内部转塔锚泊生产储油船的发展研究

内部转塔锚泊生产储油船是海上石油浮式生产系统适用于深水及恶劣环境条件的一种新型生产系统。本文对锚泊系统的动力分析、转塔装置的性能研究、生产储油船船型设计研究、系统模型在风浪流水池中的系泊试验、船体结构的强度分析等基本问题进行了比较全面的综合性研究。研究结果表明,此种生产系统对我国近海油田非常适用,在技术上也是完全可行的。     

土地资源储备制度对海域资源管理的启示

文章在详细剖析土地资源储备与土地资源储备制度概念内涵、我国土地储备制度发展过程及其主要土地储备模式的基础上,分析了我国实行海域资源储备管理的现实需求、发展现状及其存在的主要问题,并以土地资源储备管理为启迪,提出构建海域资源整治储备中心、实行海域资源的分类多途径储备、完善海域资源价值评估与有偿使用制度等海域资源储备管理思路。     

典型海上升压站地震储备承载系数研究

海上升压站是海上风电场中不可或缺的组成部分,其结构型式与传统的海上油气平台有所差异,完全套用现有抗震分析方法可能使结构设计不经济。由于地质条件特点不同,国外海上风电场鲜有位于高地震烈度区的案例,因此当前有关海上升压站抗震设计的理论和经验也不充分。针对我国首个位于高地震烈度区内的海上升压站,建立精细化有限元模型,利用非线性静力推覆分析方法,并结合敏感性分析结果与工程实际情况给出其地震储备承载系数的合理化取值,为今后典型海上升压站的抗震设计提供参考与借鉴。     

大型海工结构物建造场地滑道强度安全储备分析

为了适应当前的海洋开发需求,海洋工程结构物的大型化已成为必然发展趋势,这使得原有海工建造施工场地的滑道处于临界承载状态,给安全生产带来了巨大隐患。本文针对典型滑道结构,采用有限元参数化建模技术(ANSYS Parametric Design Language,ANSYSAPDL)模拟上部载荷滑块在滑道板上的灵活布置,对滑道强度储备进行分析。研究表明:设计载荷下,滑道板的强度储备较滑道桩体及滑道桩侧土小,滑道强度的控制因素为滑道板强度;改变上部载荷滑块的位置,探索不同位置处滑道极限承载力,提高施工建造过程中滑道利用率。     

在北海和阿拉斯加深层储油岩体中繁荣生长的喜高温太古细菌

为了调查深层储油岩体中存在的喜高温微生物，从北海东设得兰海盆锡斯尔海岸之外的石油生产平台上，首次从处理设施上侧井口刚冒出的储油岩体油流中采集了样品．稍后，从美国阿拉斯加北坡普拉德霍湾，恩迪科特和库帕勒克油田33口井中采集到类似样品．     

超大型海洋浮式储油系统的风险评估

对超大型海洋浮式储油系统的危险灾害识别、失效概率计算、失效后果评估、风险准则评定和风险管理决策等几个主要步骤进行了风险分析,计算结果为在设置防坡堤情况下,储油船漂移的概率为2 217×10-6,沉没的概率为6 778×10-8,结构损坏的概率为6 300×10-7,总的经济损失为70万人民币;在未设置防波堤的情况下,储油船漂移的概率为3 167×10-3,沉没的概率为9 683×10-5,结构损坏的概率为9 000×10-4,总的经济损失为9 91亿人民币。结果表明,采取合理的措施,如在储油船系泊地点设置防波堤,以降低风险水平是十分必要的。     

海上固定式平台结构安全储备研究综述

海洋平台长期暴露在海洋环境当中,因此复杂的海上环境载荷以及爆炸、火灾等偶然载荷作用会对平台的安全造成很大的威胁。安全储备概念的提出就是为了对结构的安全性进行量化评价。对现阶段结构安全储备的研究进行分析和总结,为海洋平台结构安全性的定量分析提供思路,从而能够更合理地提高海洋平台结构的安全储备。首先概述了海洋平台方面安全储备的发展过程。综述了结构安全储备方面的相关概念、分类方式、评价标准以及相关的安全储备性能指标。从确定性研究方法和基于概率的研究方法两方面,对海洋平台安全储备研究现状进行对比和总结,并分别列举了构件层次的安全储备和与海洋平台结构相关的RSR和CMR等安全储备指标及研究方法,并提出了一些关于海洋平台结构安全储备研究的问题和思路。     

中国海洋大学船舶中心

东方红2号海洋综合研究船由国家计委、财政部、教育部和地方政府共同投资9000万元建造，1996年投入使用。该船建造时，借鉴了国际上第三代海洋科学考察船的先进设计思想和建造经验，具有科学性、先进性、适居性、经济型和安全性，是目前我国最先进的海洋科学考察船。     

中国海洋大学船舶中心

东方红2号海洋综合研究船由国家计委、财政部、教育部和地方政府共同投资9000万元建造，1996年投入使用。该船建造时，借鉴了国际上第三代海洋科学考察船的先进设计思想和建造经验。具有科学性、先进性、适居性、经济型和安全性，是目前我国最先进的海洋科学考察船。     

深海下储油器系统的压力补偿动态特性研究

对深海3 000m液压源储油器,采用兼具压力补偿和体积补偿的胶囊作为其压力补偿器.针对动态运行时可能存在的补偿量不足的问题,提出了储油器系统不失稳时的压力动态补偿设计准则,然后择选一组优化参数设计出储油器系统样机,分别完成在模拟执行元件和环境压力变化时的高压舱下的实验测试,结果表明在两种变工况下储油器内压力均能很好地跟随环境压力的变化,验证了该结构及其设计准则是合理的,为水下液压源储油器系统的压力自平衡设计及可靠运行提供了相应的理论依据和技术支撑.     

Microbial Biomass and Organic Nutrients in the Deep-Sea Sediments of the Central Indian Ocean Basin

In order to assess the impact of deep-sea mining on the in situ benthic life, we measured the microbial standing stock and concentration of organic nutrients in the deep-sea sediments of the Central Indian Ocean Basin in the Indian pioneer area. Sediments were collected using box core and grab samples during September 1996. The total bacterial numbers ranged from 10 10 -10 11 cells per g -1 dry weight sediment. There was a marginal decrease in the number of bacteria from surface to 30 cm depth, though the subsurface section registered a higher number than did the surface. The highest numbers were encountered at depths of 4-8 cm. The retrievable number of bacteria were two orders less in comparison with the direct total counts of bacteria. An almost homogeneous distribution of bacteria, total organic carbon, living biomass, and lipids throughout the depth of cores indicates active microbial and benthic processes in the deep sea sediments. On the other hand, a uniform distribution of total counts of bacteria, carbohydrates, and total organic carbon in all the cores indicates their stable nature and suggests that they can serve as useful parameters for long-term monitoring of the area after the benthic disturbance. Further studies on temporal variability in this region would not only verify the observed norms of distribution of these variables but would also help to understand restabilization processes after the simulated benthic disturbance.     

Assessing the Validity of Seismo-Acoustic Predictor Equations for Obtaining Seabed and Sub-Surface Sediment Physical Properties

The interdependence between the seismo-acoustic properties of a marine sediment and its geotechnical/physical parameters has been known for many years, and it has been postulated that this should allow the extraction of geotechnical information from seismic data. Though in the literature many correlations have been published for the surficial layer, there is a lack of information for greater sediment depths. In this article, a desktop study on a synthetic seafloor model illustrates how the application of published near-surface prediction equations to subsurface sediments (up to several tens of meters burial depth) can lead to spurious predictions. To test this further, acoustic and geotechnical properties were measured on a number of sediment core samples, some of which were subjected to loading in acoustically-equipped consolidation cells (oedometers) to simulate greater burial depth conditions. For low effective pressures (representing small burial depths extending to around 10 meters subsurface), the general applicability of established relationships was confirmed: the prediction of porosity, bulk density, and mean grain size from acoustic velocity and impedance appears generally possible for the investigated sedimentary environments. As effective pressure increases through, the observed relationships deviate more and more from the established ones for the near-surface area. For the samples tested in this study, in some instances increasing pressure even resulted in decreasing velocities. There are several possible explanations for this abnormal behavior, including the presence of gas, overconsolidation, or bimodal grain size distribution. The results indicate that an appropriate depth correction must be introduced into the published prediction equations in order to obtain reliable estimates of physical sediment properties for greater subsurface depths.     

海上大直径钢管桩打桩过程中桩周土强度弱化研究

海上大直径钢管桩打桩过程中,桩周土体受到强烈扰动而发生强度弱化,掌握桩周土体强度弱化规律对于准确预测打桩过程、保证工程安全具有重要意义。为研究土体强度弱化规律,开展了环剪试验模拟打桩对桩周土体的扰动,测试土体强度随剪切速率的变化规律,建立了描述土体强度弱化规律的拟合公式,引入到打桩分析软件中。研究结果表明：土体的强度折减程度不仅与土体本身的性质有关还受到土体的埋深和剪切速率的影响,埋深越深土体强度折减程度越低,剪切速率越高土体强度折减越高,在打桩分析中可采用这里推荐的线性折减方法来模拟不同深度处土体强度的折减规律。     

Geoacoustic Inversion via Genetic Algorithm and Its Application to Manganese Sediment Identification

An acoustic inversion method using a wide-band signal and two near field receivers is proposed and applied to multiple layered seabed models including a manganese sediment. The inversion problem can be formulated into a probabilistic model comprised of signals, a forward model, and additive noise. The forward model simulates wide-band signals, such as chirp signals, and is chosen to be the source-waveletconvolution plane wave modeling method. The wavelet matching technique, using weighted least-squares fitting, estimates the sediment sound-speed and thickness on which determination of the possible numerical ranges for a priori uniform distribution is based. The genetic algorithm is applied to a global optimization problem to find a maximum a posteriori solution for determined a priori search space. Here the object function is defined by an L 2 norm of the difference between measured and modeled signals. Not only the marginal pdf but also its statistics are calculated by numerical evaluation of integrals using the samples selected during importance sampling process of the genetic algorithm.     

Interannual Sea Level Variations and Annual Tides in the Northwestern Pacific

Specific properties of the interannual sea level variations and annual tides in the Northwestern Pacific were studied. Several tide stations were monitored. The monthly mean sea level for the year of 1995 was analyzed at each tide station. A seismic event in 1995, some tectonic activity around the subject area, and the Kuroshio (the oceanic western boundary current) may possibly contaminate results which would have occurred from the astronomical annual tide alone.     

Flow Cytometric Analysis of Coastal Lagoon Bacterioplankton and Picophytoplankton: Fixation and Storage Effects

The effect of different fixation and storage protocols on the flow cytometric (FCM) simultaneous analysis of bacterioplankton and phytoplankton in coastal seawater samples (Mediterranean coastal lagoons) was investigated. FCM measurements (cell number, fluorescence and scatter characteristics) were obtained through DAPI staining. Three fixatives [glutaraldehyde (GA), formaldehyde (FA) and paraformaldehyde (PFA)] and two storage (3 months duration) methods (5 °C and −196 °C) were tested. Two dominant populations were detected in studied samples: bacteria and eukaryotic picophytoplankton. Adding fixatives (2% final concentration) appears necessary to obtain FCM exhaustive counts of all the bacteria and phytoplanktonic cells. This was related to the permeation effect of fixatives which allowed a better DAPI staining of the cells. Maximum fluorescence, i.e. optimal staining of the cells was obtained with FA or PFA, and significant lower fluorescences with GA. Fixed samples stored at 5 °C induced rapid cell loss. Only storage in liquid nitrogen of samples fixed with FA or PFA, allows mid-term (≥4 months) preservation of bacteria or picophytoplankton cell numbers, and limited evolution of DAPI-induced fluorescence and scatter characteristics.     

INFORMATION FOR AUTHORS

<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology,     

Deep-Sea Sediment Compression Curves: Some Controlling Factors, Spurious Overconsolidation, Predictions, and Geophysical Reproduction

Oedometer tests have been carried out on 70 undisturbed surficial clays (at approximately 250 mm below the mudline), mostly collected by free-fall corers from sites widely scattered throughout the deep-sea North Atlantic. Acoustic measurements were also made, initially on contiguous samples and ultimately on the same sample using a geophysically instrumented oedometer which also collected electrical resistivity data. Apart from those quiescent areas below the carbonate compensation depth, such as north of the West Indies where very fine clays exist, most of the samples are silty clays whose geotechnical-geophysical properties are dependent on the type of clay minerals present (and their ability to take in moisture), the sand-size fraction, and the quantity of carbonate present. Thus the pure clays have high compressibilities which decrease on the addition of coarse particles, while the converse is true for the acoustic parameters, these increasing with the sand fraction. Using the notion of the intrinsic compression line for all samples, and comparison to it of the measured compression curves, it is clear that, contrary to some previously held ideas, most deep-sea clays are normally consolidated; the addition of carbonate has the effect of creating an open, stronger sediment skeleton. Interestingly, where information is available, the variation with depth of a sample's acoustic velocity follows the void ratio pressure relationship of the compression curve. This allows the construction of an in-situ sediment compression curve using the in-situ geophysical observations.