黄河三角洲埕北典型海域工程地质环境及粒度指示性分析

发布时间：2018-02-24 22:14

本文关键词： 黄河三角洲工程地质环境指标物理力学参数粒度指示参量数理相关统计工程地质条件　出处：《中国海洋大学》2014年硕士论文　论文类型：学位论文

【摘要】：埕岛浅海油气开发工程所处海域，位于受渤海北东向强浪直接冲击的黄河复式三角洲东北部。自黄河1976年改道后，本海区河流泥沙直接输入大幅减少，海岸和水下岸坡遭到大幅度的侵蚀后退，位于该海域的海上石油产区也基本上处于较强的侵蚀冲刷状态。该海域潮汐复杂，潮流作用较强，风暴潮多发，水动力作用较强。这些因素的综合作用使得本海区海况特征、浅层地质条件以及海底松软沉积物变形情况十分复杂，易发生多种灾害地质现象，因而使得海底管线所处的海洋工程环境较易产生变化。海洋工程环境的变化易使海底管道处于强烈的腐蚀环境，造成研究区海底管道失效。因此，系统的、科学的海洋沉积环境变化对工程地质条件影响的研究，就变得尤为必要。本文资料依托胜利埕岛油田海洋环境地质调查评估项目，通过海上调查取样、原位试验及室内实验，分析处理得到工程地质参数、水深以及粒度参数资料。本文通过研究表层沉积物的盐度、pH、Eh、密度、含水率等工程地质环境指标和水深、粒度参数等的平面分布规律，以及钻孔沉积土体的物理力学参数和粒度参数的垂向分布规律，在对其进行统计相关性分析的基础上，得到地质环境与粒度特征的统计学相关关系，并进行线性回归拟合，得到各个工程地质参数与粒度指示参量之间的相关关系曲线，进而研究粒度特征对工程地质条件的指示性。分析结果表明，对表层沉积物而言，其分布特征主要受控于水深因素。其工程地质环境指标和粒度参数在研究区的分布规律具有分带性，西部和西南部沉积物pH、Eh、密度较高，盐度、含水率较低，平均粒径、中值粒径、偏态值、峰态值较大，分选系数较小，沉积物偏粗，沉积物粒级较为集中，沉积物以较粗的砂质粉砂和粉砂质砂为主；东部和东北部沉积物pH、Eh、密度较低，盐度、含水率较高，平均粒径、中值粒径、偏态值、峰态值较小，沉积物偏细，沉积物粒级分布较宽，以较细的粉砂和粘土质粉砂为主。中部位于二者之间，为过渡地带。根据表层沉积物运移趋势，结合相关关系可以得出，由岸向海，l栍倨胶獯郧常味戎怠⒑仕嫠钤龃蠖龃螅琾H、Eh、密度随水深增大而减小；l栍倨胶獯陨睿粱镅味戎怠⒑仕嫠钤龃蠖跣。琾H、Eh、密度随水深增大而增大。对于埕岛研究区中部中心一号平台附近海域柱状样沉积物而言，土体的物理力学参数与粒度参数以及取样深度也存在着一定的相关关系。据此，可对各地质历史时期沉积环境下形成的工程地质条件进行评估。其评估结果与对比钻孔实验所得数据基本一致。因此，，对于埕岛海域中心一号平台柱状样沉积物，其粒度特征对土体工程地质物理力学参数具有良好的指示性，可以作为评估土体工程地质物理力学参数的经验指标。本文研究丰富了海底工程地质环境研究的内容，为研究区工程地质环境分析提供理论依据，这对于研究区海底管道铺设及海洋工程建设等课题有着一定的实际应用价值。
[Abstract]:Offshore oil and gas development projects in the area, is located in Bohai North East to strong wave direct impact of the Yellow River double delta northeast. Since the Yellow River in 1976 after the diversion of river sediment in this area is directly input significantly reduced, coastal and underwater slope erosion greatly backward, in the waters of the sea oil producing areas it is basically a strong erosion state. The tidal current is complex, strong storm surge prone, the strong hydrodynamic effect. A combination of these factors makes the characteristics of shallow sea sea conditions, geological conditions and loose seabed soft sediment deformation is very complex, a variety of geological disaster prone to the phenomenon, which makes the ocean the submarine pipeline engineering environment is easy to change. Change of marine engineering environment to submarine pipeline in strong corrosive environment, causing pipeline failure. Therefore the study area, It is particularly necessary to study the influence of the systematic and scientific marine sedimentary environment on the engineering geological conditions.
Based on the Shengli Chengdao oil field marine environmental geological survey and evaluation project, the data of engineering geology, water depth and grain size parameters are obtained through marine investigation and sampling, in-situ test and laboratory experiments.
Through the study of Surface Sediment Salinity, pH, Eh, density, moisture content and other engineering geological environment index and water depth, the plane distribution of grain size parameters, the mechanical and physical parameters of soil and sedimentary grain size parameters of the vertical distribution, based on its statistical correlation analysis, statistical correlation get the geological environment and the characteristics of grain size, and linear regression, the correlation curve obtained between the various engineering geological parameters and size parameters, and then study the grain size characteristics of the engineering geological conditions of the indicator.
The analysis results show that the surface sediments, the distribution is mainly controlled by water depth factors. The distribution of engineering geological environment index and grain size parameters in the study area with zoning, West and southwest sediments pH, Eh, high density, salinity, water content is low, the average particle size, mean particle size, the skewness and kurtosis value is greater, the sorting coefficient is smaller, coarse sediments, sediment grain size is relatively concentrated, the sediment to coarse sandy silt and silty sand; the eastern and northeastern sediment pH, Eh, low density, high salinity, water ratio, average particle size, mean particle size, the skewness and kurtosis value is small, thin sediment, sediment particle size distribution is wide, with fine silt and clayey silt. Located in the middle between the two, as the transition zone. According to the sediment transport trends, combined with the relationship can be obtained by L from coast to sea. As a glue? Often? Taste and Li Shi Rong.??? Ju Ju Qian Huo Xi Jie? H, Eh, density decreases with depth; L from the meteorite Rui Liang glue??? Rong and lazy smell of americium?? Li Shi Qian Ju Huo Xian?? Jie. H, Eh and the density increases with the increase of water depth.
In Chengdao area of Central Research Center on the platform near the sea core sediments, soil physical and mechanical parameters and grain size parameters and sampling depth also has certain correlation. Accordingly, to evaluate the formation of sedimentary environment of various geological history under the engineering geological conditions. The evaluation results are basically consistent with the data comparison of drilling experimental results. Therefore, for the Chengdao center on the platform of core sediments, grain size distribution has a good indication on the physical and mechanical parameters of soil engineering geology, the experience can be used as indicators of soil physical and mechanical parameters of engineering geology evaluation.
This study enriches the research contents of the engineering geological environment of the seabed, and provides a theoretical basis for the analysis of engineering geological environment in the study area, which is of practical value for the research of submarine pipeline laying and marine engineering construction in the study area.

【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P736;P642

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