近岸岛屿毗邻海域作为陆架边缘海中最具代表性的区域之一,是重要的海-陆过渡区域。在自然环境变动与人类活动的双重影响下,其生态系统具有多样性和复杂性。长岛毗邻海域具有典型的海岛生态环境特征,为渤黄海渔业种类的洄游通道和关键栖...近岸岛屿毗邻海域作为陆架边缘海中最具代表性的区域之一,是重要的海-陆过渡区域。在自然环境变动与人类活动的双重影响下,其生态系统具有多样性和复杂性。长岛毗邻海域具有典型的海岛生态环境特征,为渤黄海渔业种类的洄游通道和关键栖息地,对该海域生态系统食物网结构和能流过程具有重要意义。2021年3月至12月,山东长岛近海渔业资源国家野外科学观测研究站在长岛毗邻海域开展10航次,每航次10站的底层渔业生物逐月调查与样品测定。通过对渔获物的生物学测定数据进行计算,获得相对重要性指数(index of relative importance,IRI)、物种更替率、单位捕捞努力量渔获量(catch per unit effort,CPUE)以及包含Margalef丰富度指数(D)、Shannon-Wiener多样性指数(H′)和Pielou均匀度指数(J′)在内的生物多样性指数,构成了本数据集。基于多人全样本交叉复核完成审查与校对过程,确保数据集的规范性与准确性。本数据集可为渤黄海底层渔业生物时空格局和海岛生态系统研究提供数据支撑。展开更多
The research is about the effect of a layer of varying density of sea-bottom sediments on spatial correlation of sea-bottom backscattering. The relationship between scattering cross section and spatial correlation is ...The research is about the effect of a layer of varying density of sea-bottom sediments on spatial correlation of sea-bottom backscattering. The relationship between scattering cross section and spatial correlation is that backscattering cross section decreases quickly and the spatial correlation becomes stronger as the incident angle increases. Therefore, the density- depth profile is introduced into sea-bottom high-frequency backscattering echo model, which is used to simulate sea-bottom backscattering and calculate the function of spatial correlation. The influence of the density gradient on spatial correlation of sea-bottom backscattering is investigated by analyzing the relations between vertical gradient of density and the scattering cross section. As can be seen from the simulation results, the impact of the density gradient on the spatial correlation is found more significant. While the density gradient increases, the scattering cross-section and the radius of the spatial correlation broaden, the spatial correlation becomes stronger. At the same time, the scattering cross-section decreases more quickly as the incident angle increases.展开更多
The influence of vessel attitude on spatial-temporal correlation of sea-bottom re- verberation is discussed. The theoretical correlation function is deduced in consideration of the attitude of vessel. The relationship...The influence of vessel attitude on spatial-temporal correlation of sea-bottom re- verberation is discussed. The theoretical correlation function is deduced in consideration of the attitude of vessel. The relationship of the spatial-temporal correlation and the vessel attitude is obtained： The greater the sway of the vessel on some direction is, the faster the correlation coefficient decreases on the direction. The theoretical correlation function agrees well with the simulation result when sea-bottom has no large-scale relief but has isotropic roughness. The actual sea-bottom usually has large-scale relief and anisotropic roughness, so the vessel attitude and the large-scale relief cannot determine the shape of the correlation function, but trial data has proved their combined influence. In addition, the influence of the vessel attitude on the measurement of vertical velocity is discussed.展开更多
The BZ 34-1 oilfield is a typical gas cap edge water reservoir in the Bohai oilfield. The main characteristics of the oilfield were multi-phase sand body stacking and the sand body was composed of three parts: gas cap...The BZ 34-1 oilfield is a typical gas cap edge water reservoir in the Bohai oilfield. The main characteristics of the oilfield were multi-phase sand body stacking and the sand body was composed of three parts: gas cap, oil reservoir, and edge water. The actual production site results show that the permeability difference of multi-layer sand bodies has a serious impact on the development effect. This article establishes a typical reservoir model numerical model based on the total recovery degree of the reservoir and the recovery degree of each layer, and analyzes the impact of permeability gradient. As the permeability gradient increases, the total recovery degree of all four well patterns decreases, and the total recovery degree gradually decreases. The recovery degree of low permeability layers gradually decreases, and the recovery degree of high permeability layers gradually increases. As the permeability gradient increases, the degree of recovery gradually decreases under different water contents. As the permeability gradient increases, the reduction rate of remaining oil saturation in low permeability layers is slower, while the reduction rate of remaining oil saturation in high permeability layers was faster. By analyzing the impact of permeability gradient on the development effect of oil fields, we could further deepen our understanding of gas cap edge water reservoirs and guide the development of this type of oil field.展开更多
文摘近岸岛屿毗邻海域作为陆架边缘海中最具代表性的区域之一,是重要的海-陆过渡区域。在自然环境变动与人类活动的双重影响下,其生态系统具有多样性和复杂性。长岛毗邻海域具有典型的海岛生态环境特征,为渤黄海渔业种类的洄游通道和关键栖息地,对该海域生态系统食物网结构和能流过程具有重要意义。2021年3月至12月,山东长岛近海渔业资源国家野外科学观测研究站在长岛毗邻海域开展10航次,每航次10站的底层渔业生物逐月调查与样品测定。通过对渔获物的生物学测定数据进行计算,获得相对重要性指数(index of relative importance,IRI)、物种更替率、单位捕捞努力量渔获量(catch per unit effort,CPUE)以及包含Margalef丰富度指数(D)、Shannon-Wiener多样性指数(H′)和Pielou均匀度指数(J′)在内的生物多样性指数,构成了本数据集。基于多人全样本交叉复核完成审查与校对过程,确保数据集的规范性与准确性。本数据集可为渤黄海底层渔业生物时空格局和海岛生态系统研究提供数据支撑。
文摘The research is about the effect of a layer of varying density of sea-bottom sediments on spatial correlation of sea-bottom backscattering. The relationship between scattering cross section and spatial correlation is that backscattering cross section decreases quickly and the spatial correlation becomes stronger as the incident angle increases. Therefore, the density- depth profile is introduced into sea-bottom high-frequency backscattering echo model, which is used to simulate sea-bottom backscattering and calculate the function of spatial correlation. The influence of the density gradient on spatial correlation of sea-bottom backscattering is investigated by analyzing the relations between vertical gradient of density and the scattering cross section. As can be seen from the simulation results, the impact of the density gradient on the spatial correlation is found more significant. While the density gradient increases, the scattering cross-section and the radius of the spatial correlation broaden, the spatial correlation becomes stronger. At the same time, the scattering cross-section decreases more quickly as the incident angle increases.
文摘The influence of vessel attitude on spatial-temporal correlation of sea-bottom re- verberation is discussed. The theoretical correlation function is deduced in consideration of the attitude of vessel. The relationship of the spatial-temporal correlation and the vessel attitude is obtained： The greater the sway of the vessel on some direction is, the faster the correlation coefficient decreases on the direction. The theoretical correlation function agrees well with the simulation result when sea-bottom has no large-scale relief but has isotropic roughness. The actual sea-bottom usually has large-scale relief and anisotropic roughness, so the vessel attitude and the large-scale relief cannot determine the shape of the correlation function, but trial data has proved their combined influence. In addition, the influence of the vessel attitude on the measurement of vertical velocity is discussed.
文摘The BZ 34-1 oilfield is a typical gas cap edge water reservoir in the Bohai oilfield. The main characteristics of the oilfield were multi-phase sand body stacking and the sand body was composed of three parts: gas cap, oil reservoir, and edge water. The actual production site results show that the permeability difference of multi-layer sand bodies has a serious impact on the development effect. This article establishes a typical reservoir model numerical model based on the total recovery degree of the reservoir and the recovery degree of each layer, and analyzes the impact of permeability gradient. As the permeability gradient increases, the total recovery degree of all four well patterns decreases, and the total recovery degree gradually decreases. The recovery degree of low permeability layers gradually decreases, and the recovery degree of high permeability layers gradually increases. As the permeability gradient increases, the degree of recovery gradually decreases under different water contents. As the permeability gradient increases, the reduction rate of remaining oil saturation in low permeability layers is slower, while the reduction rate of remaining oil saturation in high permeability layers was faster. By analyzing the impact of permeability gradient on the development effect of oil fields, we could further deepen our understanding of gas cap edge water reservoirs and guide the development of this type of oil field.
