与误判率进行对比，结合本文方法分类后得到的平均谱比曲线，均可表明应用本文方法进行强震台站场地分类具有合理性。  相似文献   

Reservoir architecture and heterogeneity distribution in floodplain sandstones: Key features in outcrop,core and wireline logs     

Luis Miguel Yeste  Augusto N. Varela  César Viseras  Neil D. Mcdougall  Fernando García-García 《Sedimentology》2020,67(7):3355-3388

  相似文献   

安徽省大气颗粒物污染特征分析     

易明建  邓淑梅  汪水兵  卫尤文  戴海夏 《地球化学》2021,50(1):36-45

对2016年全年颗粒物监测浓度数据进行统计分析,得到了安徽省颗粒物污染的空间分布、浓度和粒径,以及污染传输特征。结果表明,淮河以北、沿江和江淮之间、长江以南和皖南山区城市颗粒物污染随地理位置不同表现出明显的区域化特征,污染程度由北向南减轻,污染过程明显表现出由北向南逐步扩散传输的规律,污染程度越重,污染深入南方的范围越广,持续时间也越长。冬季污染较重的城市,上午出现明显的高浓度时段,全天变化为“双峰双谷”型。夏、秋季节夜间细颗粒物(PM2.5)浓度贡献比增加。PM2.5与PM10(可吸入颗粒物)质量浓度比值冬季最高,春季较低。污染重的城市冬季PM2.5占比高。  相似文献