Nonlinear Effect of Wave Propagation in Shallow Water

—In this paper,a nonlinear model is presented to describe wave transformation in shallow wat-er with the zero-vorticity equation of wave-number vector and energy conservation equation.Thenonlinear effect due to an empirical dispersion relation(by Hedges)is compared with that of Dalrymple＇sdispersion relation.The model is tested against the laboratory measurements for the case of a submergedelliptical shoal on a slope beach,where both refraction and diffraction are significant.The computation re-sults,compared with those obtained through linear dispersion relation.show that the nonlinear effect ofwave transformation in shallow water is important.And the empirical dispersion relation is suitable for re-searching the nonlinearity of wave in shallow water.     

南海北部陆坡深水区浅层天然气藏特征

南海北部陆坡深水区的浅层天然气藏是一种伴随天然气水合物的新型油气藏, 具有埋藏浅、规模大的特点, 其埋藏深度一般小于300m。浅层天然气藏由深部裂解气沿断裂上升被天然气水合物封盖而形成, 识别似海底反射(BSR)是寻找浅层天然气藏有效方法。浅层天然气藏的气源主要有热解气、生物气和混合气, 陆坡张性断裂是气体运移的主要通道, 水合物下部的砂层是浅层天然气藏的主要储集层, 水合物层则是封盖层。从南海发现的天然气水合物分布特征看, 浅层天然气藏在陆坡深水区广泛分布且气藏厚度大, 潜在资源量非常可观, 是一种新型的开采成本相对低廉的油气藏。     

基于多源信息融合的浅海超低频声源目标探测关键技术及实现

以多传感器信息融合理论为指导,结合现代信息处理技术与数据驱动建模及科学计算技术,研究浅海超低频声源目标激发共存地震波的复合声场中超低频声波传播特性和数据驱动建模的水下目标深度识别等关键技术,并论证了技术实现方案及路径。结果表明:以复合矢量水听器、地震波监测仪等多传感器信息融合理论为指导研究前海超低频声源目标可以克服传统声场建模存在的问题,有助于浅海超低频声源目标探测及改善海洋水下声学监测手段。在提高声呐探测设备的测量准确度、精度方面具有重要的理论意义,对周边海域为浅海的我国海防具有实战价值。     

浅水波长计算问题

浅水波周期保持常值,而波长缩减时其计算需进行迭代。提出了两个精度较高的经验公式供计算应用。水深波长比差值ΔLD0的变化规律反映出浅水波长缩减为一复杂过程,并与波能密度加大相关。LD0≤0.14时,特别是LD0=0.056前后,其特征会更加显著,由此可探讨波长变化的内在机理。     

南黄海西部地区浅层气的浅部埋藏地质背景

根据南黄海西部地区6000km多的浅地层剖面解释成果,对浅层气埋藏的载气地质体和地层时代两方面进行了分析。结果表明,南黄海西部地区浅层气主要存在于埋藏三角洲相、古湖泊相、古河道相、古潮沟相地质体中,在中更新世晚期以来的两期海相地层（全新世和晚更新世）和两期陆相地层（玉木冰期、里斯冰期）中都存在浅层气的地震反射。     

更具开发前景的浅成天然气水合物

浅成天然气水合物呈致密块状赋存在海床面上或海床附近,在全球大陆坡上有广范的分布,由于其饱和度高及赋存部位浅因而被认为更适于开采。与甲烷渗漏、气体烟囱和水合物丘密切相伴的浅成天然气水合物,是在构造活动带由高通量的富甲烷流体以集束方式沿断层或断裂破碎带上升形成的。推测在我国南海北坡也可能存在浅成天然气水合物。     

珠江口盆地惠州凹陷恩平组源岩特征及勘探潜力

惠州凹陷是珠江口盆地已经证实的富生烃凹陷,存在文昌组和恩平组两套有效烃源岩,一直以来都是以文昌组中深湖相烃源岩为勘探重点。随着勘探的深入,惠州地区以恩平组为代表的浅湖-沼泽相烃源岩的贡献越来越明显,惠州凹陷东部新区基本都为浅湖-沼泽相烃源岩供烃,周边井钻探证实该套烃源岩已经成藏。通过构造-结构剖析、物源分析、地震相调研对比、沉积体系细致研究以及对浅湖-沼泽相烃源岩的特征分析,揭示了惠东地区浅湖-沼泽相烃源岩优势发育机理。经过计算,惠东新区浅湖-沼泽相烃源岩资源量为8.6亿t,占到惠东地区总资源量的3/4,具有较大的勘探潜力。在总结惠东新区浅湖-沼泽相烃源岩特征的基础上优选出惠东新区浅湖-沼泽相烃源岩最有利勘探区带。本次研究摆脱了惠州凹陷单一烃源岩勘探束缚,推动了新区勘探进程。     

Nutrients,light and phytoplankton production in the shallow,tropical coastal waters of Bandon Bay,Southern Thailand

Phytoplankton primary production and its regulation by light and nutrient availability were investigated in the shallow, tropical coastal waters of Bandon Bay, Southern Thailand. The bay was meso‐eutrophicated and highly turbid, receiving river water discharge. Water column stratification was consistently weak during both rainy and dry seasons. Dissolved inorganic nitrogen (DIN) was higher off the river mouth than in the other regions, suggesting that river water discharge was a main source of DIN. By contrast, dissolved inorganic phosphorus (DIP) showed a significant negative correlation with total water depth, implying that regeneration around the sea floor was an important source of DIP. Surface DIN and DIP showed positive correlations with surface primary production (PP) and water column primary productivity (ΣPP*), respectively. The combined correlation and model analyses indicate that total water depth had an ambivalent influence on water column primary production (ΣPP); shallower water depth induced more active regeneration of nutrients, but it also caused higher turbidity and lower light availability as a result of enhanced resuspension of sediments. Furthermore, there was a vertical constraint for phytoplankton during the rainy season: total water depth tended to be shallower than euphotic zone depth. In conclusion, light limitation and vertical constraint owing to shallow water depth appear to be more important than nutrient limitation for water column primary production in Bandon Bay.     

新型张力腿式储油处理平台的动力响应分析

针对目前小油田早期生产中存在的不足,提出一种适用于浅水海域的新型张力腿式储油处理平台,该平台主要由储油箱、浮箱、吸力桩、系泊链和甲板结构构成,具备原油处理和储存功能。应用非线性时域耦合分析法,研究了有义波高、平均波周期、水深对该平台的运动响应和系泊链张力的影响。计算结果表明,波高对平台动力响应有较大影响,有义波高每增加0.4 m,平台水平位移相应增加0.408 m,而系泊链力随有义波高的增加呈准线性增大;波周期对平台水平运动影响显著,平均波周期从6.5 s逐级变化至8.5 s时,最大水平位移自3.760 m渐增至5.467 m,而波周期对系泊链力影响较小,变化率一般小于10%;该新型平台对水深大于20 m的浅水海域有良好的动力特性,而对水深小于20 m的海域却表现异常。因此,该新型张力腿式平台能满足水深不小于20 m浅海区的油田早期生产需要。     

河口变形效应与涌潮的形成

作者采用非线性潮波方程,假定河口的宽度B(x)和深度h(x)是任意可微函数,导出了涌潮发生的条件,并讨论了各种变形情况下涌潮的形成。得出结论是,在涌潮形成过程中起决定作用的是浅水非线性效应,而河口变形效应则是起促进作用的。